<resent with Jens' email address fixed> Hi,
This reverts commit 34b48db66e08, which caused significant iozone performance regressions and uncovered a silent data corruption bug in at least one disk. For SAN storage, we've seen initial write and re-write performance drop 25-50% across all I/O sizes. On locally attached storage, we've seen regressions of 40% for all I/O types, but only for I/O sizes larger than 1MB. In addition to the performance issues, we've also seen data corruption on one disk/hba combination. See http://marc.info/?l=linux-ide&m=143680539400526&w=2 Signed-off-by: Jeff Moyer <[email protected]> --- I'm open to other suggestions on how to address this, but the performance regression is seen across a number of our different test platforms, and the silent data corruption really scares me. Did we ever get performance numbers that showed a benefit to lifting the max_sectors_kb cap? 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, }; -- 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/
