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3771 lines
104 KiB
3771 lines
104 KiB
/* |
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* kernel/cpuset.c |
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* |
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* Processor and Memory placement constraints for sets of tasks. |
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* |
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* Copyright (C) 2003 BULL SA. |
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* Copyright (C) 2004-2007 Silicon Graphics, Inc. |
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* Copyright (C) 2006 Google, Inc |
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* |
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* Portions derived from Patrick Mochel's sysfs code. |
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* sysfs is Copyright (c) 2001-3 Patrick Mochel |
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* |
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* 2003-10-10 Written by Simon Derr. |
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* 2003-10-22 Updates by Stephen Hemminger. |
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* 2004 May-July Rework by Paul Jackson. |
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* 2006 Rework by Paul Menage to use generic cgroups |
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* 2008 Rework of the scheduler domains and CPU hotplug handling |
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* by Max Krasnyansky |
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* |
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* This file is subject to the terms and conditions of the GNU General Public |
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* License. See the file COPYING in the main directory of the Linux |
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* distribution for more details. |
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*/ |
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|
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#include <linux/cpu.h> |
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#include <linux/cpumask.h> |
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#include <linux/cpuset.h> |
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#include <linux/err.h> |
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#include <linux/errno.h> |
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#include <linux/file.h> |
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#include <linux/fs.h> |
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#include <linux/init.h> |
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#include <linux/interrupt.h> |
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#include <linux/kernel.h> |
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#include <linux/kmod.h> |
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#include <linux/list.h> |
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#include <linux/mempolicy.h> |
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#include <linux/mm.h> |
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#include <linux/memory.h> |
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#include <linux/export.h> |
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#include <linux/mount.h> |
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#include <linux/fs_context.h> |
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#include <linux/namei.h> |
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#include <linux/pagemap.h> |
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#include <linux/proc_fs.h> |
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#include <linux/rcupdate.h> |
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#include <linux/sched.h> |
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#include <linux/sched/deadline.h> |
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#include <linux/sched/mm.h> |
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#include <linux/sched/task.h> |
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#include <linux/seq_file.h> |
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#include <linux/security.h> |
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#include <linux/slab.h> |
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#include <linux/spinlock.h> |
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#include <linux/stat.h> |
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#include <linux/string.h> |
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#include <linux/time.h> |
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#include <linux/time64.h> |
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#include <linux/backing-dev.h> |
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#include <linux/sort.h> |
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#include <linux/oom.h> |
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#include <linux/sched/isolation.h> |
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#include <linux/uaccess.h> |
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#include <linux/atomic.h> |
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#include <linux/mutex.h> |
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#include <linux/cgroup.h> |
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#include <linux/wait.h> |
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|
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DEFINE_STATIC_KEY_FALSE(cpusets_pre_enable_key); |
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DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key); |
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|
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/* |
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* There could be abnormal cpuset configurations for cpu or memory |
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* node binding, add this key to provide a quick low-cost judgement |
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* of the situation. |
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*/ |
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DEFINE_STATIC_KEY_FALSE(cpusets_insane_config_key); |
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|
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/* See "Frequency meter" comments, below. */ |
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|
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struct fmeter { |
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int cnt; /* unprocessed events count */ |
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int val; /* most recent output value */ |
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time64_t time; /* clock (secs) when val computed */ |
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spinlock_t lock; /* guards read or write of above */ |
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}; |
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|
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struct cpuset { |
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struct cgroup_subsys_state css; |
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|
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unsigned long flags; /* "unsigned long" so bitops work */ |
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|
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/* |
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* On default hierarchy: |
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* |
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* The user-configured masks can only be changed by writing to |
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* cpuset.cpus and cpuset.mems, and won't be limited by the |
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* parent masks. |
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* |
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* The effective masks is the real masks that apply to the tasks |
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* in the cpuset. They may be changed if the configured masks are |
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* changed or hotplug happens. |
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* |
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* effective_mask == configured_mask & parent's effective_mask, |
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* and if it ends up empty, it will inherit the parent's mask. |
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* |
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* |
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* On legacy hierarchy: |
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* |
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* The user-configured masks are always the same with effective masks. |
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*/ |
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|
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/* user-configured CPUs and Memory Nodes allow to tasks */ |
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cpumask_var_t cpus_allowed; |
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nodemask_t mems_allowed; |
|
|
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/* effective CPUs and Memory Nodes allow to tasks */ |
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cpumask_var_t effective_cpus; |
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nodemask_t effective_mems; |
|
|
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/* |
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* CPUs allocated to child sub-partitions (default hierarchy only) |
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* - CPUs granted by the parent = effective_cpus U subparts_cpus |
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* - effective_cpus and subparts_cpus are mutually exclusive. |
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* |
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* effective_cpus contains only onlined CPUs, but subparts_cpus |
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* may have offlined ones. |
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*/ |
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cpumask_var_t subparts_cpus; |
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|
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/* |
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* This is old Memory Nodes tasks took on. |
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* |
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* - top_cpuset.old_mems_allowed is initialized to mems_allowed. |
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* - A new cpuset's old_mems_allowed is initialized when some |
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* task is moved into it. |
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* - old_mems_allowed is used in cpuset_migrate_mm() when we change |
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* cpuset.mems_allowed and have tasks' nodemask updated, and |
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* then old_mems_allowed is updated to mems_allowed. |
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*/ |
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nodemask_t old_mems_allowed; |
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|
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struct fmeter fmeter; /* memory_pressure filter */ |
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|
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/* |
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* Tasks are being attached to this cpuset. Used to prevent |
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* zeroing cpus/mems_allowed between ->can_attach() and ->attach(). |
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*/ |
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int attach_in_progress; |
|
|
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/* partition number for rebuild_sched_domains() */ |
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int pn; |
|
|
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/* for custom sched domain */ |
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int relax_domain_level; |
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|
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/* number of CPUs in subparts_cpus */ |
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int nr_subparts_cpus; |
|
|
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/* partition root state */ |
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int partition_root_state; |
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|
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/* |
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* Default hierarchy only: |
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* use_parent_ecpus - set if using parent's effective_cpus |
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* child_ecpus_count - # of children with use_parent_ecpus set |
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*/ |
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int use_parent_ecpus; |
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int child_ecpus_count; |
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|
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/* Handle for cpuset.cpus.partition */ |
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struct cgroup_file partition_file; |
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}; |
|
|
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/* |
|
* Partition root states: |
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* |
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* 0 - not a partition root |
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* |
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* 1 - partition root |
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* |
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* -1 - invalid partition root |
|
* None of the cpus in cpus_allowed can be put into the parent's |
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* subparts_cpus. In this case, the cpuset is not a real partition |
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* root anymore. However, the CPU_EXCLUSIVE bit will still be set |
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* and the cpuset can be restored back to a partition root if the |
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* parent cpuset can give more CPUs back to this child cpuset. |
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*/ |
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#define PRS_DISABLED 0 |
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#define PRS_ENABLED 1 |
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#define PRS_ERROR -1 |
|
|
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/* |
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* Temporary cpumasks for working with partitions that are passed among |
|
* functions to avoid memory allocation in inner functions. |
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*/ |
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struct tmpmasks { |
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cpumask_var_t addmask, delmask; /* For partition root */ |
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cpumask_var_t new_cpus; /* For update_cpumasks_hier() */ |
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}; |
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|
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static inline struct cpuset *css_cs(struct cgroup_subsys_state *css) |
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{ |
