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authorSuleiman Souhlal <ssouhlal@FreeBSD.org>2012-12-19 02:21:41 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-19 03:02:12 +0400
commit4c9c535968cacf507c5febe49e6ec5123eadf207 (patch)
tree726189ffffb689f1fcef87a8fb1d60a2632f88ae
parenta0956d54492eb7257b09230680a8812b42cdee92 (diff)
downloadlinux-4c9c535968cacf507c5febe49e6ec5123eadf207.tar.xz
memcg: reclaim when more than one page needed
mem_cgroup_do_charge() was written before kmem accounting, and expects three cases: being called for 1 page, being called for a stock of 32 pages, or being called for a hugepage. If we call for 2 or 3 pages (and both the stack and several slabs used in process creation are such, at least with the debug options I had), it assumed it's being called for stock and just retried without reclaiming. Fix that by passing down a minsize argument in addition to the csize. And what to do about that (csize == PAGE_SIZE && ret) retry? If it's needed at all (and presumably is since it's there, perhaps to handle races), then it should be extended to more than PAGE_SIZE, yet how far? And should there be a retry count limit, of what? For now retry up to COSTLY_ORDER (as page_alloc.c does) and make sure not to do it if __GFP_NORETRY. v4: fixed nr pages calculation pointed out by Christoph Lameter. Signed-off-by: Suleiman Souhlal <suleiman@google.com> Signed-off-by: Glauber Costa <glommer@parallels.com> Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Frederic Weisbecker <fweisbec@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: JoonSoo Kim <js1304@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c16
1 files changed, 9 insertions, 7 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 92887b286246..20e3619870ae 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2258,7 +2258,8 @@ enum {
};
static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
- unsigned int nr_pages, bool oom_check)
+ unsigned int nr_pages, unsigned int min_pages,
+ bool oom_check)
{
unsigned long csize = nr_pages * PAGE_SIZE;
struct mem_cgroup *mem_over_limit;
@@ -2281,18 +2282,18 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
} else
mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
/*
- * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
- * of regular pages (CHARGE_BATCH), or a single regular page (1).
- *
* Never reclaim on behalf of optional batching, retry with a
* single page instead.
*/
- if (nr_pages == CHARGE_BATCH)
+ if (nr_pages > min_pages)
return CHARGE_RETRY;
if (!(gfp_mask & __GFP_WAIT))
return CHARGE_WOULDBLOCK;
+ if (gfp_mask & __GFP_NORETRY)
+ return CHARGE_NOMEM;
+
ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
return CHARGE_RETRY;
@@ -2305,7 +2306,7 @@ static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
* unlikely to succeed so close to the limit, and we fall back
* to regular pages anyway in case of failure.
*/
- if (nr_pages == 1 && ret)
+ if (nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER) && ret)
return CHARGE_RETRY;
/*
@@ -2439,7 +2440,8 @@ again:
nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
}
- ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, oom_check);
+ ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, nr_pages,
+ oom_check);
switch (ret) {
case CHARGE_OK:
break;