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author | Kiyoshi Ueda <k-ueda@ct.jp.nec.com> | 2009-06-22 10:12:27 +0100 |
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committer | Alasdair G Kergon <agk@redhat.com> | 2009-06-22 10:12:27 +0100 |
commit | 02ab823fd1a27d193bda06b74fdad685a20a3e5e (patch) | |
tree | 04b3db6e494f483fef34a55e487e88f6d7c585a5 /drivers/hwmon/fschmd.c | |
parent | 2bd023452592e5f5cf90dd426cc39b7632b15b76 (diff) |
dm mpath: add start_io and nr_bytes to path selectors
This patch makes two additions to the dm path selector interface for
dynamic load balancers:
o a new hook, start_io()
o a new parameter 'nr_bytes' to select_path()/start_io()/end_io()
to pass the size of the I/O
start_io() is called when a target driver actually submits I/O
to the selected path.
Path selectors can use it to start accounting of the I/O.
(e.g. counting the number of in-flight I/Os.)
The start_io hook is based on the patch posted by Stefan Bader:
https://www.redhat.com/archives/dm-devel/2005-October/msg00050.html
nr_bytes, the size of the I/O, is so path selectors can take the
size of the I/O into account when deciding which path to use.
dm-service-time uses it to estimate service time, for example.
(Added the nr_bytes member to dm_mpath_io instead of using existing
details.bi_size, since request-based dm patch deletes it.)
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/hwmon/fschmd.c')
0 files changed, 0 insertions, 0 deletions