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authorMikulas Patocka <mpatocka@redhat.com>2013-03-02 02:45:49 +0400
committerAlasdair G Kergon <agk@redhat.com>2013-03-02 02:45:49 +0400
commitdf5d2e9089c7d5b8c46f767e4278610ea3e815b9 (patch)
tree5285aa8b0c794da419133a209437b32a11aa8a8d /drivers/md/dm-raid1.c
parenta26062416ef8add48f16fbadded2b5f6fb84d024 (diff)
downloadlinux-df5d2e9089c7d5b8c46f767e4278610ea3e815b9.tar.xz
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 <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm-raid1.c')
-rw-r--r--drivers/md/dm-raid1.c5
1 files changed, 4 insertions, 1 deletions
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;