From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: [PATCH v3 05/28] memcg: Reclaim when more than one page needed. Date: Fri, 25 May 2012 17:03:25 +0400 Message-ID: <1337951028-3427-6-git-send-email-glommer@parallels.com> References: <1337951028-3427-1-git-send-email-glommer@parallels.com> Return-path: In-Reply-To: <1337951028-3427-1-git-send-email-glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org, Tejun Heo , Li Zefan , Greg Thelen , Suleiman Souhlal , Michal Hocko , Johannes Weiner , devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, David Rientjes , Glauber Costa 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 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. Signed-off-by: Suleiman Souhlal Signed-off-by: Glauber Costa Reviewed-by: Kamezawa Hiroyuki --- mm/memcontrol.c | 18 +++++++++++------- 1 files changed, 11 insertions(+), 7 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 248d80b..47d3979 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 <= (PAGE_SIZE << 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; -- 1.7.7.6