The patch titled
Subject: mm: memcontrol: rearrange charging fast path
has been added to the -mm tree. Its filename is
mm-memcontrol-rearrange-charging-fast-path.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-rearrange-charging-fast-path.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-rearrange-charging-fast-path.patch
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------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: mm: memcontrol: rearrange charging fast path
The charging path currently starts out with OOM condition checks when OOM
is the rarest possible case.
Rearrange this code to run OOM/task dying checks only after trying the
percpu charge and the res_counter charge and bail out before entering
reclaim. Attempting a charge does not hurt an (oom-)killed task as much
as every charge attempt having to check OOM conditions. Also, only check
__GFP_NOFAIL when the charge would actually fail.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 33 +++++++++++++++++----------------
1 file changed, 17 insertions(+), 16 deletions(-)
diff -puN mm/memcontrol.c~mm-memcontrol-rearrange-charging-fast-path mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcontrol-rearrange-charging-fast-path
+++ a/mm/memcontrol.c
@@ -2575,22 +2575,6 @@ static int mem_cgroup_try_charge(struct
if (mem_cgroup_is_root(memcg))
goto done;
- /*
- * Unlike in global OOM situations, memcg is not in a physical
- * memory shortage. Allow dying and OOM-killed tasks to
- * bypass the last charges so that they can exit quickly and
- * free their memory.
- */
- if (unlikely(test_thread_flag(TIF_MEMDIE) ||
- fatal_signal_pending(current) ||
- current->flags & PF_EXITING))
- goto bypass;
-
- if (unlikely(task_in_memcg_oom(current)))
- goto nomem;
-
- if (gfp_mask & __GFP_NOFAIL)
- oom = false;
retry:
if (consume_stock(memcg, nr_pages))
goto done;
@@ -2612,6 +2596,20 @@ retry:
goto retry;
}
+ /*
+ * Unlike in global OOM situations, memcg is not in a physical
+ * memory shortage. Allow dying and OOM-killed tasks to
+ * bypass the last charges so that they can exit quickly and
+ * free their memory.
+ */
+ if (unlikely(test_thread_flag(TIF_MEMDIE) ||
+ fatal_signal_pending(current) ||
+ current->flags & PF_EXITING))
+ goto bypass;
+
+ if (unlikely(task_in_memcg_oom(current)))
+ goto nomem;
+
if (!(gfp_mask & __GFP_WAIT))
goto nomem;
@@ -2640,6 +2638,9 @@ retry:
if (mem_cgroup_wait_acct_move(mem_over_limit))
goto retry;
+ if (gfp_mask & __GFP_NOFAIL)
+ goto bypass;
+
if (fatal_signal_pending(current))
goto bypass;
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
vmalloc-use-rcu-list-iterator-to-reduce-vmap_area_lock-contention.patch
memcg-cleanup-memcg_cache_params-refcnt-usage.patch
memcg-destroy-kmem-caches-when-last-slab-is-freed.patch
memcg-mark-caches-that-belong-to-offline-memcgs-as-dead.patch
slub-dont-fail-kmem_cache_shrink-if-slab-placement-optimization-fails.patch
slub-make-slab_free-non-preemptable.patch
memcg-wait-for-kfrees-to-finish-before-destroying-cache.patch
slub-make-dead-memcg-caches-discard-free-slabs-immediately.patch
slab-do-not-keep-free-objects-slabs-on-dead-memcg-caches.patch
mm-memcontrol-fold-mem_cgroup_do_charge.patch
mm-memcontrol-rearrange-charging-fast-path.patch
mm-memcontrol-reclaim-at-least-once-for-__gfp_noretry.patch
mm-huge_memory-use-gfp_transhuge-when-charging-huge-pages.patch
mm-memcontrol-retry-reclaim-for-oom-disabled-and-__gfp_nofail-charges.patch
mm-memcontrol-remove-explicit-oom-parameter-in-charge-path.patch
mm-memcontrol-simplify-move-precharge-function.patch
mm-memcontrol-catch-root-bypass-in-move-precharge.patch
mm-memcontrol-use-root_mem_cgroup-res_counter.patch
mm-memcontrol-remove-ordering-between-pc-mem_cgroup-and-pagecgroupused.patch
mm-memcontrol-do-not-acquire-page_cgroup-lock-for-kmem-pages.patch
mm-memcontrol-rewrite-charge-api.patch
mm-memcontrol-rewrite-uncharge-api.patch
memcg-deprecate-memoryforce_empty-knob.patch
memcg-deprecate-memoryforce_empty-knob-fix.patch
debugging-keep-track-of-page-owners.patch
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