tree 186359995e27df92fd6539ad0a0657df8e79322e
parent 69f63c5c34d0b34ee2cbf10c5ff7fcff0404879e
author Nick Piggin <nickpiggin@yahoo.com.au> 1120016713 -0700
committer Linus Torvalds <torvalds@ppc970.osdl.org> 1120018834 -0700

[PATCH] blk: __make_request efficiency

In the case where the request is not able to be merged by the elevator, don't
retake the lock and retry the merge mechanism after allocating a new request.

Instead assume that the chance of a merge remains slim, and now that we've
done most of the work allocating a request we may as well just go with it.

Also be rid of the GFP_ATOMIC allocation: we've got working mempools for the
block layer now, so let's save atomic memory for things like networking.

Lastly, in get_request_wait, do an initial get_request call before going into
the waitqueue.  This is reported to help efficiency.

Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>