From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f72.google.com (mail-it0-f72.google.com [209.85.214.72]) by kanga.kvack.org (Postfix) with ESMTP id 952BC828E1 for ; Tue, 2 Aug 2016 08:42:31 -0400 (EDT) Received: by mail-it0-f72.google.com with SMTP id x130so4525670ite.3 for ; Tue, 02 Aug 2016 05:42:31 -0700 (PDT) Received: from EUR02-AM5-obe.outbound.protection.outlook.com (mail-eopbgr00121.outbound.protection.outlook.com. [40.107.0.121]) by mx.google.com with ESMTPS id r12si1427210otb.267.2016.08.02.05.42.30 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 02 Aug 2016 05:42:30 -0700 (PDT) Date: Tue, 2 Aug 2016 15:42:20 +0300 From: Vladimir Davydov Subject: Re: [PATCH] radix-tree: account nodes to memcg only if explicitly requested Message-ID: <20160802124220.GC13263@esperanza> References: <1470057188-7864-1-git-send-email-vdavydov@virtuozzo.com> <20160802115111.GG12403@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20160802115111.GG12403@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , Johannes Weiner , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, Aug 02, 2016 at 01:51:12PM +0200, Michal Hocko wrote: > On Mon 01-08-16 16:13:08, Vladimir Davydov wrote: > > Radix trees may be used not only for storing page cache pages, so > > unconditionally accounting radix tree nodes to the current memory cgroup > > is bad: if a radix tree node is used for storing data shared among > > different cgroups we risk pinning dead memory cgroups forever. So let's > > only account radix tree nodes if it was explicitly requested by passing > > __GFP_ACCOUNT to INIT_RADIX_TREE. Currently, we only want to account > > page cache entries, so mark mapping->page_tree so. > > > > Signed-off-by: Vladimir Davydov > > OK, the patch makes sense to me. Such a false sharing would be really > tedious to debug > > Do we want to mark it for stable 4.6 to prevent from some pathological > issues. The patch is simple enough. Makes sense, expecially taking into account that kmemcg is enabled by default now. I'll resend the patch for stable then. > > Acked-by: Michal Hocko Thanks! -- 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