Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934584AbbHLJOS (ORCPT ); Wed, 12 Aug 2015 05:14:18 -0400 Received: from mail-wi0-f174.google.com ([209.85.212.174]:34944 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932119AbbHLJOO (ORCPT ); Wed, 12 Aug 2015 05:14:14 -0400 Date: Wed, 12 Aug 2015 11:14:11 +0200 From: Michal Hocko To: Greg Thelen Cc: LKML , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Johannes Weiner , Tetsuo Handa , Dave Chinner , "Theodore Ts'o" , linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, Jan Kara Subject: Re: [RFC 4/8] jbd, jbd2: Do not fail journal because of frozen_buffer allocation failure Message-ID: <20150812091411.GB14940@dhcp22.suse.cz> References: <1438768284-30927-1-git-send-email-mhocko@kernel.org> <1438768284-30927-5-git-send-email-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Content-Length: 4073 Lines: 103 On Wed 05-08-15 09:49:24, Greg Thelen wrote: > > mhocko@kernel.org wrote: > > > From: Michal Hocko > > > > Journal transaction might fail prematurely because the frozen_buffer > > is allocated by GFP_NOFS request: > > [ 72.440013] do_get_write_access: OOM for frozen_buffer > > [ 72.440014] EXT4-fs: ext4_reserve_inode_write:4729: aborting transaction: Out of memory in __ext4_journal_get_write_access > > [ 72.440015] EXT4-fs error (device sda1) in ext4_reserve_inode_write:4735: Out of memory > > (...snipped....) > > [ 72.495559] do_get_write_access: OOM for frozen_buffer > > [ 72.495560] EXT4-fs: ext4_reserve_inode_write:4729: aborting transaction: Out of memory in __ext4_journal_get_write_access > > [ 72.496839] do_get_write_access: OOM for frozen_buffer > > [ 72.496841] EXT4-fs: ext4_reserve_inode_write:4729: aborting transaction: Out of memory in __ext4_journal_get_write_access > > [ 72.505766] Aborting journal on device sda1-8. > > [ 72.505851] EXT4-fs (sda1): Remounting filesystem read-only > > > > This wasn't a problem until "mm: page_alloc: do not lock up GFP_NOFS > > allocations upon OOM" because small GPF_NOFS allocations never failed. > > This allocation seems essential for the journal and GFP_NOFS is too > > restrictive to the memory allocator so let's use __GFP_NOFAIL here to > > emulate the previous behavior. > > > > jbd code has the very same issue so let's do the same there as well. > > > > Signed-off-by: Michal Hocko > > --- > > fs/jbd/transaction.c | 11 +---------- > > fs/jbd2/transaction.c | 14 +++----------- > > 2 files changed, 4 insertions(+), 21 deletions(-) > > > > diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c > > index 1695ba8334a2..bf7474deda2f 100644 > > --- a/fs/jbd/transaction.c > > +++ b/fs/jbd/transaction.c > > @@ -673,16 +673,7 @@ do_get_write_access(handle_t *handle, struct journal_head *jh, > > jbd_unlock_bh_state(bh); > > frozen_buffer = > > jbd_alloc(jh2bh(jh)->b_size, > > - GFP_NOFS); > > - if (!frozen_buffer) { > > - printk(KERN_ERR > > - "%s: OOM for frozen_buffer\n", > > - __func__); > > - JBUFFER_TRACE(jh, "oom!"); > > - error = -ENOMEM; > > - jbd_lock_bh_state(bh); > > - goto done; > > - } > > + GFP_NOFS|__GFP_NOFAIL); > > goto repeat; > > } > > jh->b_frozen_data = frozen_buffer; > > diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c > > index ff2f2e6ad311..bff071e21553 100644 > > --- a/fs/jbd2/transaction.c > > +++ b/fs/jbd2/transaction.c > > @@ -923,16 +923,7 @@ do_get_write_access(handle_t *handle, struct journal_head *jh, > > jbd_unlock_bh_state(bh); > > frozen_buffer = > > jbd2_alloc(jh2bh(jh)->b_size, > > - GFP_NOFS); > > - if (!frozen_buffer) { > > - printk(KERN_ERR > > - "%s: OOM for frozen_buffer\n", > > - __func__); > > - JBUFFER_TRACE(jh, "oom!"); > > - error = -ENOMEM; > > - jbd_lock_bh_state(bh); > > - goto done; > > - } > > + GFP_NOFS|__GFP_NOFAIL); > > goto repeat; > > } > > jh->b_frozen_data = frozen_buffer; > > @@ -1157,7 +1148,8 @@ int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh) > > > > repeat: > > if (!jh->b_committed_data) { > > - committed_data = jbd2_alloc(jh2bh(jh)->b_size, GFP_NOFS); > > + committed_data = jbd2_alloc(jh2bh(jh)->b_size, > > + GFP_NOFS|__GFP_NOFAIL); > > if (!committed_data) { > > printk(KERN_ERR "%s: No memory for committed data\n", > > __func__); > > Is this "if (!committed_data) {" check now dead code? > > I also see other similar suspected dead sites in the rest of the series. You are absolutely right. I have updated the patches. Thanks! -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/