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From: Dave Chinner <david@fromorbit.com>
To: Brian Foster <bfoster@redhat.com>
Cc: linux-xfs@vger.kernel.org, linux-mm@kvack.org,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 18/24] xfs: reduce kswapd blocking on inode locking.
Date: Thu, 8 Aug 2019 09:16:47 +1000	[thread overview]
Message-ID: <20190807231647.GS7777@dread.disaster.area> (raw)
In-Reply-To: <20190807113009.GC19707@bfoster>

On Wed, Aug 07, 2019 at 07:30:09AM -0400, Brian Foster wrote:
> Second (and not necessarily caused by this patch), the ireclaim flag
> semantics are kind of a mess. As you've already noted, we currently
> block on some locks even with SYNC_TRYLOCK, yet the cluster flushing
> code has no concept of these flags (so we always trylock, never wait on
> unpin, for some reason use the shared ilock vs. the exclusive ilock,
> etc.). Further, with this patch TRYLOCK|WAIT basically means that if we
> happen to get the lock, we flush and wait on I/O so we can free the
> inode(s), but if somebody else has flushed the inode (we don't get the
> flush lock) we decide not to wait on the I/O that might (or might not)
> already be in progress. I find that a bit inconsistent. It also makes me
> slightly concerned that we're (ab)using flag semantics for a bug fix
> (waiting on inodes we've just flushed from the same task), but it looks
> like this is all going to change quite a bit still so I'm not going to
> worry too much about this mostly existing mess until I grok the bigger
> picture changes... :P

Yes, SYNC_TRYLOCK/SYNC_WAIT semantics are a mess, but they all go
away later in the patchset.  Non-blocking reclaim makes SYNC_TRYLOCK
go away because everything becomes try-lock based, and SYNC_WAIT goes
away because only the xfs_reclaim_inodes() function needs to wait
for reclaim completion and so that gets it's own LRU walker
implementation and the mode parameter is removed.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

  reply	other threads:[~2019-08-07 23:17 UTC|newest]