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return css ? container_of(css, struct cpuset, css) : NULL; |
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} |
|
|
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/* Retrieve the cpuset for a task */ |
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static inline struct cpuset *task_cs(struct task_struct *task) |
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{ |
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return css_cs(task_css(task, cpuset_cgrp_id)); |
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} |
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|
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static inline struct cpuset *parent_cs(struct cpuset *cs) |
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{ |
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return css_cs(cs->css.parent); |
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} |
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|
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/* bits in struct cpuset flags field */ |
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typedef enum { |
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CS_ONLINE, |
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CS_CPU_EXCLUSIVE, |
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CS_MEM_EXCLUSIVE, |
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CS_MEM_HARDWALL, |
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CS_MEMORY_MIGRATE, |
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CS_SCHED_LOAD_BALANCE, |
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CS_SPREAD_PAGE, |
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CS_SPREAD_SLAB, |
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} cpuset_flagbits_t; |
|
|
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/* convenient tests for these bits */ |
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static inline bool is_cpuset_online(struct cpuset *cs) |
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{ |
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return test_bit(CS_ONLINE, &cs->flags) && !css_is_dying(&cs->css); |
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} |
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|
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static inline int is_cpu_exclusive(const struct cpuset *cs) |
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{ |
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return test_bit(CS_CPU_EXCLUSIVE, &cs->flags); |
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} |
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|
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static inline int is_mem_exclusive(const struct cpuset *cs) |
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{ |
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return test_bit(CS_MEM_EXCLUSIVE, &cs->flags); |
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} |
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|
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static inline int is_mem_hardwall(const struct cpuset *cs) |
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{ |
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return test_bit(CS_MEM_HARDWALL, &cs->flags); |
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} |
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|
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static inline int is_sched_load_balance(const struct cpuset *cs) |
|
{ |
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return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); |
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} |
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|
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static inline int is_memory_migrate(const struct cpuset *cs) |
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{ |
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return test_bit(CS_MEMORY_MIGRATE, &cs->flags); |
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} |
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|
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static inline int is_spread_page(const struct cpuset *cs) |
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{ |
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return test_bit(CS_SPREAD_PAGE, &cs->flags); |
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} |
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|
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static inline int is_spread_slab(const struct cpuset *cs) |
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{ |
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return test_bit(CS_SPREAD_SLAB, &cs->flags); |
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} |
|
|
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static inline int is_partition_root(const struct cpuset *cs) |
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{ |
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return cs->partition_root_state > 0; |
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} |
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|
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/* |
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* Send notification event of whenever partition_root_state changes. |
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*/ |
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static inline void notify_partition_change(struct cpuset *cs, |
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int old_prs, int new_prs) |
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{ |
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if (old_prs != new_prs) |
|
cgroup_file_notify(&cs->partition_file); |
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} |
|
|
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static struct cpuset top_cpuset = { |
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.flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) | |
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(1 << CS_MEM_EXCLUSIVE)), |
|
.partition_root_state = PRS_ENABLED, |
|
}; |
|
|
|
/** |
|
* cpuset_for_each_child - traverse online children of a cpuset |
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* @child_cs: loop cursor pointing to the current child |
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* @pos_css: used for iteration |
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* @parent_cs: target cpuset to walk children of |
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* |
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* Walk @child_cs through the online children of @parent_cs. Must be used |
|
* with RCU read locked. |
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*/ |
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#define cpuset_for_each_child(child_cs, pos_css, parent_cs) \ |
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css_for_each_child((pos_css), &(parent_cs)->css) \ |
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if (is_cpuset_online(((child_cs) = css_cs((pos_css))))) |
|
|
|
/** |
|
* cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants |
|
* @des_cs: loop cursor pointing to the current descendant |
|
* @pos_css: used for iteration |
|
* @root_cs: target cpuset to walk ancestor of |
|
* |
|
* Walk @des_cs through the online descendants of @root_cs. Must be used |
|
* with RCU read locked. The caller may modify @pos_css by calling |
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* css_rightmost_descendant() to skip subtree. @root_cs is included in the |
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* iteration and the first node to be visited. |
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*/ |
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#define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs) \ |
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css_for_each_descendant_pre((pos_css), &(root_cs)->css) \ |
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if (is_cpuset_online(((des_cs) = css_cs((pos_css))))) |
|
|
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/* |
|
* There are two global locks guarding cpuset structures - cpuset_rwsem and |
|
* callback_lock. We also require taking task_lock() when dereferencing a |
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* task's cpuset pointer. See "The task_lock() exception", at the end of this |
|
* comment. The cpuset code uses only cpuset_rwsem write lock. Other |
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* kernel subsystems can use cpuset_read_lock()/cpuset_read_unlock() to |
|
* prevent change to cpuset structures. |
|
* |
|
* A task must hold both locks to modify cpusets. If a task holds |
|
* cpuset_rwsem, it blocks others wanting that rwsem, ensuring that it |
|
* is the only task able to also acquire callback_lock and be able to |
|
* modify cpusets. It can perform various checks on the cpuset structure |
|
* first, knowing nothing will change. It can also allocate memory while |
|
* just holding cpuset_rwsem. While it is performing these checks, various |
|
* callback routines can briefly acquire callback_lock to query cpusets. |
|
* Once it is ready to make the changes, it takes callback_lock, blocking |
|
* everyone else. |
|
* |
|
* Calls to the kernel memory allocator can not be made while holding |
|
* callback_lock, as that would risk double tripping on callback_lock |
|
* from one of the callbacks into the cpuset code from within |
|
* __alloc_pages(). |
|
* |
|
* If a task is only holding callback_lock, then it has read-only |
|
* access to cpusets. |
|
* |
|
* Now, the task_struct fields mems_allowed and mempolicy may be changed |
|
* by other task, we use alloc_lock in the task_struct fields to protect |
|
* them. |
|
* |
|
* The cpuset_common_file_read() handlers only hold callback_lock across |
|
* small pieces of code, such as when reading out possibly multi-word |
|
* cpumasks and nodemasks. |
|
* |
|
* Accessing a task's cpuset should be done in accordance with the |
|
* guidelines for accessing subsystem state in kernel/cgroup.c |
|
*/ |
|
|
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DEFINE_STATIC_PERCPU_RWSEM(cpuset_rwsem); |
|
|
|
void cpuset_read_lock(void) |
|
{ |
|
percpu_down_read(&cpuset_rwsem); |
|
} |
|
|
|
void cpuset_read_unlock(void) |
|
{ |
|
percpu_up_read(&cpuset_rwsem); |
|
} |
|
|
|
static DEFINE_SPINLOCK(callback_lock); |
|
|
|
static struct workqueue_struct *cpuset_migrate_mm_wq; |
|
|
|
/* |
|
* CPU / memory hotplug is handled asynchronously. |
|
*/ |
|
static void cpuset_hotplug_workfn(struct work_struct *work); |
|
static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn); |
|
|
|
static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq); |
|
|
|
static inline void check_insane_mems_config(nodemask_t *nodes) |
|
{ |
|
if (!cpusets_insane_config() && |
|
movable_only_nodes(nodes)) { |
|
static_branch_enable(&cpusets_insane_config_key); |
|
pr_info("Unsupported (movable nodes only) cpuset configuration detected (nmask=%*pbl)!\n" |
|
"Cpuset allocations might fail even with a lot of memory available.\n", |
|
nodemask_pr_args(nodes)); |
|
} |
|
} |
|
|
|
/* |
|
* Cgroup v2 behavior is used on the "cpus" and "mems" control files when |
|
* on default hierarchy or when the cpuset_v2_mode flag is set by mounting |
|
* the v1 cpuset cgroup filesystem with the "cpuset_v2_mode" mount option. |
|
* With v2 behavior, "cpus" and "mems" are always what the users have |
|
* requested and won't be changed by hotplug events. Only the effective |
|
* cpus or mems will be affected. |
|
*/ |
|
static inline bool is_in_v2_mode(void) |
|
{ |
|
return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || |
|
(cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE); |
|
} |
|
|
|
/* |
|
* Return in pmask the portion of a task's cpusets's cpus_allowed that |
|
* are online and are capable of running the task. If none are found, |
|
* walk up the cpuset hierarchy until we find one that does have some |
|
* appropriate cpus. |
|
* |
|
* One way or another, we guarantee to return some non-empty subset |
|
* of cpu_online_mask. |
|
* |
|
* Call with callback_lock or cpuset_rwsem held. |
|
*/ |
|
static void guarantee_online_cpus(struct task_struct *tsk, |
|
struct cpumask *pmask) |
|
{ |
|
const struct cpumask *possible_mask = task_cpu_possible_mask(tsk); |
|
struct cpuset *cs; |
|
|
|
if (WARN_ON(!cpumask_and(pmask, possible_mask, cpu_online_mask))) |
|
cpumask_copy(pmask, cpu_online_mask); |
|
|
|
rcu_read_lock(); |
|
cs = task_cs(tsk); |
|
|
|
while (!cpumask_intersects(cs->effective_cpus, pmask)) { |
|
cs = parent_cs(cs); |
|
if (unlikely(!cs)) { |
|
/* |
|
* The top cpuset doesn't have any online cpu as a |
|
* consequence of a race between cpuset_hotplug_work |
|
* and cpu hotplug notifier. But we know the top |
|
* cpuset's effective_cpus is on its way to be |
|
* identical to cpu_online_mask. |
|
*/ |
|
goto out_unlock; |
|
} |
|
} |
|
cpumask_and(pmask, pmask, cs->effective_cpus); |
|
|
|
out_unlock: |
|
rcu_read_unlock(); |
|
} |
|
|
|
/* |
|
* Return in *pmask the portion of a cpusets's mems_allowed that |
|
* are online, with memory. If none are online with memory, walk |
|
* up the cpuset hierarchy until we find one that does have some |
|
* online mems. The top cpuset always has some mems online. |
|
* |
|
* One way or another, we guarantee to return some non-empty subset |
|
* of node_states[N_MEMORY]. |
|
* |
|
* Call with callback_lock or cpuset_rwsem held. |
|
*/ |
|
static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask) |
|
{ |
|
while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY])) |
|
cs = parent_cs(cs); |
|
nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]); |
|
} |
|
|
|
/* |
|
* update task's spread flag if cpuset's page/slab spread flag is set |
|
* |
|
* Call with callback_lock or cpuset_rwsem held. |
|
*/ |
|
static void cpuset_update_task_spread_flag(struct cpuset *cs, |
|
struct task_struct *tsk) |
|
{ |
|
if (is_spread_page(cs)) |
|
task_set_spread_page(tsk); |
|
else |
|
task_clear_spread_page(tsk); |
|
|
|
if (is_spread_slab(cs)) |
|
task_set_spread_slab(tsk); |
|
else |
|
task_clear_spread_slab(tsk); |
|
} |
|
|
|
/* |
|
* is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q? |
|
* |
|
* One cpuset is a subset of another if all its allowed CPUs and |
|
* Memory Nodes are a subset of the other, and its exclusive flags |
|
* are only set if the other's are set. Call holding cpuset_rwsem. |
|
*/ |
|
|
|
static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q) |
|
{ |
|
return cpumask_subset(p->cpus_allowed, q->cpus_allowed) && |
|
nodes_subset(p->mems_allowed, q->mems_allowed) && |
|
is_cpu_exclusive(p) <= is_cpu_exclusive(q) && |
|
is_mem_exclusive(p) <= is_mem_exclusive(q); |
|
} |
|
|
|
/** |
|
* alloc_cpumasks - allocate three cpumasks for cpuset |
|
* @cs: the cpuset that have cpumasks to be allocated. |
|
* @tmp: the tmpmasks structure pointer |
|
* Return: 0 if successful, -ENOMEM otherwise. |
|
* |
|
* Only one of the two input arguments should be non-NULL. |
|
*/ |
|
static inline int alloc_cpumasks(struct cpuset *cs, struct tmpmasks *tmp) |
|
{ |
|
cpumask_var_t *pmask1, *pmask2, *pmask3; |
|
|
|
if (cs) { |
|
pmask1 = &cs->cpus_allowed; |
|
pmask2 = &cs->effective_cpus; |
|
pmask3 = &cs->subparts_cpus; |
|
} else { |
|
pmask1 = &tmp->new_cpus; |
|
pmask2 = &tmp->addmask; |
|
pmask3 = &tmp->delmask; |
|
} |
|
|
|
if (!zalloc_cpumask_var(pmask1, GFP_KERNEL)) |
|
return -ENOMEM; |
|
|
|
if (!zalloc_cpumask_var(pmask2, GFP_KERNEL)) |
|
goto free_one; |
|
|
|
if (!zalloc_cpumask_var(pmask3, GFP_KERNEL)) |
|
goto free_two; |
|
|
|
return 0; |
|
|
|
free_two: |
|
free_cpumask_var(*pmask2); |
|
free_one: |
|
free_cpumask_var(*pmask1); |
|
return -ENOMEM; |
|
} |
|
|
|
/** |
|
* free_cpumasks - free cpumasks in a tmpmasks structure |
|
* @cs: the cpuset that have cpumasks to be free. |
|
* @tmp: the tmpmasks structure pointer |
|
*/ |
|
static inline void free_cpumasks(struct cpuset *cs, struct tmpmasks *tmp) |
|
