Re: [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used explicitly from memalloc_no{fs,io}_{save,restore} context

From	Michal Hocko <mhocko@kernel.org>
Newsgroups	linux.kernel
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	2016-04-28 10:20 +0200
Message-ID	<rsPl1-8pu-29@gated-at.bofh.it> (permalink)
References	<rs9OO-76D-1@gated-at.bofh.it> <rs9OP-76D-23@gated-at.bofh.it> <rsk7w-7on-11@gated-at.bofh.it>
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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

Thread

[PATCH 0/2] scop GFP_NOFS api Michal Hocko <mhocko@kernel.org> - 2016-04-26 14:00 +0200
  [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used explicitly from memalloc_no{fs,io}_{save,restore} context Michal Hocko <mhocko@kernel.org> - 2016-04-26 14:00 +0200
    Re: [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used  explicitly from memalloc_no{fs,io}_{save,restore} context Dave Chinner <david@fromorbit.com> - 2016-04-27 01:00 +0200
      Re: [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used  explicitly from memalloc_no{fs,io}_{save,restore} context Michal Hocko <mhocko@kernel.org> - 2016-04-27 10:10 +0200
        Re: [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used  explicitly from memalloc_no{fs,io}_{save,restore} context Dave Chinner <david@fromorbit.com> - 2016-04-28 01:00 +0200
      Re: [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used  explicitly from memalloc_no{fs,io}_{save,restore} context Michal Hocko <mhocko@kernel.org> - 2016-04-28 10:20 +0200
        Re: [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used  explicitly from memalloc_no{fs,io}_{save,restore} context Dave Chinner <david@fromorbit.com> - 2016-04-29 00:00 +0200
          Re: [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used  explicitly from memalloc_no{fs,io}_{save,restore} context Michal Hocko <mhocko@kernel.org> - 2016-04-29 14:20 +0200
            Re: [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used  explicitly from memalloc_no{fs,io}_{save,restore} context Dave Chinner <david@fromorbit.com> - 2016-04-30 01:50 +0200
              Re: [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used  explicitly from memalloc_no{fs,io}_{save,restore} context Michal Hocko <mhocko@kernel.org> - 2016-05-03 17:40 +0200
                Re: [PATCH 2/2] mm, debug: report when GFP_NO{FS,IO} is used  explicitly from memalloc_no{fs,io}_{save,restore} context Dave Chinner <david@fromorbit.com> - 2016-05-04 02:10 +0200
  [PATCH 1/2] mm: add PF_MEMALLOC_NOFS Michal Hocko <mhocko@kernel.org> - 2016-04-26 14:00 +0200
    Re: [PATCH 1/2] mm: add PF_MEMALLOC_NOFS Dave Chinner <david@fromorbit.com> - 2016-04-27 01:10 +0200
      Re: [PATCH 1/2] mm: add PF_MEMALLOC_NOFS Michal Hocko <mhocko@kernel.org> - 2016-04-27 10:00 +0200
    Re: [PATCH 1/2] mm: add PF_MEMALLOC_NOFS Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-04-27 13:00 +0200
      Re: [PATCH 1/2] mm: add PF_MEMALLOC_NOFS Michal Hocko <mhocko@kernel.org> - 2016-04-27 13:20 +0200
        Re: [PATCH 1/2] mm: add PF_MEMALLOC_NOFS Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2016-04-27 16:50 +0200
          Re: [PATCH 1/2] mm: add PF_MEMALLOC_NOFS Michal Hocko <mhocko@kernel.org> - 2016-04-27 22:10 +0200
    [PATCH 1.1/2] xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS Michal Hocko <mhocko@kernel.org> - 2016-04-27 14:00 +0200
      [PATCH 1.2/2] mm: introduce memalloc_nofs_{save,restore} API Michal Hocko <mhocko@kernel.org> - 2016-04-27 14:00 +0200
        Re: [PATCH 1.2/2] mm: introduce memalloc_nofs_{save,restore} API Michal Hocko <mhocko@kernel.org> - 2016-04-27 15:10 +0200
        Re: [PATCH 1.2/2] mm: introduce memalloc_nofs_{save,restore} API Michal Hocko <mhocko@kernel.org> - 2016-04-27 22:10 +0200
          Re: [PATCH 1.2/2] mm: introduce memalloc_nofs_{save,restore} API Michal Hocko <mhocko@kernel.org> - 2016-04-27 22:40 +0200
        Re: [PATCH 1.2/2] mm: introduce memalloc_nofs_{save,restore} API Michal Hocko <mhocko@kernel.org> - 2016-04-27 23:20 +0200
      Re: [PATCH 1.1/2] xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS Andreas Dilger <adilger@dilger.ca> - 2016-04-27 19:50 +0200
        Re: [PATCH 1.1/2] xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS Michal Hocko <mhocko@kernel.org> - 2016-04-27 21:50 +0200
  Re: [PATCH 0/2] scop GFP_NOFS api NeilBrown <mr@neil.brown.name> - 2016-04-29 08:20 +0200
    Re: [Cluster-devel] [PATCH 0/2] scop GFP_NOFS api Steven Whitehouse <swhiteho@redhat.com> - 2016-04-29 12:30 +0200
      Re: [Cluster-devel] [PATCH 0/2] scop GFP_NOFS api NeilBrown <mr@neil.brown.name> - 2016-04-30 23:20 +0200
    Re: [PATCH 0/2] scop GFP_NOFS api Michal Hocko <mhocko@kernel.org> - 2016-04-29 14:10 +0200
      Re: [PATCH 0/2] scop GFP_NOFS api Dave Chinner <david@fromorbit.com> - 2016-04-30 02:30 +0200
      Re: [PATCH 0/2] scop GFP_NOFS api NeilBrown <mr@neil.brown.name> - 2016-05-01 00:00 +0200
        Re: [PATCH 0/2] scop GFP_NOFS api Michal Hocko <mhocko@kernel.org> - 2016-05-03 17:20 +0200
          Re: [PATCH 0/2] scop GFP_NOFS api NeilBrown <mr@neil.brown.name> - 2016-05-04 01:30 +0200
    Re: [PATCH 0/2] scop GFP_NOFS api Dave Chinner <david@fromorbit.com> - 2016-04-30 02:20 +0200
      Re: [PATCH 0/2] scop GFP_NOFS api NeilBrown <mr@neil.brown.name> - 2016-05-01 00:30 +0200
        Re: [PATCH 0/2] scop GFP_NOFS api Dave Chinner <david@fromorbit.com> - 2016-05-04 03:10 +0200
          Re: [PATCH 0/2] scop GFP_NOFS api NeilBrown <mr@neil.brown.name> - 2016-05-06 05:30 +0200

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