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From: Gao Xiang <hsiangkao@redhat.com>
To: linux-xfs@vger.kernel.org
Cc: Dave Chinner <david@fromorbit.com>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	Brian Foster <bfoster@redhat.com>,
	Gao Xiang <hsiangkao@redhat.com>
Subject: [RFC PATCH 0/2] xfs: more unlinked inode list optimization v1
Date: Tue,  7 Jul 2020 21:57:39 +0800
Message-ID: <20200707135741.487-1-hsiangkao@redhat.com> (raw)

Hi forks,

This RFC patchset mainly addresses the thoughts [*] and [**] from Dave's
original patchset,
https://lore.kernel.org/r/20200623095015.1934171-1-david@fromorbit.com

In short, it focues on the following ideas mentioned by Dave:
 - use bucket 0 instead of multiple buckets since in-memory double
   linked list finally works;

 - avoid taking AGI buffer and unnecessary AGI update if possible, so
   1) add a new lock and keep proper locking order to avoid deadlock;
   2) insert a new unlinked inode from the tail instead of head;

In addition, it's worth noticing 3 things:
 - xfs_iunlink_remove() should support old multiple buckets in order
   to keep old inode unlinked list (old image) working when recovering.

 - (but) OTOH, the old kernel recovery _shouldn't_ work with new image
   since the bucket_index from old xfs_iunlink_remove() is generated
   by the old formula (rather than keep in xfs_inode), which is now
   fixed as 0. So this feature is not forward compatible without some
   extra backport patches;

 - a tail xfs_inode pointer is also added in the perag, which keeps 
   track of the tail of bucket 0 since it's mainly used for xfs_iunlink().

 - the old kernel recovery shouldn't work with new image since
     its bucket_index from old kernel is 

The git tree is also available at
git://git.kernel.org/pub/scm/linux/kernel/git/xiang/linux.git tags/xfs/iunlink_opt_v1

Some limited test for debugging only is done (mainly fsstress and
manual power-cut tests), so it could not work as expected just like
my limited broken xfs knowledge. But I will go on improving this
patchset recently. 

Any comments and directions are welcome. :)

Thanks,
Gao Xiang

Gao Xiang (2):
  xfs: arrange all unlinked inodes into one list
  xfs: don't access AGI on unlinked inodes if it can

 fs/xfs/xfs_inode.c       | 283 ++++++++++++++++++++-------------------
 fs/xfs/xfs_log_recover.c |   6 +
 fs/xfs/xfs_mount.c       |   3 +
 fs/xfs/xfs_mount.h       |   3 +
 4 files changed, 160 insertions(+), 135 deletions(-)

-- 
2.18.1


             reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-07 13:57 Gao Xiang [this message]
2020-07-07 13:57 ` [RFC PATCH 1/2] xfs: arrange all unlinked inodes into one list Gao Xiang
2020-07-08 22:33   ` Dave Chinner
2020-07-09  0:17     ` Gao Xiang
2020-07-07 13:57 ` [RFC PATCH 2/2] xfs: don't access AGI on unlinked inodes if it can Gao Xiang
2020-07-08 17:03   ` Darrick J. Wong
2020-07-08 23:40     ` Gao Xiang
2020-07-08 23:33   ` Dave Chinner
2020-07-09  0:55     ` Gao Xiang
2020-07-09  2:32       ` Dave Chinner
2020-07-09 10:36         ` Gao Xiang
2020-07-09 10:47           ` Gao Xiang
2020-07-09 22:36           ` Dave Chinner
2020-07-24  6:12 ` [RFC PATCH v2 0/3] xfs: more unlinked inode list optimization v2 Gao Xiang
2020-07-24  6:12   ` [RFC PATCH v2 1/3] xfs: arrange all unlinked inodes into one list Gao Xiang
2020-07-24  6:12   ` [RFC PATCH v2 2/3] xfs: introduce perag iunlink lock Gao Xiang
2020-07-24  6:12   ` [RFC PATCH v2 3/3] xfs: insert unlinked inodes from tail Gao Xiang
2020-08-18 13:30   ` [RFC PATCH v4 0/3] xfs: more unlinked inode list optimization v4 Gao Xiang
2020-08-18 13:30     ` [RFC PATCH v4 1/3] xfs: get rid of unused pagi_unlinked_hash Gao Xiang
2020-08-19  0:54       ` Darrick J. Wong
2020-08-21  1:09         ` Dave Chinner
2020-08-18 13:30     ` [RFC PATCH v4 2/3] xfs: introduce perag iunlink lock Gao Xiang
2020-08-19  1:06       ` Darrick J. Wong
2020-08-19  1:23         ` Gao Xiang
2020-08-18 13:30     ` [RFC PATCH v4 3/3] xfs: insert unlinked inodes from tail Gao Xiang
2020-08-19  0:53     ` [RFC PATCH v4 0/3] xfs: more unlinked inode list optimization v4 Darrick J. Wong
2020-08-19  1:14       ` Gao Xiang
2020-08-20  2:46     ` Darrick J. Wong
2020-08-20  4:01       ` Gao Xiang

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