{ |
|
if (cs) { |
|
free_cpumask_var(cs->cpus_allowed); |
|
free_cpumask_var(cs->effective_cpus); |
|
free_cpumask_var(cs->subparts_cpus); |
|
} |
|
if (tmp) { |
|
free_cpumask_var(tmp->new_cpus); |
|
free_cpumask_var(tmp->addmask); |
|
free_cpumask_var(tmp->delmask); |
|
} |
|
} |
|
|
|
/** |
|
* alloc_trial_cpuset - allocate a trial cpuset |
|
* @cs: the cpuset that the trial cpuset duplicates |
|
*/ |
|
static struct cpuset *alloc_trial_cpuset(struct cpuset *cs) |
|
{ |
|
struct cpuset *trial; |
|
|
|
trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL); |
|
if (!trial) |
|
return NULL; |
|
|
|
if (alloc_cpumasks(trial, NULL)) { |
|
kfree(trial); |
|
return NULL; |
|
} |
|
|
|
cpumask_copy(trial->cpus_allowed, cs->cpus_allowed); |
|
cpumask_copy(trial->effective_cpus, cs->effective_cpus); |
|
return trial; |
|
} |
|
|
|
/** |
|
* free_cpuset - free the cpuset |
|
* @cs: the cpuset to be freed |
|
*/ |
|
static inline void free_cpuset(struct cpuset *cs) |
|
{ |
|
free_cpumasks(cs, NULL); |
|
kfree(cs); |
|
} |
|
|
|
/* |
|
* validate_change_legacy() - Validate conditions specific to legacy (v1) |
|
* behavior. |
|
*/ |
|
static int validate_change_legacy(struct cpuset *cur, struct cpuset *trial) |
|
{ |
|
struct cgroup_subsys_state *css; |
|
struct cpuset *c, *par; |
|
int ret; |
|
|
|
WARN_ON_ONCE(!rcu_read_lock_held()); |
|
|
|
/* Each of our child cpusets must be a subset of us */ |
|
ret = -EBUSY; |
|
cpuset_for_each_child(c, css, cur) |
|
if (!is_cpuset_subset(c, trial)) |
|
goto out; |
|
|
|
/* On legacy hierarchy, we must be a subset of our parent cpuset. */ |
|
ret = -EACCES; |
|
par = parent_cs(cur); |
|
if (par && !is_cpuset_subset(trial, par)) |
|
goto out; |
|
|
|
ret = 0; |
|
out: |
|
return ret; |
|
} |
|
|
|
/* |
|
* validate_change() - Used to validate that any proposed cpuset change |
|
* follows the structural rules for cpusets. |
|
* |
|
* If we replaced the flag and mask values of the current cpuset |
|
* (cur) with those values in the trial cpuset (trial), would |
|
* our various subset and exclusive rules still be valid? Presumes |
|
* cpuset_rwsem held. |
|
* |
|
* 'cur' is the address of an actual, in-use cpuset. Operations |
|
* such as list traversal that depend on the actual address of the |
|
* cpuset in the list must use cur below, not trial. |
|
* |
|
* 'trial' is the address of bulk structure copy of cur, with |
|
* perhaps one or more of the fields cpus_allowed, mems_allowed, |
|
* or flags changed to new, trial values. |
|
* |
|
* Return 0 if valid, -errno if not. |
|
*/ |
|
|
|
static int validate_change(struct cpuset *cur, struct cpuset *trial) |
|
{ |
|
struct cgroup_subsys_state *css; |
|
struct cpuset *c, *par; |
|
int ret = 0; |
|
|
|
rcu_read_lock(); |
|
|
|
if (!is_in_v2_mode()) |
|
ret = validate_change_legacy(cur, trial); |
|
if (ret) |
|
goto out; |
|
|
|
/* Remaining checks don't apply to root cpuset */ |
|
if (cur == &top_cpuset) |
|
goto out; |
|
|
|
par = parent_cs(cur); |
|
|
|
/* |
|
* If either I or some sibling (!= me) is exclusive, we can't |
|
* overlap |
|
*/ |
|
ret = -EINVAL; |
|
cpuset_for_each_child(c, css, par) { |
|
if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) && |
|
c != cur && |
|
cpumask_intersects(trial->cpus_allowed, c->cpus_allowed)) |
|
goto out; |
|
if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) && |
|
c != cur && |
|
nodes_intersects(trial->mems_allowed, c->mems_allowed)) |
|
goto out; |
|
} |
|
|
|
/* |
|
* Cpusets with tasks - existing or newly being attached - can't |
|
* be changed to have empty cpus_allowed or mems_allowed. |
|
*/ |
|
ret = -ENOSPC; |
|
if ((cgroup_is_populated(cur->css.cgroup) || cur->attach_in_progress)) { |
|
if (!cpumask_empty(cur->cpus_allowed) && |
|
cpumask_empty(trial->cpus_allowed)) |
|
goto out; |
|
if (!nodes_empty(cur->mems_allowed) && |
|
nodes_empty(trial->mems_allowed)) |
|
goto out; |
|
} |
|
|
|
/* |
|
* We can't shrink if we won't have enough room for SCHED_DEADLINE |
|
* tasks. |
|
*/ |
|
ret = -EBUSY; |
|
if (is_cpu_exclusive(cur) && |
|
!cpuset_cpumask_can_shrink(cur->cpus_allowed, |
|
trial->cpus_allowed)) |
|
goto out; |
|
|
|
ret = 0; |
|
out: |
|
rcu_read_unlock(); |
|
return ret; |
|
} |
|
|
|
#ifdef CONFIG_SMP |
|
/* |
|
* Helper routine for generate_sched_domains(). |
|
* Do cpusets a, b have overlapping effective cpus_allowed masks? |
|
*/ |
|
static int cpusets_overlap(struct cpuset *a, struct cpuset *b) |
|
{ |
|
return cpumask_intersects(a->effective_cpus, b->effective_cpus); |
|
} |
|
|
|
static void |
|
update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c) |
|
{ |
|
if (dattr->relax_domain_level < c->relax_domain_level) |
|
dattr->relax_domain_level = c->relax_domain_level; |
|
return; |
|
} |
|
|
|
static void update_domain_attr_tree(struct sched_domain_attr *dattr, |
|
struct cpuset *root_cs) |
|
{ |
|
struct cpuset *cp; |
|
struct cgroup_subsys_state *pos_css; |
|
|
|
rcu_read_lock(); |
|
cpuset_for_each_descendant_pre(cp, pos_css, root_cs) { |
|
/* skip the whole subtree if @cp doesn't have any CPU */ |
|
if (cpumask_empty(cp->cpus_allowed)) { |
|
pos_css = css_rightmost_descendant(pos_css); |
|
continue; |
|
} |
|
|
|
if (is_sched_load_balance(cp)) |
|
update_domain_attr(dattr, cp); |
|
} |
|
rcu_read_unlock(); |
|
} |
|
|
|
/* Must be called with cpuset_rwsem held. */ |
|
static inline int nr_cpusets(void) |
|
{ |
|
/* jump label reference count + the top-level cpuset */ |
|
return static_key_count(&cpusets_enabled_key.key) + 1; |
|
} |
|
|
|
/* |
|
* generate_sched_domains() |
|
* |
|
* This function builds a partial partition of the systems CPUs |
|
* A 'partial partition' is a set of non-overlapping subsets whose |
|
* union is a subset of that set. |
|
* The output of this function needs to be passed to kernel/sched/core.c |
|
* partition_sched_domains() routine, which will rebuild the scheduler's |
|
* load balancing domains (sched domains) as specified by that partial |
|
* partition. |
|
* |
|
* See "What is sched_load_balance" in Documentation/admin-guide/cgroup-v1/cpusets.rst |
|
* for a background explanation of this. |
|
* |
|
* Does not return errors, on the theory that the callers of this |
|
* routine would rather not worry about failures to rebuild sched |
|
* domains when operating in the severe memory shortage situations |
|
* that could cause allocation failures below. |
|
* |
|
* Must be called with cpuset_rwsem held. |
|
* |
|
* The three key local variables below are: |
|
* cp - cpuset pointer, used (together with pos_css) to perform a |
|
* top-down scan of all cpusets. For our purposes, rebuilding |
|
* the schedulers sched domains, we can ignore !is_sched_load_ |
|
* balance cpusets. |
|
* csa - (for CpuSet Array) Array of pointers to all the cpusets |
|
* that need to be load balanced, for convenient iterative |
|
* access by the subsequent code that finds the best partition, |
|
* i.e the set of domains (subsets) of CPUs such that the |
|
* cpus_allowed of every cpuset marked is_sched_load_balance |
|
* is a subset of one of these domains, while there are as |
|
* many such domains as possible, each as small as possible. |
|
* doms - Conversion of 'csa' to an array of cpumasks, for passing to |
|
* the kernel/sched/core.c routine partition_sched_domains() in a |
|
* convenient format, that can be easily compared to the prior |
|
* value to determine what partition elements (sched domains) |
|
* were changed (added or removed.) |
|
* |
|
* Finding the best partition (set of domains): |
|
* The triple nested loops below over i, j, k scan over the |
|
* load balanced cpusets (using the array of cpuset pointers in |
|
* csa[]) looking for pairs of cpusets that have overlapping |
|
* cpus_allowed, but which don't have the same 'pn' partition |
|
* number and gives them in the same partition number. It keeps |
|
* looping on the 'restart' label until it can no longer find |
|
* any such pairs. |
|
* |
|
* The union of the cpus_allowed masks from the set of |
|
* all cpusets having the same 'pn' value then form the one |
|
* element of the partition (one sched domain) to be passed to |
|
* partition_sched_domains(). |
|
*/ |
|
static int generate_sched_domains(cpumask_var_t **domains, |
|
struct sched_domain_attr **attributes) |
|
{ |
|
struct cpuset *cp; /* top-down scan of cpusets */ |
|
struct cpuset **csa; /* array of all cpuset ptrs */ |
|
int csn; /* how many cpuset ptrs in csa so far */ |
|
int i, j, k; /* indices for partition finding loops */ |
|
cpumask_var_t *doms; /* resulting partition; i.e. sched domains */ |
|
struct sched_domain_attr *dattr; /* attributes for custom domains */ |
|
int ndoms = 0; /* number of sched domains in result */ |
|
int nslot; /* next empty doms[] struct cpumask slot */ |
|
struct cgroup_subsys_state *pos_css; |
|
bool root_load_balance = is_sched_load_balance(&top_cpuset); |
|
|
|
doms = NULL; |
|
dattr = NULL; |
|
csa = NULL; |
|
|
|
/* Special case for the 99% of systems with one, full, sched domain */ |
|
if (root_load_balance && !top_cpuset.nr_subparts_cpus) { |
|
ndoms = 1; |
|
doms = alloc_sched_domains(ndoms); |
|
if (!doms) |
|
goto done; |
|
|
|
dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL); |
|
if (dattr) { |
|
*dattr = SD_ATTR_INIT; |
|
update_domain_attr_tree(dattr, &top_cpuset); |
|
} |
|
cpumask_and(doms[0], top_cpuset.effective_cpus, |
|
housekeeping_cpumask(HK_FLAG_DOMAIN)); |
|
|
|
goto done; |
|
} |
|
|
|
csa = kmalloc_array(nr_cpusets(), sizeof(cp), GFP_KERNEL); |
|
if (!csa) |
|
goto done; |
|
csn = 0; |
|
|
|
rcu_read_lock(); |
|
if (root_load_balance) |
|
csa[csn++] = &top_cpuset; |
|
cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) { |
|
if (cp == &top_cpuset) |
|
continue; |
|
/* |
|
* Continue traversing beyond @cp iff @cp has some CPUs and |
|
* isn't load balancing. The former is obvious. The |
|
* latter: All child cpusets contain a subset of the |
|
* parent's cpus, so just skip them, and then we call |
|
* update_domain_attr_tree() to calc relax_domain_level of |
|
* the corresponding sched domain. |
|
* |
|
* If root is load-balancing, we can skip @cp if it |
|
* is a subset of the root's effective_cpus. |
|
*/ |
|
if (!cpumask_empty(cp->cpus_allowed) && |
|
!(is_sched_load_balance(cp) && |
|
cpumask_intersects(cp->cpus_allowed, |
|
housekeeping_cpumask(HK_FLAG_DOMAIN)))) |
|
continue; |
|
|
|
if (root_load_balance && |
|
cpumask_subset(cp->cpus_allowed, top_cpuset.effective_cpus)) |
|
continue; |
|
|
|
if (is_sched_load_balance(cp) && |
|
!cpumask_empty(cp->effective_cpus)) |
|
csa[csn++] = cp; |
|
|
|
/* skip @cp's subtree if not a partition root */ |
|
if (!is_partition_root(cp)) |
|
pos_css = css_rightmost_descendant(pos_css); |
|
} |
|
rcu_read_unlock(); |
|
|
|
for (i = 0; i < csn; i++) |
|
csa[i]->pn = i; |
|
ndoms = csn; |
|
|
|
restart: |
|
/* Find the best partition (set of sched domains) */ |
|
for (i = 0; i < csn; i++) { |
|
struct cpuset *a = csa[i]; |
|
int apn = a->pn; |
|
|
|
for (j = 0; j < csn; j++) { |
|
struct cpuset *b = csa[j]; |
|
int bpn = b->pn; |
|
|
|
if (apn != bpn && cpusets_overlap(a, b)) { |
|
for (k = 0; k < csn; k++) { |
|
struct cpuset *c = csa[k]; |
|
|
|
if (c->pn == bpn) |
|
c->pn = apn; |
|
} |
|
ndoms--; /* one less element */ |
|
goto restart; |
|
} |
|
} |
|
} |
|
|
|
/* |
|
* Now we know how many domains to create. |
|
* Convert <csn, csa> to <ndoms, doms> and populate cpu masks. |
|
*/ |
|
doms = alloc_sched_domains(ndoms); |
|
if (!doms) |
|
goto done; |
|
|
|
/* |
|
* The rest of the code, including the scheduler, can deal with |
|
* dattr==NULL case. No need to abort if alloc fails. |
|
*/ |
|
dattr = kmalloc_array(ndoms, sizeof(struct sched_domain_attr), |
|
GFP_KERNEL); |
|
|
|
for (nslot = 0, i = 0; i < csn; i++) { |
|
struct cpuset *a = csa[i]; |
|
struct cpumask *dp; |
|
int apn = a->pn; |
|
|
|
if (apn < 0) { |
|
/* Skip completed partitions */ |
|
continue; |
|
} |
|
|
|
dp = doms[nslot]; |
|
|
|
if (nslot == ndoms) { |
|
static int warnings = 10; |
|
if (warnings) { |
|
pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n", |
|
nslot, ndoms, csn, i, apn); |
|
warnings--; |
|
} |
|
continue; |
|
} |
|
|
|
cpumask_clear(dp); |
|
if (dattr) |
|
*(dattr + nslot) = SD_ATTR_INIT; |
|
for (j = i; j < csn; j++) { |
|
struct cpuset *b = csa[j]; |
|
|
|
if (apn == b->pn) { |
|
cpumask_or(dp, dp, b->effective_cpus); |
|
cpumask_and(dp, dp, housekeeping_cpumask(HK_FLAG_DOMAIN)); |
|
if (dattr) |
|
update_domain_attr_tree(dattr + nslot, b); |
|
|
|
/* Done with this partition */ |
|
b->pn = -1; |
|
} |
|
} |
|
nslot++; |
|
} |
|
BUG_ON(nslot != ndoms); |
|
|
|
done: |
|
kfree(csa); |
|
|
|
/* |
|
* Fallback to the default domain if kmalloc() failed. |
|
* See comments in partition_sched_domains(). |
|
*/ |
|
if (doms == NULL) |
|
ndoms = 1; |
|
|
|
*domains = doms; |
|
*attributes = dattr; |
|
return ndoms; |
|
} |
|
|
|
static void update_tasks_root_domain(struct cpuset *cs) |
|
{ |
|
struct css_task_iter it; |
|
struct task_struct *task; |
|
|
|
css_task_iter_start(&cs->css, 0, &it); |
|
|
|
while ((task = css_task_iter_next(&it))) |
|
dl_add_task_root_domain(task); |
|
|
|
css_task_iter_end(&it); |
|
} |
|
|
|
static void rebuild_root_domains(void) |
|
{ |
|
struct cpuset *cs = NULL; |
|
struct cgroup_subsys_state *pos_css; |
|
|
|
percpu_rwsem_assert_held(&cpuset_rwsem); |
|
lockdep_assert_cpus_held(); |
|
lockdep_assert_held(&sched_domains_mutex); |
|
|
|
rcu_read_lock(); |
|
|
|
/* |
|
* Clear default root domain DL accounting, it will be computed again |
|
* if a task belongs to it. |
|
*/ |
|
dl_clear_root_domain(&def_root_domain); |
|
|
|
cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) { |
|
|
|
if (cpumask_empty(cs->effective_cpus)) { |
|
pos_css = css_rightmost_descendant(pos_css); |
|
continue; |
|
} |
|
|
|
css_get(&cs->css); |
|
|
|
rcu_read_unlock(); |
|
|
|
update_tasks_root_domain(cs); |
|
|
|
rcu_read_lock(); |
|
css_put(&cs->css); |
|
} |
|
rcu_read_unlock(); |
|
} |
|
|
|
static void |
|
partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[], |
|
struct sched_domain_attr *dattr_new) |
|
{ |
|
mutex_lock(&sched_domains_mutex); |
|
partition_sched_domains_locked(ndoms_new, doms_new, dattr_new); |
|
rebuild_root_domains(); |
|
mutex_unlock(&sched_domains_mutex); |
|
} |
|
|
|
/* |
|
* Rebuild scheduler domains. |
|
* |
|
* If the flag 'sched_load_balance' of any cpuset with non-empty |
|
* 'cpus' changes, or if the 'cpus' allowed changes in any cpuset |
|
* which has that flag enabled, or if any cpuset with a non-empty |
|
* 'cpus' is removed, then call this routine to rebuild the |
|
* scheduler's dynamic sched domains. |
|
* |
|
* Call with cpuset_rwsem held. Takes cpus_read_lock(). |
|
*/ |
|
static void rebuild_sched_domains_locked(void) |
|
{ |
|
struct cgroup_subsys_state *pos_css; |
|
struct sched_domain_attr *attr; |
|
cpumask_var_t *doms; |
|
struct cpuset *cs; |
|
int ndoms; |
|
|
|
lockdep_assert_cpus_held(); |
|
percpu_rwsem_assert_held(&cpuset_rwsem); |
|
|
|
/* |
|
* If we have raced with CPU hotplug, return early to avoid |
|
* passing doms with offlined cpu to partition_sched_domains(). |
|
* Anyways, cpuset_hotplug_workfn() will rebuild sched domains. |
|
* |
|
* With no CPUs in any subpartitions, top_cpuset's effective CPUs |
|
* should be the same as the active CPUs, so checking only top_cpuset |
|
* is enough to detect racing CPU offlines. |
|
*/ |
|
if (!top_cpuset.nr_subparts_cpus && |
|
!cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask)) |
|
return; |
|
|
|
/* |
|
* With subpartition CPUs, however, the effective CPUs of a partition |
|
* root should be only a subset of the active CPUs. Since a CPU in any |
|
* partition root could be offlined, all must be checked. |
|
*/ |
|
if (top_cpuset.nr_subparts_cpus) { |
|
rcu_read_lock(); |
|
cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) { |
|
if (!is_partition_root(cs)) { |
|
pos_css = css_rightmost_descendant(pos_css); |
|
continue; |
|
} |
|
if (!cpumask_subset(cs->effective_cpus, |
|
cpu_active_mask)) { |
|
rcu_read_unlock(); |
|
return; |
|
} |
|
} |
|
rcu_read_unlock(); |
|
} |
|
|
|
/* Generate domain masks and attrs */ |
|
ndoms = generate_sched_domains(&doms, &attr); |
|
|
|
/* Have scheduler rebuild the domains */ |
|
partition_and_rebuild_sched_domains(ndoms, doms, attr); |
|
} |
