From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ea0-f180.google.com (mail-ea0-f180.google.com [209.85.215.180]) by kanga.kvack.org (Postfix) with ESMTP id A6A8A6B0035 for ; Wed, 11 Dec 2013 04:55:51 -0500 (EST) Received: by mail-ea0-f180.google.com with SMTP id f15so2755655eak.25 for ; Wed, 11 Dec 2013 01:55:51 -0800 (PST) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTP id l44si18264465eem.61.2013.12.11.01.55.50 for ; Wed, 11 Dec 2013 01:55:50 -0800 (PST) Date: Wed, 11 Dec 2013 10:55:49 +0100 From: Michal Hocko Subject: Re: [patch 1/2] mm, memcg: avoid oom notification when current needs access to memory reserves Message-ID: <20131211095549.GA18741@dhcp22.suse.cz> References: <20131202200221.GC5524@dhcp22.suse.cz> <20131202212500.GN22729@cmpxchg.org> <20131203120454.GA12758@dhcp22.suse.cz> <20131204111318.GE8410@dhcp22.suse.cz> <20131209124840.GC3597@dhcp22.suse.cz> <20131210103827.GB20242@dhcp22.suse.cz> 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: Johannes Weiner , Andrew Morton , KAMEZAWA Hiroyuki , linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org On Tue 10-12-13 17:03:45, David Rientjes wrote: > On Tue, 10 Dec 2013, Michal Hocko wrote: > > > > What exactly would you like to see? > > > > How often do you see PF_EXITING tasks which haven't been killed causing > > a pointless notification? Because fatal_signal_pending and TIF_MEMDIE > > cases are already handled because we bypass charges in those cases (except > > for user OOM killer killed tasks which don't get TIF_MEMDIE and that > > should be fixed). > > > > Triggering a pointless notification with PF_EXITING is rare, yet one > pointless notification can be avoided with the patch. Sigh. Yes it will avoid one particular and rare race. There will still be notifications without oom kills. Anyway. Does the reclaim make any sense for PF_EXITING tasks? Shouldn't we simply bypass charges of these tasks automatically. Those tasks will free some memory anyway so why to trigger reclaim and potentially OOM in the first place? Do we need to go via TIF_MEMDIE loop in the first place? > Additionally, it also avoids a pointless notification for a racing > SIGKILL. -- Michal Hocko SUSE Labs -- 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