From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Weiner Subject: Re: [patch v2] mm, memcg: periodically schedule when emptying page list Date: Mon, 2 Jun 2014 21:15:10 -0400 Message-ID: <20140603011510.GO2878@cmpxchg.org> References: Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=cmpxchg.org; s=zene; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=Vb8vTXd1mIawy+HXC9BFVgAFq1F81KMPINSbel3Dw/4=; b=ZNpLajAVp8z9oEFpypqbI6hbwOUj0P9ZlQ6Hzc4oGhYGCHpcNFrGOtWcyuhx/sFJGh7LoNWJIFdlMA2d9KCfJ2jQZbWX7Z+2JRo0mXel8ITU4iI7BaqCTVi0fzRPFMG45Hvx6ftUkCqAM8mFNY/6j26nJNWsTWVPyE9jzncWGJw=; Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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