From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal =?iso-8859-1?Q?Koutn=FD?= Subject: Re: [PATCH] mm/memcontrol: Don't increase effective low/min if no protection needed Date: Tue, 18 Oct 2022 00:46:24 +0200 Message-ID: References: <20221011143015.1152968-1-longman@redhat.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1666046786; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=KPXn8oCISsFaCnRNyRjpdaEv1QQo5ZLAKB/NsLXVGBs=; b=NfKOqe4gHCl9/Htq5BcTbwrgFymKb4wGV1EoSbTVL1zMWiFBS0wESzuZBCcXi55G/gR0tQ dqkWXoDM2yaNsea3ydA79oc54ZMQO9pSGOy34tkFfc3j8hI+NmtNtlNXbV82hU2h+0y5E3 y7ohEeM0pH8mJna2Hkfzj+XLk/7aVQo= Content-Disposition: inline In-Reply-To: List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tejun Heo Cc: Waiman Long , Michal Hocko , Johannes Weiner , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Chris Down On Tue, Oct 11, 2022 at 07:04:32AM -1000, Tejun Heo wrote: > Wouldn't it make sense to fix the test? With recursive_prot on, the cgroup > actually is under low protection and it seems like the correct behavior is > to report the low events accordingly. It depends whether the there is a residual protection that the memory.low=0 sibling can use (with memory_recursiveprot). In the discussed LTP test, there should be no residual protection that would justify the apparently misreported memory.low events. I.e. the test is correct, the failure points to a subtle issue with distributing residual protection among siblings. Been there, (haven't) done that: 1) https://bugzilla.suse.com/show_bug.cgi?id=1196298 2) https://lore.kernel.org/r/20220325103118.GC2828-9OudH3eul5jcvrawFnH+a6VXKuFTiq87@public.gmane.org/ HTH, Michal