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From: Michal Hocko <mhocko@kernel.org>
To: Dave Chinner <david@fromorbit.com>
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Jan Kara <jack@suse.cz>,
	xfs@oss.sgi.com, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used explicitly from memalloc_no{fs,io}_{save,restore} context
Date: Thu, 28 Apr 2016 10:17:59 +0200	[thread overview]
Message-ID: <20160428081759.GA31489@dhcp22.suse.cz> (raw)
In-Reply-To: <20160426225845.GF26977@dastard>

[Trim the CC list]
On Wed 27-04-16 08:58:45, Dave Chinner wrote:
[...]
> Often these are to silence lockdep warnings (e.g. commit b17cb36
> ("xfs: fix missing KM_NOFS tags to keep lockdep happy")) because
> lockdep gets very unhappy about the same functions being called with
> different reclaim contexts. e.g.  directory block mapping might
> occur from readdir (no transaction context) or within transactions
> (create/unlink). hence paths like this are tagged with GFP_NOFS to
> stop lockdep emitting false positive warnings....

As already said in other email, I have tried to revert the above
commit and tried to run it with some fs workloads but didn't manage
to hit any lockdep splats (after I fixed my bug in the patch 1.2). I
have tried to find reports which led to this commit but didn't succeed
much. Everything is from much earlier or later. Do you happen to
remember which loads triggered them, what they looked like or have an
idea what to try to reproduce them? So far I was trying heavy parallel
fs_mark, kernbench inside a tiny virtual machine so any of those have
triggered direct reclaim all the time.

Thanks!
-- 
Michal Hocko
SUSE Labs

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  parent reply	other threads:[~2016-04-28  8:17 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-26 11:56 [PATCH 0/2] scop GFP_NOFS api Michal Hocko
2016-04-26 11:56 ` [PATCH 1/2] mm: add PF_MEMALLOC_NOFS Michal Hocko
2016-04-26 23:07   ` Dave Chinner
2016-04-27  7:51     ` Michal Hocko
2016-04-27 11:54   ` [PATCH 1.1/2] xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS Michal Hocko
2016-04-27 11:54     ` [PATCH 1.2/2] mm: introduce memalloc_nofs_{save,restore} API Michal Hocko
2016-04-27 13:07       ` Michal Hocko
2016-04-27 20:09       ` Michal Hocko
2016-04-27 20:30         ` Michal Hocko
2016-04-27 21:14       ` Michal Hocko
2016-04-27 17:41     ` [PATCH 1.1/2] xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS Andreas Dilger
2016-04-27 19:43       ` Michal Hocko
2016-04-26 11:56 ` [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used explicitly from memalloc_no{fs,io}_{save,restore} context Michal Hocko
2016-04-26 22:58   ` Dave Chinner
2016-04-27  8:03     ` Michal Hocko
2016-04-27 22:55       ` Dave Chinner
2016-04-28  8:17     ` Michal Hocko [this message]
2016-04-28 21:51       ` Dave Chinner
2016-04-29 12:12         ` Michal Hocko
2016-04-29 23:40           ` Dave Chinner
2016-05-03 15:38             ` Michal Hocko
2016-05-04  0:07               ` Dave Chinner
2016-04-29  5:35 ` [PATCH 0/2] scop GFP_NOFS api NeilBrown
2016-04-29 10:20   ` [Cluster-devel] " Steven Whitehouse
2016-04-30 21:17     ` NeilBrown
2016-04-29 12:04   ` Michal Hocko
2016-04-30  0:24     ` Dave Chinner
2016-04-30 21:55     ` NeilBrown
2016-05-03 15:13       ` Michal Hocko
2016-05-03 23:26         ` NeilBrown
2016-04-30  0:11   ` Dave Chinner
2016-04-30 22:19     ` NeilBrown
2016-05-04  1:00       ` Dave Chinner
2016-05-06  3:20         ` NeilBrown

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