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381 lines
8.2 KiB
381 lines
8.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Debug controller |
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* |
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* WARNING: This controller is for cgroup core debugging only. |
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* Its interfaces are unstable and subject to changes at any time. |
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*/ |
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#include <linux/ctype.h> |
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#include <linux/mm.h> |
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#include <linux/slab.h> |
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#include "cgroup-internal.h" |
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static struct cgroup_subsys_state * |
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debug_css_alloc(struct cgroup_subsys_state *parent_css) |
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{ |
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struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL); |
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if (!css) |
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return ERR_PTR(-ENOMEM); |
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return css; |
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} |
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static void debug_css_free(struct cgroup_subsys_state *css) |
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{ |
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kfree(css); |
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} |
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/* |
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* debug_taskcount_read - return the number of tasks in a cgroup. |
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* @cgrp: the cgroup in question |
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*/ |
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static u64 debug_taskcount_read(struct cgroup_subsys_state *css, |
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struct cftype *cft) |
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{ |
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return cgroup_task_count(css->cgroup); |
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} |
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static int current_css_set_read(struct seq_file *seq, void *v) |
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{ |
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struct kernfs_open_file *of = seq->private; |
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struct css_set *cset; |
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struct cgroup_subsys *ss; |
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struct cgroup_subsys_state *css; |
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int i, refcnt; |
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if (!cgroup_kn_lock_live(of->kn, false)) |
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return -ENODEV; |
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spin_lock_irq(&css_set_lock); |
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rcu_read_lock(); |
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cset = task_css_set(current); |
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refcnt = refcount_read(&cset->refcount); |
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seq_printf(seq, "css_set %pK %d", cset, refcnt); |
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if (refcnt > cset->nr_tasks) |
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seq_printf(seq, " +%d", refcnt - cset->nr_tasks); |
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seq_puts(seq, "\n"); |
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/* |
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* Print the css'es stored in the current css_set. |
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*/ |
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for_each_subsys(ss, i) { |
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css = cset->subsys[ss->id]; |
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if (!css) |
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continue; |
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seq_printf(seq, "%2d: %-4s\t- %p[%d]\n", ss->id, ss->name, |
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css, css->id); |
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} |
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rcu_read_unlock(); |
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spin_unlock_irq(&css_set_lock); |
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cgroup_kn_unlock(of->kn); |
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return 0; |
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} |
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static u64 current_css_set_refcount_read(struct cgroup_subsys_state *css, |
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struct cftype *cft) |
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{ |
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u64 count; |
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rcu_read_lock(); |
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count = refcount_read(&task_css_set(current)->refcount); |
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rcu_read_unlock(); |
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return count; |
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} |
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static int current_css_set_cg_links_read(struct seq_file *seq, void *v) |
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{ |
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struct cgrp_cset_link *link; |
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struct css_set *cset; |
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char *name_buf; |
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name_buf = kmalloc(NAME_MAX + 1, GFP_KERNEL); |
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if (!name_buf) |
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return -ENOMEM; |
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spin_lock_irq(&css_set_lock); |
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rcu_read_lock(); |
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cset = task_css_set(current); |
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list_for_each_entry(link, &cset->cgrp_links, cgrp_link) { |
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struct cgroup *c = link->cgrp; |
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cgroup_name(c, name_buf, NAME_MAX + 1); |
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seq_printf(seq, "Root %d group %s\n", |
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c->root->hierarchy_id, name_buf); |
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} |
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rcu_read_unlock(); |
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spin_unlock_irq(&css_set_lock); |
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kfree(name_buf); |
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return 0; |
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} |
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#define MAX_TASKS_SHOWN_PER_CSS 25 |
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static int cgroup_css_links_read(struct seq_file *seq, void *v) |
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{ |
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struct cgroup_subsys_state *css = seq_css(seq); |
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struct cgrp_cset_link *link; |
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int dead_cnt = 0, extra_refs = 0, threaded_csets = 0; |
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spin_lock_irq(&css_set_lock); |
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list_for_each_entry(link, &css->cgroup->cset_links, cset_link) { |
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struct css_set *cset = link->cset; |
