Commits
Mel Gorman committed f2187599189
mm, truncate: remove all exceptional entries from pagevec under one lock
During truncate each entry in a pagevec is checked to see if it is an
exceptional entry and if so, the shadow entry is cleaned up. This is
potentially expensive as multiple entries for a mapping locks/unlocks
the tree lock. This batches the operation such that any exceptional
entries removed from a pagevec only acquire the mapping tree lock once.
The corner case where this is more expensive is where there is only one
exceptional entry but this is unlikely due to temporal locality and how
it affects LRU ordering. Note that for truncations of small files
created recently, this patch should show no gain because it only batches
the handling of exceptional entries.
sparsetruncate (large)
4.14.0-rc4 4.14.0-rc4
pickhelper-v1r1 batchshadow-v1r1
Min Time 38.00 ( 0.00%) 27.00 ( 28.95%)
1st-qrtle Time 40.00 ( 0.00%) 28.00 ( 30.00%)
2nd-qrtle Time 44.00 ( 0.00%) 41.00 ( 6.82%)
3rd-qrtle Time 146.00 ( 0.00%) 147.00 ( -0.68%)
Max-90% Time 153.00 ( 0.00%) 153.00 ( 0.00%)
Max-95% Time 155.00 ( 0.00%) 156.00 ( -0.65%)
Max-99% Time 181.00 ( 0.00%) 171.00 ( 5.52%)
Amean Time 93.04 ( 0.00%) 88.43 ( 4.96%)
Best99%Amean Time 92.08 ( 0.00%) 86.13 ( 6.46%)
Best95%Amean Time 89.19 ( 0.00%) 83.13 ( 6.80%)
Best90%Amean Time 85.60 ( 0.00%) 79.15 ( 7.53%)
Best75%Amean Time 72.95 ( 0.00%) 65.09 ( 10.78%)
Best50%Amean Time 39.86 ( 0.00%) 28.20 ( 29.25%)
Best25%Amean Time 39.44 ( 0.00%) 27.70 ( 29.77%)
bonnie
4.14.0-rc4 4.14.0-rc4
pickhelper-v1r1 batchshadow-v1r1
Hmean SeqCreate ops 71.92 ( 0.00%) 76.78 ( 6.76%)
Hmean SeqCreate read 42.42 ( 0.00%) 45.01 ( 6.10%)
Hmean SeqCreate del 26519.88 ( 0.00%) 27191.87 ( 2.53%)
Hmean RandCreate ops 71.92 ( 0.00%) 76.95 ( 7.00%)
Hmean RandCreate read 44.44 ( 0.00%) 49.23 ( 10.78%)
Hmean RandCreate del 24948.62 ( 0.00%) 24764.97 ( -0.74%)
Truncation of a large number of files shows a substantial gain with 99%
of files being truncated 6.46% faster. bonnie shows a modest gain of
2.53%
[jack@suse.cz: fix truncate_exceptional_pvec_entries()]
Link: http://lkml.kernel.org/r/20171108164226.26788-1-jack@suse.cz
Link: http://lkml.kernel.org/r/20171018075952.10627-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>