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719 lines
17 KiB
719 lines
17 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Collaborative memory management interface. |
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* |
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* Copyright (C) 2008 IBM Corporation |
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* Author(s): Brian King ([email protected]), |
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*/ |
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|
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#include <linux/ctype.h> |
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#include <linux/delay.h> |
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#include <linux/errno.h> |
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#include <linux/fs.h> |
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#include <linux/gfp.h> |
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#include <linux/kthread.h> |
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#include <linux/module.h> |
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#include <linux/oom.h> |
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#include <linux/reboot.h> |
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#include <linux/sched.h> |
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#include <linux/stringify.h> |
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#include <linux/swap.h> |
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#include <linux/device.h> |
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#include <linux/mount.h> |
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#include <linux/pseudo_fs.h> |
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#include <linux/magic.h> |
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#include <linux/balloon_compaction.h> |
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#include <asm/firmware.h> |
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#include <asm/hvcall.h> |
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#include <asm/mmu.h> |
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#include <linux/uaccess.h> |
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#include <linux/memory.h> |
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#include <asm/plpar_wrappers.h> |
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|
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#include "pseries.h" |
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|
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#define CMM_DRIVER_VERSION "1.0.0" |
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#define CMM_DEFAULT_DELAY 1 |
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#define CMM_HOTPLUG_DELAY 5 |
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#define CMM_DEBUG 0 |
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#define CMM_DISABLE 0 |
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#define CMM_OOM_KB 1024 |
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#define CMM_MIN_MEM_MB 256 |
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#define KB2PAGES(_p) ((_p)>>(PAGE_SHIFT-10)) |
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#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10)) |
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|
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#define CMM_MEM_HOTPLUG_PRI 1 |
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|
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static unsigned int delay = CMM_DEFAULT_DELAY; |
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static unsigned int hotplug_delay = CMM_HOTPLUG_DELAY; |
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static unsigned int oom_kb = CMM_OOM_KB; |
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static unsigned int cmm_debug = CMM_DEBUG; |
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static unsigned int cmm_disabled = CMM_DISABLE; |
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static unsigned long min_mem_mb = CMM_MIN_MEM_MB; |
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static bool __read_mostly simulate; |
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static unsigned long simulate_loan_target_kb; |
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static struct device cmm_dev; |
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|
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MODULE_AUTHOR("Brian King <[email protected]>"); |
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MODULE_DESCRIPTION("IBM System p Collaborative Memory Manager"); |
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MODULE_LICENSE("GPL"); |
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MODULE_VERSION(CMM_DRIVER_VERSION); |
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|
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module_param_named(delay, delay, uint, 0644); |
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MODULE_PARM_DESC(delay, "Delay (in seconds) between polls to query hypervisor paging requests. " |
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"[Default=" __stringify(CMM_DEFAULT_DELAY) "]"); |
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module_param_named(hotplug_delay, hotplug_delay, uint, 0644); |
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MODULE_PARM_DESC(hotplug_delay, "Delay (in seconds) after memory hotplug remove " |
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"before loaning resumes. " |
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"[Default=" __stringify(CMM_HOTPLUG_DELAY) "]"); |
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module_param_named(oom_kb, oom_kb, uint, 0644); |
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MODULE_PARM_DESC(oom_kb, "Amount of memory in kb to free on OOM. " |
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"[Default=" __stringify(CMM_OOM_KB) "]"); |
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module_param_named(min_mem_mb, min_mem_mb, ulong, 0644); |
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MODULE_PARM_DESC(min_mem_mb, "Minimum amount of memory (in MB) to not balloon. " |
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"[Default=" __stringify(CMM_MIN_MEM_MB) "]"); |
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module_param_named(debug, cmm_debug, uint, 0644); |
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MODULE_PARM_DESC(debug, "Enable module debugging logging. Set to 1 to enable. " |
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"[Default=" __stringify(CMM_DEBUG) "]"); |
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module_param_named(simulate, simulate, bool, 0444); |
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MODULE_PARM_DESC(simulate, "Enable simulation mode (no communication with hw)."); |
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|