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struct task_struct *task; |
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int count = 0; |
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int refcnt = refcount_read(&cset->refcount); |
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/* |
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* Print out the proc_cset and threaded_cset relationship |
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* and highlight difference between refcount and task_count. |
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*/ |
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seq_printf(seq, "css_set %pK", cset); |
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if (rcu_dereference_protected(cset->dom_cset, 1) != cset) { |
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threaded_csets++; |
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seq_printf(seq, "=>%pK", cset->dom_cset); |
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} |
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if (!list_empty(&cset->threaded_csets)) { |
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struct css_set *tcset; |
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int idx = 0; |
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list_for_each_entry(tcset, &cset->threaded_csets, |
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threaded_csets_node) { |
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seq_puts(seq, idx ? "," : "<="); |
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seq_printf(seq, "%pK", tcset); |
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idx++; |
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} |
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} else { |
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seq_printf(seq, " %d", refcnt); |
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if (refcnt - cset->nr_tasks > 0) { |
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int extra = refcnt - cset->nr_tasks; |
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seq_printf(seq, " +%d", extra); |
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/* |
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* Take out the one additional reference in |
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* init_css_set. |
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*/ |
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if (cset == &init_css_set) |
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extra--; |
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extra_refs += extra; |
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} |
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} |
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seq_puts(seq, "\n"); |
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list_for_each_entry(task, &cset->tasks, cg_list) { |
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if (count++ <= MAX_TASKS_SHOWN_PER_CSS) |
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seq_printf(seq, " task %d\n", |
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task_pid_vnr(task)); |
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} |
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list_for_each_entry(task, &cset->mg_tasks, cg_list) { |
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if (count++ <= MAX_TASKS_SHOWN_PER_CSS) |
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seq_printf(seq, " task %d\n", |
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task_pid_vnr(task)); |
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} |
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/* show # of overflowed tasks */ |
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if (count > MAX_TASKS_SHOWN_PER_CSS) |
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seq_printf(seq, " ... (%d)\n", |
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count - MAX_TASKS_SHOWN_PER_CSS); |
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if (cset->dead) { |
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seq_puts(seq, " [dead]\n"); |
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dead_cnt++; |
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} |
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WARN_ON(count != cset->nr_tasks); |
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} |
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spin_unlock_irq(&css_set_lock); |
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if (!dead_cnt && !extra_refs && !threaded_csets) |
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return 0; |
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seq_puts(seq, "\n"); |
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if (threaded_csets) |
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seq_printf(seq, "threaded css_sets = %d\n", threaded_csets); |
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if (extra_refs) |
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seq_printf(seq, "extra references = %d\n", extra_refs); |
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if (dead_cnt) |
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seq_printf(seq, "dead css_sets = %d\n", dead_cnt); |
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return 0; |
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} |
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static int cgroup_subsys_states_read(struct seq_file *seq, void *v) |
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{ |
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struct kernfs_open_file *of = seq->private; |
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struct cgroup *cgrp; |
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struct cgroup_subsys *ss; |
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struct cgroup_subsys_state *css; |
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char pbuf[16]; |
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int i; |
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cgrp = cgroup_kn_lock_live(of->kn, false); |
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if (!cgrp) |
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return -ENODEV; |
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for_each_subsys(ss, i) { |
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css = rcu_dereference_check(cgrp->subsys[ss->id], true); |
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if (!css) |
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continue; |
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pbuf[0] = '\0'; |
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/* Show the parent CSS if applicable*/ |
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if (css->parent) |
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snprintf(pbuf, sizeof(pbuf) - 1, " P=%d", |
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css->parent->id); |
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seq_printf(seq, "%2d: %-4s\t- %p[%d] %d%s\n", ss->id, ss->name, |
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css, css->id, |
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atomic_read(&css->online_cnt), pbuf); |
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} |
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cgroup_kn_unlock(of->kn); |
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return 0; |
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} |
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static void cgroup_masks_read_one(struct seq_file *seq, const char *name, |
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u16 mask) |
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{ |
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struct cgroup_subsys *ss; |
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int ssid; |
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bool first = true; |
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seq_printf(seq, "%-17s: ", name); |
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for_each_subsys(ss, ssid) { |
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if (!(mask & (1 << ssid))) |
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continue; |
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if (!first) |
