From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755587AbbCROzd (ORCPT ); Wed, 18 Mar 2015 10:55:33 -0400 Received: from cantor2.suse.de ([195.135.220.15]:60171 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755486AbbCROza (ORCPT ); Wed, 18 Mar 2015 10:55:30 -0400 Date: Wed, 18 Mar 2015 15:55:28 +0100 From: Michal Hocko To: Rik van Riel Cc: Andrew Morton , Al Viro , Johannes Weiner , Mel Gorman , Neil Brown , Tetsuo Handa , Sage Weil , Mark Fasheh , linux-mm@kvack.org, LKML Subject: Re: [PATCH] mm: Use GFP_KERNEL allocation for the page cache in page_cache_read Message-ID: <20150318145528.GK17241@dhcp22.suse.cz> References: <1426687766-518-1-git-send-email-mhocko@suse.cz> <55098F3B.7070000@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55098F3B.7070000@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? Btw. how would that work as we already have GFP_KERNEL allocation few lines below? -- Michal Hocko SUSE Labs