The patch titled
Subject: memcg: force charge kmem counter too
has been added to the -mm tree. Its filename is
memcg-force-charge-kmem-counter-too.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/memcg-force-charge-kmem-counter-too.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/memcg-force-charge-kmem-counter-too.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
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------------------------------------------------------
From: Shakeel Butt <shakeelb@xxxxxxxxxx>
Subject: memcg: force charge kmem counter too
Based on several conditions the kernel can decide to force charge an
allocation for a memcg i.e. overcharge memcg->memory and memcg->memsw
counters. Do the same for memcg->kmem counter too. In cgroup-v1, this
bug can cause a __GFP_NOFAIL kmem allocation fail if an explicit limit on
kmem counter is set and reached.
Link: http://lkml.kernel.org/r/20180525185501.82098-1-shakeelb@xxxxxxxxxx
Signed-off-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff -puN mm/memcontrol.c~memcg-force-charge-kmem-counter-too mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-force-charge-kmem-counter-too
+++ a/mm/memcontrol.c
@@ -1894,6 +1894,18 @@ void mem_cgroup_handle_over_high(void)
current->memcg_nr_pages_over_high = 0;
}
+/*
+ * Based on try_charge() force charge conditions.
+ */
+static inline bool should_force_charge(gfp_t gfp_mask)
+{
+ return (unlikely(tsk_is_oom_victim(current) ||
+ fatal_signal_pending(current) ||
+ current->flags & PF_EXITING ||
+ current->flags & PF_MEMALLOC ||
+ gfp_mask & __GFP_NOFAIL));
+}
+
static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
unsigned int nr_pages)
{
@@ -2009,6 +2021,8 @@ force:
* The allocation either can't fail or will lead to more memory
* being freed very soon. Allow memory usage go over the limit
* temporarily by force charging it.
+ *
+ * NOTE: Please keep the should_force_charge() conditions in sync.
*/
page_counter_charge(&memcg->memory, nr_pages);
if (do_memsw_account())
@@ -2332,8 +2346,11 @@ int memcg_kmem_charge_memcg(struct page
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
!page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) {
- cancel_charge(memcg, nr_pages);
- return -ENOMEM;
+ if (!should_force_charge(gfp)) {
+ cancel_charge(memcg, nr_pages);
+ return -ENOMEM;
+ }
+ page_counter_charge(&memcg->kmem, nr_pages);
}
page->mem_cgroup = memcg;
_
Patches currently in -mm which might be from shakeelb@xxxxxxxxxx are
mm-fix-race-between-kmem_cache-destroy-create-and-deactivate.patch
mm-fix-race-between-kmem_cache-destroy-create-and-deactivate-v2.patch
mm-memcg-remote-memcg-charging-for-kmem-allocations.patch
fs-fsnotify-account-fsnotify-metadata-to-kmemcg.patch
mm-memcontrol-drain-stocks-on-resize-limit.patch
mm-save-two-stranding-bit-in-gfp_mask.patch
memcg-force-charge-kmem-counter-too.patch
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