[patch 02/10] mm: memcontrol: rearrange charging fast path
From: Johannes Weiner <hannes@cmpxchg.org>
Date: 2014-05-29 16:16:24
Also in:
linux-mm, lkml
Subsystem:
control group - memory resource controller (memcg), memory management, the rest · Maintainers:
Johannes Weiner, Michal Hocko, Roman Gushchin, Shakeel Butt, Andrew Morton, Linus Torvalds
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@cmpxchg.org> --- mm/memcontrol.c | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c3c10ab98355..46b3e37542ad 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c@@ -2576,22 +2576,6 @@ static int mem_cgroup_try_charge(struct mem_cgroup *memcg, 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;
@@ -2613,6 +2597,20 @@ 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;
@@ -2641,6 +2639,9 @@ 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;
--
1.9.3
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