[PATCH] mm/memcg: add MAX_CHARGE_BATCH to limit unnecessary charge overhead
From: Wanpeng Li <hidden>
Date: 2012-06-24 02:16:57
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
From: Wanpeng Li <redacted> Since exceeded unused cached charges would add pressure to mem_cgroup_do_charge, more overhead would burn cpu cycles when mem_cgroup_do_charge cause page reclaim or even OOM be triggered just for such exceeded unused cached charges. Add MAX_CHARGE_BATCH to limit max cached charges. Signed-off-by: Wanpeng Li <redacted> --- mm/memcontrol.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0e092eb..1ff317a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c@@ -1954,6 +1954,14 @@ void mem_cgroup_update_page_stat(struct page *page, * TODO: maybe necessary to use big numbers in big irons. */ #define CHARGE_BATCH 32U + +/* + * Max size of charge stock. Since exceeded unused cached charges would + * add pressure to mem_cgroup_do_charge which will cause page reclaim or + * even oom be triggered. + */ +#define MAX_CHARGE_BATCH 1024U + struct memcg_stock_pcp { struct mem_cgroup *cached; /* this never be root cgroup */ unsigned int nr_pages;
@@ -2250,6 +2258,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, unsigned int batch = max(CHARGE_BATCH, nr_pages); int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; struct mem_cgroup *memcg = NULL; + struct memcg_stock_pcp *stock; int ret; /*
@@ -2320,6 +2329,13 @@ again: rcu_read_unlock(); } + stock = &get_cpu_var(memcg_stock); + if (memcg == stock->cached && stock->nr_pages) { + if (stock->nr_pages > MAX_CHARGE_BATCH) + batch = nr_pages; + } + put_cpu_var(memcg_stock); + do { bool oom_check;
--
1.7.9.5
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