From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f72.google.com (mail-it0-f72.google.com [209.85.214.72]) by kanga.kvack.org (Postfix) with ESMTP id 4BED56B000A for ; Tue, 3 Jul 2018 10:26:14 -0400 (EDT) Received: by mail-it0-f72.google.com with SMTP id v142-v6so1992608itb.1 for ; Tue, 03 Jul 2018 07:26:14 -0700 (PDT) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [202.181.97.72]) by mx.google.com with ESMTPS id a124-v6si1162383ite.38.2018.07.03.07.26.12 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Jul 2018 07:26:13 -0700 (PDT) From: Tetsuo Handa Subject: [PATCH 8/8] mm,page_alloc: Move the short sleep to should_reclaim_retry(). Date: Tue, 3 Jul 2018 23:25:09 +0900 Message-Id: <1530627910-3415-9-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> In-Reply-To: <1530627910-3415-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> References: <1530627910-3415-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, akpm@linux-foundation.org Cc: torvalds@linux-foundation.org, Michal Hocko , Tetsuo Handa , David Rientjes , Johannes Weiner , Roman Gushchin , Tejun Heo , Vladimir Davydov From: Michal Hocko Since the page allocator can now spend CPU resource for oom_reap_mm() for their interested OOM domains, the short sleep for waiting for the owner of oom_lock no longer makes sense. should_reclaim_retry() should be a natural reschedule point. PF_WQ_WORKER is a special case which needs a stronger rescheduling policy. Doing that unconditionally seems more straightforward than depending on a zone being a good candidate for a further reclaim. Thus, move the short sleep for waiting for the owner of oom_lock (which coincidentally also serves as a guaranteed sleep for PF_WQ_WORKER threads) to should_reclaim_retry(). Signed-off-by: Michal Hocko Cc: Tetsuo Handa Cc: Roman Gushchin Cc: Michal Hocko Cc: Johannes Weiner Cc: Vladimir Davydov Cc: David Rientjes Cc: Tejun Heo --- mm/page_alloc.c | 40 ++++++++++++++++++---------------------- 1 file changed, 18 insertions(+), 22 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 4c648f7..010b536 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3904,6 +3904,7 @@ bool gfp_pfmemalloc_allowed(gfp_t gfp_mask) { struct zone *zone; struct zoneref *z; + bool ret = false; /* * Costly allocations might have made a progress but this doesn't mean @@ -3967,25 +3968,26 @@ bool gfp_pfmemalloc_allowed(gfp_t gfp_mask) } } - /* - * Memory allocation/reclaim might be called from a WQ - * context and the current implementation of the WQ - * concurrency control doesn't recognize that - * a particular WQ is congested if the worker thread is - * looping without ever sleeping. Therefore we have to - * do a short sleep here rather than calling - * cond_resched(). - */ - if (current->flags & PF_WQ_WORKER) - schedule_timeout_uninterruptible(1); - else - cond_resched(); - - return true; + ret = true; + goto out; } } - return false; +out: + /* + * Memory allocation/reclaim might be called from a WQ + * context and the current implementation of the WQ + * concurrency control doesn't recognize that + * a particular WQ is congested if the worker thread is + * looping without ever sleeping. Therefore we have to + * do a short sleep here rather than calling + * cond_resched(). + */ + if (current->flags & PF_WQ_WORKER) + schedule_timeout_uninterruptible(1); + else + cond_resched(); + return ret; } static inline bool @@ -4226,12 +4228,6 @@ bool gfp_pfmemalloc_allowed(gfp_t gfp_mask) /* Retry as long as the OOM killer is making progress */ if (did_some_progress) { no_progress_loops = 0; - /* - * This schedule_timeout_*() serves as a guaranteed sleep for - * PF_WQ_WORKER threads when __zone_watermark_ok() == false. - */ - if (!tsk_is_oom_victim(current)) - schedule_timeout_uninterruptible(1); goto retry; } -- 1.8.3.1