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From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Dave Chinner <david@fromorbit.com>
Cc: Michal Hocko <mhocko@kernel.org>,
	linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	"Theodore Ts'o" <tytso@mit.edu>, Chris Mason <clm@fb.com>,
	David Sterba <dsterba@suse.cz>, Jan Kara <jack@suse.cz>,
	ceph-devel@vger.kernel.org, cluster-devel@redhat.com,
	linux-nfs@vger.kernel.org, logfs@logfs.org,
	linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-btrfs@vger.kernel.org, linux-mtd@lists.infradead.org,
	reiserfs-devel@vger.kernel.org,
	linux-ntfs-dev@lists.sourceforge.net,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-afs@lists.infradead.org,
	LKML <linux-kernel@vger.kernel.org>,
	Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH 2/9] xfs: introduce and use KM_NOLOCKDEP to silence reclaim lockdep false positives
Date: Mon, 19 Dec 2016 14:06:19 -0800	[thread overview]
Message-ID: <20161219220619.GA7296@birch.djwong.org> (raw)
In-Reply-To: <20161219212413.GN4326@dastard>

On Tue, Dec 20, 2016 at 08:24:13AM +1100, Dave Chinner wrote:
> On Thu, Dec 15, 2016 at 03:07:08PM +0100, Michal Hocko wrote:
> > From: Michal Hocko <mhocko@suse.com>
> > 
> > Now that the page allocator offers __GFP_NOLOCKDEP let's introduce
> > KM_NOLOCKDEP alias for the xfs allocation APIs. While we are at it
> > also change KM_NOFS users introduced by b17cb364dbbb ("xfs: fix missing
> > KM_NOFS tags to keep lockdep happy") and use the new flag for them
> > instead. There is really no reason to make these allocations contexts
> > weaker just because of the lockdep which even might not be enabled
> > in most cases.
> > 
> > Signed-off-by: Michal Hocko <mhocko@suse.com>
> 
> I'd suggest that it might be better to drop this patch for now -
> it's not necessary for the context flag changeover but does
> introduce a risk of regressions if the conversion is wrong.

I was just about to write in that while I didn't see anything obviously
wrong with the NOFS removals, I also don't know for sure that we can't
end up recursively in those code paths (specifically the directory
traversal thing).

--D

> Hence I think this is better as a completely separate series
> which audits and changes all the unnecessary KM_NOFS allocations
> in one go. I've never liked whack-a-mole style changes like this -
> do it once, do it properly....
> 
> Cheers,
> 
> Dave.
> -- 
> Dave Chinner
> david@fromorbit.com
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

  reply	other threads:[~2016-12-19 22:07 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-15 14:07 [PATCH 0/9 v2] scope GFP_NOFS api Michal Hocko
2016-12-15 14:07 ` [PATCH 1/9] lockdep: allow to disable reclaim lockup detection Michal Hocko
2016-12-15 14:07 ` [PATCH 2/9] xfs: introduce and use KM_NOLOCKDEP to silence reclaim lockdep false positives Michal Hocko
2016-12-16 15:40   ` [PATCH 2/9 v2] " Michal Hocko
2016-12-16 16:37     ` Brian Foster
2016-12-16 22:01       ` Michal Hocko
2016-12-19 21:24   ` [PATCH 2/9] " Dave Chinner
2016-12-19 22:06     ` Darrick J. Wong [this message]
2016-12-20 21:39       ` Dave Chinner
2016-12-20  8:38     ` Michal Hocko
2016-12-15 14:07 ` [PATCH 3/9] xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS Michal Hocko
2016-12-16 16:38   ` Brian Foster
2016-12-15 14:07 ` [PATCH 4/9] mm: introduce memalloc_nofs_{save,restore} API Michal Hocko
2016-12-15 14:07 ` [PATCH 5/9] xfs: use memalloc_nofs_{save,restore} instead of memalloc_noio* Michal Hocko
2016-12-16 16:38   ` Brian Foster
2016-12-16 22:00     ` [PATCH 5/9 v2] " Michal Hocko
2016-12-15 14:07 ` [PATCH 6/9] jbd2: mark the transaction context with the scope GFP_NOFS context Michal Hocko
2016-12-16  8:39   ` Jan Kara
2016-12-15 14:07 ` [PATCH 7/9] jbd2: make the whole kjournald2 kthread NOFS safe Michal Hocko
2016-12-16  8:40   ` Jan Kara
2016-12-15 14:07 ` [PATCH 8/9] Revert "ext4: avoid deadlocks in the writeback path by using sb_getblk_gfp" Michal Hocko
2016-12-16  8:41   ` Jan Kara
2016-12-15 14:07 ` [PATCH 9/9] Revert "ext4: fix wrong gfp type under transaction" Michal Hocko
2016-12-16  8:43   ` Jan Kara
2016-12-16 12:46 ` [DEBUG PATCH 0/2] debug explicit GFP_NO{FS,IO} usage from the scope context Michal Hocko
2016-12-16 12:46   ` [DEBUG PATCH 1/2] mm, debug: report when GFP_NO{FS,IO} is used explicitly from memalloc_no{fs,io}_{save,restore} context Michal Hocko
2016-12-16 12:46   ` [DEBUG PATCH 2/2] silent warnings which we cannot do anything about Michal Hocko
2016-12-16 15:05 ` [PATCH 0/9 v2] scope GFP_NOFS api Mike Galbraith
2016-12-16 15:35   ` Michal Hocko
2016-12-16 16:27     ` Mike Galbraith
2016-12-19  9:25       ` Jan Kara
2016-12-22  9:38 ` Michal Hocko

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