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#define cmm_dbg(...) if (cmm_debug) { printk(KERN_INFO "cmm: "__VA_ARGS__); } |
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|
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static atomic_long_t loaned_pages; |
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static unsigned long loaned_pages_target; |
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static unsigned long oom_freed_pages; |
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|
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static DEFINE_MUTEX(hotplug_mutex); |
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static int hotplug_occurred; /* protected by the hotplug mutex */ |
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|
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static struct task_struct *cmm_thread_ptr; |
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static struct balloon_dev_info b_dev_info; |
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|
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static long plpar_page_set_loaned(struct page *page) |
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{ |
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const unsigned long vpa = page_to_phys(page); |
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unsigned long cmo_page_sz = cmo_get_page_size(); |
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long rc = 0; |
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int i; |
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|
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if (unlikely(simulate)) |
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return 0; |
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|
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for (i = 0; !rc && i < PAGE_SIZE; i += cmo_page_sz) |
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rc = plpar_hcall_norets(H_PAGE_INIT, H_PAGE_SET_LOANED, vpa + i, 0); |
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|
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for (i -= cmo_page_sz; rc && i != 0; i -= cmo_page_sz) |
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plpar_hcall_norets(H_PAGE_INIT, H_PAGE_SET_ACTIVE, |
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vpa + i - cmo_page_sz, 0); |
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|
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return rc; |
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} |
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|
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static long plpar_page_set_active(struct page *page) |
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{ |
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const unsigned long vpa = page_to_phys(page); |
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unsigned long cmo_page_sz = cmo_get_page_size(); |
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long rc = 0; |
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int i; |
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|
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if (unlikely(simulate)) |
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return 0; |
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for (i = 0; !rc && i < PAGE_SIZE; i += cmo_page_sz) |
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rc = plpar_hcall_norets(H_PAGE_INIT, H_PAGE_SET_ACTIVE, vpa + i, 0); |
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|
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for (i -= cmo_page_sz; rc && i != 0; i -= cmo_page_sz) |
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plpar_hcall_norets(H_PAGE_INIT, H_PAGE_SET_LOANED, |
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vpa + i - cmo_page_sz, 0); |
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|
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return rc; |
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} |
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|
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/** |
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* cmm_alloc_pages - Allocate pages and mark them as loaned |
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* @nr: number of pages to allocate |
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* |
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* Return value: |
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* number of pages requested to be allocated which were not |
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**/ |
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static long cmm_alloc_pages(long nr) |
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{ |
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struct page *page; |
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long rc; |
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|
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cmm_dbg("Begin request for %ld pages\n", nr); |
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|
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while (nr) { |
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/* Exit if a hotplug operation is in progress or occurred */ |
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if (mutex_trylock(&hotplug_mutex)) { |
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if (hotplug_occurred) { |
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mutex_unlock(&hotplug_mutex); |
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break; |
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} |
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mutex_unlock(&hotplug_mutex); |
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} else { |
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break; |
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} |
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|
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page = balloon_page_alloc(); |
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if (!page) |
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break; |
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rc = plpar_page_set_loaned(page); |
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if (rc) { |
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pr_err("%s: Can not set page to loaned. rc=%ld\n", __func__, rc); |
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__free_page(page); |
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break; |
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} |
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|
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balloon_page_enqueue(&b_dev_info, page); |
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atomic_long_inc(&loaned_pages); |
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adjust_managed_page_count(page, -1); |
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nr--; |
