From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f70.google.com (mail-lf0-f70.google.com [209.85.215.70]) by kanga.kvack.org (Postfix) with ESMTP id 814E7828E1 for ; Tue, 2 Aug 2016 08:46:47 -0400 (EDT) Received: by mail-lf0-f70.google.com with SMTP id e7so93935784lfe.0 for ; Tue, 02 Aug 2016 05:46:47 -0700 (PDT) Received: from mail-wm0-f66.google.com (mail-wm0-f66.google.com. [74.125.82.66]) by mx.google.com with ESMTPS id c6si2478602wjq.184.2016.08.02.05.46.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 02 Aug 2016 05:46:46 -0700 (PDT) Received: by mail-wm0-f66.google.com with SMTP id x83so30536810wma.3 for ; Tue, 02 Aug 2016 05:46:46 -0700 (PDT) Date: Tue, 2 Aug 2016 14:46:45 +0200 From: Michal Hocko Subject: Re: [PATCH] radix-tree: account nodes to memcg only if explicitly requested Message-ID: <20160802124644.GL12403@dhcp22.suse.cz> References: <1470057188-7864-1-git-send-email-vdavydov@virtuozzo.com> <20160802115111.GG12403@dhcp22.suse.cz> <20160802124220.GC13263@esperanza> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160802124220.GC13263@esperanza> Sender: owner-linux-mm@kvack.org List-ID: To: Vladimir Davydov Cc: Andrew Morton , Johannes Weiner , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue 02-08-16 15:42:20, Vladimir Davydov wrote: > 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. Maybe Andrew just want's to mark it for stable with Fixes: 58e698af4c63 ("radix-tree: account radix_tree_node to memory cgroup") Cc: stable # 4.6 > > 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 -- 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