/usr/src/kernel-patches/lustre/patches/raid5-large-io.patch is in linux-patch-lustre 1.8.5+dfsg-3ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | This patch changes max request size to <chunk size> * <disks>
in order to allow Lustre to submit large I/Os and avoid
unnecessary reads.
Index: linux-2.6.9/drivers/md/raid5.c
===================================================================
--- linux-2.6.9.orig/drivers/md/raid5.c 2006-05-22 00:01:30.000000000 +0400
+++ linux-2.6.9/drivers/md/raid5.c 2006-05-22 00:09:56.000000000 +0400
@@ -1609,6 +1609,11 @@ static int run (mddev_t *mddev)
mddev->queue->unplug_fn = raid5_unplug_device;
mddev->queue->issue_flush_fn = raid5_issue_flush;
+ /* in order to support large I/Os */
+ blk_queue_max_sectors(mddev->queue, mddev->chunk_size * mddev->raid_disks >> 9);
+ mddev->queue->max_phys_segments = mddev->chunk_size * mddev->raid_disks >> PAGE_SHIFT;
+ mddev->queue->max_hw_segments = mddev->chunk_size * mddev->raid_disks >> PAGE_SHIFT;;
+
PRINTK("raid5: run(%s) called.\n", mdname(mddev));
ITERATE_RDEV(mddev,rdev,tmp) {
|