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authorJohannes Weiner <hannes@cmpxchg.org>2013-09-12 15:13:42 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-11-21 09:22:56 -0800
commit11f34787b50ce71f66b85ad8790beaa5eee3f897 (patch)
treeadcde8d7963d1426991067916366ae3f5ec11c8a /mm
parented368ae78e6eafc10368e97246610d676bec3060 (diff)
downloadlinux-linaro-stable-11f34787b50ce71f66b85ad8790beaa5eee3f897.tar.gz
mm: memcg: enable memcg OOM killer only for user faults
commit 519e52473ebe9db5cdef44670d5a97f1fd53d721 upstream. 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> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/filemap.c11
-rw-r--r--mm/memcontrol.c2
-rw-r--r--mm/memory.c40
3 files changed, 41 insertions, 12 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 7905fe721aa8..c466f4c449e9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -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;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f45e21ab9cea..c0607d27ce87 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2613,7 +2613,7 @@ 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)))
diff --git a/mm/memory.c b/mm/memory.c
index ebe0f285c0e7..59f450c5c0a3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3754,22 +3754,14 @@ unlock:
/*
* 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 @@ retry:
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.