From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f175.google.com (mail-pd0-f175.google.com [209.85.192.175]) by kanga.kvack.org (Postfix) with ESMTP id A520E6B0038 for ; Thu, 19 Mar 2015 07:12:35 -0400 (EDT) Received: by pdbni2 with SMTP id ni2so73399354pdb.1 for ; Thu, 19 Mar 2015 04:12:35 -0700 (PDT) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [2001:e42:101:1:202:181:97:72]) by mx.google.com with ESMTPS id d15si2500183pdl.13.2015.03.19.04.12.34 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Thu, 19 Mar 2015 04:12:34 -0700 (PDT) Subject: Re: [PATCH] mm: Use GFP_KERNEL allocation for the page cache inpage_cache_read From: Tetsuo Handa References: <1426687766-518-1-git-send-email-mhocko@suse.cz> <55098F3B.7070000@redhat.com> <20150318145528.GK17241@dhcp22.suse.cz> <20150319071439.GE28621@dastard> In-Reply-To: <20150319071439.GE28621@dastard> Message-Id: <201503192011.BAH65682.MVQJFOtSLOFFOH@I-love.SAKURA.ne.jp> Date: Thu, 19 Mar 2015 20:11:51 +0900 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org List-ID: To: david@fromorbit.com, mhocko@suse.cz Cc: riel@redhat.com, akpm@linux-foundation.org, viro@zeniv.linux.org.uk, hannes@cmpxchg.org, mgorman@suse.de, neilb@suse.de, sage@inktank.com, mfasheh@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Dave Chinner wrote: > On Wed, Mar 18, 2015 at 03:55:28PM +0100, Michal Hocko wrote: > > On Wed 18-03-15 10:44:11, Rik van Riel wrote: > > > On 03/18/2015 10:09 AM, Michal Hocko wrote: > > > > page_cache_read has been historically using page_cache_alloc_cold to > > > > allocate a new page. This means that mapping_gfp_mask is used as the > > > > base for the gfp_mask. Many filesystems are setting this mask to > > > > GFP_NOFS to prevent from fs recursion issues. page_cache_read is, > > > > however, not called from the fs layer > > > > > > Is that true for filesystems that have directories in > > > the page cache? > > > > I haven't found any explicit callers of filemap_fault except for ocfs2 > > and ceph and those seem OK to me. Which filesystems you have in mind? > > Just about every major filesystem calls filemap_fault through the > .fault callout. > > C symbol: filemap_fault > > File Function Line > 0 9p/vfs_file.c 831 .fault = filemap_fault, > 1 9p/vfs_file.c 838 .fault = filemap_fault, > 2 btrfs/file.c 2081 .fault = filemap_fault, > 3 cifs/file.c 3242 .fault = filemap_fault, > 4 ext4/file.c 215 .fault = filemap_fault, > 5 f2fs/file.c 93 .fault = filemap_fault, > 6 fuse/file.c 2062 .fault = filemap_fault, > 7 gfs2/file.c 498 .fault = filemap_fault, > 8 nfs/file.c 653 .fault = filemap_fault, > 9 nilfs2/file.c 128 .fault = filemap_fault, > a ubifs/file.c 1536 .fault = filemap_fault, > b xfs/xfs_file.c 1420 .fault = filemap_fault, > > > > Btw. how would that work as we already have GFP_KERNEL allocation few > > lines below? > > GFP_KERNEL allocation for mappings is simply wrong. All mapping > allocations where the caller cannot pass a gfp_mask need to obey > the mapping_gfp_mask that is set by the mapping owner.... > Is there any chance to annotate which GFP flag needs to be used like https://lkml.org/lkml/2015/3/17/507 ? > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com > -- 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