|
#else /* !CONFIG_SMP */ |
|
static void rebuild_sched_domains_locked(void) |
|
{ |
|
} |
|
#endif /* CONFIG_SMP */ |
|
|
|
void rebuild_sched_domains(void) |
|
{ |
|
cpus_read_lock(); |
|
percpu_down_write(&cpuset_rwsem); |
|
rebuild_sched_domains_locked(); |
|
percpu_up_write(&cpuset_rwsem); |
|
cpus_read_unlock(); |
|
} |
|
|
|
/** |
|
* update_tasks_cpumask - Update the cpumasks of tasks in the cpuset. |
|
* @cs: the cpuset in which each task's cpus_allowed mask needs to be changed |
|
* |
|
* Iterate through each task of @cs updating its cpus_allowed to the |
|
* effective cpuset's. As this function is called with cpuset_rwsem held, |
|
* cpuset membership stays stable. |
|
*/ |
|
static void update_tasks_cpumask(struct cpuset *cs) |
|
{ |
|
struct css_task_iter it; |
|
struct task_struct *task; |
|
|
|
css_task_iter_start(&cs->css, 0, &it); |
|
while ((task = css_task_iter_next(&it))) |
|
set_cpus_allowed_ptr(task, cs->effective_cpus); |
|
css_task_iter_end(&it); |
|
} |
|
|
|
/** |
|
* compute_effective_cpumask - Compute the effective cpumask of the cpuset |
|
* @new_cpus: the temp variable for the new effective_cpus mask |
|
* @cs: the cpuset the need to recompute the new effective_cpus mask |
|
* @parent: the parent cpuset |
|
* |
|
* If the parent has subpartition CPUs, include them in the list of |
|
* allowable CPUs in computing the new effective_cpus mask. Since offlined |
|
* CPUs are not removed from subparts_cpus, we have to use cpu_active_mask |
|
* to mask those out. |
|
*/ |
|
static void compute_effective_cpumask(struct cpumask *new_cpus, |
|
struct cpuset *cs, struct cpuset *parent) |
|
{ |
|
if (parent->nr_subparts_cpus) { |
|
cpumask_or(new_cpus, parent->effective_cpus, |
|
parent->subparts_cpus); |
|
cpumask_and(new_cpus, new_cpus, cs->cpus_allowed); |
|
cpumask_and(new_cpus, new_cpus, cpu_active_mask); |
|
} else { |
|
cpumask_and(new_cpus, cs->cpus_allowed, parent->effective_cpus); |
|
} |
|
} |
|
|
|
/* |
|
* Commands for update_parent_subparts_cpumask |
|
*/ |
|
enum subparts_cmd { |
|
partcmd_enable, /* Enable partition root */ |
|
partcmd_disable, /* Disable partition root */ |
|
partcmd_update, /* Update parent's subparts_cpus */ |
|
}; |
|
|
|
/** |
|
* update_parent_subparts_cpumask - update subparts_cpus mask of parent cpuset |
|
* @cpuset: The cpuset that requests change in partition root state |
|
* @cmd: Partition root state change command |
|
* @newmask: Optional new cpumask for partcmd_update |
|
* @tmp: Temporary addmask and delmask |
|
* Return: 0, 1 or an error code |
|
* |
|
* For partcmd_enable, the cpuset is being transformed from a non-partition |
|
* root to a partition root. The cpus_allowed mask of the given cpuset will |
|
* be put into parent's subparts_cpus and taken away from parent's |
|
* effective_cpus. The function will return 0 if all the CPUs listed in |
|
* cpus_allowed can be granted or an error code will be returned. |
|
* |
|
* For partcmd_disable, the cpuset is being transofrmed from a partition |
|
* root back to a non-partition root. Any CPUs in cpus_allowed that are in |
|
* parent's subparts_cpus will be taken away from that cpumask and put back |
|
* into parent's effective_cpus. 0 should always be returned. |
|
* |
|
* For partcmd_update, if the optional newmask is specified, the cpu |
|
* list is to be changed from cpus_allowed to newmask. Otherwise, |
|
* cpus_allowed is assumed to remain the same. The cpuset should either |
|
* be a partition root or an invalid partition root. The partition root |
|
* state may change if newmask is NULL and none of the requested CPUs can |
|
* be granted by the parent. The function will return 1 if changes to |
|
* parent's subparts_cpus and effective_cpus happen or 0 otherwise. |
|
* Error code should only be returned when newmask is non-NULL. |
|
* |
|
* The partcmd_enable and partcmd_disable commands are used by |
|
* update_prstate(). The partcmd_update command is used by |
|
* update_cpumasks_hier() with newmask NULL and update_cpumask() with |
|
* newmask set. |
|
* |
|
* The checking is more strict when enabling partition root than the |
|
* other two commands. |
|
* |
|
* Because of the implicit cpu exclusive nature of a partition root, |
|
* cpumask changes that violates the cpu exclusivity rule will not be |
|
* permitted when checked by validate_change(). |
|
*/ |
|
static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd, |
|
struct cpumask *newmask, |
|
struct tmpmasks *tmp) |
|
{ |
|
struct cpuset *parent = parent_cs(cpuset); |
|
int adding; /* Moving cpus from effective_cpus to subparts_cpus */ |
|
int deleting; /* Moving cpus from subparts_cpus to effective_cpus */ |
|
int old_prs, new_prs; |
|
bool part_error = false; /* Partition error? */ |
|
|
|
percpu_rwsem_assert_held(&cpuset_rwsem); |
|
|
|
/* |
|
* The parent must be a partition root. |
|
* The new cpumask, if present, or the current cpus_allowed must |
|
* not be empty. |
|
*/ |
|
if (!is_partition_root(parent) || |
|
(newmask && cpumask_empty(newmask)) || |
|
(!newmask && cpumask_empty(cpuset->cpus_allowed))) |
|
return -EINVAL; |
|
|
|
/* |
|
* Enabling/disabling partition root is not allowed if there are |
|
* online children. |
|
*/ |
|
if ((cmd != partcmd_update) && css_has_online_children(&cpuset->css)) |
|
return -EBUSY; |
|
|
|
/* |
|
* Enabling partition root is not allowed if not all the CPUs |
|
* can be granted from parent's effective_cpus or at least one |
|
* CPU will be left after that. |
|
*/ |
|
if ((cmd == partcmd_enable) && |
|
(!cpumask_subset(cpuset->cpus_allowed, parent->effective_cpus) || |
|
cpumask_equal(cpuset->cpus_allowed, parent->effective_cpus))) |
|
return -EINVAL; |
|
|
|
/* |
|
* A cpumask update cannot make parent's effective_cpus become empty. |
|
*/ |
|
adding = deleting = false; |
|
old_prs = new_prs = cpuset->partition_root_state; |
|
if (cmd == partcmd_enable) { |
|
cpumask_copy(tmp->addmask, cpuset->cpus_allowed); |
|
adding = true; |
|
} else if (cmd == partcmd_disable) { |
|
deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed, |
|
parent->subparts_cpus); |
|
} else if (newmask) { |
|
/* |
|
* partcmd_update with newmask: |
|
* |
|
* delmask = cpus_allowed & ~newmask & parent->subparts_cpus |
|
* addmask = newmask & parent->effective_cpus |
|
* & ~parent->subparts_cpus |
|
*/ |
|
cpumask_andnot(tmp->delmask, cpuset->cpus_allowed, newmask); |
|
deleting = cpumask_and(tmp->delmask, tmp->delmask, |
|
parent->subparts_cpus); |
|
|
|
cpumask_and(tmp->addmask, newmask, parent->effective_cpus); |
|
adding = cpumask_andnot(tmp->addmask, tmp->addmask, |
|
parent->subparts_cpus); |
|
/* |
|
* Return error if the new effective_cpus could become empty. |
|
*/ |
|
if (adding && |
|
cpumask_equal(parent->effective_cpus, tmp->addmask)) { |
|
if (!deleting) |
|
return -EINVAL; |
|
/* |
|
* As some of the CPUs in subparts_cpus might have |
|
* been offlined, we need to compute the real delmask |
|
* to confirm that. |
|
*/ |
|
if (!cpumask_and(tmp->addmask, tmp->delmask, |
|
cpu_active_mask)) |
|
return -EINVAL; |
|
cpumask_copy(tmp->addmask, parent->effective_cpus); |
|
} |
|
} else { |
|
/* |
|
* partcmd_update w/o newmask: |
|
* |
|
* addmask = cpus_allowed & parent->effective_cpus |
|
* |
|
* Note that parent's subparts_cpus may have been |
|
* pre-shrunk in case there is a change in the cpu list. |
|
* So no deletion is needed. |
|
*/ |
|
adding = cpumask_and(tmp->addmask, cpuset->cpus_allowed, |
|
parent->effective_cpus); |
|
part_error = cpumask_equal(tmp->addmask, |
|
parent->effective_cpus); |
|
} |
|
|
|
if (cmd == partcmd_update) { |
|
int prev_prs = cpuset->partition_root_state; |
|
|
|
/* |
|
* Check for possible transition between PRS_ENABLED |
|
* and PRS_ERROR. |
|
*/ |
|
switch (cpuset->partition_root_state) { |
|
case PRS_ENABLED: |
|
if (part_error) |
|
new_prs = PRS_ERROR; |
|
break; |
|
case PRS_ERROR: |
|
if (!part_error) |
|
new_prs = PRS_ENABLED; |
|
break; |
|
} |
|
/* |
|
* Set part_error if previously in invalid state. |
|
*/ |
|
part_error = (prev_prs == PRS_ERROR); |
|
} |
|
|
|
if (!part_error && (new_prs == PRS_ERROR)) |
|
return 0; /* Nothing need to be done */ |
|
|
|
if (new_prs == PRS_ERROR) { |
|
/* |
|
* Remove all its cpus from parent's subparts_cpus. |
|
*/ |
|
adding = false; |
|
deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed, |
|
parent->subparts_cpus); |
|
} |
|
|
|
if (!adding && !deleting && (new_prs == old_prs)) |
|
return 0; |
|
|
|
/* |
|
* Change the parent's subparts_cpus. |
|
* Newly added CPUs will be removed from effective_cpus and |
|
* newly deleted ones will be added back to effective_cpus. |
|
*/ |
|
spin_lock_irq(&callback_lock); |
|
if (adding) { |
|
cpumask_or(parent->subparts_cpus, |
|
parent->subparts_cpus, tmp->addmask); |
|
cpumask_andnot(parent->effective_cpus, |
|
parent->effective_cpus, tmp->addmask); |
|
} |
|
if (deleting) { |
|
cpumask_andnot(parent->subparts_cpus, |
|
parent->subparts_cpus, tmp->delmask); |
|
/* |
|
* Some of the CPUs in subparts_cpus might have been offlined. |
|
*/ |
|
cpumask_and(tmp->delmask, tmp->delmask, cpu_active_mask); |
|
cpumask_or(parent->effective_cpus, |
|
parent->effective_cpus, tmp->delmask); |
|
} |
|
|
|
parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus); |
|
|
|
if (old_prs != new_prs) |
|
cpuset->partition_root_state = new_prs; |
|
|
|
spin_unlock_irq(&callback_lock); |
|
notify_partition_change(cpuset, old_prs, new_prs); |
|
|
|
return cmd == partcmd_update; |
|
} |
|
|
|
/* |
|
* update_cpumasks_hier - Update effective cpumasks and tasks in the subtree |
|
* @cs: the cpuset to consider |
|
* @tmp: temp variables for calculating effective_cpus & partition setup |
|
* |
|
* When configured cpumask is changed, the effective cpumasks of this cpuset |
|
* and all its descendants need to be updated. |
|
* |
|
* On legacy hierarchy, effective_cpus will be the same with cpu_allowed. |
|
* |
|
* Called with cpuset_rwsem held |
|
*/ |
|
static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp) |
|
{ |
|
struct cpuset *cp; |
|
struct cgroup_subsys_state *pos_css; |
|
bool need_rebuild_sched_domains = false; |
|
int old_prs, new_prs; |
|
|
|
rcu_read_lock(); |
|
cpuset_for_each_descendant_pre(cp, pos_css, cs) { |
|
struct cpuset *parent = parent_cs(cp); |
|
|
|
compute_effective_cpumask(tmp->new_cpus, cp, parent); |
|
|
|
/* |
|
* If it becomes empty, inherit the effective mask of the |
|
* parent, which is guaranteed to have some CPUs. |
|
*/ |
|
if (is_in_v2_mode() && cpumask_empty(tmp->new_cpus)) { |
|
cpumask_copy(tmp->new_cpus, parent->effective_cpus); |
|
if (!cp->use_parent_ecpus) { |
|
cp->use_parent_ecpus = true; |
|
parent->child_ecpus_count++; |
|
} |
|
} else if (cp->use_parent_ecpus) { |
|
cp->use_parent_ecpus = false; |
|
WARN_ON_ONCE(!parent->child_ecpus_count); |
|
parent->child_ecpus_count--; |
|
} |
|
|
|
/* |
|
* Skip the whole subtree if the cpumask remains the same |
|
* and has no partition root state. |
|
*/ |
|
if (!cp->partition_root_state && |
|
cpumask_equal(tmp->new_cpus, cp->effective_cpus)) { |
|
pos_css = css_rightmost_descendant(pos_css); |
|
continue; |
|
} |
|
|
|
/* |
|
* update_parent_subparts_cpumask() should have been called |
|
* for cs already in update_cpumask(). We should also call |
|
* update_tasks_cpumask() again for tasks in the parent |
|
* cpuset if the parent's subparts_cpus changes. |
|
*/ |
|
old_prs = new_prs = cp->partition_root_state; |
|
if ((cp != cs) && old_prs) { |
|
switch (parent->partition_root_state) { |
|
case PRS_DISABLED: |
|
/* |
|
* If parent is not a partition root or an |
|
* invalid partition root, clear its state |
|
* and its CS_CPU_EXCLUSIVE flag. |
|
*/ |
|
WARN_ON_ONCE(cp->partition_root_state |
|
!= PRS_ERROR); |
|
new_prs = PRS_DISABLED; |
|
|
|
/* |
|
* clear_bit() is an atomic operation and |
|
* readers aren't interested in the state |
|
* of CS_CPU_EXCLUSIVE anyway. So we can |
|
* just update the flag without holding |
|
* the callback_lock. |
|
*/ |
|
clear_bit(CS_CPU_EXCLUSIVE, &cp->flags); |
|
break; |
|
|
|
case PRS_ENABLED: |
|
if (update_parent_subparts_cpumask(cp, partcmd_update, NULL, tmp)) |
|
update_tasks_cpumask(parent); |
|
break; |
|
|
|
case PRS_ERROR: |
|
/* |
|
* When parent is invalid, it has to be too. |
|
*/ |
|
new_prs = PRS_ERROR; |
|
break; |
|
} |
|
} |
|
|
|
if (!css_tryget_online(&cp->css)) |
|
continue; |
|
rcu_read_unlock(); |
|
|
|
spin_lock_irq(&callback_lock); |
|
|
|
cpumask_copy(cp->effective_cpus, tmp->new_cpus); |
|
if (cp->nr_subparts_cpus && (new_prs != PRS_ENABLED)) { |
|
cp->nr_subparts_cpus = 0; |
|
cpumask_clear(cp->subparts_cpus); |
|
} else if (cp->nr_subparts_cpus) { |
|
/* |
|
* Make sure that effective_cpus & subparts_cpus |
|
* are mutually exclusive. |
|
* |
|
* In the unlikely event that effective_cpus |
|
* becomes empty. we clear cp->nr_subparts_cpus and |
|
* let its child partition roots to compete for |
|
* CPUs again. |
|
*/ |
|
cpumask_andnot(cp->effective_cpus, cp->effective_cpus, |
|
cp->subparts_cpus); |
|
if (cpumask_empty(cp->effective_cpus)) { |
|
cpumask_copy(cp->effective_cpus, tmp->new_cpus); |
|
cpumask_clear(cp->subparts_cpus); |
|
cp->nr_subparts_cpus = 0; |
|
} else if (!cpumask_subset(cp->subparts_cpus, |
|
tmp->new_cpus)) { |
|
cpumask_andnot(cp->subparts_cpus, |
|
cp->subparts_cpus, tmp->new_cpus); |
|
cp->nr_subparts_cpus |
|
= cpumask_weight(cp->subparts_cpus); |
|
} |
|
} |
|
|
|
if (new_prs != old_prs) |
|
cp->partition_root_state = new_prs; |
|
|
|
spin_unlock_irq(&callback_lock); |
|
notify_partition_change(cp, old_prs, new_prs); |
|
|
|
WARN_ON(!is_in_v2_mode() && |
|
!cpumask_equal(cp->cpus_allowed, cp->effective_cpus)); |
|
|
|
update_tasks_cpumask(cp); |
|
|
|
/* |
|
* On legacy hierarchy, if the effective cpumask of any non- |
|
* empty cpuset is changed, we need to rebuild sched domains. |
|
* On default hierarchy, the cpuset needs to be a partition |
|
* root as well. |
|
*/ |
|
if (!cpumask_empty(cp->cpus_allowed) && |
|
is_sched_load_balance(cp) && |
|
(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || |
|
is_partition_root(cp))) |
|
need_rebuild_sched_domains = true; |
|
|
|
rcu_read_lock(); |
|
css_put(&cp->css); |
|
} |
|
rcu_read_unlock(); |
|
|
|
if (need_rebuild_sched_domains) |
|
rebuild_sched_domains_locked(); |
|
} |
|
|
|
/** |
|
* update_sibling_cpumasks - Update siblings cpumasks |
|
* @parent: Parent cpuset |
|
* @cs: Current cpuset |
|
* @tmp: Temp variables |
|
*/ |
|
static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs, |
|
struct tmpmasks *tmp) |
|
{ |
|
struct cpuset *sibling; |
|
struct cgroup_subsys_state *pos_css; |
|
|
|
percpu_rwsem_assert_held(&cpuset_rwsem); |
|
|
|
/* |
|
* Check all its siblings and call update_cpumasks_hier() |
|
* if their use_parent_ecpus flag is set in order for them |
|
* to use the right effective_cpus value. |
|
* |
|
* The update_cpumasks_hier() function may sleep. So we have to |
|
* release the RCU read lock before calling it. |
|
*/ |
|
rcu_read_lock(); |
|
cpuset_for_each_child(sibling, pos_css, parent) { |
|
if (sibling == cs) |
|
continue; |
|
if (!sibling->use_parent_ecpus) |
|
continue; |
|
if (!css_tryget_online(&sibling->css)) |
|
continue; |
|
|
|
rcu_read_unlock(); |
|
update_cpumasks_hier(sibling, tmp); |
|
rcu_read_lock(); |
|
css_put(&sibling->css); |
|
} |
|
rcu_read_unlock(); |
|
} |
|
|
|
/** |
|
* update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it |
|
* @cs: the cpuset to consider |
|
* @trialcs: trial cpuset |
|
* @buf: buffer of cpu numbers written to this cpuset |
|
*/ |
|
static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, |
|
const char *buf) |
|
{ |
|
int retval; |
|
struct tmpmasks tmp; |
|
|
|
/* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */ |
|
if (cs == &top_cpuset) |
|
return -EACCES; |
|
|
|
/* |
|
* An empty cpus_allowed is ok only if the cpuset has no tasks. |
|
* Since cpulist_parse() fails on an empty mask, we special case |
|
* that parsing. The validate_change() call ensures that cpusets |
|
* with tasks have cpus. |
|
*/ |
|
if (!*buf) { |
|
cpumask_clear(trialcs->cpus_allowed); |
|
} else { |
|
retval = cpulist_parse(buf, trialcs->cpus_allowed); |
|
if (retval < 0) |
|
return retval; |
|
|
|
if (!cpumask_subset(trialcs->cpus_allowed, |
|
top_cpuset.cpus_allowed)) |
|
return -EINVAL; |