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seq_puts(seq, ", "); |
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seq_puts(seq, ss->name); |
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first = false; |
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} |
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seq_putc(seq, '\n'); |
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} |
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static int cgroup_masks_read(struct seq_file *seq, void *v) |
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{ |
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struct kernfs_open_file *of = seq->private; |
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struct cgroup *cgrp; |
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cgrp = cgroup_kn_lock_live(of->kn, false); |
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if (!cgrp) |
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return -ENODEV; |
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cgroup_masks_read_one(seq, "subtree_control", cgrp->subtree_control); |
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cgroup_masks_read_one(seq, "subtree_ss_mask", cgrp->subtree_ss_mask); |
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cgroup_kn_unlock(of->kn); |
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return 0; |
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} |
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static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft) |
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{ |
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return (!cgroup_is_populated(css->cgroup) && |
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!css_has_online_children(&css->cgroup->self)); |
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} |
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static struct cftype debug_legacy_files[] = { |
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{ |
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.name = "taskcount", |
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.read_u64 = debug_taskcount_read, |
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}, |
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{ |
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.name = "current_css_set", |
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.seq_show = current_css_set_read, |
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.flags = CFTYPE_ONLY_ON_ROOT, |
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}, |
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{ |
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.name = "current_css_set_refcount", |
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.read_u64 = current_css_set_refcount_read, |
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.flags = CFTYPE_ONLY_ON_ROOT, |
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}, |
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{ |
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.name = "current_css_set_cg_links", |
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.seq_show = current_css_set_cg_links_read, |
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.flags = CFTYPE_ONLY_ON_ROOT, |
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}, |
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{ |
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.name = "cgroup_css_links", |
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.seq_show = cgroup_css_links_read, |
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}, |
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{ |
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.name = "cgroup_subsys_states", |
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.seq_show = cgroup_subsys_states_read, |
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}, |
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{ |
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.name = "cgroup_masks", |
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.seq_show = cgroup_masks_read, |
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}, |
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{ |
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.name = "releasable", |
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.read_u64 = releasable_read, |
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}, |
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{ } /* terminate */ |
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}; |
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static struct cftype debug_files[] = { |
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{ |
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.name = "taskcount", |
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.read_u64 = debug_taskcount_read, |
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}, |
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{ |
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.name = "current_css_set", |
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.seq_show = current_css_set_read, |
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.flags = CFTYPE_ONLY_ON_ROOT, |
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}, |
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{ |
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.name = "current_css_set_refcount", |
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.read_u64 = current_css_set_refcount_read, |
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.flags = CFTYPE_ONLY_ON_ROOT, |
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}, |
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{ |
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.name = "current_css_set_cg_links", |
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.seq_show = current_css_set_cg_links_read, |
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.flags = CFTYPE_ONLY_ON_ROOT, |
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}, |
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{ |
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.name = "css_links", |
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.seq_show = cgroup_css_links_read, |
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}, |
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{ |
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.name = "csses", |
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.seq_show = cgroup_subsys_states_read, |
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}, |
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{ |
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.name = "masks", |
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.seq_show = cgroup_masks_read, |
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}, |
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{ } /* terminate */ |
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}; |
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struct cgroup_subsys debug_cgrp_subsys = { |
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.css_alloc = debug_css_alloc, |
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.css_free = debug_css_free, |
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.legacy_cftypes = debug_legacy_files, |
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}; |
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/* |
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* On v2, debug is an implicit controller enabled by "cgroup_debug" boot |
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* parameter. |
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*/ |
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void __init enable_debug_cgroup(void) |
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{ |
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debug_cgrp_subsys.dfl_cftypes = debug_files; |
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debug_cgrp_subsys.implicit_on_dfl = true; |
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debug_cgrp_subsys.threaded = true; |
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}
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