This is a note to let you know that I've just added the patch titled
mm: memcg: enable memcg OOM killer only for user faults
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-memcg-enable-memcg-oom-killer-only-for-user-faults.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 519e52473ebe9db5cdef44670d5a97f1fd53d721 Mon Sep 17 00:00:00 2001
From: Johannes Weiner <[email protected]>
Date: Thu, 12 Sep 2013 15:13:42 -0700
Subject: mm: memcg: enable memcg OOM killer only for user faults
From: Johannes Weiner <[email protected]>
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 <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: azurIt <[email protected]>
Cc: KOSAKI Motohiro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Cong Wang <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
include/linux/memcontrol.h | 44 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/sched.h | 3 +++
mm/filemap.c | 11 ++++++++++-
mm/memcontrol.c | 2 +-
mm/memory.c | 40 ++++++++++++++++++++++++++++++----------
5 files changed, 88 insertions(+), 12 deletions(-)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -124,6 +124,37 @@ extern void mem_cgroup_print_oom_info(st
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
@@ -347,6 +378,19 @@ static inline void mem_cgroup_end_update
{
}
+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)
{
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1411,6 +1411,9 @@ 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_HAVE_HW_BREAKPOINT
atomic_t ptrace_bp_refcnt;
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1614,6 +1614,7 @@ int filemap_fault(struct vm_area_struct
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
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
* 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;
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2613,7 +2613,7 @@ static int mem_cgroup_do_charge(struct m
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)))
--- 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.
Patches currently in stable-queue which might be from [email protected] are
queue-3.10/arch-mm-do-not-invoke-oom-killer-on-kernel-fault-oom.patch
queue-3.10/x86-finish-user-fault-error-path-with-fatal-signal.patch
queue-3.10/mm-memcg-enable-memcg-oom-killer-only-for-user-faults.patch
queue-3.10/mm-invoke-oom-killer-from-remaining-unconverted-page-fault-handlers.patch
queue-3.10/arch-mm-remove-obsolete-init-oom-protection.patch
queue-3.10/arch-mm-pass-userspace-fault-flag-to-generic-fault-handler.patch
--
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