block: remove artifical max_hw_sectors cap

Set max_sectors to the value the drivers provides as hardware limit by default. Linux had proper I/O throttling for a long time and doesn't rely on a artifically small maximum I/O size anymore. By not limiting the I/O size by default we remove an annoying tuning step required for most Linux installation. Note that both the user, and if absolutely required the driver can still impose a limit for FS requests below max_hw_sectors_kb. Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
xlks · Oct 21, 2014 · 34b48db · 34b48db
1 parent c2661b8
commit 34b48db
Show file tree

Hide file tree

Showing 3 changed files with 2 additions and 5 deletions.
diff --git a/block/blk-settings.c b/block/blk-settings.c
@@ -257,9 +257,7 @@ void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_
 		       __func__, max_hw_sectors);
 	}
 
-	limits->max_hw_sectors = max_hw_sectors;
-	limits->max_sectors = min_t(unsigned int, max_hw_sectors,
-				    BLK_DEF_MAX_SECTORS);
+	limits->max_sectors = limits->max_hw_sectors = max_hw_sectors;
 }
 EXPORT_SYMBOL(blk_limits_max_hw_sectors);
 

diff --git a/drivers/block/aoe/aoeblk.c b/drivers/block/aoe/aoeblk.c
@@ -395,7 +395,7 @@ aoeblk_gdalloc(void *vp)
 	WARN_ON(d->flags & DEVFL_TKILL);
 	WARN_ON(d->gd);
 	WARN_ON(d->flags & DEVFL_UP);
-	blk_queue_max_hw_sectors(q, BLK_DEF_MAX_SECTORS);
+	blk_queue_max_hw_sectors(q, 1024);
 	q->backing_dev_info.name = "aoe";
 	q->backing_dev_info.ra_pages = READ_AHEAD / PAGE_CACHE_SIZE;
 	d->bufpool = mp;

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
@@ -1186,7 +1186,6 @@ extern int blk_verify_command(unsigned char *cmd, fmode_t has_write_perm);
 enum blk_default_limits {
 	BLK_MAX_SEGMENTS	= 128,
 	BLK_SAFE_MAX_SECTORS	= 255,
-	BLK_DEF_MAX_SECTORS	= 1024,
 	BLK_MAX_SEGMENT_SIZE	= 65536,
 	BLK_SEG_BOUNDARY_MASK	= 0xFFFFFFFFUL,
 };