From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757608Ab2FRKbQ (ORCPT ); Mon, 18 Jun 2012 06:31:16 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:24932 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757419Ab2FRKbK (ORCPT ); Mon, 18 Jun 2012 06:31:10 -0400 From: Glauber Costa To: Cc: Pekka Enberg , Cristoph Lameter , David Rientjes , , , , , Frederic Weisbecker , Suleiman Souhlal , Glauber Costa Subject: [PATCH v4 07/25] memcg: Reclaim when more than one page needed. Date: Mon, 18 Jun 2012 14:28:00 +0400 Message-Id: <1340015298-14133-8-git-send-email-glommer@parallels.com> X-Mailer: git-send-email 1.7.10.2 In-Reply-To: <1340015298-14133-1-git-send-email-glommer@parallels.com> References: <1340015298-14133-1-git-send-email-glommer@parallels.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Suleiman Souhlal mem_cgroup_do_charge() was written before slab 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 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), stay safe with a cond_resched(), 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 Signed-off-by: Glauber Costa Reviewed-by: Kamezawa Hiroyuki --- mm/memcontrol.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 00b9f1e..b6cb075 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2187,7 +2187,8 @@ 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; @@ -2210,18 +2211,18 @@ 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; @@ -2234,8 +2235,10 @@ 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) { + cond_resched(); return CHARGE_RETRY; + } /* * At task move, charge accounts can be doubly counted. So, it's @@ -2369,7 +2372,8 @@ 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; -- 1.7.10.2