|
} |
|
|
|
/* Nothing to do if the cpus didn't change */ |
|
if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed)) |
|
return 0; |
|
|
|
retval = validate_change(cs, trialcs); |
|
if (retval < 0) |
|
return retval; |
|
|
|
#ifdef CONFIG_CPUMASK_OFFSTACK |
|
/* |
|
* Use the cpumasks in trialcs for tmpmasks when they are pointers |
|
* to allocated cpumasks. |
|
*/ |
|
tmp.addmask = trialcs->subparts_cpus; |
|
tmp.delmask = trialcs->effective_cpus; |
|
tmp.new_cpus = trialcs->cpus_allowed; |
|
#endif |
|
|
|
if (cs->partition_root_state) { |
|
/* Cpumask of a partition root cannot be empty */ |
|
if (cpumask_empty(trialcs->cpus_allowed)) |
|
return -EINVAL; |
|
if (update_parent_subparts_cpumask(cs, partcmd_update, |
|
trialcs->cpus_allowed, &tmp) < 0) |
|
return -EINVAL; |
|
} |
|
|
|
spin_lock_irq(&callback_lock); |
|
cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); |
|
|
|
/* |
|
* Make sure that subparts_cpus is a subset of cpus_allowed. |
|
*/ |
|
if (cs->nr_subparts_cpus) { |
|
cpumask_and(cs->subparts_cpus, cs->subparts_cpus, cs->cpus_allowed); |
|
cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus); |
|
} |
|
spin_unlock_irq(&callback_lock); |
|
|
|
update_cpumasks_hier(cs, &tmp); |
|
|
|
if (cs->partition_root_state) { |
|
struct cpuset *parent = parent_cs(cs); |
|
|
|
/* |
|
* For partition root, update the cpumasks of sibling |
|
* cpusets if they use parent's effective_cpus. |
|
*/ |
|
if (parent->child_ecpus_count) |
|
update_sibling_cpumasks(parent, cs, &tmp); |
|
} |
|
return 0; |
|
} |
|
|
|
/* |
|
* Migrate memory region from one set of nodes to another. This is |
|
* performed asynchronously as it can be called from process migration path |
|
* holding locks involved in process management. All mm migrations are |
|
* performed in the queued order and can be waited for by flushing |
|
* cpuset_migrate_mm_wq. |
|
*/ |
|
|
|
struct cpuset_migrate_mm_work { |
|
struct work_struct work; |
|
struct mm_struct *mm; |
|
nodemask_t from; |
|
nodemask_t to; |
|
}; |
|
|
|
static void cpuset_migrate_mm_workfn(struct work_struct *work) |
|
{ |
|
struct cpuset_migrate_mm_work *mwork = |
|
container_of(work, struct cpuset_migrate_mm_work, work); |
|
|
|
/* on a wq worker, no need to worry about %current's mems_allowed */ |
|
do_migrate_pages(mwork->mm, &mwork->from, &mwork->to, MPOL_MF_MOVE_ALL); |
|
mmput(mwork->mm); |
|
kfree(mwork); |
|
} |
|
|
|
static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from, |
|
const nodemask_t *to) |
|
{ |
|
struct cpuset_migrate_mm_work *mwork; |
|
|
|
if (nodes_equal(*from, *to)) { |
|
mmput(mm); |
|
return; |
|
} |
|
|
|
mwork = kzalloc(sizeof(*mwork), GFP_KERNEL); |
|
if (mwork) { |
|
mwork->mm = mm; |
|
mwork->from = *from; |
|
mwork->to = *to; |
|
INIT_WORK(&mwork->work, cpuset_migrate_mm_workfn); |
|
queue_work(cpuset_migrate_mm_wq, &mwork->work); |
|
} else { |
|
mmput(mm); |
|
} |
|
} |
|
|
|
static void cpuset_post_attach(void) |
|
{ |
|
flush_workqueue(cpuset_migrate_mm_wq); |
|
} |
|
|
|
/* |
|
* cpuset_change_task_nodemask - change task's mems_allowed and mempolicy |
|
* @tsk: the task to change |
|
* @newmems: new nodes that the task will be set |
|
* |
|
* We use the mems_allowed_seq seqlock to safely update both tsk->mems_allowed |
|
* and rebind an eventual tasks' mempolicy. If the task is allocating in |
|
* parallel, it might temporarily see an empty intersection, which results in |
|
* a seqlock check and retry before OOM or allocation failure. |
|
*/ |
|
static void cpuset_change_task_nodemask(struct task_struct *tsk, |
|
nodemask_t *newmems) |
|
{ |
|
task_lock(tsk); |
|
|
|
local_irq_disable(); |
|
write_seqcount_begin(&tsk->mems_allowed_seq); |
|
|
|
nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems); |
|
mpol_rebind_task(tsk, newmems); |
|
tsk->mems_allowed = *newmems; |
|
|
|
write_seqcount_end(&tsk->mems_allowed_seq); |
|
local_irq_enable(); |
|
|
|
task_unlock(tsk); |
|
} |
|
|
|
static void *cpuset_being_rebound; |
|
|
|
/** |
|
* update_tasks_nodemask - Update the nodemasks of tasks in the cpuset. |
|
* @cs: the cpuset in which each task's mems_allowed mask needs to be changed |
|
* |
|
* Iterate through each task of @cs updating its mems_allowed to the |
|
* effective cpuset's. As this function is called with cpuset_rwsem held, |
|
* cpuset membership stays stable. |
|
*/ |
|
static void update_tasks_nodemask(struct cpuset *cs) |
|
{ |
|
static nodemask_t newmems; /* protected by cpuset_rwsem */ |
|
struct css_task_iter it; |
|
struct task_struct *task; |
|
|
|
cpuset_being_rebound = cs; /* causes mpol_dup() rebind */ |
|
|
|
guarantee_online_mems(cs, &newmems); |
|
|
|
/* |
|
* The mpol_rebind_mm() call takes mmap_lock, which we couldn't |
|
* take while holding tasklist_lock. Forks can happen - the |
|
* mpol_dup() cpuset_being_rebound check will catch such forks, |
|
* and rebind their vma mempolicies too. Because we still hold |
|
* the global cpuset_rwsem, we know that no other rebind effort |
|
* will be contending for the global variable cpuset_being_rebound. |
|
* It's ok if we rebind the same mm twice; mpol_rebind_mm() |
|
* is idempotent. Also migrate pages in each mm to new nodes. |
|
*/ |
|
css_task_iter_start(&cs->css, 0, &it); |
|
while ((task = css_task_iter_next(&it))) { |
|
struct mm_struct *mm; |
|
bool migrate; |
|
|
|
cpuset_change_task_nodemask(task, &newmems); |
|
|
|
mm = get_task_mm(task); |
|
if (!mm) |
|
continue; |
|
|
|
migrate = is_memory_migrate(cs); |
|
|
|
mpol_rebind_mm(mm, &cs->mems_allowed); |
|
if (migrate) |
|
cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems); |
|
else |
|
mmput(mm); |
|
} |
|
css_task_iter_end(&it); |
|
|
|
/* |
|
* All the tasks' nodemasks have been updated, update |
|
* cs->old_mems_allowed. |
|
*/ |
|
cs->old_mems_allowed = newmems; |
|
|
|
/* We're done rebinding vmas to this cpuset's new mems_allowed. */ |
|
cpuset_being_rebound = NULL; |
|
} |
|
|
|
/* |
|
* update_nodemasks_hier - Update effective nodemasks and tasks in the subtree |
|
* @cs: the cpuset to consider |
|
* @new_mems: a temp variable for calculating new effective_mems |
|
* |
|
* When configured nodemask is changed, the effective nodemasks of this cpuset |
|
* and all its descendants need to be updated. |
|
* |
|
* On legacy hierarchy, effective_mems will be the same with mems_allowed. |
|
* |
|
* Called with cpuset_rwsem held |
|
*/ |
|
static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems) |
|
{ |
|
struct cpuset *cp; |
|
struct cgroup_subsys_state *pos_css; |
|
|
|
rcu_read_lock(); |
|
cpuset_for_each_descendant_pre(cp, pos_css, cs) { |
|
struct cpuset *parent = parent_cs(cp); |
|
|
|
nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems); |
|
|
|
/* |
|
* If it becomes empty, inherit the effective mask of the |
|
* parent, which is guaranteed to have some MEMs. |
|
*/ |
|
if (is_in_v2_mode() && nodes_empty(*new_mems)) |
|
*new_mems = parent->effective_mems; |
|
|
|
/* Skip the whole subtree if the nodemask remains the same. */ |
|
if (nodes_equal(*new_mems, cp->effective_mems)) { |
|
pos_css = css_rightmost_descendant(pos_css); |
|
continue; |
|
} |
|
|
|
if (!css_tryget_online(&cp->css)) |
|
continue; |
|
rcu_read_unlock(); |
|
|
|
spin_lock_irq(&callback_lock); |
|
cp->effective_mems = *new_mems; |
|
spin_unlock_irq(&callback_lock); |
|
|
|
WARN_ON(!is_in_v2_mode() && |
|
!nodes_equal(cp->mems_allowed, cp->effective_mems)); |
|
|
|
update_tasks_nodemask(cp); |
|
|
|
rcu_read_lock(); |
|
css_put(&cp->css); |
|
} |
|
rcu_read_unlock(); |
|
} |
|
|
|
/* |
|
* Handle user request to change the 'mems' memory placement |
|
* of a cpuset. Needs to validate the request, update the |
|
* cpusets mems_allowed, and for each task in the cpuset, |
|
* update mems_allowed and rebind task's mempolicy and any vma |
|
* mempolicies and if the cpuset is marked 'memory_migrate', |
|
* migrate the tasks pages to the new memory. |
|
* |
|
* Call with cpuset_rwsem held. May take callback_lock during call. |
|
* Will take tasklist_lock, scan tasklist for tasks in cpuset cs, |
|
* lock each such tasks mm->mmap_lock, scan its vma's and rebind |
|
* their mempolicies to the cpusets new mems_allowed. |
|
*/ |
|
static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs, |
|
const char *buf) |
|
{ |
|
int retval; |
|
|
|
/* |
|
* top_cpuset.mems_allowed tracks node_stats[N_MEMORY]; |
|
* it's read-only |
|
*/ |
|
if (cs == &top_cpuset) { |
|
retval = -EACCES; |
|
goto done; |
|
} |
|
|
|
/* |
|
* An empty mems_allowed is ok iff there are no tasks in the cpuset. |
|
* Since nodelist_parse() fails on an empty mask, we special case |
|
* that parsing. The validate_change() call ensures that cpusets |
|
* with tasks have memory. |
|
*/ |
|
if (!*buf) { |
|
nodes_clear(trialcs->mems_allowed); |
|
} else { |
|
retval = nodelist_parse(buf, trialcs->mems_allowed); |
|
if (retval < 0) |
|
goto done; |
|
|
|
if (!nodes_subset(trialcs->mems_allowed, |
|
top_cpuset.mems_allowed)) { |
|
retval = -EINVAL; |
|
goto done; |
|
} |
|
} |
|
|
|
if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) { |
|
retval = 0; /* Too easy - nothing to do */ |
|
goto done; |
|
} |
|
retval = validate_change(cs, trialcs); |
|
if (retval < 0) |
|
goto done; |
|
|
|
check_insane_mems_config(&trialcs->mems_allowed); |
|
|
|
spin_lock_irq(&callback_lock); |
|
cs->mems_allowed = trialcs->mems_allowed; |
|
spin_unlock_irq(&callback_lock); |
|
|
|
/* use trialcs->mems_allowed as a temp variable */ |
|
update_nodemasks_hier(cs, &trialcs->mems_allowed); |
|
done: |
|
return retval; |
|
} |
|
|
|
bool current_cpuset_is_being_rebound(void) |
|
{ |
|
bool ret; |
|
|
|
rcu_read_lock(); |
|
ret = task_cs(current) == cpuset_being_rebound; |
|
rcu_read_unlock(); |
|
|
|
return ret; |
|
} |
|
|
|
static int update_relax_domain_level(struct cpuset *cs, s64 val) |
|
{ |
|
#ifdef CONFIG_SMP |
|
if (val < -1 || val >= sched_domain_level_max) |
|
return -EINVAL; |
|
#endif |
|
|
|
if (val != cs->relax_domain_level) { |
|
cs->relax_domain_level = val; |
|
if (!cpumask_empty(cs->cpus_allowed) && |
|
is_sched_load_balance(cs)) |
|
rebuild_sched_domains_locked(); |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
/** |
|
* update_tasks_flags - update the spread flags of tasks in the cpuset. |
|
* @cs: the cpuset in which each task's spread flags needs to be changed |
|
* |
|
* Iterate through each task of @cs updating its spread flags. As this |
|
* function is called with cpuset_rwsem held, cpuset membership stays |
|
* stable. |
|
*/ |
|
static void update_tasks_flags(struct cpuset *cs) |
|
{ |
|
struct css_task_iter it; |
|
struct task_struct *task; |
|
|
|
css_task_iter_start(&cs->css, 0, &it); |
|
while ((task = css_task_iter_next(&it))) |
|
cpuset_update_task_spread_flag(cs, task); |
|
css_task_iter_end(&it); |
|
} |
|
|
|
/* |
|
* update_flag - read a 0 or a 1 in a file and update associated flag |
|
* bit: the bit to update (see cpuset_flagbits_t) |
|
* cs: the cpuset to update |
|
* turning_on: whether the flag is being set or cleared |
|
* |
|
* Call with cpuset_rwsem held. |
|
*/ |
|
|
|
static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs, |
|
int turning_on) |
|
{ |
|
struct cpuset *trialcs; |
|
int balance_flag_changed; |
|
int spread_flag_changed; |
|
int err; |
|
|
|
trialcs = alloc_trial_cpuset(cs); |
|
if (!trialcs) |
|
return -ENOMEM; |
|
|
|
if (turning_on) |
|
set_bit(bit, &trialcs->flags); |
|
else |
|
clear_bit(bit, &trialcs->flags); |
|
|
|
err = validate_change(cs, trialcs); |
|
if (err < 0) |
|
goto out; |
|
|
|
balance_flag_changed = (is_sched_load_balance(cs) != |
|
is_sched_load_balance(trialcs)); |
|
|
|
spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs)) |
|
|| (is_spread_page(cs) != is_spread_page(trialcs))); |
|
|
|
spin_lock_irq(&callback_lock); |
|
cs->flags = trialcs->flags; |
|
spin_unlock_irq(&callback_lock); |
|
|
|
if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed) |
|
rebuild_sched_domains_locked(); |
|
|
|
if (spread_flag_changed) |
|
update_tasks_flags(cs); |
|
out: |
|
free_cpuset(trialcs); |
|
return err; |
|
} |
|
|
|
/* |
|
* update_prstate - update partititon_root_state |
|
* cs: the cpuset to update |
|
* new_prs: new partition root state |
|
* |
|
* Call with cpuset_rwsem held. |
|
*/ |
|
static int update_prstate(struct cpuset *cs, int new_prs) |
|
{ |
|
int err, old_prs = cs->partition_root_state; |
|
struct cpuset *parent = parent_cs(cs); |
|
struct tmpmasks tmpmask; |
|
|
|
if (old_prs == new_prs) |
|
return 0; |
|
|
|
/* |
|
* Cannot force a partial or invalid partition root to a full |
|
* partition root. |
|
*/ |
|
if (new_prs && (old_prs == PRS_ERROR)) |
|
return -EINVAL; |
|
|
|
if (alloc_cpumasks(NULL, &tmpmask)) |
|
return -ENOMEM; |
|
|
|
err = -EINVAL; |
|
if (!old_prs) { |
|
/* |
|
* Turning on partition root requires setting the |
|
* CS_CPU_EXCLUSIVE bit implicitly as well and cpus_allowed |
|
* cannot be NULL. |
|
*/ |
|
if (cpumask_empty(cs->cpus_allowed)) |
|
goto out; |
|
|
|
err = update_flag(CS_CPU_EXCLUSIVE, cs, 1); |
|
if (err) |
|
goto out; |
|
|
|
err = update_parent_subparts_cpumask(cs, partcmd_enable, |
|
NULL, &tmpmask); |
|
if (err) { |
|
update_flag(CS_CPU_EXCLUSIVE, cs, 0); |
|
goto out; |
|
} |
|
} else { |
|
/* |
|
* Turning off partition root will clear the |
|
* CS_CPU_EXCLUSIVE bit. |
|
*/ |
|
if (old_prs == PRS_ERROR) { |
|
update_flag(CS_CPU_EXCLUSIVE, cs, 0); |
|
err = 0; |
|
goto out; |
|
} |
|
|
|
err = update_parent_subparts_cpumask(cs, partcmd_disable, |
|
NULL, &tmpmask); |
|
if (err) |
|
goto out; |
|
|
|
/* Turning off CS_CPU_EXCLUSIVE will not return error */ |
|
update_flag(CS_CPU_EXCLUSIVE, cs, 0); |
|
} |
|
|
|
/* |
|
* Update cpumask of parent's tasks except when it is the top |
|
* cpuset as some system daemons cannot be mapped to other CPUs. |
|
*/ |
|
if (parent != &top_cpuset) |
|
update_tasks_cpumask(parent); |
|
|
|
if (parent->child_ecpus_count) |
|
update_sibling_cpumasks(parent, cs, &tmpmask); |
|
|
|
rebuild_sched_domains_locked(); |
|
out: |
|
if (!err) { |
|
spin_lock_irq(&callback_lock); |
|
cs->partition_root_state = new_prs; |
|
spin_unlock_irq(&callback_lock); |
|
notify_partition_change(cs, old_prs, new_prs); |
|
} |
|
|
|
free_cpumasks(NULL, &tmpmask); |
|
return err; |
|
} |
|
|
|
/* |
|
* Frequency meter - How fast is some event occurring? |
|
* |
|
* These routines manage a digitally filtered, constant time based, |
|
* event frequency meter. There are four routines: |
|
* fmeter_init() - initialize a frequency meter. |
|
* fmeter_markevent() - called each time the event happens. |
|
* fmeter_getrate() - returns the recent rate of such events. |
|
* fmeter_update() - internal routine used to update fmeter. |
|
* |
|
* A common data structure is passed to each of these routines, |
|
* which is used to keep track of the state required to manage the |
|
* frequency meter and its digital filter. |
|
* |
|
* The filter works on the number of events marked per unit time. |
|
* The filter is single-pole low-pass recursive (IIR). The time unit |
|
* is 1 second. Arithmetic is done using 32-bit integers scaled to |
|
* simulate 3 decimal digits of precision (multiplied by 1000). |
|
* |
|
* With an FM_COEF of 933, and a time base of 1 second, the filter |
|
* has a half-life of 10 seconds, meaning that if the events quit |
|
* happening, then the rate returned from the fmeter_getrate() |
|
* will be cut in half each 10 seconds, until it converges to zero. |
|
* |
|
* It is not worth doing a real infinitely recursive filter. If more |
|
* than FM_MAXTICKS ticks have elapsed since the last filter event, |
|
* just compute FM_MAXTICKS ticks worth, by which point the level |
|
* will be stable. |
|
* |
|
* Limit the count of unprocessed events to FM_MAXCNT, so as to avoid |
|
* arithmetic overflow in the fmeter_update() routine. |
|
* |
|
* Given the simple 32 bit integer arithmetic used, this meter works |
|
* best for reporting rates between one per millisecond (msec) and |
|
* one per 32 (approx) seconds. At constant rates faster than one |
|
* per msec it maxes out at values just under 1,000,000. At constant |
|
* rates between one per msec, and one per second it will stabilize |
|
* to a value N*1000, where N is the rate of events per second. |
|
* At constant rates between one per second and one per 32 seconds, |
