From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f47.google.com (mail-wm0-f47.google.com [74.125.82.47]) by kanga.kvack.org (Postfix) with ESMTP id 1F0EE6B0005 for ; Thu, 25 Feb 2016 04:01:36 -0500 (EST) Received: by mail-wm0-f47.google.com with SMTP id b205so22286284wmb.1 for ; Thu, 25 Feb 2016 01:01:36 -0800 (PST) Received: from mail-wm0-f52.google.com (mail-wm0-f52.google.com. [74.125.82.52]) by mx.google.com with ESMTPS id g139si2975277wmd.7.2016.02.25.01.01.34 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 25 Feb 2016 01:01:34 -0800 (PST) Received: by mail-wm0-f52.google.com with SMTP id c200so18223508wme.0 for ; Thu, 25 Feb 2016 01:01:34 -0800 (PST) Subject: Re: [PATCH RFC] ext4: use __GFP_NOFAIL in ext4_free_blocks() References: <20160224170912.2195.8153.stgit@buzz> From: Nikolay Borisov Message-ID: <56CEC2EC.5000506@kyup.com> Date: Thu, 25 Feb 2016 11:01:32 +0200 MIME-Version: 1.0 In-Reply-To: <20160224170912.2195.8153.stgit@buzz> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Konstantin Khlebnikov , Theodore Ts'o Cc: Michal Hocko , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dmitry Monakhov , Johannes Weiner , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org On 02/24/2016 07:09 PM, Konstantin Khlebnikov wrote: > This might be unexpected but pages allocated for sbi->s_buddy_cache are > charged to current memory cgroup. So, GFP_NOFS allocation could fail if > current task has been killed by OOM or if current memory cgroup has no > free memory left. Block allocator cannot handle such failures here yet. > > Signed-off-by: Konstantin Khlebnikov Adding new users of GFP_NOFAIL is deprecated. Where exactly does the block allocator fail, I skimmed the code and failing ext4_mb_load_buddy seems to be handled at all call sites. There are some BUG_ONs but from the comments there I guess they should occur when we try to find a page and not allocate a new one? -- 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