Re: [PATCH v4 1/2] xfs: avoid double restore PF_MEMALLOC_NOFS if transaction reservation fails

From: Yafang Shao <laoar.shao@gmail.com>
To: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <willy@infradead.org>,
	Christoph Hellwig <hch@infradead.org>,
	 "Darrick J. Wong" <darrick.wong@oracle.com>,
	Michal Hocko <mhocko@kernel.org>,
	linux-xfs@vger.kernel.org,  linux-fsdevel@vger.kernel.org,
	Linux MM <linux-mm@kvack.org>,
	 Yafang Shao <shaoyafang@didiglobal.com>
Subject: Re: [PATCH v4 1/2] xfs: avoid double restore PF_MEMALLOC_NOFS if transaction reservation fails
Date: Fri, 7 Aug 2020 12:05:26 +0800	[thread overview]
Message-ID: <CALOAHbD4jVnMGgG1Gi1b8XqATexPipnUeVkHGN+n5xGbab0hOw@mail.gmail.com> (raw)
In-Reply-To: <20200805012809.GF2114@dread.disaster.area>

On Wed, Aug 5, 2020 at 9:28 AM Dave Chinner <david@fromorbit.com> wrote:
>
> On Wed, Aug 05, 2020 at 12:50:38AM +0100, Matthew Wilcox wrote:
> > On Wed, Aug 05, 2020 at 09:20:05AM +1000, Dave Chinner wrote:
> > > Also, please convert these to memalloc_nofs_save()/restore() calls
> > > as that is the way we are supposed to mark these regions now.
> >
> > I have a patch for that!
>
> Did you compile test it? :)
>
> > ---
> >  fs/xfs/kmem.c      |  2 +-
> >  fs/xfs/xfs_aops.c  |  4 ++--
> >  fs/xfs/xfs_buf.c   |  2 +-
> >  fs/xfs/xfs_linux.h |  6 ------
> >  fs/xfs/xfs_trans.c | 14 +++++++-------
> >  fs/xfs/xfs_trans.h |  2 +-
> >  6 files changed, 12 insertions(+), 18 deletions(-)
>
> .....
>
> > diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h
> > index 9f70d2f68e05..e1daf242a53b 100644
> > --- a/fs/xfs/xfs_linux.h
> > +++ b/fs/xfs/xfs_linux.h
> > @@ -104,12 +104,6 @@ typedef __u32                    xfs_nlink_t;
> >  #define current_cpu()                (raw_smp_processor_id())
> >  #define current_pid()                (current->pid)
> >  #define current_test_flags(f)        (current->flags & (f))
> > -#define current_set_flags_nested(sp, f)              \
> > -             (*(sp) = current->flags, current->flags |= (f))
> > -#define current_clear_flags_nested(sp, f)    \
> > -             (*(sp) = current->flags, current->flags &= ~(f))
> > -#define current_restore_flags_nested(sp, f)  \
> > -             (current->flags = ((current->flags & ~(f)) | (*(sp) & (f))))
>
> current_set_flags_nested() and current_restore_flags_nested()
> are used in xfs_btree_split_worker() in fs/xfs/libxfs/xfs_btree.c
> and that's not a file you modified in this patch...
>

It is in Willy's another patch "mm: Add become_kswapd and
restore_kswapd"[1], which can be committed independently from
"Overhaul memalloc_no*" series. I will carry it in the next version.

[1] https://lore.kernel.org/linux-mm/20200625113122.7540-3-willy@infradead.org/#t
[2] https://lore.kernel.org/linux-mm/20200625113122.7540-1-willy@infradead.org/

-- 
Thanks
Yafang