jbd2: fix checkpoint cleanup performance regression

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journal_clean_one_cp_list() has been merged into
journal_shrink_one_cp_list(), but do chekpoint buffer cleanup from the
committing process is just a best effort, it should stop scan once it
meet a busy buffer, or else it will cause a lot of invalid buffer scan
and checks. We catch a performance regression when doing fs_mark tests
below.

Test cmd:
 ./fs_mark  -d  scratch  -s  1024  -n  10000  -t  1  -D  100  -N  100

Before merging checkpoint buffer cleanup:
 FSUse%        Count         Size    Files/sec     App Overhead
     95        10000         1024       8304.9            49033

After merging checkpoint buffer cleanup:
 FSUse%        Count         Size    Files/sec     App Overhead
     95        10000         1024       7649.0            50012
 FSUse%        Count         Size    Files/sec     App Overhead
     95        10000         1024       2107.1            50871

After merging checkpoint buffer cleanup, the total loop count in
journal_shrink_one_cp_list() could be up to 6,261,600+ (50,000+ ~
100,000+ in general), most of them are invalid. This patch fix it
through passing 'shrink_type' into journal_shrink_one_cp_list() and add
a new 'SHRINK_BUSY_STOP' to indicate it should stop once meet a busy
buffer. After fix, the loop count descending back to 10,000+.

After this fix:
 FSUse%        Count         Size    Files/sec     App Overhead
     95        10000         1024       8558.4            49109

Cc: stable@kernel.org
Fixes: b98dba273a ("jbd2: remove journal_clean_one_cp_list()")
Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230714025528.564988-2-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

...

This commit is contained in:

Zhang Yi 2023-07-14 10:55:26 +08:00 • committed by Theodore Ts'o

parent 4eea9fbed9

commit 373ac52179

1 changed files with 14 additions and 6 deletions

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fs/jbd2/checkpoint.c

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