this is against 2.6.19-git17 hope this correct raz On 12/11/06, Jens Axboe <[EMAIL PROTECTED]> wrote:
On Mon, Dec 11 2006, Raz Ben-Jehuda(caro) wrote: > On 12/11/06, Jens Axboe <[EMAIL PROTECTED]> wrote: > >On Sun, Dec 10 2006, [EMAIL PROTECTED] wrote: > >> From: "Raz Ben-Jehuda(caro)" <[EMAIL PROTECTED]> > >> > >> This will encourage read request to be on only one device, so we will > >often be > >> able to bypass the cache for read requests. > >> > >> Signed-off-by: Neil Brown <[EMAIL PROTECTED]> > >> Cc: Jens Axboe <[EMAIL PROTECTED]> > >> Signed-off-by: Andrew Morton <[EMAIL PROTECTED]> > >> --- > >> > >> drivers/md/raid5.c | 24 ++++++++++++++++++++++++ > >> 1 file changed, 24 insertions(+) > >> > >> diff -puN drivers/md/raid5.c~md-define-raid5_mergeable_bvec > >drivers/md/raid5.c > >> --- a/drivers/md/raid5.c~md-define-raid5_mergeable_bvec > >> +++ a/drivers/md/raid5.c > >> @@ -2611,6 +2611,28 @@ static int raid5_congested(void *data, i > >> return 0; > >> } > >> > >> +/* We want read requests to align with chunks where possible, > >> + * but write requests don't need to. > >> + */ > >> +static int raid5_mergeable_bvec(request_queue_t *q, struct bio *bio, > >struct bio_vec *biovec) > >> +{ > >> + mddev_t *mddev = q->queuedata; > >> + sector_t sector = bio->bi_sector + get_start_sect(bio->bi_bdev); > >> + int max; > >> + unsigned int chunk_sectors = mddev->chunk_size >> 9; > >> + unsigned int bio_sectors = bio->bi_size >> 9; > >> + > >> + if (bio_data_dir(bio)) > >> + return biovec->bv_len; /* always allow writes to be > >mergeable */ > > > >Please don't ever do that - you are making assumptions on the value of > >READ and WRITE. > > > > if (bio_data_dir(bio) == WRITE) > > ... > > > >If this has already been merged, please submit a patch correcting it. > >People end up copying code like this :-) > > > >-- > >Jens Axboe > > > > > > thanks Jens > the attached is a fix.But the patch is already merged, so the patch needs to be against Linus' current tree. -- Jens Axboe
-- Raz
--- linux-2.6.19/drivers/md/raid5.c 2006-12-11 11:33:23.000000000 +0000 +++ linux-2.6.19-git17/drivers/md/raid5.c 2006-12-11 11:31:27.000000000 +0000 @@ -2567,7 +2567,7 @@ unsigned int chunk_sectors = mddev->chunk_size >> 9; unsigned int bio_sectors = bio->bi_size >> 9; - if (bio_data_dir(bio)) + if (bio_data_dir(bio) == WRITE ) return biovec->bv_len; /* always allow writes to be mergeable */ max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
