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authorLinus Torvalds <torvalds@linux-foundation.org>2011-07-25 10:33:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-07-25 10:33:36 -0700
commit096a705bbc080a4041636d07514560da8d78acbe (patch)
tree38c3c01225709ffa53419083ea6332f8a72610de /Documentation
parentfea80311a939a746533a6d7e7c3183729d6a3faf (diff)
parent5757a6d76cdf6dda2a492c09b985c015e86779b1 (diff)
Merge branch 'for-3.1/core' of git://git.kernel.dk/linux-block
* 'for-3.1/core' of git://git.kernel.dk/linux-block: (24 commits) block: strict rq_affinity backing-dev: use synchronize_rcu_expedited instead of synchronize_rcu block: fix patch import error in max_discard_sectors check block: reorder request_queue to remove 64 bit alignment padding CFQ: add think time check for group CFQ: add think time check for service tree CFQ: move think time check variables to a separate struct fixlet: Remove fs_excl from struct task. cfq: Remove special treatment for metadata rqs. block: document blk_plug list access block: avoid building too big plug list compat_ioctl: fix make headers_check regression block: eliminate potential for infinite loop in blkdev_issue_discard compat_ioctl: fix warning caused by qemu block: flush MEDIA_CHANGE from drivers on close(2) blk-throttle: Make total_nr_queued unsigned block: Add __attribute__((format(printf...) and fix fallout fs/partitions/check.c: make local symbols static block:remove some spare spaces in genhd.c block:fix the comment error in blkdev.h ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/block/queue-sysfs.txt10
1 files changed, 7 insertions, 3 deletions
diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt
index f65274081c8d..d8147b336c35 100644
--- a/Documentation/block/queue-sysfs.txt
+++ b/Documentation/block/queue-sysfs.txt
@@ -45,9 +45,13 @@ device.
rq_affinity (RW)
----------------
-If this option is enabled, the block layer will migrate request completions
-to the CPU that originally submitted the request. For some workloads
-this provides a significant reduction in CPU cycles due to caching effects.
+If this option is '1', the block layer will migrate request completions to the
+cpu "group" that originally submitted the request. For some workloads this
+provides a significant reduction in CPU cycles due to caching effects.
+
+For storage configurations that need to maximize distribution of completion
+processing setting this option to '2' forces the completion to run on the
+requesting cpu (bypassing the "group" aggregation logic).
scheduler (RW)
--------------