This reverts commit 34b48db66e08ca1c1bc07cf305d672ac940268dc. That commit caused performance regressions for streaming I/O workloads on a number of different storage devices, from SATA disks to external RAID arrays. It also managed to trip up some buggy firmware in at least one drive, causing data corruption.
The next patch will bump the default max_sectors_kb value to 1280, which will accommodate a 10-data-disk stripe write with chunk size 128k. In the testing I've done using iozone, fio, and aio-stress, a value of 1280 does not show a big performance difference from 512. This will hopefully still help the software RAID setup that Christoph saw the original performance gains with while still not regressing other storage configurations. Signed-off-by: Jeff Moyer <[email protected]> --- block/blk-settings.c | 4 +++- drivers/block/aoe/aoeblk.c | 2 +- include/linux/blkdev.h | 1 + 3 files changed, 5 insertions(+), 2 deletions(-) diff --git a/block/blk-settings.c b/block/blk-settings.c index 12600bf..b160f89 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -257,7 +257,9 @@ void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_ __func__, max_hw_sectors); } - limits->max_sectors = limits->max_hw_sectors = max_hw_sectors; + limits->max_hw_sectors = max_hw_sectors; + limits->max_sectors = min_t(unsigned int, max_hw_sectors, + BLK_DEF_MAX_SECTORS); } EXPORT_SYMBOL(blk_limits_max_hw_sectors); diff --git a/drivers/block/aoe/aoeblk.c b/drivers/block/aoe/aoeblk.c index 46c282f..dd73e1f 100644 --- 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, 1024); + blk_queue_max_hw_sectors(q, BLK_DEF_MAX_SECTORS); 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 index d4068c1..1fd459e1 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1138,6 +1138,7 @@ 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, }; -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
