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authorJeff Moyer <jmoyer@redhat.com>2015-08-13 14:57:56 -0400
committerJens Axboe <axboe@fb.com>2015-08-18 13:21:13 -0700
commit30e2bc08b2bb7c069246feee78f7ed4006e130fe (patch)
tree51526a90f372dca0811c93e0311c5b5301d094be /block/blk-settings.c
parent0048b4837affd153897ed1222283492070027aa9 (diff)
downloadlinux-linaro-stable-30e2bc08b2bb7c069246feee78f7ed4006e130fe.tar.gz
Revert "block: remove artifical max_hw_sectors cap"
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 <jmoyer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-settings.c')
-rw-r--r--block/blk-settings.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 9df73991b231..d27b4e272356 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -236,7 +236,9 @@ 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);