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* [PATCH 0/7 v2] Speed up page cache truncation
@ 2017-10-17 16:21 ` Jan Kara
  0 siblings, 0 replies; 18+ messages in thread
From: Jan Kara @ 2017-10-17 16:21 UTC (permalink / raw)
  To: linux-mm; +Cc: linux-fsdevel, Mel Gorman, Kirill A. Shutemov, Jan Kara

Hello,

when rebasing our enterprise distro to a newer kernel (from 4.4 to 4.12) we
have noticed a regression in bonnie++ benchmark when deleting files.
Eventually we have tracked this down to a fact that page cache truncation got
slower by about 10%. There were both gains and losses in the above interval of
kernels but we have been able to identify that commit 83929372f629 "filemap:
prepare find and delete operations for huge pages" caused about 10% regression
on its own.

After some investigation it didn't seem easily possible to fix the regression
while maintaining the THP in page cache functionality so we've decided to
optimize the page cache truncation path instead to make up for the change.
This series is a result of that effort.

Patch 1 is an easy speedup of cancel_dirty_page(). Patches 2-6 refactor page
cache truncation code so that it is easier to batch radix tree operations.
Patch 7 implements batching of deletes from the radix tree which more than
makes up for the original regression.

Andrew, can you please consider merging these patches? Thanks!

Changes since v1:
* Added acks and reviewed-by tags


								Honza

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^ permalink raw reply	[flat|nested] 18+ messages in thread
* [PATCH 0/7 v1] Speed up page cache truncation
@ 2017-10-10 15:19 Jan Kara
  2017-10-10 15:19   ` Jan Kara
  0 siblings, 1 reply; 18+ messages in thread
From: Jan Kara @ 2017-10-10 15:19 UTC (permalink / raw)
  To: linux-mm; +Cc: Mel Gorman, Kirill A. Shutemov, linux-fsdevel, Jan Kara

Hello,

when rebasing our enterprise distro to a newer kernel (from 4.4 to 4.12) we
have noticed a regression in bonnie++ benchmark when deleting files.
Eventually we have tracked this down to a fact that page cache truncation got
slower by about 10%. There were both gains and losses in the above interval of
kernels but we have been able to identify that commit 83929372f629 "filemap:
prepare find and delete operations for huge pages" caused about 10% regression
on its own.

After some investigation it didn't seem easily possible to fix the regression
while maintaining the THP in page cache functionality so we've decided to
optimize the page cache truncation path instead to make up for the change.
This series is a result of that effort.

Patch 1 is an easy speedup of cancel_dirty_page(). Patches 2-6 refactor page
cache truncation code so that it is easier to batch radix tree operations.
Patch 7 implements batching of deletes from the radix tree which more than
makes up for the original regression.

What do people think about this series?

								Honza

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To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

^ permalink raw reply	[flat|nested] 18+ messages in thread

end of thread, other threads:[~2017-10-17 16:21 UTC | newest]

Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-10-17 16:21 [PATCH 0/7 v2] Speed up page cache truncation Jan Kara
2017-10-17 16:21 ` Jan Kara
2017-10-17 16:21 ` [PATCH 1/7] mm: Speedup cancel_dirty_page() for clean pages Jan Kara
2017-10-17 16:21   ` Jan Kara
2017-10-17 16:21 ` [PATCH 2/7] mm: Refactor truncate_complete_page() Jan Kara
2017-10-17 16:21   ` Jan Kara
2017-10-17 16:21 ` [PATCH 3/7] mm: Factor out page cache page freeing into a separate function Jan Kara
2017-10-17 16:21   ` Jan Kara
2017-10-17 16:21 ` [PATCH 4/7] mm: Move accounting updates before page_cache_tree_delete() Jan Kara
2017-10-17 16:21   ` Jan Kara
2017-10-17 16:21 ` [PATCH 5/7] mm: Move clearing of page->mapping to page_cache_tree_delete() Jan Kara
2017-10-17 16:21   ` Jan Kara
2017-10-17 16:21 ` [PATCH 6/7] mm: Factor out checks and accounting from __delete_from_page_cache() Jan Kara
2017-10-17 16:21   ` Jan Kara
2017-10-17 16:21 ` [PATCH 7/7] mm: Batch radix tree operations when truncating pages Jan Kara
2017-10-17 16:21   ` Jan Kara
  -- strict thread matches above, loose matches on Subject: below --
2017-10-10 15:19 [PATCH 0/7 v1] Speed up page cache truncation Jan Kara
2017-10-10 15:19 ` [PATCH 6/7] mm: Factor out checks and accounting from __delete_from_page_cache() Jan Kara
2017-10-10 15:19   ` Jan Kara

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