|
* it will be choppy, moving up on the seconds that have an event, |
|
* and then decaying until the next event. At rates slower than |
|
* about one in 32 seconds, it decays all the way back to zero between |
|
* each event. |
|
*/ |
|
|
|
#define FM_COEF 933 /* coefficient for half-life of 10 secs */ |
|
#define FM_MAXTICKS ((u32)99) /* useless computing more ticks than this */ |
|
#define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */ |
|
#define FM_SCALE 1000 /* faux fixed point scale */ |
|
|
|
/* Initialize a frequency meter */ |
|
static void fmeter_init(struct fmeter *fmp) |
|
{ |
|
fmp->cnt = 0; |
|
fmp->val = 0; |
|
fmp->time = 0; |
|
spin_lock_init(&fmp->lock); |
|
} |
|
|
|
/* Internal meter update - process cnt events and update value */ |
|
static void fmeter_update(struct fmeter *fmp) |
|
{ |
|
time64_t now; |
|
u32 ticks; |
|
|
|
now = ktime_get_seconds(); |
|
ticks = now - fmp->time; |
|
|
|
if (ticks == 0) |
|
return; |
|
|
|
ticks = min(FM_MAXTICKS, ticks); |
|
while (ticks-- > 0) |
|
fmp->val = (FM_COEF * fmp->val) / FM_SCALE; |
|
fmp->time = now; |
|
|
|
fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE; |
|
fmp->cnt = 0; |
|
} |
|
|
|
/* Process any previous ticks, then bump cnt by one (times scale). */ |
|
static void fmeter_markevent(struct fmeter *fmp) |
|
{ |
|
spin_lock(&fmp->lock); |
|
fmeter_update(fmp); |
|
fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE); |
|
spin_unlock(&fmp->lock); |
|
} |
|
|
|
/* Process any previous ticks, then return current value. */ |
|
static int fmeter_getrate(struct fmeter *fmp) |
|
{ |
|
int val; |
|
|
|
spin_lock(&fmp->lock); |
|
fmeter_update(fmp); |
|
val = fmp->val; |
|
spin_unlock(&fmp->lock); |
|
return val; |
|
} |
|
|
|
static struct cpuset *cpuset_attach_old_cs; |
|
|
|
/* Called by cgroups to determine if a cpuset is usable; cpuset_rwsem held */ |
|
static int cpuset_can_attach(struct cgroup_taskset *tset) |
|
{ |
|
struct cgroup_subsys_state *css; |
|
struct cpuset *cs; |
|
struct task_struct *task; |
|
int ret; |
|
|
|
/* used later by cpuset_attach() */ |
|
cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css)); |
|
cs = css_cs(css); |
|
|
|
percpu_down_write(&cpuset_rwsem); |
|
|
|
/* allow moving tasks into an empty cpuset if on default hierarchy */ |
|
ret = -ENOSPC; |
|
if (!is_in_v2_mode() && |
|
(cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))) |
|
goto out_unlock; |
|
|
|
cgroup_taskset_for_each(task, css, tset) { |
|
ret = task_can_attach(task, cs->cpus_allowed); |
|
if (ret) |
|
goto out_unlock; |
|
ret = security_task_setscheduler(task); |
|
if (ret) |
|
goto out_unlock; |
|
} |
|
|
|
/* |
|
* Mark attach is in progress. This makes validate_change() fail |
|
* changes which zero cpus/mems_allowed. |
|
*/ |
|
cs->attach_in_progress++; |
|
ret = 0; |
|
out_unlock: |
|
percpu_up_write(&cpuset_rwsem); |
|
return ret; |
|
} |
|
|
|
static void cpuset_cancel_attach(struct cgroup_taskset *tset) |
|
{ |
|
struct cgroup_subsys_state *css; |
|
|
|
cgroup_taskset_first(tset, &css); |
|
|
|
percpu_down_write(&cpuset_rwsem); |
|
css_cs(css)->attach_in_progress--; |
|
percpu_up_write(&cpuset_rwsem); |
|
} |
|
|
|
/* |
|
* Protected by cpuset_rwsem. cpus_attach is used only by cpuset_attach() |
|
* but we can't allocate it dynamically there. Define it global and |
|
* allocate from cpuset_init(). |
|
*/ |
|
static cpumask_var_t cpus_attach; |
|
|
|
static void cpuset_attach(struct cgroup_taskset *tset) |
|
{ |
|
/* static buf protected by cpuset_rwsem */ |
|
static nodemask_t cpuset_attach_nodemask_to; |
|
struct task_struct *task; |
|
struct task_struct *leader; |
|
struct cgroup_subsys_state *css; |
|
struct cpuset *cs; |
|
struct cpuset *oldcs = cpuset_attach_old_cs; |
|
|
|
cgroup_taskset_first(tset, &css); |
|
cs = css_cs(css); |
|
|
|
cpus_read_lock(); |
|
percpu_down_write(&cpuset_rwsem); |
|
|
|
guarantee_online_mems(cs, &cpuset_attach_nodemask_to); |
|
|
|
cgroup_taskset_for_each(task, css, tset) { |
|
if (cs != &top_cpuset) |
|
guarantee_online_cpus(task, cpus_attach); |
|
else |
|
cpumask_copy(cpus_attach, task_cpu_possible_mask(task)); |
|
/* |
|
* can_attach beforehand should guarantee that this doesn't |
|
* fail. TODO: have a better way to handle failure here |
|
*/ |
|
WARN_ON_ONCE(set_cpus_allowed_ptr(task, cpus_attach)); |
|
|
|
cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to); |
|
cpuset_update_task_spread_flag(cs, task); |
|
} |
|
|
|
/* |
|
* Change mm for all threadgroup leaders. This is expensive and may |
|
* sleep and should be moved outside migration path proper. |
|
*/ |
|
cpuset_attach_nodemask_to = cs->effective_mems; |
|
cgroup_taskset_for_each_leader(leader, css, tset) { |
|
struct mm_struct *mm = get_task_mm(leader); |
|
|
|
if (mm) { |
|
mpol_rebind_mm(mm, &cpuset_attach_nodemask_to); |
|
|
|
/* |
|
* old_mems_allowed is the same with mems_allowed |
|
* here, except if this task is being moved |
|
* automatically due to hotplug. In that case |
|
* @mems_allowed has been updated and is empty, so |
|
* @old_mems_allowed is the right nodesets that we |
|
* migrate mm from. |
|
*/ |
|
if (is_memory_migrate(cs)) |
|
cpuset_migrate_mm(mm, &oldcs->old_mems_allowed, |
|
&cpuset_attach_nodemask_to); |
|
else |
|
mmput(mm); |
|
} |
|
} |
|
|
|
cs->old_mems_allowed = cpuset_attach_nodemask_to; |
|
|
|
cs->attach_in_progress--; |
|
if (!cs->attach_in_progress) |
|
wake_up(&cpuset_attach_wq); |
|
|
|
percpu_up_write(&cpuset_rwsem); |
|
cpus_read_unlock(); |
|
} |
|
|
|
/* The various types of files and directories in a cpuset file system */ |
|
|
|
typedef enum { |
|
FILE_MEMORY_MIGRATE, |
|
FILE_CPULIST, |
|
FILE_MEMLIST, |
|
FILE_EFFECTIVE_CPULIST, |
|
FILE_EFFECTIVE_MEMLIST, |
|
FILE_SUBPARTS_CPULIST, |
|
FILE_CPU_EXCLUSIVE, |
|
FILE_MEM_EXCLUSIVE, |
|
FILE_MEM_HARDWALL, |
|
FILE_SCHED_LOAD_BALANCE, |
|
FILE_PARTITION_ROOT, |
|
FILE_SCHED_RELAX_DOMAIN_LEVEL, |
|
FILE_MEMORY_PRESSURE_ENABLED, |
|
FILE_MEMORY_PRESSURE, |
|
FILE_SPREAD_PAGE, |
|
FILE_SPREAD_SLAB, |
|
} cpuset_filetype_t; |
|
|
|
static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft, |
|
u64 val) |
|
{ |
|
struct cpuset *cs = css_cs(css); |
|
cpuset_filetype_t type = cft->private; |
|
int retval = 0; |
|
|
|
cpus_read_lock(); |
|
percpu_down_write(&cpuset_rwsem); |
|
if (!is_cpuset_online(cs)) { |
|
retval = -ENODEV; |
|
goto out_unlock; |
|
} |
|
|
|
switch (type) { |
|
case FILE_CPU_EXCLUSIVE: |
|
retval = update_flag(CS_CPU_EXCLUSIVE, cs, val); |
|
break; |
|
case FILE_MEM_EXCLUSIVE: |
|
retval = update_flag(CS_MEM_EXCLUSIVE, cs, val); |
|
break; |
|
case FILE_MEM_HARDWALL: |
|
retval = update_flag(CS_MEM_HARDWALL, cs, val); |
|
break; |
|
case FILE_SCHED_LOAD_BALANCE: |
|
retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val); |
|
break; |
|
case FILE_MEMORY_MIGRATE: |
|
retval = update_flag(CS_MEMORY_MIGRATE, cs, val); |
|
break; |
|
case FILE_MEMORY_PRESSURE_ENABLED: |
|
cpuset_memory_pressure_enabled = !!val; |
|
break; |
|
case FILE_SPREAD_PAGE: |
|
retval = update_flag(CS_SPREAD_PAGE, cs, val); |
|
break; |
|
case FILE_SPREAD_SLAB: |
|
retval = update_flag(CS_SPREAD_SLAB, cs, val); |
|
break; |
|
default: |
|
retval = -EINVAL; |
|
break; |
|
} |
|
out_unlock: |
|
percpu_up_write(&cpuset_rwsem); |
|
cpus_read_unlock(); |
|
return retval; |
|
} |
|
|
|
static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft, |
|
s64 val) |
|
{ |
|
struct cpuset *cs = css_cs(css); |
|
cpuset_filetype_t type = cft->private; |
|
int retval = -ENODEV; |
|
|
|
cpus_read_lock(); |
|
percpu_down_write(&cpuset_rwsem); |
|
if (!is_cpuset_online(cs)) |
|
goto out_unlock; |
|
|
|
switch (type) { |
|
case FILE_SCHED_RELAX_DOMAIN_LEVEL: |
|
retval = update_relax_domain_level(cs, val); |
|
break; |
|
default: |
|
retval = -EINVAL; |
|
break; |
|
} |
|
out_unlock: |
|
percpu_up_write(&cpuset_rwsem); |
|
cpus_read_unlock(); |
|
return retval; |
|
} |
|
|
|
/* |
|
* Common handling for a write to a "cpus" or "mems" file. |
|
*/ |
|
static ssize_t cpuset_write_resmask(struct kernfs_open_file *of, |
|
char *buf, size_t nbytes, loff_t off) |
|
{ |
|
struct cpuset *cs = css_cs(of_css(of)); |
|
struct cpuset *trialcs; |
|
int retval = -ENODEV; |
|
|
|
buf = strstrip(buf); |
|
|
|
/* |
|
* CPU or memory hotunplug may leave @cs w/o any execution |
|
* resources, in which case the hotplug code asynchronously updates |
|
* configuration and transfers all tasks to the nearest ancestor |
|
* which can execute. |
|
* |
|
* As writes to "cpus" or "mems" may restore @cs's execution |
|
* resources, wait for the previously scheduled operations before |
|
* proceeding, so that we don't end up keep removing tasks added |
|
* after execution capability is restored. |
|
* |
|
* cpuset_hotplug_work calls back into cgroup core via |
|
* cgroup_transfer_tasks() and waiting for it from a cgroupfs |
|
* operation like this one can lead to a deadlock through kernfs |
|
* active_ref protection. Let's break the protection. Losing the |
|
* protection is okay as we check whether @cs is online after |
|
* grabbing cpuset_rwsem anyway. This only happens on the legacy |
|
* hierarchies. |
|
*/ |
|
css_get(&cs->css); |
|
kernfs_break_active_protection(of->kn); |
|
flush_work(&cpuset_hotplug_work); |
|
|
|
cpus_read_lock(); |
|
percpu_down_write(&cpuset_rwsem); |
|
if (!is_cpuset_online(cs)) |
|
goto out_unlock; |
|
|
|
trialcs = alloc_trial_cpuset(cs); |
|
if (!trialcs) { |
|
retval = -ENOMEM; |
|
goto out_unlock; |
|
} |
|
|
|
switch (of_cft(of)->private) { |
|
case FILE_CPULIST: |
|
retval = update_cpumask(cs, trialcs, buf); |
|
break; |
|
case FILE_MEMLIST: |
|
retval = update_nodemask(cs, trialcs, buf); |
|
break; |
|
default: |
|
retval = -EINVAL; |
|
break; |
|
} |
|
|
|
free_cpuset(trialcs); |
|
out_unlock: |
|
percpu_up_write(&cpuset_rwsem); |
|
cpus_read_unlock(); |
|
kernfs_unbreak_active_protection(of->kn); |
|
css_put(&cs->css); |
|
flush_workqueue(cpuset_migrate_mm_wq); |
|
return retval ?: nbytes; |
|
} |
|
|
|
/* |
|
* These ascii lists should be read in a single call, by using a user |
|
* buffer large enough to hold the entire map. If read in smaller |
|
* chunks, there is no guarantee of atomicity. Since the display format |
|
* used, list of ranges of sequential numbers, is variable length, |
|
* and since these maps can change value dynamically, one could read |
|
* gibberish by doing partial reads while a list was changing. |
|
*/ |
|
static int cpuset_common_seq_show(struct seq_file *sf, void *v) |
|
{ |
|
struct cpuset *cs = css_cs(seq_css(sf)); |
|
cpuset_filetype_t type = seq_cft(sf)->private; |
|
int ret = 0; |
|
|
|
spin_lock_irq(&callback_lock); |
|
|
|
switch (type) { |
|
case FILE_CPULIST: |
|
seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->cpus_allowed)); |
|
break; |
|
case FILE_MEMLIST: |
|
seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->mems_allowed)); |
|
break; |
|
case FILE_EFFECTIVE_CPULIST: |
|
seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->effective_cpus)); |
|
break; |
|
case FILE_EFFECTIVE_MEMLIST: |
|
seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->effective_mems)); |
|
break; |
|
case FILE_SUBPARTS_CPULIST: |
|
seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->subparts_cpus)); |
|
break; |
|
default: |
|
ret = -EINVAL; |
|
} |
|
|
|
spin_unlock_irq(&callback_lock); |
|
return ret; |
|
} |
|
|
|
static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft) |
|
{ |
|
struct cpuset *cs = css_cs(css); |
|
cpuset_filetype_t type = cft->private; |
|
switch (type) { |
|
case FILE_CPU_EXCLUSIVE: |
|
return is_cpu_exclusive(cs); |
|
case FILE_MEM_EXCLUSIVE: |
|
return is_mem_exclusive(cs); |
|
case FILE_MEM_HARDWALL: |
|
return is_mem_hardwall(cs); |
|
case FILE_SCHED_LOAD_BALANCE: |
|
return is_sched_load_balance(cs); |
|
case FILE_MEMORY_MIGRATE: |
|
return is_memory_migrate(cs); |
|
case FILE_MEMORY_PRESSURE_ENABLED: |
|
return cpuset_memory_pressure_enabled; |
|
case FILE_MEMORY_PRESSURE: |
|
return fmeter_getrate(&cs->fmeter); |
|
case FILE_SPREAD_PAGE: |
|
return is_spread_page(cs); |
|
case FILE_SPREAD_SLAB: |
|
return is_spread_slab(cs); |
|
default: |
|
BUG(); |
|
} |
|
|
|
/* Unreachable but makes gcc happy */ |
|
return 0; |
|
} |
|
|
|
static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft) |
|
{ |
|
struct cpuset *cs = css_cs(css); |
|
cpuset_filetype_t type = cft->private; |
|
switch (type) { |
|
case FILE_SCHED_RELAX_DOMAIN_LEVEL: |
|
return cs->relax_domain_level; |
|
default: |
|
BUG(); |
|
} |
|
|
|
/* Unreachable but makes gcc happy */ |
|
return 0; |
|
} |
|
|
|
static int sched_partition_show(struct seq_file *seq, void *v) |
|
{ |
|
struct cpuset *cs = css_cs(seq_css(seq)); |
|
|
|
switch (cs->partition_root_state) { |
|
case PRS_ENABLED: |
|
seq_puts(seq, "root\n"); |
|
break; |
|
case PRS_DISABLED: |
|
seq_puts(seq, "member\n"); |
|
break; |
|
case PRS_ERROR: |
|
seq_puts(seq, "root invalid\n"); |
|
break; |
|
} |
|
return 0; |
|
} |
|
|
|
static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf, |
|
size_t nbytes, loff_t off) |
|
{ |
|
struct cpuset *cs = css_cs(of_css(of)); |
|
int val; |
|
int retval = -ENODEV; |
|
|
|
buf = strstrip(buf); |
|
|
|
/* |
|
* Convert "root" to ENABLED, and convert "member" to DISABLED. |
|
*/ |
|
if (!strcmp(buf, "root")) |
|
val = PRS_ENABLED; |
|
else if (!strcmp(buf, "member")) |
|
val = PRS_DISABLED; |
|
else |
|
return -EINVAL; |
|
|
|
css_get(&cs->css); |
|
cpus_read_lock(); |
|
percpu_down_write(&cpuset_rwsem); |
|
if (!is_cpuset_online(cs)) |
|
goto out_unlock; |
|
|
|
retval = update_prstate(cs, val); |
|
out_unlock: |
|
percpu_up_write(&cpuset_rwsem); |
|
cpus_read_unlock(); |
|
css_put(&cs->css); |
|
return retval ?: nbytes; |
|
} |
|
|
|
/* |
|
* for the common functions, 'private' gives the type of file |
|
*/ |
|
|
|
static struct cftype legacy_files[] = { |
|
{ |
|
.name = "cpus", |
|
.seq_show = cpuset_common_seq_show, |
|
.write = cpuset_write_resmask, |
|
.max_write_len = (100U + 6 * NR_CPUS), |
|
.private = FILE_CPULIST, |
|
}, |
|
|
|
{ |
|
.name = "mems", |
|
.seq_show = cpuset_common_seq_show, |
|
.write = cpuset_write_resmask, |
|
.max_write_len = (100U + 6 * MAX_NUMNODES), |
|
.private = FILE_MEMLIST, |
|
}, |
|
|
|
{ |
|
.name = "effective_cpus", |
|
.seq_show = cpuset_common_seq_show, |
|
.private = FILE_EFFECTIVE_CPULIST, |
|
}, |
|
|
|
{ |
|
.name = "effective_mems", |
|
.seq_show = cpuset_common_seq_show, |
|
.private = FILE_EFFECTIVE_MEMLIST, |
|
}, |
|
|
|
{ |
|
.name = "cpu_exclusive", |
|
.read_u64 = cpuset_read_u64, |
|
.write_u64 = cpuset_write_u64, |
|
.private = FILE_CPU_EXCLUSIVE, |
|
}, |
|
|
|
{ |
|
.name = "mem_exclusive", |
|
.read_u64 = cpuset_read_u64, |
|
.write_u64 = cpuset_write_u64, |
|
.private = FILE_MEM_EXCLUSIVE, |
|
}, |
|
|
|
{ |
|
.name = "mem_hardwall", |
|
.read_u64 = cpuset_read_u64, |
|
.write_u64 = cpuset_write_u64, |
|
.private = FILE_MEM_HARDWALL, |
|
}, |
|
|
|
{ |
|
.name = "sched_load_balance", |
|
.read_u64 = cpuset_read_u64, |
|
.write_u64 = cpuset_write_u64, |
|
.private = FILE_SCHED_LOAD_BALANCE, |
|
}, |
|
|
|
{ |
|
.name = "sched_relax_domain_level", |
|
.read_s64 = cpuset_read_s64, |
|
.write_s64 = cpuset_write_s64, |
|
.private = FILE_SCHED_RELAX_DOMAIN_LEVEL, |
|
}, |
|
|
|
{ |
|
.name = "memory_migrate", |
|
.read_u64 = cpuset_read_u64, |
|
.write_u64 = cpuset_write_u64, |
|
.private = FILE_MEMORY_MIGRATE, |
|
}, |
|
|
|
{ |
|
.name = "memory_pressure", |
|
.read_u64 = cpuset_read_u64, |
|
.private = FILE_MEMORY_PRESSURE, |
|
}, |
|
|
|
{ |
|
.name = "memory_spread_page", |
|
.read_u64 = cpuset_read_u64, |
|
.write_u64 = cpuset_write_u64, |
|
.private = FILE_SPREAD_PAGE, |
|
}, |
|
|
|
{ |
|
.name = "memory_spread_slab", |
|
.read_u64 = cpuset_read_u64, |
|
.write_u64 = cpuset_write_u64, |
|
.private = FILE_SPREAD_SLAB, |
|
}, |
|
|
|
{ |
|
.name = "memory_pressure_enabled", |
|
.flags = CFTYPE_ONLY_ON_ROOT, |
|
.read_u64 = cpuset_read_u64, |
|
.write_u64 = cpuset_write_u64, |
|
.private = FILE_MEMORY_PRESSURE_ENABLED, |
|
}, |
|
|
|
{ } /* terminate */ |
|
}; |
|
|
|
/* |
|
* This is currently a minimal set for the default hierarchy. It can be |
|
* expanded later on by migrating more features and control files from v1. |
|
*/ |
|
static struct cftype dfl_files[] = { |
|
{ |
|
.name = "cpus", |
|
.seq_show = cpuset_common_seq_show, |
