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author | Miquel van Smoorenburg <mikevs@xs4all.net> | 2009-01-06 14:39:02 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-06 15:58:59 -0800 |
commit | 38c8e6180939e5619140b2e9e479cb26029ff8b1 (patch) | |
tree | 1980f3dadfa02ac6c1fc2ad7236205af54f7972a /mm/page-writeback.c | |
parent | 75aa199410359dc5fbcf9025ff7af98a9d20f0d5 (diff) | |
download | op-kernel-dev-38c8e6180939e5619140b2e9e479cb26029ff8b1.zip op-kernel-dev-38c8e6180939e5619140b2e9e479cb26029ff8b1.tar.gz |
do_mpage_readpage(): don't submit lots of small bios on boundary
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@xs4all.net>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page-writeback.c')
0 files changed, 0 insertions, 0 deletions