path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2012-04-13 18:07:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-04-13 18:07:19 -0700
commitd8dd0b6d4836bce81cece60509ef3b157a420776 (patch)
tree7a28f327a15443d6c9d091f3d272abd107251ab7 /Documentation
parent2d59dcfb54ade45cacc59a6e7bd96b8c19088c3d (diff)
parent1b2e19f17ed327af6add02978efdf354e4f8e4df (diff)
Merge branch 'for-3.4/core' of git://git.kernel.dk/linux-block
Pull block core bits from Jens Axboe: "It's a nice and quiet round this time, since most of the tricky stuff has been pushed to 3.5 to give it more time to mature. After a few hectic block IO core changes for 3.3 and 3.2, I'm quite happy with a slow round. Really minor stuff in here, the only real functional change is making the auto-unplug threshold a per-queue entity. The threshold is set so that it's low enough that we don't hold off IO for too long, but still big enough to get a nice benefit from the batched insert (and hence queue lock cost reduction). For raid configurations, this currently breaks down." * 'for-3.4/core' of git://git.kernel.dk/linux-block: block: make auto block plug flush threshold per-disk based Documentation: Add sysfs ABI change for cfq's target latency. block: Make cfq_target_latency tunable through sysfs. block: use lockdep_assert_held for queue locking block: blk_alloc_queue_node(): use caller's GFP flags instead of GFP_KERNEL
Diffstat (limited to 'Documentation')
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-cfq-target-latency b/Documentation/ABI/testing/sysfs-cfq-target-latency
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+What: /sys/block/<device>/iosched/target_latency
+Date: March 2012
+contact: Tao Ma <boyu.mt@taobao.com>
+ The /sys/block/<device>/iosched/target_latency only exists
+ when the user sets cfq to /sys/block/<device>/scheduler.
+ It contains an estimated latency time for the cfq. cfq will
+ use it to calculate the time slice used for every task.