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mm: memcg: enable memcg OOM killer only for user faults

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System calls and kernel faults (uaccess, gup) can handle an out of memory
situation gracefully and just return -ENOMEM.

Enable the memcg OOM killer only for user faults, where it's really the
only option available.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: azurIt <azurit@pobox.sk>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Weiner 2013-09-12 15:13:42 -07:00 committed by Linus Torvalds
parent 3a13c4d761
commit 519e52473e
5 changed files with 88 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

44
include/linux/memcontrol.h
View file

@ -151,6 +151,37 @@ extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
extern void mem_cgroup_replace_page_cache(struct page *oldpage,
struct page *newpage);
/**
* mem_cgroup_toggle_oom - toggle the memcg OOM killer for the current task
* @new: true to enable, false to disable
*
* Toggle whether a failed memcg charge should invoke the OOM killer
* or just return -ENOMEM. Returns the previous toggle state.
*/
static inline bool mem_cgroup_toggle_oom(bool new)
{
bool old;
old = current->memcg_oom.may_oom;
current->memcg_oom.may_oom = new;
return old;
}
static inline void mem_cgroup_enable_oom(void)
{
bool old = mem_cgroup_toggle_oom(true);
WARN_ON(old == true);
}
static inline void mem_cgroup_disable_oom(void)
{
bool old = mem_cgroup_toggle_oom(false);
WARN_ON(old == false);
}
#ifdef CONFIG_MEMCG_SWAP
extern int do_swap_account;
#endif
@ -383,6 +414,19 @@ static inline void mem_cgroup_end_update_page_stat(struct page *page,
{
}
static inline bool mem_cgroup_toggle_oom(bool new)
{
return false;
}
static inline void mem_cgroup_enable_oom(void)
{
}
static inline void mem_cgroup_disable_oom(void)
{
}
static inline void mem_cgroup_inc_page_stat(struct page *page,
enum mem_cgroup_page_stat_item idx)
{

3
include/linux/sched.h
View file

@ -1393,6 +1393,9 @@ struct task_struct {
unsigned long memsw_nr_pages; /* uncharged mem+swap usage */
} memcg_batch;
unsigned int memcg_kmem_skip_account;
struct memcg_oom_info {
unsigned int may_oom:1;
} memcg_oom;
#endif
#ifdef CONFIG_UPROBES
struct uprobe_task *utask;

11
mm/filemap.c
View file

@ -1614,6 +1614,7 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
struct inode *inode = mapping->host;
pgoff_t offset = vmf->pgoff;
struct page *page;
bool memcg_oom;
pgoff_t size;
int ret = 0;
@ -1622,7 +1623,11 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
return VM_FAULT_SIGBUS;
/*
* Do we have something in the page cache already?
* Do we have something in the page cache already? Either
* way, try readahead, but disable the memcg OOM killer for it
* as readahead is optional and no errors are propagated up
* the fault stack. The OOM killer is enabled while trying to
* instantiate the faulting page individually below.
*/
page = find_get_page(mapping, offset);
if (likely(page) && !(vmf->flags & FAULT_FLAG_TRIED)) {
@ -1630,10 +1635,14 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
* We found the page, so try async readahead before
* waiting for the lock.
*/
memcg_oom = mem_cgroup_toggle_oom(false);
do_async_mmap_readahead(vma, ra, file, page, offset);
mem_cgroup_toggle_oom(memcg_oom);
} else if (!page) {
/* No page in the page cache at all */
memcg_oom = mem_cgroup_toggle_oom(false);
do_sync_mmap_readahead(vma, ra, file, offset);
mem_cgroup_toggle_oom(memcg_oom);
count_vm_event(PGMAJFAULT);
mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
ret = VM_FAULT_MAJOR;

2
mm/memcontrol.c
View file

@ -2454,7 +2454,7 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
return CHARGE_RETRY;
/* If we don't need to call oom-killer at el, return immediately */
if (!oom_check)
if (!oom_check || !current->memcg_oom.may_oom)
return CHARGE_NOMEM;
/* check OOM */
if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask, get_order(csize)))

40
mm/memory.c
View file

@ -3754,22 +3754,14 @@ int handle_pte_fault(struct mm_struct *mm,
/*
* By the time we get here, we already hold the mm semaphore
*/
int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, unsigned int flags)
static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, unsigned int flags)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
__set_current_state(TASK_RUNNING);
count_vm_event(PGFAULT);
mem_cgroup_count_vm_event(mm, PGFAULT);
/* do counter updates before entering really critical section. */
check_sync_rss_stat(current);
if (unlikely(is_vm_hugetlb_page(vma)))
return hugetlb_fault(mm, vma, address, flags);
@ -3850,6 +3842,34 @@ int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
return handle_pte_fault(mm, vma, address, pte, pmd, flags);
}
int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, unsigned int flags)
{
int ret;
__set_current_state(TASK_RUNNING);
count_vm_event(PGFAULT);
mem_cgroup_count_vm_event(mm, PGFAULT);
/* do counter updates before entering really critical section. */
check_sync_rss_stat(current);
/*
* Enable the memcg OOM handling for faults triggered in user
* space. Kernel faults are handled more gracefully.
*/
if (flags & FAULT_FLAG_USER)
mem_cgroup_enable_oom();
ret = __handle_mm_fault(mm, vma, address, flags);
if (flags & FAULT_FLAG_USER)
mem_cgroup_disable_oom();
return ret;
}
#ifndef __PAGETABLE_PUD_FOLDED
/*
* Allocate page upper directory.