From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f45.google.com (mail-oi0-f45.google.com [209.85.218.45]) by kanga.kvack.org (Postfix) with ESMTP id 7F9586B0253 for ; Thu, 22 Oct 2015 17:42:58 -0400 (EDT) Received: by oifu63 with SMTP id u63so12836620oif.2 for ; Thu, 22 Oct 2015 14:42:58 -0700 (PDT) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [2001:e42:101:1:202:181:97:72]) by mx.google.com with ESMTPS id zf8si9620393obc.81.2015.10.22.14.42.57 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Thu, 22 Oct 2015 14:42:57 -0700 (PDT) Subject: Re: [PATCH] mm,vmscan: Use accurate values for zone_reclaimable()checks From: Tetsuo Handa References: <20151022151528.GG30579@mtj.duckdns.org> <20151022153559.GF26854@dhcp22.suse.cz> <20151022153703.GA3899@mtj.duckdns.org> <20151022154922.GG26854@dhcp22.suse.cz> <20151022184226.GA19289@mtj.duckdns.org> In-Reply-To: <20151022184226.GA19289@mtj.duckdns.org> Message-Id: <201510230642.HDF57807.QJtSOVFFOMLHOF@I-love.SAKURA.ne.jp> Date: Fri, 23 Oct 2015 06:42:43 +0900 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org List-ID: To: htejun@gmail.com, mhocko@kernel.org Cc: cl@linux.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, rientjes@google.com, oleg@redhat.com, kwalker@redhat.com, akpm@linux-foundation.org, hannes@cmpxchg.org, vdavydov@parallels.com, skozina@redhat.com, mgorman@suse.de, riel@redhat.com Tejun Heo wrote: > On Thu, Oct 22, 2015 at 05:49:22PM +0200, Michal Hocko wrote: > > I am confused. What makes rescuer to not run? Nothing seems to be > > hogging CPUs, we are just out of workers which are loopin in the > > allocator but that is preemptible context. > > It's concurrency management. Workqueue thinks that the pool is making > positive forward progress and doesn't schedule anything else for > execution while that work item is burning cpu cycles. Then, isn't below change easier to backport which will also alleviate needlessly burning CPU cycles? --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3385,6 +3385,7 @@ retry: ((gfp_mask & __GFP_REPEAT) && pages_reclaimed < (1 << order))) { /* Wait for some write requests to complete then retry */ wait_iff_congested(ac->preferred_zone, BLK_RW_ASYNC, HZ/50); + schedule_timeout_uninterruptible(1); goto retry; } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org