The patch titled
md: define raid5_mergeable_bvec
has been added to the -mm tree. Its filename is
md-define-raid5_mergeable_bvec.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: md: define raid5_mergeable_bvec
From: NeilBrown <neilb@xxxxxxx>
This will encourage read request to be on only one device, so we will often be
able to bypass the cache for read requests.
Cc: "Raz Ben-Jehuda(caro)" <raziebe@xxxxxxxxx>
Signed-off-by: Neil Brown <neilb@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
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 */
+
+ max = (chunk_sectors - ((sector & (chunk_sectors - 1)) + bio_sectors)) << 9;
+ if (max < 0) max = 0;
+ if (max <= biovec->bv_len && bio_sectors == 0)
+ return biovec->bv_len;
+ else
+ return max;
+}
+
static int make_request(request_queue_t *q, struct bio * bi)
{
mddev_t *mddev = q->queuedata;
@@ -3320,6 +3342,8 @@ static int run(mddev_t *mddev)
mddev->array_size = mddev->size * (conf->previous_raid_disks -
conf->max_degraded);
+ blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
+
return 0;
abort:
if (conf) {
_
Patches currently in -mm which might be from neilb@xxxxxxx are
md-check-bio-address-after-mapping-through-partitions.patch
md-send-online-offline-uevents-when-an-md-array-starts-stops.patch
sunrpc-add-missing-spin_unlock.patch
lockdep-annotate-nfs-nfsd-in-kernel-sockets.patch
lockdep-annotate-nfs-nfsd-in-kernel-sockets-tidy.patch
remove-lock_key-approach-to-managing-nested-bd_mutex-locks.patch
simplify-some-aspects-of-bd_mutex-nesting.patch
use-mutex_lock_nested-for-bd_mutex-to-avoid-lockdep-warning.patch
avoid-lockdep-warning-in-md.patch
lockdep-annotate-nfsd4-recover-code.patch
md-change-lifetime-rules-for-md-devices.patch
md-define-raid5_mergeable_bvec.patch
md-handle-bypassing-the-read-cache-assuming-nothing-fails.patch
md-allow-reads-that-have-bypassed-the-cache-to-be-retried-on-failure.patch
md-enable-bypassing-cache-for-reads.patch
md-conditionalize-some-code.patch
md-dm-reduce-stack-usage-with-stacked-block-devices.patch
-
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