The patch titled
do_mpage_readpage(): don't submit lots of small bios on boundary
has been removed from the -mm tree. Its filename was
do_mpage_readpage-dont-submit-lots-of-small-bios-on-boundary.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: do_mpage_readpage(): don't submit lots of small bios on boundary
From: Miquel van Smoorenburg <mikevs@xxxxxxxxxx>
While tracing I/O patterns with blktrace (a great tool) a few weeks ago I
identified a minor issue in fs/mpage.c
As the comment above mpage_readpages() says, a fs's get_block function
will set BH_Boundary when it maps a block just before a block for which
extra I/O is required.
Since get_block() can map a range of pages, for all these pages the
BH_Boundary flag will be set. But we only need to push what I/O we have
accumulated at the last block of this range.
This makes do_mpage_readpage() send out the largest possible bio instead
of a bunch of page-sized ones in the BH_Boundary case.
Signed-off-by: Miquel van Smoorenburg <mikevs@xxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/mpage.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff -puN fs/mpage.c~do_mpage_readpage-dont-submit-lots-of-small-bios-on-boundary fs/mpage.c
--- a/fs/mpage.c~do_mpage_readpage-dont-submit-lots-of-small-bios-on-boundary
+++ a/fs/mpage.c
@@ -308,7 +308,10 @@ alloc_new:
goto alloc_new;
}
- if (buffer_boundary(map_bh) || (first_hole != blocks_per_page))
+ relative_block = block_in_file - *first_logical_block;
+ nblocks = map_bh->b_size >> blkbits;
+ if ((buffer_boundary(map_bh) && relative_block == nblocks) ||
+ (first_hole != blocks_per_page))
bio = mpage_bio_submit(READ, bio);
else
*last_block_in_bio = blocks[blocks_per_page - 1];
_
Patches currently in -mm which might be from mikevs@xxxxxxxxxx are
origin.patch
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