From df5d2e9089c7d5b8c46f767e4278610ea3e815b9 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Fri, 1 Mar 2013 22:45:49 +0000 Subject: 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 --- drivers/md/dm-raid1.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/md/dm-raid1.c') diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c index e2ea97723e10..d053098c6a91 100644 --- a/drivers/md/dm-raid1.c +++ b/drivers/md/dm-raid1.c @@ -82,6 +82,9 @@ struct mirror_set { struct mirror mirror[0]; }; +DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(raid1_resync_throttle, + "A percentage of time allocated for raid resynchronization"); + static void wakeup_mirrord(void *context) { struct mirror_set *ms = context; @@ -1111,7 +1114,7 @@ static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv) goto err_destroy_wq; } - ms->kcopyd_client = dm_kcopyd_client_create(); + ms->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle); if (IS_ERR(ms->kcopyd_client)) { r = PTR_ERR(ms->kcopyd_client); goto err_destroy_wq; -- cgit v1.2.3-59-g8ed1b