[PATCH 0/2] block: Reinstate BLK_DEF_MAX_SECTORS

From: Jeff Moyer
Date: Thu Aug 13 2015 - 14:58:39 EST

Commit 34b48db66e08 (block: remove artificial max_hw_sectors cap)
caused performance regressions for streaming I/O workloads across
a range of storage from SATA disks to enterprise storage arrays.
I was unable to actually show a performance gain for any storage
I have access to. However, the patch was introduced to boost
performance on software RAID over SATA disks, and I don't have
access to such a configuration.

The compromise is to reinstate BLK_DEF_MAX_SECTORS, but to bump it
up to 2560 from 1024. This number should allow full stripe writes
to 10 data disks with a chunk size of 128KB, and at the same time
does not regress the storage I have access to.

[PATCH 1/2] Revert "block: remove artifical max_hw_sectors cap"
[PATCH 2/2] block: bump BLK_DEF_MAX_SECTORS to 2560

block/blk-settings.c | 4 +++-
drivers/block/aoe/aoeblk.c | 2 +-
include/linux/blkdev.h | 1 +
3 files changed, 5 insertions(+), 2 deletions(-)
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