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} |
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|
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cmm_dbg("End request with %ld pages unfulfilled\n", nr); |
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return nr; |
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} |
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|
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/** |
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* cmm_free_pages - Free pages and mark them as active |
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* @nr: number of pages to free |
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* |
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* Return value: |
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* number of pages requested to be freed which were not |
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**/ |
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static long cmm_free_pages(long nr) |
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{ |
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struct page *page; |
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|
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cmm_dbg("Begin free of %ld pages.\n", nr); |
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while (nr) { |
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page = balloon_page_dequeue(&b_dev_info); |
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if (!page) |
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break; |
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plpar_page_set_active(page); |
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adjust_managed_page_count(page, 1); |
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__free_page(page); |
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atomic_long_dec(&loaned_pages); |
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nr--; |
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} |
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cmm_dbg("End request with %ld pages unfulfilled\n", nr); |
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return nr; |
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} |
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|
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/** |
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* cmm_oom_notify - OOM notifier |
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* @self: notifier block struct |
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* @dummy: not used |
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* @parm: returned - number of pages freed |
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* |
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* Return value: |
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* NOTIFY_OK |
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**/ |
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static int cmm_oom_notify(struct notifier_block *self, |
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unsigned long dummy, void *parm) |
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{ |
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unsigned long *freed = parm; |
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long nr = KB2PAGES(oom_kb); |
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|
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cmm_dbg("OOM processing started\n"); |
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nr = cmm_free_pages(nr); |
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loaned_pages_target = atomic_long_read(&loaned_pages); |
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*freed += KB2PAGES(oom_kb) - nr; |
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oom_freed_pages += KB2PAGES(oom_kb) - nr; |
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cmm_dbg("OOM processing complete\n"); |
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return NOTIFY_OK; |
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} |
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|
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/** |
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* cmm_get_mpp - Read memory performance parameters |
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* |
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* Makes hcall to query the current page loan request from the hypervisor. |
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* |
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* Return value: |
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* nothing |
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**/ |
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static void cmm_get_mpp(void) |
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{ |
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const long __loaned_pages = atomic_long_read(&loaned_pages); |
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const long total_pages = totalram_pages() + __loaned_pages; |
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int rc; |
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struct hvcall_mpp_data mpp_data; |
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signed long active_pages_target, page_loan_request, target; |
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signed long min_mem_pages = (min_mem_mb * 1024 * 1024) / PAGE_SIZE; |
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|
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if (likely(!simulate)) { |
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rc = h_get_mpp(&mpp_data); |
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if (rc != H_SUCCESS) |
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return; |
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page_loan_request = div_s64((s64)mpp_data.loan_request, |
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PAGE_SIZE); |
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target = page_loan_request + __loaned_pages; |
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} else { |
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target = KB2PAGES(simulate_loan_target_kb); |
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page_loan_request = target - __loaned_pages; |
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} |
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if (target < 0 || total_pages < min_mem_pages) |
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target = 0; |
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if (target > oom_freed_pages) |
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target -= oom_freed_pages; |
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else |
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target = 0; |
