From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: Re: [PATCH v2 02/11] memcg: Reclaim when more than one page needed. Date: Mon, 13 Aug 2012 12:05:38 +0400 Message-ID: <5028B552.2070708@parallels.com> References: <1344517279-30646-1-git-send-email-glommer@parallels.com> <1344517279-30646-3-git-send-email-glommer@parallels.com> <20120810185417.GB16110@dhcp22.suse.cz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120810185417.GB16110-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Michal Hocko Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, Johannes Weiner , Andrew Morton , kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org, Christoph Lameter , David Rientjes , Pekka Enberg , Suleiman Souhlal On 08/10/2012 10:54 PM, Michal Hocko wrote: > On Thu 09-08-12 17:01:10, Glauber Costa wrote: >> From: Suleiman Souhlal >> >> mem_cgroup_do_charge() was written before kmem accounting, and expects >> three cases: being called for 1 page, being called for a stock of 32 >> pages, or being called for a hugepage. If we call for 2 or 3 pages (and >> both the stack and several slabs used in process creation are such, at >> least with the debug options I had), it assumed it's being called for >> stock and just retried without reclaiming. >> >> Fix that by passing down a minsize argument in addition to the csize. >> >> And what to do about that (csize == PAGE_SIZE && ret) retry? If it's >> needed at all (and presumably is since it's there, perhaps to handle >> races), then it should be extended to more than PAGE_SIZE, yet how far? >> And should there be a retry count limit, of what? For now retry up to >> COSTLY_ORDER (as page_alloc.c does) and make sure not to do it if >> __GFP_NORETRY. >> >> [v4: fixed nr pages calculation pointed out by Christoph Lameter ] >> >> Signed-off-by: Suleiman Souhlal >> Signed-off-by: Glauber Costa >> Reviewed-by: Kamezawa Hiroyuki > > I am not happy with the min_pages argument but we can do something more > clever later. > > Acked-by: Michal Hocko > I am a bit confused here. Does your ack come before or after your other comments on this patch?