|
.write = cpuset_write_resmask, |
|
.max_write_len = (100U + 6 * NR_CPUS), |
|
.private = FILE_CPULIST, |
|
.flags = CFTYPE_NOT_ON_ROOT, |
|
}, |
|
|
|
{ |
|
.name = "mems", |
|
.seq_show = cpuset_common_seq_show, |
|
.write = cpuset_write_resmask, |
|
.max_write_len = (100U + 6 * MAX_NUMNODES), |
|
.private = FILE_MEMLIST, |
|
.flags = CFTYPE_NOT_ON_ROOT, |
|
}, |
|
|
|
{ |
|
.name = "cpus.effective", |
|
.seq_show = cpuset_common_seq_show, |
|
.private = FILE_EFFECTIVE_CPULIST, |
|
}, |
|
|
|
{ |
|
.name = "mems.effective", |
|
.seq_show = cpuset_common_seq_show, |
|
.private = FILE_EFFECTIVE_MEMLIST, |
|
}, |
|
|
|
{ |
|
.name = "cpus.partition", |
|
.seq_show = sched_partition_show, |
|
.write = sched_partition_write, |
|
.private = FILE_PARTITION_ROOT, |
|
.flags = CFTYPE_NOT_ON_ROOT, |
|
.file_offset = offsetof(struct cpuset, partition_file), |
|
}, |
|
|
|
{ |
|
.name = "cpus.subpartitions", |
|
.seq_show = cpuset_common_seq_show, |
|
.private = FILE_SUBPARTS_CPULIST, |
|
.flags = CFTYPE_DEBUG, |
|
}, |
|
|
|
{ } /* terminate */ |
|
}; |
|
|
|
|
|
/* |
|
* cpuset_css_alloc - allocate a cpuset css |
|
* cgrp: control group that the new cpuset will be part of |
|
*/ |
|
|
|
static struct cgroup_subsys_state * |
|
cpuset_css_alloc(struct cgroup_subsys_state *parent_css) |
|
{ |
|
struct cpuset *cs; |
|
|
|
if (!parent_css) |
|
return &top_cpuset.css; |
|
|
|
cs = kzalloc(sizeof(*cs), GFP_KERNEL); |
|
if (!cs) |
|
return ERR_PTR(-ENOMEM); |
|
|
|
if (alloc_cpumasks(cs, NULL)) { |
|
kfree(cs); |
|
return ERR_PTR(-ENOMEM); |
|
} |
|
|
|
__set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); |
|
nodes_clear(cs->mems_allowed); |
|
nodes_clear(cs->effective_mems); |
|
fmeter_init(&cs->fmeter); |
|
cs->relax_domain_level = -1; |
|
|
|
/* Set CS_MEMORY_MIGRATE for default hierarchy */ |
|
if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) |
|
__set_bit(CS_MEMORY_MIGRATE, &cs->flags); |
|
|
|
return &cs->css; |
|
} |
|
|
|
static int cpuset_css_online(struct cgroup_subsys_state *css) |
|
{ |
|
struct cpuset *cs = css_cs(css); |
|
struct cpuset *parent = parent_cs(cs); |
|
struct cpuset *tmp_cs; |
|
struct cgroup_subsys_state *pos_css; |
|
|
|
if (!parent) |
|
return 0; |
|
|
|
cpus_read_lock(); |
|
percpu_down_write(&cpuset_rwsem); |
|
|
|
set_bit(CS_ONLINE, &cs->flags); |
|
if (is_spread_page(parent)) |
|
set_bit(CS_SPREAD_PAGE, &cs->flags); |
|
if (is_spread_slab(parent)) |
|
set_bit(CS_SPREAD_SLAB, &cs->flags); |
|
|
|
cpuset_inc(); |
|
|
|
spin_lock_irq(&callback_lock); |
|
if (is_in_v2_mode()) { |
|
cpumask_copy(cs->effective_cpus, parent->effective_cpus); |
|
cs->effective_mems = parent->effective_mems; |
|
cs->use_parent_ecpus = true; |
|
parent->child_ecpus_count++; |
|
} |
|
spin_unlock_irq(&callback_lock); |
|
|
|
if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags)) |
|
goto out_unlock; |
|
|
|
/* |
|
* Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is |
|
* set. This flag handling is implemented in cgroup core for |
|
* histrical reasons - the flag may be specified during mount. |
|
* |
|
* Currently, if any sibling cpusets have exclusive cpus or mem, we |
|
* refuse to clone the configuration - thereby refusing the task to |
|
* be entered, and as a result refusing the sys_unshare() or |
|
* clone() which initiated it. If this becomes a problem for some |
|
* users who wish to allow that scenario, then this could be |
|
* changed to grant parent->cpus_allowed-sibling_cpus_exclusive |
|
* (and likewise for mems) to the new cgroup. |
|
*/ |
|
rcu_read_lock(); |
|
cpuset_for_each_child(tmp_cs, pos_css, parent) { |
|
if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) { |
|
rcu_read_unlock(); |
|
goto out_unlock; |
|
} |
|
} |
|
rcu_read_unlock(); |
|
|
|
spin_lock_irq(&callback_lock); |
|
cs->mems_allowed = parent->mems_allowed; |
|
cs->effective_mems = parent->mems_allowed; |
|
cpumask_copy(cs->cpus_allowed, parent->cpus_allowed); |
|
cpumask_copy(cs->effective_cpus, parent->cpus_allowed); |
|
spin_unlock_irq(&callback_lock); |
|
out_unlock: |
|
percpu_up_write(&cpuset_rwsem); |
|
cpus_read_unlock(); |
|
return 0; |
|
} |
|
|
|
/* |
|
* If the cpuset being removed has its flag 'sched_load_balance' |
|
* enabled, then simulate turning sched_load_balance off, which |
|
* will call rebuild_sched_domains_locked(). That is not needed |
|
* in the default hierarchy where only changes in partition |
|
* will cause repartitioning. |
|
* |
|
* If the cpuset has the 'sched.partition' flag enabled, simulate |
|
* turning 'sched.partition" off. |
|
*/ |
|
|
|
static void cpuset_css_offline(struct cgroup_subsys_state *css) |
|
{ |
|
struct cpuset *cs = css_cs(css); |
|
|
|
cpus_read_lock(); |
|
percpu_down_write(&cpuset_rwsem); |
|
|
|
if (is_partition_root(cs)) |
|
update_prstate(cs, 0); |
|
|
|
if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && |
|
is_sched_load_balance(cs)) |
|
update_flag(CS_SCHED_LOAD_BALANCE, cs, 0); |
|
|
|
if (cs->use_parent_ecpus) { |
|
struct cpuset *parent = parent_cs(cs); |
|
|
|
cs->use_parent_ecpus = false; |
|
parent->child_ecpus_count--; |
|
} |
|
|
|
cpuset_dec(); |
|
clear_bit(CS_ONLINE, &cs->flags); |
|
|
|
percpu_up_write(&cpuset_rwsem); |
|
cpus_read_unlock(); |
|
} |
|
|
|
static void cpuset_css_free(struct cgroup_subsys_state *css) |
|
{ |
|
struct cpuset *cs = css_cs(css); |
|
|
|
free_cpuset(cs); |
|
} |
|
|
|
static void cpuset_bind(struct cgroup_subsys_state *root_css) |
|
{ |
|
percpu_down_write(&cpuset_rwsem); |
|
spin_lock_irq(&callback_lock); |
|
|
|
if (is_in_v2_mode()) { |
|
cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask); |
|
top_cpuset.mems_allowed = node_possible_map; |
|
} else { |
|
cpumask_copy(top_cpuset.cpus_allowed, |
|
top_cpuset.effective_cpus); |
|
top_cpuset.mems_allowed = top_cpuset.effective_mems; |
|
} |
|
|
|
spin_unlock_irq(&callback_lock); |
|
percpu_up_write(&cpuset_rwsem); |
|
} |
|
|
|
/* |
|
* Make sure the new task conform to the current state of its parent, |
|
* which could have been changed by cpuset just after it inherits the |
|
* state from the parent and before it sits on the cgroup's task list. |
|
*/ |
|
static void cpuset_fork(struct task_struct *task) |
|
{ |
|
if (task_css_is_root(task, cpuset_cgrp_id)) |
|
return; |
|
|
|
set_cpus_allowed_ptr(task, current->cpus_ptr); |
|
task->mems_allowed = current->mems_allowed; |
|
} |
|
|
|
struct cgroup_subsys cpuset_cgrp_subsys = { |
|
.css_alloc = cpuset_css_alloc, |
|
.css_online = cpuset_css_online, |
|
.css_offline = cpuset_css_offline, |
|
.css_free = cpuset_css_free, |
|
.can_attach = cpuset_can_attach, |
|
.cancel_attach = cpuset_cancel_attach, |
|
.attach = cpuset_attach, |
|
.post_attach = cpuset_post_attach, |
|
.bind = cpuset_bind, |
|
.fork = cpuset_fork, |
|
.legacy_cftypes = legacy_files, |
|
.dfl_cftypes = dfl_files, |
|
.early_init = true, |
|
.threaded = true, |
|
}; |
|
|
|
/** |
|
* cpuset_init - initialize cpusets at system boot |
|
* |
|
* Description: Initialize top_cpuset |
|
**/ |
|
|
|
int __init cpuset_init(void) |
|
{ |
|
BUG_ON(percpu_init_rwsem(&cpuset_rwsem)); |
|
|
|
BUG_ON(!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL)); |
|
BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL)); |
|
BUG_ON(!zalloc_cpumask_var(&top_cpuset.subparts_cpus, GFP_KERNEL)); |
|
|
|
cpumask_setall(top_cpuset.cpus_allowed); |
|
nodes_setall(top_cpuset.mems_allowed); |
|
cpumask_setall(top_cpuset.effective_cpus); |
|
nodes_setall(top_cpuset.effective_mems); |
|
|
|
fmeter_init(&top_cpuset.fmeter); |
|
set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags); |
|
top_cpuset.relax_domain_level = -1; |
|
|
|
BUG_ON(!alloc_cpumask_var(&cpus_attach, GFP_KERNEL)); |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* If CPU and/or memory hotplug handlers, below, unplug any CPUs |
|
* or memory nodes, we need to walk over the cpuset hierarchy, |
|
* removing that CPU or node from all cpusets. If this removes the |
|
* last CPU or node from a cpuset, then move the tasks in the empty |
|
* cpuset to its next-highest non-empty parent. |
|
*/ |
|
static void remove_tasks_in_empty_cpuset(struct cpuset *cs) |
|
{ |
|
struct cpuset *parent; |
|
|
|
/* |
|
* Find its next-highest non-empty parent, (top cpuset |
|
* has online cpus, so can't be empty). |
|
*/ |
|
parent = parent_cs(cs); |
|
while (cpumask_empty(parent->cpus_allowed) || |
|
nodes_empty(parent->mems_allowed)) |
|
parent = parent_cs(parent); |
|
|
|
if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) { |
|
pr_err("cpuset: failed to transfer tasks out of empty cpuset "); |
|
pr_cont_cgroup_name(cs->css.cgroup); |
|
pr_cont("\n"); |
|
} |
|
} |
|
|
|
static void |
|
hotplug_update_tasks_legacy(struct cpuset *cs, |
|
struct cpumask *new_cpus, nodemask_t *new_mems, |
|
bool cpus_updated, bool mems_updated) |
|
{ |
|
bool is_empty; |
|
|
|
spin_lock_irq(&callback_lock); |
|
cpumask_copy(cs->cpus_allowed, new_cpus); |
|
cpumask_copy(cs->effective_cpus, new_cpus); |
|
cs->mems_allowed = *new_mems; |
|
cs->effective_mems = *new_mems; |
|
spin_unlock_irq(&callback_lock); |
|
|
|
/* |
|
* Don't call update_tasks_cpumask() if the cpuset becomes empty, |
|
* as the tasks will be migratecd to an ancestor. |
|
*/ |
|
if (cpus_updated && !cpumask_empty(cs->cpus_allowed)) |
|
update_tasks_cpumask(cs); |
|
if (mems_updated && !nodes_empty(cs->mems_allowed)) |
|
update_tasks_nodemask(cs); |
|
|
|
is_empty = cpumask_empty(cs->cpus_allowed) || |
|
nodes_empty(cs->mems_allowed); |
|
|
|
percpu_up_write(&cpuset_rwsem); |
|
|
|
/* |
|
* Move tasks to the nearest ancestor with execution resources, |
|
* This is full cgroup operation which will also call back into |
|
* cpuset. Should be done outside any lock. |
|
*/ |
|
if (is_empty) |
|
remove_tasks_in_empty_cpuset(cs); |
|
|
|
percpu_down_write(&cpuset_rwsem); |
|
} |
|
|
|
static void |
|
hotplug_update_tasks(struct cpuset *cs, |
|
struct cpumask *new_cpus, nodemask_t *new_mems, |
|
bool cpus_updated, bool mems_updated) |
|
{ |
|
if (cpumask_empty(new_cpus)) |
|
cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus); |
|
if (nodes_empty(*new_mems)) |
|
*new_mems = parent_cs(cs)->effective_mems; |
|
|
|
spin_lock_irq(&callback_lock); |
|
cpumask_copy(cs->effective_cpus, new_cpus); |
|
cs->effective_mems = *new_mems; |
|
spin_unlock_irq(&callback_lock); |
|
|
|
if (cpus_updated) |
|
update_tasks_cpumask(cs); |
|
if (mems_updated) |
|
update_tasks_nodemask(cs); |
|
} |
|
|
|
static bool force_rebuild; |
|
|
|
void cpuset_force_rebuild(void) |
|
{ |
|
force_rebuild = true; |
|
} |
|
|
|
/** |
|
* cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug |
|
* @cs: cpuset in interest |
|
* @tmp: the tmpmasks structure pointer |
|
* |
|
* Compare @cs's cpu and mem masks against top_cpuset and if some have gone |
|
* offline, update @cs accordingly. If @cs ends up with no CPU or memory, |
|
* all its tasks are moved to the nearest ancestor with both resources. |
|
*/ |
|
static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) |
|
{ |
|
static cpumask_t new_cpus; |
|
static nodemask_t new_mems; |
|
bool cpus_updated; |
|
bool mems_updated; |
|
struct cpuset *parent; |
|
retry: |
|
wait_event(cpuset_attach_wq, cs->attach_in_progress == 0); |
|
|
|
percpu_down_write(&cpuset_rwsem); |
|
|
|
/* |
|
* We have raced with task attaching. We wait until attaching |
|
* is finished, so we won't attach a task to an empty cpuset. |
|
*/ |
|
if (cs->attach_in_progress) { |
|
percpu_up_write(&cpuset_rwsem); |
|
goto retry; |
|
} |
|
|
|
parent = parent_cs(cs); |
|
compute_effective_cpumask(&new_cpus, cs, parent); |
|
nodes_and(new_mems, cs->mems_allowed, parent->effective_mems); |
|
|
|
if (cs->nr_subparts_cpus) |
|
/* |
|
* Make sure that CPUs allocated to child partitions |
|
* do not show up in effective_cpus. |
|
*/ |
|
cpumask_andnot(&new_cpus, &new_cpus, cs->subparts_cpus); |
|
|
|
if (!tmp || !cs->partition_root_state) |
|
goto update_tasks; |
|
|
|
/* |
|
* In the unlikely event that a partition root has empty |
|
* effective_cpus or its parent becomes erroneous, we have to |
|
* transition it to the erroneous state. |
|
*/ |
|
if (is_partition_root(cs) && (cpumask_empty(&new_cpus) || |
|
(parent->partition_root_state == PRS_ERROR))) { |
|
if (cs->nr_subparts_cpus) { |
|
spin_lock_irq(&callback_lock); |
|
cs->nr_subparts_cpus = 0; |
|
cpumask_clear(cs->subparts_cpus); |
|
spin_unlock_irq(&callback_lock); |
|
compute_effective_cpumask(&new_cpus, cs, parent); |
|
} |
|
|
|
/* |
|
* If the effective_cpus is empty because the child |
|
* partitions take away all the CPUs, we can keep |
|
* the current partition and let the child partitions |
|
* fight for available CPUs. |
|
*/ |
|
if ((parent->partition_root_state == PRS_ERROR) || |
|
cpumask_empty(&new_cpus)) { |
|
int old_prs; |
|
|
|
update_parent_subparts_cpumask(cs, partcmd_disable, |
|
NULL, tmp); |
|
old_prs = cs->partition_root_state; |
|
if (old_prs != PRS_ERROR) { |
|
spin_lock_irq(&callback_lock); |
|
cs->partition_root_state = PRS_ERROR; |
|
spin_unlock_irq(&callback_lock); |
|
notify_partition_change(cs, old_prs, PRS_ERROR); |
|
} |
|
} |
|
cpuset_force_rebuild(); |
|
} |
|
|
|
/* |
|
* On the other hand, an erroneous partition root may be transitioned |
|
* back to a regular one or a partition root with no CPU allocated |
|
* from the parent may change to erroneous. |
|
*/ |
|
if (is_partition_root(parent) && |
|
((cs->partition_root_state == PRS_ERROR) || |
|
!cpumask_intersects(&new_cpus, parent->subparts_cpus)) && |
|
update_parent_subparts_cpumask(cs, partcmd_update, NULL, tmp)) |
|
cpuset_force_rebuild(); |
|
|
|
update_tasks: |
|
cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus); |
|
mems_updated = !nodes_equal(new_mems, cs->effective_mems); |
|
|
|
if (mems_updated) |
|
check_insane_mems_config(&new_mems); |
|
|
|
if (is_in_v2_mode()) |
|
hotplug_update_tasks(cs, &new_cpus, &new_mems, |
|
cpus_updated, mems_updated); |
|
else |
|
hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems, |
|
cpus_updated, mems_updated); |
|
|
|
percpu_up_write(&cpuset_rwsem); |
|
} |
|
|
|
/** |
|
* cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset |
|
* |
|
* This function is called after either CPU or memory configuration has |
|
* changed and updates cpuset accordingly. The top_cpuset is always |
|
* synchronized to cpu_active_mask and N_MEMORY, which is necessary in |
|
* order to make cpusets transparent (of no affect) on systems that are |
|
* actively using CPU hotplug but making no active use of cpusets. |
|
* |
|
* Non-root cpusets are only affected by offlining. If any CPUs or memory |
|
* nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on |
|
* all descendants. |
|
* |
|
* Note that CPU offlining during suspend is ignored. We don't modify |
|
* cpusets across suspend/resume cycles at all. |
|
*/ |
|
static void cpuset_hotplug_workfn(struct work_struct *work) |
|
{ |
|
static cpumask_t new_cpus; |
|
static nodemask_t new_mems; |
|
bool cpus_updated, mems_updated; |
|
bool on_dfl = is_in_v2_mode(); |
|
struct tmpmasks tmp, *ptmp = NULL; |
|
|
|
if (on_dfl && !alloc_cpumasks(NULL, &tmp)) |
|
ptmp = &tmp; |
|
|
|
percpu_down_write(&cpuset_rwsem); |
|
|
|
/* fetch the available cpus/mems and find out which changed how */ |
|
cpumask_copy(&new_cpus, cpu_active_mask); |
|
new_mems = node_states[N_MEMORY]; |
|
|
|
/* |
|
* If subparts_cpus is populated, it is likely that the check below |
|
* will produce a false positive on cpus_updated when the cpu list |
|
* isn't changed. It is extra work, but it is better to be safe. |
|
*/ |
|
cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus); |
|
mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems); |
|
|
|
/* |
|
* In the rare case that hotplug removes all the cpus in subparts_cpus, |
|
* we assumed that cpus are updated. |
|
*/ |
|
if (!cpus_updated && top_cpuset.nr_subparts_cpus) |
|
cpus_updated = true; |
|
|
|
/* synchronize cpus_allowed to cpu_active_mask */ |
|
if (cpus_updated) { |
|
spin_lock_irq(&callback_lock); |
|
if (!on_dfl) |
|
cpumask_copy(top_cpuset.cpus_allowed, &new_cpus); |
|
/* |
|
* Make sure that CPUs allocated to child partitions |
|
* do not show up in effective_cpus. If no CPU is left, |
|
* we clear the subparts_cpus & let the child partitions |
|
* fight for the CPUs again. |
|