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active_pages_target = total_pages - target; |
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|
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if (min_mem_pages > active_pages_target) |
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target = total_pages - min_mem_pages; |
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if (target < 0) |
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target = 0; |
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loaned_pages_target = target; |
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cmm_dbg("delta = %ld, loaned = %lu, target = %lu, oom = %lu, totalram = %lu\n", |
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page_loan_request, __loaned_pages, loaned_pages_target, |
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oom_freed_pages, totalram_pages()); |
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} |
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static struct notifier_block cmm_oom_nb = { |
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.notifier_call = cmm_oom_notify |
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}; |
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/** |
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* cmm_thread - CMM task thread |
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* @dummy: not used |
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* |
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* Return value: |
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* 0 |
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**/ |
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static int cmm_thread(void *dummy) |
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{ |
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unsigned long timeleft; |
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long __loaned_pages; |
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|
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while (1) { |
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timeleft = msleep_interruptible(delay * 1000); |
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|
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if (kthread_should_stop() || timeleft) |
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break; |
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if (mutex_trylock(&hotplug_mutex)) { |
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if (hotplug_occurred) { |
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hotplug_occurred = 0; |
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mutex_unlock(&hotplug_mutex); |
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cmm_dbg("Hotplug operation has occurred, " |
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"loaning activity suspended " |
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"for %d seconds.\n", |
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hotplug_delay); |
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timeleft = msleep_interruptible(hotplug_delay * |
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1000); |
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if (kthread_should_stop() || timeleft) |
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break; |
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continue; |
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} |
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mutex_unlock(&hotplug_mutex); |
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} else { |
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cmm_dbg("Hotplug operation in progress, activity " |
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"suspended\n"); |
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continue; |
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} |
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cmm_get_mpp(); |
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__loaned_pages = atomic_long_read(&loaned_pages); |
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if (loaned_pages_target > __loaned_pages) { |
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if (cmm_alloc_pages(loaned_pages_target - __loaned_pages)) |
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loaned_pages_target = __loaned_pages; |
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} else if (loaned_pages_target < __loaned_pages) |
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cmm_free_pages(__loaned_pages - loaned_pages_target); |
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} |
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return 0; |
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} |
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|
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#define CMM_SHOW(name, format, args...) \ |
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static ssize_t show_##name(struct device *dev, \ |
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struct device_attribute *attr, \ |
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char *buf) \ |
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{ \ |
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return sprintf(buf, format, ##args); \ |
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} \ |
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static DEVICE_ATTR(name, 0444, show_##name, NULL) |
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|
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CMM_SHOW(loaned_kb, "%lu\n", PAGES2KB(atomic_long_read(&loaned_pages))); |
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CMM_SHOW(loaned_target_kb, "%lu\n", PAGES2KB(loaned_pages_target)); |
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|
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static ssize_t show_oom_pages(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return sprintf(buf, "%lu\n", PAGES2KB(oom_freed_pages)); |
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} |
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|
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static ssize_t store_oom_pages(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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unsigned long val = simple_strtoul (buf, NULL, 10); |
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|
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if (!capable(CAP_SYS_ADMIN)) |
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return -EPERM; |
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if (val != 0) |
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return -EBADMSG; |
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|
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oom_freed_pages = 0; |
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return count; |
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} |
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|
