Revision 347e0899b1c75d907f01ac883ca38d37fe9bfa42 authored by Andy King on 07 March 2013, 15:29:08 UTC, committed by Greg Kroah-Hartman on 15 March 2013, 19:58:12 UTC
When sending between processes, we always schedule a work item. Our work info struct has the message embedded in the middle, which means that we end up overwriting subsequent fields when we copy the (variable-length) message into it. Move it to the end of the struct. Acked-by: Dmitry Torokhov <dtor@vmware.com> Signed-off-by: Andy King <acking@vmware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 parent 61ec7e7
dm-queue-length.txt
dm-queue-length
===============
dm-queue-length is a path selector module for device-mapper targets,
which selects a path with the least number of in-flight I/Os.
The path selector name is 'queue-length'.
Table parameters for each path: [<repeat_count>]
<repeat_count>: The number of I/Os to dispatch using the selected
path before switching to the next path.
If not given, internal default is used. To check
the default value, see the activated table.
Status for each path: <status> <fail-count> <in-flight>
<status>: 'A' if the path is active, 'F' if the path is failed.
<fail-count>: The number of path failures.
<in-flight>: The number of in-flight I/Os on the path.
Algorithm
=========
dm-queue-length increments/decrements 'in-flight' when an I/O is
dispatched/completed respectively.
dm-queue-length selects a path with the minimum 'in-flight'.
Examples
========
In case that 2 paths (sda and sdb) are used with repeat_count == 128.
# echo "0 10 multipath 0 0 1 1 queue-length 0 2 1 8:0 128 8:16 128" \
dmsetup create test
#
# dmsetup table
test: 0 10 multipath 0 0 1 1 queue-length 0 2 1 8:0 128 8:16 128
#
# dmsetup status
test: 0 10 multipath 2 0 0 0 1 1 E 0 2 1 8:0 A 0 0 8:16 A 0 0
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