From: Mikulas Patocka Date: Fri, 1 Mar 2013 22:45:49 +0000 (+0000) Subject: dm kcopyd: introduce configurable throttling X-Git-Tag: v3.9-rc1~19^2~9 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=df5d2e9089c7d5b8c46f767e4278610ea3e815b9;p=pandora-kernel.git dm kcopyd: introduce configurable throttling This patch allows the administrator to reduce the rate at which kcopyd issues I/O. Each module that uses kcopyd acquires a throttle parameter that can be set in /sys/module/*/parameters. We maintain a history of kcopyd usage by each module in the variables io_period and total_period in struct dm_kcopyd_throttle. The actual kcopyd activity is calculated as a percentage of time equal to "(100 * io_period / total_period)". This is compared with the user-defined throttle percentage threshold and if it is exceeded, we sleep. Signed-off-by: Mikulas Patocka Signed-off-by: Alasdair G Kergon --- Reading git-diff-tree failed