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static DEVICE_ATTR(oom_freed_kb, 0644, |
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show_oom_pages, store_oom_pages); |
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|
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static struct device_attribute *cmm_attrs[] = { |
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&dev_attr_loaned_kb, |
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&dev_attr_loaned_target_kb, |
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&dev_attr_oom_freed_kb, |
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}; |
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|
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static DEVICE_ULONG_ATTR(simulate_loan_target_kb, 0644, |
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simulate_loan_target_kb); |
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|
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static struct bus_type cmm_subsys = { |
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.name = "cmm", |
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.dev_name = "cmm", |
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}; |
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|
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static void cmm_release_device(struct device *dev) |
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{ |
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} |
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|
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/** |
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* cmm_sysfs_register - Register with sysfs |
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* |
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* Return value: |
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* 0 on success / other on failure |
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**/ |
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static int cmm_sysfs_register(struct device *dev) |
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{ |
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int i, rc; |
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|
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if ((rc = subsys_system_register(&cmm_subsys, NULL))) |
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return rc; |
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|
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dev->id = 0; |
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dev->bus = &cmm_subsys; |
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dev->release = cmm_release_device; |
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|
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if ((rc = device_register(dev))) |
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goto subsys_unregister; |
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for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) { |
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if ((rc = device_create_file(dev, cmm_attrs[i]))) |
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goto fail; |
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} |
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if (!simulate) |
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return 0; |
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rc = device_create_file(dev, &dev_attr_simulate_loan_target_kb.attr); |
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if (rc) |
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goto fail; |
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return 0; |
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|
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fail: |
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while (--i >= 0) |
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device_remove_file(dev, cmm_attrs[i]); |
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device_unregister(dev); |
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subsys_unregister: |
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bus_unregister(&cmm_subsys); |
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return rc; |
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} |
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|
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/** |
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* cmm_unregister_sysfs - Unregister from sysfs |
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* |
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**/ |
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static void cmm_unregister_sysfs(struct device *dev) |
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{ |
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int i; |
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|
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for (i = 0; i < ARRAY_SIZE(cmm_attrs); i++) |
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device_remove_file(dev, cmm_attrs[i]); |
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device_unregister(dev); |
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bus_unregister(&cmm_subsys); |
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} |
|
|
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/** |
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* cmm_reboot_notifier - Make sure pages are not still marked as "loaned" |
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* |
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**/ |
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static int cmm_reboot_notifier(struct notifier_block *nb, |
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unsigned long action, void *unused) |
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{ |
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if (action == SYS_RESTART) { |
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if (cmm_thread_ptr) |
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kthread_stop(cmm_thread_ptr); |
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cmm_thread_ptr = NULL; |
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cmm_free_pages(atomic_long_read(&loaned_pages)); |
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} |
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return NOTIFY_DONE; |
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} |
|
|
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static struct notifier_block cmm_reboot_nb = { |
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.notifier_call = cmm_reboot_notifier, |
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}; |
|
|
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/** |
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* cmm_memory_cb - Handle memory hotplug notifier calls |
|
* @self: notifier block struct |
|
* @action: action to take |
