From: Matthew Wilcox <willy@infradead.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-xfs@vger.kernel.org, dm-devel@redhat.com,
Mikulas Patocka <mpatocka@redhat.com>,
Jens Axboe <axboe@kernel.dk>, NeilBrown <neilb@suse.de>,
Yafang Shao <laoar.shao@gmail.com>
Subject: Re: [PATCH 0/6] Overhaul memalloc_no*
Date: Thu, 25 Jun 2020 21:40:44 +0100 [thread overview]
Message-ID: <20200625204044.GH7703@casper.infradead.org> (raw)
In-Reply-To: <20200625203611.GS1320@dhcp22.suse.cz>
On Thu, Jun 25, 2020 at 10:36:11PM +0200, Michal Hocko wrote:
> On Thu 25-06-20 11:48:32, Darrick J. Wong wrote:
> > On Thu, Jun 25, 2020 at 12:31:16PM +0100, Matthew Wilcox (Oracle) wrote:
> > > I want a memalloc_nowait like we have memalloc_noio and memalloc_nofs
> > > for an upcoming patch series, and Jens also wants it for non-blocking
> > > io_uring. It turns out we already have dm-bufio which could benefit
> > > from memalloc_nowait, so it may as well go into the tree now.
> > >
> > > The biggest problem is that we're basically out of PF_ flags, so we need
> > > to find somewhere else to store the PF_MEMALLOC_NOWAIT flag. It turns
> > > out the PF_ flags are really supposed to be used for flags which are
> > > accessed from other tasks, and the MEMALLOC flags are only going to
> > > be used by this task. So shuffling everything around frees up some PF
> > > flags and generally makes the world a better place.
> >
> > So, uh, how does this intersect with the patch "xfs: reintroduce
> > PF_FSTRANS for transaction reservation recursion protection" that
> > re-adds PF_TRANS because uh I guess we lost some subtlety or another at
> > some point?
>
> This is independent, really. It just relocates the NOFS flag. PF_TRANS
> is reintroduced for a different reason. When I have replaced the
> original PF_TRANS by PF_MEMALLOC_NOFS I didn't realized that xfs doesn't
> need only the NOFS semantic but also the transaction tracking so this
> cannot be a single bit only. So it has to be added back. But
> PF_MEMALLOC_NOFS needs to stay for the scoped NOFS semantic.
If XFS needs to track transactions, why doesn't it use
current->journal_info like btrfs/ceph/ext4/gfs2/nilfs2/reiserfs?
next prev parent reply other threads:[~2020-06-25 20:40 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-25 11:31 [PATCH 0/6] Overhaul memalloc_no* Matthew Wilcox (Oracle)
2020-06-25 11:31 ` [PATCH 1/6] mm: Replace PF_MEMALLOC_NOIO with memalloc_noio Matthew Wilcox (Oracle)
2020-06-25 12:22 ` Michal Hocko
2020-06-25 12:34 ` Matthew Wilcox
2020-06-25 12:42 ` Michal Hocko
2020-06-25 11:31 ` [PATCH 2/6] mm: Add become_kswapd and restore_kswapd Matthew Wilcox (Oracle)
2020-06-25 12:31 ` Michal Hocko
2020-06-25 11:31 ` [PATCH 3/6] xfs: Convert to memalloc_nofs_save Matthew Wilcox (Oracle)
2020-06-25 11:31 ` [PATCH 4/6] mm: Replace PF_MEMALLOC_NOFS with memalloc_nofs Matthew Wilcox (Oracle)
2020-06-25 13:35 ` Michal Hocko
2020-06-25 11:31 ` [PATCH 5/6] mm: Replace PF_MEMALLOC_NOIO with memalloc_nocma Matthew Wilcox (Oracle)
2020-06-25 11:31 ` [PATCH 6/6] mm: Add memalloc_nowait Matthew Wilcox (Oracle)
2020-06-25 12:40 ` Michal Hocko
2020-06-25 13:10 ` Matthew Wilcox
2020-06-25 13:34 ` Michal Hocko
2020-06-25 19:05 ` kernel test robot
2020-06-25 23:51 ` kernel test robot
2020-06-29 5:08 ` Mike Rapoport
2020-06-29 12:18 ` Matthew Wilcox
2020-06-29 12:52 ` Michal Hocko
2020-06-29 13:45 ` Mike Rapoport
2020-06-29 21:28 ` Matthew Wilcox
2020-06-30 6:34 ` Michal Hocko
2020-07-01 4:12 ` Matthew Wilcox
2020-07-01 5:53 ` Michal Hocko
2020-07-01 7:04 ` Mike Rapoport
2020-09-24 0:39 ` Mike Snitzer
2020-09-24 1:10 ` Matthew Wilcox
2020-10-23 14:49 ` Daniel Vetter
2020-06-25 18:48 ` [PATCH 0/6] Overhaul memalloc_no* Darrick J. Wong
2020-06-25 20:34 ` Matthew Wilcox
2020-06-25 20:36 ` Michal Hocko
2020-06-25 20:40 ` Matthew Wilcox [this message]
2020-06-26 15:02 ` Mikulas Patocka
2020-06-26 23:08 ` Dave Chinner
2020-06-27 13:09 ` Mikulas Patocka
2020-06-29 0:35 ` Dave Chinner
2020-06-29 13:43 ` Mikulas Patocka
2020-06-29 22:34 ` Dave Chinner
2020-07-03 14:26 ` [PATCH] dm-bufio: do cleanup from a workqueue Mikulas Patocka
2020-06-29 8:22 ` [PATCH 0/6] Overhaul memalloc_no* Michal Hocko
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