*/ |
|
if (top_cpuset.nr_subparts_cpus) { |
|
if (cpumask_subset(&new_cpus, |
|
top_cpuset.subparts_cpus)) { |
|
top_cpuset.nr_subparts_cpus = 0; |
|
cpumask_clear(top_cpuset.subparts_cpus); |
|
} else { |
|
cpumask_andnot(&new_cpus, &new_cpus, |
|
top_cpuset.subparts_cpus); |
|
} |
|
} |
|
cpumask_copy(top_cpuset.effective_cpus, &new_cpus); |
|
spin_unlock_irq(&callback_lock); |
|
/* we don't mess with cpumasks of tasks in top_cpuset */ |
|
} |
|
|
|
/* synchronize mems_allowed to N_MEMORY */ |
|
if (mems_updated) { |
|
spin_lock_irq(&callback_lock); |
|
if (!on_dfl) |
|
top_cpuset.mems_allowed = new_mems; |
|
top_cpuset.effective_mems = new_mems; |
|
spin_unlock_irq(&callback_lock); |
|
update_tasks_nodemask(&top_cpuset); |
|
} |
|
|
|
percpu_up_write(&cpuset_rwsem); |
|
|
|
/* if cpus or mems changed, we need to propagate to descendants */ |
|
if (cpus_updated || mems_updated) { |
|
struct cpuset *cs; |
|
struct cgroup_subsys_state *pos_css; |
|
|
|
rcu_read_lock(); |
|
cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) { |
|
if (cs == &top_cpuset || !css_tryget_online(&cs->css)) |
|
continue; |
|
rcu_read_unlock(); |
|
|
|
cpuset_hotplug_update_tasks(cs, ptmp); |
|
|
|
rcu_read_lock(); |
|
css_put(&cs->css); |
|
} |
|
rcu_read_unlock(); |
|
} |
|
|
|
/* rebuild sched domains if cpus_allowed has changed */ |
|
if (cpus_updated || force_rebuild) { |
|
force_rebuild = false; |
|
rebuild_sched_domains(); |
|
} |
|
|
|
free_cpumasks(NULL, ptmp); |
|
} |
|
|
|
void cpuset_update_active_cpus(void) |
|
{ |
|
/* |
|
* We're inside cpu hotplug critical region which usually nests |
|
* inside cgroup synchronization. Bounce actual hotplug processing |
|
* to a work item to avoid reverse locking order. |
|
*/ |
|
schedule_work(&cpuset_hotplug_work); |
|
} |
|
|
|
void cpuset_wait_for_hotplug(void) |
|
{ |
|
flush_work(&cpuset_hotplug_work); |
|
} |
|
|
|
/* |
|
* Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY]. |
|
* Call this routine anytime after node_states[N_MEMORY] changes. |
|
* See cpuset_update_active_cpus() for CPU hotplug handling. |
|
*/ |
|
static int cpuset_track_online_nodes(struct notifier_block *self, |
|
unsigned long action, void *arg) |
|
{ |
|
schedule_work(&cpuset_hotplug_work); |
|
return NOTIFY_OK; |
|
} |
|
|
|
static struct notifier_block cpuset_track_online_nodes_nb = { |
|
.notifier_call = cpuset_track_online_nodes, |
|
.priority = 10, /* ??! */ |
|
}; |
|
|
|
/** |
|
* cpuset_init_smp - initialize cpus_allowed |
|
* |
|
* Description: Finish top cpuset after cpu, node maps are initialized |
|
*/ |
|
void __init cpuset_init_smp(void) |
|
{ |
|
cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask); |
|
top_cpuset.mems_allowed = node_states[N_MEMORY]; |
|
top_cpuset.old_mems_allowed = top_cpuset.mems_allowed; |
|
|
|
cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask); |
|
top_cpuset.effective_mems = node_states[N_MEMORY]; |
|
|
|
register_hotmemory_notifier(&cpuset_track_online_nodes_nb); |
|
|
|
cpuset_migrate_mm_wq = alloc_ordered_workqueue("cpuset_migrate_mm", 0); |
|
BUG_ON(!cpuset_migrate_mm_wq); |
|
} |
|
|
|
/** |
|
* cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset. |
|
* @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed. |
|
* @pmask: pointer to struct cpumask variable to receive cpus_allowed set. |
|
* |
|
* Description: Returns the cpumask_var_t cpus_allowed of the cpuset |
|
* attached to the specified @tsk. Guaranteed to return some non-empty |
|
* subset of cpu_online_mask, even if this means going outside the |
|
* tasks cpuset. |
|
**/ |
|
|
|
void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask) |
|
{ |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&callback_lock, flags); |
|
guarantee_online_cpus(tsk, pmask); |
|
spin_unlock_irqrestore(&callback_lock, flags); |
|
} |
|
|
|
/** |
|
* cpuset_cpus_allowed_fallback - final fallback before complete catastrophe. |
|
* @tsk: pointer to task_struct with which the scheduler is struggling |
|
* |
|
* Description: In the case that the scheduler cannot find an allowed cpu in |
|
* tsk->cpus_allowed, we fall back to task_cs(tsk)->cpus_allowed. In legacy |
|
* mode however, this value is the same as task_cs(tsk)->effective_cpus, |
|
* which will not contain a sane cpumask during cases such as cpu hotplugging. |
|
* This is the absolute last resort for the scheduler and it is only used if |
|
* _every_ other avenue has been traveled. |
|
* |
|
* Returns true if the affinity of @tsk was changed, false otherwise. |
|
**/ |
|
|
|
bool cpuset_cpus_allowed_fallback(struct task_struct *tsk) |
|
{ |
|
const struct cpumask *possible_mask = task_cpu_possible_mask(tsk); |
|
const struct cpumask *cs_mask; |
|
bool changed = false; |
|
|
|
rcu_read_lock(); |
|
cs_mask = task_cs(tsk)->cpus_allowed; |
|
if (is_in_v2_mode() && cpumask_subset(cs_mask, possible_mask)) { |
|
do_set_cpus_allowed(tsk, cs_mask); |
|
changed = true; |
|
} |
|
rcu_read_unlock(); |
|
|
|
/* |
|
* We own tsk->cpus_allowed, nobody can change it under us. |
|
* |
|
* But we used cs && cs->cpus_allowed lockless and thus can |
|
* race with cgroup_attach_task() or update_cpumask() and get |
|
* the wrong tsk->cpus_allowed. However, both cases imply the |
|
* subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr() |
|
* which takes task_rq_lock(). |
|
* |
|
* If we are called after it dropped the lock we must see all |
|
* changes in tsk_cs()->cpus_allowed. Otherwise we can temporary |
|
* set any mask even if it is not right from task_cs() pov, |
|
* the pending set_cpus_allowed_ptr() will fix things. |
|
* |
|
* select_fallback_rq() will fix things ups and set cpu_possible_mask |
|
* if required. |
|
*/ |
|
return changed; |
|
} |
|
|
|
void __init cpuset_init_current_mems_allowed(void) |
|
{ |
|
nodes_setall(current->mems_allowed); |
|
} |
|
|
|
/** |
|
* cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset. |
|
* @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed. |
|
* |
|
* Description: Returns the nodemask_t mems_allowed of the cpuset |
|
* attached to the specified @tsk. Guaranteed to return some non-empty |
|
* subset of node_states[N_MEMORY], even if this means going outside the |
|
* tasks cpuset. |
|
**/ |
|
|
|
nodemask_t cpuset_mems_allowed(struct task_struct *tsk) |
|
{ |
|
nodemask_t mask; |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&callback_lock, flags); |
|
rcu_read_lock(); |
|
guarantee_online_mems(task_cs(tsk), &mask); |
|
rcu_read_unlock(); |
|
spin_unlock_irqrestore(&callback_lock, flags); |
|
|
|
return mask; |
|
} |
|
|
|
/** |
|
* cpuset_nodemask_valid_mems_allowed - check nodemask vs. current mems_allowed |
|
* @nodemask: the nodemask to be checked |
|
* |
|
* Are any of the nodes in the nodemask allowed in current->mems_allowed? |
|
*/ |
|
int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask) |
|
{ |
|
return nodes_intersects(*nodemask, current->mems_allowed); |
|
} |
|
|
|
/* |
|
* nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or |
|
* mem_hardwall ancestor to the specified cpuset. Call holding |
|
* callback_lock. If no ancestor is mem_exclusive or mem_hardwall |
|
* (an unusual configuration), then returns the root cpuset. |
|
*/ |
|
static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs) |
|
{ |
|
while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs)) |
|
cs = parent_cs(cs); |
|
return cs; |
|
} |
|
|
|
/* |
|
* __cpuset_node_allowed - Can we allocate on a memory node? |
|
* @node: is this an allowed node? |
|
* @gfp_mask: memory allocation flags |
|
* |
|
* If we're in interrupt, yes, we can always allocate. If @node is set in |
|
* current's mems_allowed, yes. If it's not a __GFP_HARDWALL request and this |
|
* node is set in the nearest hardwalled cpuset ancestor to current's cpuset, |
|
* yes. If current has access to memory reserves as an oom victim, yes. |
|
* Otherwise, no. |
|
* |
|
* GFP_USER allocations are marked with the __GFP_HARDWALL bit, |
|
* and do not allow allocations outside the current tasks cpuset |
|
* unless the task has been OOM killed. |
|
* GFP_KERNEL allocations are not so marked, so can escape to the |
|
* nearest enclosing hardwalled ancestor cpuset. |
|
* |
|
* Scanning up parent cpusets requires callback_lock. The |
|
* __alloc_pages() routine only calls here with __GFP_HARDWALL bit |
|
* _not_ set if it's a GFP_KERNEL allocation, and all nodes in the |
|
* current tasks mems_allowed came up empty on the first pass over |
|
* the zonelist. So only GFP_KERNEL allocations, if all nodes in the |
|
* cpuset are short of memory, might require taking the callback_lock. |
|
* |
|
* The first call here from mm/page_alloc:get_page_from_freelist() |
|
* has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets, |
|
* so no allocation on a node outside the cpuset is allowed (unless |
|
* in interrupt, of course). |
|
* |
|
* The second pass through get_page_from_freelist() doesn't even call |
|
* here for GFP_ATOMIC calls. For those calls, the __alloc_pages() |
|
* variable 'wait' is not set, and the bit ALLOC_CPUSET is not set |
|
* in alloc_flags. That logic and the checks below have the combined |
|
* affect that: |
|
* in_interrupt - any node ok (current task context irrelevant) |
|
* GFP_ATOMIC - any node ok |
|
* tsk_is_oom_victim - any node ok |
|
* GFP_KERNEL - any node in enclosing hardwalled cpuset ok |
|
* GFP_USER - only nodes in current tasks mems allowed ok. |
|
*/ |
|
bool __cpuset_node_allowed(int node, gfp_t gfp_mask) |
|
{ |
|
struct cpuset *cs; /* current cpuset ancestors */ |
|
bool allowed; /* is allocation in zone z allowed? */ |
|
unsigned long flags; |
|
|
|
if (in_interrupt()) |
|
return true; |
|
if (node_isset(node, current->mems_allowed)) |
|
return true; |
|
/* |
|
* Allow tasks that have access to memory reserves because they have |
|
* been OOM killed to get memory anywhere. |
|
*/ |
|
if (unlikely(tsk_is_oom_victim(current))) |
|
return true; |
|
if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */ |
|
return false; |
|
|
|
if (current->flags & PF_EXITING) /* Let dying task have memory */ |
|
return true; |
|
|
|
/* Not hardwall and node outside mems_allowed: scan up cpusets */ |
|
spin_lock_irqsave(&callback_lock, flags); |
|
|
|
rcu_read_lock(); |
|
cs = nearest_hardwall_ancestor(task_cs(current)); |
|
allowed = node_isset(node, cs->mems_allowed); |
|
rcu_read_unlock(); |
|
|
|
spin_unlock_irqrestore(&callback_lock, flags); |
|
return allowed; |
|
} |
|
|
|
/** |
|
* cpuset_mem_spread_node() - On which node to begin search for a file page |
|
* cpuset_slab_spread_node() - On which node to begin search for a slab page |
|
* |
|
* If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for |
|
* tasks in a cpuset with is_spread_page or is_spread_slab set), |
|
* and if the memory allocation used cpuset_mem_spread_node() |
|
* to determine on which node to start looking, as it will for |
|
* certain page cache or slab cache pages such as used for file |
|
* system buffers and inode caches, then instead of starting on the |
|
* local node to look for a free page, rather spread the starting |
|
* node around the tasks mems_allowed nodes. |
|
* |
|
* We don't have to worry about the returned node being offline |
|
* because "it can't happen", and even if it did, it would be ok. |
|
* |
|
* The routines calling guarantee_online_mems() are careful to |
|
* only set nodes in task->mems_allowed that are online. So it |
|
* should not be possible for the following code to return an |
|
* offline node. But if it did, that would be ok, as this routine |
|
* is not returning the node where the allocation must be, only |
|
* the node where the search should start. The zonelist passed to |
|
* __alloc_pages() will include all nodes. If the slab allocator |
|
* is passed an offline node, it will fall back to the local node. |
|
* See kmem_cache_alloc_node(). |
|
*/ |
|
|
|
static int cpuset_spread_node(int *rotor) |
|
{ |
|
return *rotor = next_node_in(*rotor, current->mems_allowed); |
|
} |
|
|
|
int cpuset_mem_spread_node(void) |
|
{ |
|
if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE) |
|
current->cpuset_mem_spread_rotor = |
|
node_random(¤t->mems_allowed); |
|
|
|
return cpuset_spread_node(¤t->cpuset_mem_spread_rotor); |
|
} |
|
|
|
int cpuset_slab_spread_node(void) |
|
{ |
|
if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE) |
|
current->cpuset_slab_spread_rotor = |
|
node_random(¤t->mems_allowed); |
|
|
|
return cpuset_spread_node(¤t->cpuset_slab_spread_rotor); |
|
} |
|
|
|
EXPORT_SYMBOL_GPL(cpuset_mem_spread_node); |
|
|
|
/** |
|
* cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's? |
|
* @tsk1: pointer to task_struct of some task. |
|
* @tsk2: pointer to task_struct of some other task. |
|
* |
|
* Description: Return true if @tsk1's mems_allowed intersects the |
|
* mems_allowed of @tsk2. Used by the OOM killer to determine if |
|
* one of the task's memory usage might impact the memory available |
|
* to the other. |
|
**/ |
|
|
|
int cpuset_mems_allowed_intersects(const struct task_struct *tsk1, |
|
const struct task_struct *tsk2) |
|
{ |
|
return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed); |
|
} |
|
|
|
/** |
|
* cpuset_print_current_mems_allowed - prints current's cpuset and mems_allowed |
|
* |
|
* Description: Prints current's name, cpuset name, and cached copy of its |
|
* mems_allowed to the kernel log. |
|
*/ |
|
void cpuset_print_current_mems_allowed(void) |
|
{ |
|
struct cgroup *cgrp; |
|
|
|
rcu_read_lock(); |
|
|
|
cgrp = task_cs(current)->css.cgroup; |
|
pr_cont(",cpuset="); |
|
pr_cont_cgroup_name(cgrp); |
|
pr_cont(",mems_allowed=%*pbl", |
|
nodemask_pr_args(¤t->mems_allowed)); |
|
|
|
rcu_read_unlock(); |
|
} |
|
|
|
/* |
|
* Collection of memory_pressure is suppressed unless |
|
* this flag is enabled by writing "1" to the special |
|
* cpuset file 'memory_pressure_enabled' in the root cpuset. |
|
*/ |
|
|
|
int cpuset_memory_pressure_enabled __read_mostly; |
|
|
|
/* |
|
* __cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims. |
|
* |
|
* Keep a running average of the rate of synchronous (direct) |
|
* page reclaim efforts initiated by tasks in each cpuset. |
|
* |
|
* This represents the rate at which some task in the cpuset |
|
* ran low on memory on all nodes it was allowed to use, and |
|
* had to enter the kernels page reclaim code in an effort to |
|
* create more free memory by tossing clean pages or swapping |
|
* or writing dirty pages. |
|
* |
|
* Display to user space in the per-cpuset read-only file |
|
* "memory_pressure". Value displayed is an integer |
|
* representing the recent rate of entry into the synchronous |
|
* (direct) page reclaim by any task attached to the cpuset. |
|
*/ |
|
|
|
void __cpuset_memory_pressure_bump(void) |
|
{ |
|
rcu_read_lock(); |
|
fmeter_markevent(&task_cs(current)->fmeter); |
|
rcu_read_unlock(); |
|
} |
|
|
|
#ifdef CONFIG_PROC_PID_CPUSET |
|
/* |
|
* proc_cpuset_show() |
|
* - Print tasks cpuset path into seq_file. |
|
* - Used for /proc/<pid>/cpuset. |
|
* - No need to task_lock(tsk) on this tsk->cpuset reference, as it |
|
* doesn't really matter if tsk->cpuset changes after we read it, |
|
* and we take cpuset_rwsem, keeping cpuset_attach() from changing it |
|
* anyway. |
|
*/ |
|
int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, |
|
struct pid *pid, struct task_struct *tsk) |
|
{ |
|
char *buf; |
|
struct cgroup_subsys_state *css; |
|
int retval; |
|
|
|
retval = -ENOMEM; |
|
buf = kmalloc(PATH_MAX, GFP_KERNEL); |
|
if (!buf) |
|
goto out; |
|
|
|
css = task_get_css(tsk, cpuset_cgrp_id); |
|
retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX, |
|
current->nsproxy->cgroup_ns); |
|
css_put(css); |
|
if (retval >= PATH_MAX) |
|
retval = -ENAMETOOLONG; |
|
if (retval < 0) |
|
goto out_free; |
|
seq_puts(m, buf); |
|
seq_putc(m, '\n'); |
|
retval = 0; |
|
out_free: |
|
kfree(buf); |
|
out: |
|
return retval; |
|
} |
|
#endif /* CONFIG_PROC_PID_CPUSET */ |
|
|
|
/* Display task mems_allowed in /proc/<pid>/status file. */ |
|
void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task) |
|
{ |
|
seq_printf(m, "Mems_allowed:\t%*pb\n", |
|
nodemask_pr_args(&task->mems_allowed)); |
|
seq_printf(m, "Mems_allowed_list:\t%*pbl\n", |
|
nodemask_pr_args(&task->mems_allowed)); |
|
}
|
|
|