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* @arg: struct memory_notify data for handler |
|
* |
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* Return value: |
|
* NOTIFY_OK or notifier error based on subfunction return value |
|
* |
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**/ |
|
static int cmm_memory_cb(struct notifier_block *self, |
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unsigned long action, void *arg) |
|
{ |
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int ret = 0; |
|
|
|
switch (action) { |
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case MEM_GOING_OFFLINE: |
|
mutex_lock(&hotplug_mutex); |
|
hotplug_occurred = 1; |
|
break; |
|
case MEM_OFFLINE: |
|
case MEM_CANCEL_OFFLINE: |
|
mutex_unlock(&hotplug_mutex); |
|
cmm_dbg("Memory offline operation complete.\n"); |
|
break; |
|
case MEM_GOING_ONLINE: |
|
case MEM_ONLINE: |
|
case MEM_CANCEL_ONLINE: |
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break; |
|
} |
|
|
|
return notifier_from_errno(ret); |
|
} |
|
|
|
static struct notifier_block cmm_mem_nb = { |
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.notifier_call = cmm_memory_cb, |
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.priority = CMM_MEM_HOTPLUG_PRI |
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}; |
|
|
|
#ifdef CONFIG_BALLOON_COMPACTION |
|
static struct vfsmount *balloon_mnt; |
|
|
|
static int cmm_init_fs_context(struct fs_context *fc) |
|
{ |
|
return init_pseudo(fc, PPC_CMM_MAGIC) ? 0 : -ENOMEM; |
|
} |
|
|
|
static struct file_system_type balloon_fs = { |
|
.name = "ppc-cmm", |
|
.init_fs_context = cmm_init_fs_context, |
|
.kill_sb = kill_anon_super, |
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}; |
|
|
|
static int cmm_migratepage(struct balloon_dev_info *b_dev_info, |
|
struct page *newpage, struct page *page, |
|
enum migrate_mode mode) |
|
{ |
|
unsigned long flags; |
|
|
|
/* |
|
* loan/"inflate" the newpage first. |
|
* |
|
* We might race against the cmm_thread who might discover after our |
|
* loan request that another page is to be unloaned. However, once |
|
* the cmm_thread runs again later, this error will automatically |
|
* be corrected. |
|
*/ |
|
if (plpar_page_set_loaned(newpage)) { |
|
/* Unlikely, but possible. Tell the caller not to retry now. */ |
|
pr_err_ratelimited("%s: Cannot set page to loaned.", __func__); |
|
return -EBUSY; |
|
} |
|
|
|
/* balloon page list reference */ |
|
get_page(newpage); |
|
|
|
/* |
|
* When we migrate a page to a different zone, we have to fixup the |
|
* count of both involved zones as we adjusted the managed page count |
|
* when inflating. |
|
*/ |
|
if (page_zone(page) != page_zone(newpage)) { |
|
adjust_managed_page_count(page, 1); |
|
adjust_managed_page_count(newpage, -1); |
|
} |
|
|
|
spin_lock_irqsave(&b_dev_info->pages_lock, flags); |
|
balloon_page_insert(b_dev_info, newpage); |
|
balloon_page_delete(page); |
|
b_dev_info->isolated_pages--; |
|
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags); |
|
|
|
/* |
|
* activate/"deflate" the old page. We ignore any errors just like the |
|
* other callers. |
|
*/ |
|
plpar_page_set_active(page); |
|
|
|
/* balloon page list reference */ |
|
put_page(page); |
|
|
|
return MIGRATEPAGE_SUCCESS; |
|
} |
|
|
|
static int cmm_balloon_compaction_init(void) |
|
{ |
|
int rc; |
|
|
|
balloon_devinfo_init(&b_dev_info); |
|
b_dev_info.migratepage = cmm_migratepage; |
|
|
|
balloon_mnt = kern_mount(&balloon_fs); |
|
if (IS_ERR(balloon_mnt)) { |
|
rc = PTR_ERR(balloon_mnt); |
|
balloon_mnt = NULL; |
|
return rc; |
|
} |
|
|
|
b_dev_info.inode = alloc_anon_inode(balloon_mnt->mnt_sb); |
|
if (IS_ERR(b_dev_info.inode)) { |
|
rc = PTR_ERR(b_dev_info.inode); |
|
b_dev_info.inode = NULL; |
|
kern_unmount(balloon_mnt); |
|
balloon_mnt = NULL; |
|
return rc; |
|
} |
|
|
|
b_dev_info.inode->i_mapping->a_ops = &balloon_aops; |
|
return 0; |
|
} |
|
static void cmm_balloon_compaction_deinit(void) |
|
{ |
|
if (b_dev_info.inode) |
|
iput(b_dev_info.inode); |
|
b_dev_info.inode = NULL; |
|
kern_unmount(balloon_mnt); |
|
balloon_mnt = NULL; |
|
} |
|
#else /* CONFIG_BALLOON_COMPACTION */ |
|
static int cmm_balloon_compaction_init(void) |
|
{ |
|
return 0; |
|
} |
|
|
|
static void cmm_balloon_compaction_deinit(void) |
|
{ |
|
} |
|
#endif /* CONFIG_BALLOON_COMPACTION */ |
|
|
|
/** |
|
* cmm_init - Module initialization |
|
* |
|
* Return value: |
|
* 0 on success / other on failure |
|
**/ |
|
static int cmm_init(void) |
|
{ |
|
int rc; |
|
|
|
if (!firmware_has_feature(FW_FEATURE_CMO) && !simulate) |
|
return -EOPNOTSUPP; |
|
|
|
rc = cmm_balloon_compaction_init(); |
|
if (rc) |
|
return rc; |
|
|
|
rc = register_oom_notifier(&cmm_oom_nb); |
|
if (rc < 0) |
|
goto out_balloon_compaction; |
|
|
|
if ((rc = register_reboot_notifier(&cmm_reboot_nb))) |
|
goto out_oom_notifier; |
|
|
|
if ((rc = cmm_sysfs_register(&cmm_dev))) |
|
goto out_reboot_notifier; |
|
|
|
rc = register_memory_notifier(&cmm_mem_nb); |
|
if (rc) |
|
goto out_unregister_notifier; |
|
|
|
if (cmm_disabled) |
|
return 0; |
|
|
|
cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread"); |
|
if (IS_ERR(cmm_thread_ptr)) { |
|
rc = PTR_ERR(cmm_thread_ptr); |
|
goto out_unregister_notifier; |
|
} |
|
|
|
return 0; |
|
out_unregister_notifier: |
|
unregister_memory_notifier(&cmm_mem_nb); |
|
cmm_unregister_sysfs(&cmm_dev); |
|
out_reboot_notifier: |
|
unregister_reboot_notifier(&cmm_reboot_nb); |
|
out_oom_notifier: |
|
unregister_oom_notifier(&cmm_oom_nb); |
|
out_balloon_compaction: |
|
cmm_balloon_compaction_deinit(); |
|
return rc; |
|
} |
|
|
|
/** |
|
* cmm_exit - Module exit |
|
* |
|
* Return value: |
|
* nothing |
|
**/ |
|
static void cmm_exit(void) |
|
{ |
|
if (cmm_thread_ptr) |
|
kthread_stop(cmm_thread_ptr); |
|
unregister_oom_notifier(&cmm_oom_nb); |
|
unregister_reboot_notifier(&cmm_reboot_nb); |
|
unregister_memory_notifier(&cmm_mem_nb); |
|
cmm_free_pages(atomic_long_read(&loaned_pages)); |
|
cmm_unregister_sysfs(&cmm_dev); |
|
cmm_balloon_compaction_deinit(); |
|
} |
|
|
|
/** |
|
* cmm_set_disable - Disable/Enable CMM |
|
* |
|
* Return value: |
|
* 0 on success / other on failure |
|
**/ |
|
static int cmm_set_disable(const char *val, const struct kernel_param *kp) |
|
{ |
|
int disable = simple_strtoul(val, NULL, 10); |
|
|
|
if (disable != 0 && disable != 1) |
|
return -EINVAL; |
|
|
|
if (disable && !cmm_disabled) { |
|
if (cmm_thread_ptr) |
|
kthread_stop(cmm_thread_ptr); |
|
cmm_thread_ptr = NULL; |
|
cmm_free_pages(atomic_long_read(&loaned_pages)); |
|
} else if (!disable && cmm_disabled) { |
|
cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread"); |
|
if (IS_ERR(cmm_thread_ptr)) |
|
return PTR_ERR(cmm_thread_ptr); |
|
} |
|
|
|
cmm_disabled = disable; |
|
return 0; |
|
} |
|
|
|
module_param_call(disable, cmm_set_disable, param_get_uint, |
|
&cmm_disabled, 0644); |
|
MODULE_PARM_DESC(disable, "Disable CMM. Set to 1 to disable. " |
|
"[Default=" __stringify(CMM_DISABLE) "]"); |
|
|
|
module_init(cmm_init); |
|
module_exit(cmm_exit);
|
|
|