Thread overview: 87+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-01  2:17 [RFC] [PATCH 00/24] mm, xfs: non-blocking inode reclaim Dave Chinner
2019-08-01  2:17 ` [PATCH 01/24] mm: directed shrinker work deferral Dave Chinner
2019-08-02 15:27   ` Brian Foster
2019-08-04  1:49     ` Dave Chinner
2019-08-05 17:42       ` Brian Foster
2019-08-05 23:43         ` Dave Chinner
2019-08-06 12:27           ` Brian Foster
2019-08-06 22:22             ` Dave Chinner
2019-08-07 11:13               ` Brian Foster
2019-08-01  2:17 ` [PATCH 02/24] shrinkers: use will_defer for GFP_NOFS sensitive shrinkers Dave Chinner
2019-08-02 15:27   ` Brian Foster
2019-08-04  1:50     ` Dave Chinner
2019-08-01  2:17 ` [PATCH 03/24] mm: factor shrinker work calculations Dave Chinner
2019-08-02 15:08   ` Nikolay Borisov
2019-08-04  2:05     ` Dave Chinner
2019-08-02 15:31   ` Brian Foster
2019-08-01  2:17 ` [PATCH 04/24] shrinker: defer work only to kswapd Dave Chinner
2019-08-02 15:34   ` Brian Foster
2019-08-04 16:48   ` Nikolay Borisov
2019-08-04 21:37     ` Dave Chinner
2019-08-07 16:12   ` kbuild test robot
2019-08-07 18:00   ` kbuild test robot
2019-08-01  2:17 ` [PATCH 05/24] shrinker: clean up variable types and tracepoints Dave Chinner
2019-08-01  2:17 ` [PATCH 06/24] mm: reclaim_state records pages reclaimed, not slabs Dave Chinner
2019-08-01  2:17 ` [PATCH 07/24] mm: back off direct reclaim on excessive shrinker deferral Dave Chinner
2019-08-01  2:17 ` [PATCH 08/24] mm: kswapd backoff for shrinkers Dave Chinner
2019-08-01  2:17 ` [PATCH 09/24] xfs: don't allow log IO to be throttled Dave Chinner
2019-08-01 13:39   ` Chris Mason
2019-08-01 23:58     ` Dave Chinner
2019-08-02  8:12       ` Christoph Hellwig
2019-08-02 14:11       ` Chris Mason
2019-08-02 18:34         ` Matthew Wilcox
2019-08-02 23:28         ` Dave Chinner
2019-08-05 18:32           ` Chris Mason
2019-08-05 23:09             ` Dave Chinner
2019-08-01  2:17 ` [PATCH 10/24] xfs: fix missed wakeup on l_flush_wait Dave Chinner
2019-08-01  2:17 ` [PATCH 11/24] xfs:: account for memory freed from metadata buffers Dave Chinner
2019-08-01  8:16   ` Christoph Hellwig
2019-08-01  9:21     ` Dave Chinner
2019-08-06  5:51       ` Christoph Hellwig
2019-08-01  2:17 ` [PATCH 12/24] xfs: correctly acount for reclaimable slabs Dave Chinner
2019-08-06  5:52   ` Christoph Hellwig
2019-08-06 21:05     ` Dave Chinner
2019-08-01  2:17 ` [PATCH 13/24] xfs: synchronous AIL pushing Dave Chinner
2019-08-05 17:51   ` Brian Foster
2019-08-05 23:21     ` Dave Chinner
2019-08-06 12:29       ` Brian Foster
2019-08-01  2:17 ` [PATCH 14/24] xfs: tail updates only need to occur when LSN changes Dave Chinner
2019-08-05 17:53   ` Brian Foster
2019-08-05 23:28     ` Dave Chinner
2019-08-06  5:33       ` Dave Chinner
2019-08-06 12:53         ` Brian Foster
2019-08-06 21:11           ` Dave Chinner
2019-08-01  2:17 ` [PATCH 15/24] xfs: eagerly free shadow buffers to reduce CIL footprint Dave Chinner
2019-08-05 18:03   ` Brian Foster
2019-08-05 23:33     ` Dave Chinner
2019-08-06 12:57       ` Brian Foster
2019-08-06 21:21         ` Dave Chinner
2019-08-01  2:17 ` [PATCH 16/24] xfs: Lower CIL flush limit for large logs Dave Chinner
2019-08-04 17:12   ` Nikolay Borisov
2019-08-01  2:17 ` [PATCH 17/24] xfs: don't block kswapd in inode reclaim Dave Chinner
2019-08-06 18:21   ` Brian Foster
2019-08-06 21:27     ` Dave Chinner
2019-08-07 11:14       ` Brian Foster
2019-08-01  2:17 ` [PATCH 18/24] xfs: reduce kswapd blocking on inode locking Dave Chinner
2019-08-06 18:22   ` Brian Foster
2019-08-06 21:33     ` Dave Chinner
2019-08-07 11:30       ` Brian Foster
2019-08-07 23:16         ` Dave Chinner [this message]
2019-08-01  2:17 ` [PATCH 19/24] xfs: kill background reclaim work Dave Chinner
2019-08-01  2:17 ` [PATCH 20/24] xfs: use AIL pushing for inode reclaim IO Dave Chinner
2019-08-07 18:09   ` Brian Foster
2019-08-07 23:10     ` Dave Chinner
2019-08-08 16:20       ` Brian Foster
2019-08-01  2:17 ` [PATCH 21/24] xfs: remove mode from xfs_reclaim_inodes() Dave Chinner
2019-08-01  2:17 ` [PATCH 22/24] xfs: track reclaimable inodes using a LRU list Dave Chinner
2019-08-08 16:36   ` Brian Foster
2019-08-09  0:10     ` Dave Chinner
2019-08-01  2:17 ` [PATCH 23/24] xfs: reclaim inodes from the LRU Dave Chinner
2019-08-08 16:39   ` Brian Foster
2019-08-09  1:20     ` Dave Chinner
2019-08-09 12:36       ` Brian Foster
2019-08-11  2:17         ` Dave Chinner
2019-08-11 12:46           ` Brian Foster
2019-08-01  2:17 ` [PATCH 24/24] xfs: remove unusued old inode reclaim code Dave Chinner
2019-08-06  5:57 ` [RFC] [PATCH 00/24] mm, xfs: non-blocking inode reclaim Christoph Hellwig
2019-08-06 21:37   ` Dave Chinner

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