From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f182.google.com (mail-we0-f182.google.com [74.125.82.182]) by kanga.kvack.org (Postfix) with ESMTP id 24A836B00BA for ; Mon, 2 Jun 2014 21:15:18 -0400 (EDT) Received: by mail-we0-f182.google.com with SMTP id t60so5875763wes.41 for ; Mon, 02 Jun 2014 18:15:17 -0700 (PDT) Received: from zene.cmpxchg.org (zene.cmpxchg.org. [2a01:238:4224:fa00:ca1f:9ef3:caee:a2bd]) by mx.google.com with ESMTPS id g12si25059712wiv.37.2014.06.02.18.15.16 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 02 Jun 2014 18:15:16 -0700 (PDT) Date: Mon, 2 Jun 2014 21:15:10 -0400 From: Johannes Weiner Subject: Re: [patch v2] mm, memcg: periodically schedule when emptying page list Message-ID: <20140603011510.GO2878@cmpxchg.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Andrew Morton , Hugh Dickins , Michal Hocko , linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org On Mon, Jun 02, 2014 at 05:51:25PM -0700, David Rientjes wrote: > From: Hugh Dickins > > mem_cgroup_force_empty_list() can iterate a large number of pages on an lru and > mem_cgroup_move_parent() doesn't return an errno unless certain criteria, none > of which indicate that the iteration may be taking too long, is met. > > We have encountered the following stack trace many times indicating > "need_resched set for > 51000020 ns (51 ticks) without schedule", for example: > > scheduler_tick() > > mem_cgroup_move_account+0x4d/0x1d5 > mem_cgroup_move_parent+0x8d/0x109 > mem_cgroup_reparent_charges+0x149/0x2ba > mem_cgroup_css_offline+0xeb/0x11b > cgroup_offline_fn+0x68/0x16b > process_one_work+0x129/0x350 > > If this iteration is taking too long, we still need to do cond_resched() even > when an individual page is not busy. > > [rientjes@google.com: changelog] > Signed-off-by: Hugh Dickins > Signed-off-by: David Rientjes Acked-by: Johannes Weiner -- 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