]> git.baikalelectronics.ru Git - kernel.git/commit
[PATCH] optimize o_direct on block devices
authorChen, Kenneth W <kenneth.w.chen@intel.com>
Wed, 13 Dec 2006 08:34:36 +0000 (00:34 -0800)
committerLinus Torvalds <torvalds@woody.osdl.org>
Wed, 13 Dec 2006 17:05:50 +0000 (09:05 -0800)
commit011b1bef14f956d0052ffa8f4e959600f8648c62
tree7de9cc41910c55e32aba0f8cc07f73923b7cb515
parent20926e5f05aa1b7610e9290b17e7d1fd463cf490
[PATCH] optimize o_direct on block devices

Implement block device specific .direct_IO method instead of going through
generic direct_io_worker for block device.

direct_io_worker() is fairly complex because it needs to handle O_DIRECT on
file system, where it needs to perform block allocation, hole detection,
extents file on write, and tons of other corner cases.  The end result is
that it takes tons of CPU time to submit an I/O.

For block device, the block allocation is much simpler and a tight triple
loop can be written to iterate each iovec and each page within the iovec in
order to construct/prepare bio structure and then subsequently submit it to
the block layer.  This significantly speeds up O_D on block device.

[akpm@osdl.org: small speedup]
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
fs/bio.c
fs/block_dev.c
include/linux/aio.h
include/linux/bio.h