path: root/block
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authorShaohua Li writes <shaohua.li@intel.com>2010-12-13 14:32:22 +0100
committerJens Axboe <jaxboe@fusionio.com>2010-12-13 14:32:22 +0100
commite4ea0c16a85d221ebcc3a21f32e321440459e0fc (patch)
tree47acf4da84f9a448e6eb6172a5440ccc60696ed9 /block
parent760701bfe14faee8ea0608a9cab2046071d98a39 (diff)
block cfq: select new workload if priority changed
If priority is changed, continuing to check workload_expires and service tree count of the previous workload does not make sense. We should always choose the workload with lowest key of new priority in such case. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block')
1 files changed, 5 insertions, 0 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 5d0349d602f..9b186fd6bf4 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2101,6 +2101,7 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
unsigned count;
struct cfq_rb_root *st;
unsigned group_slice;
+ enum wl_prio_t original_prio = cfqd->serving_prio;
if (!cfqg) {
cfqd->serving_prio = IDLE_WORKLOAD;
@@ -2119,6 +2120,9 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
+ if (original_prio != cfqd->serving_prio)
+ goto new_workload;
* For RT and BE, we have to choose also the type
* (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
@@ -2133,6 +2137,7 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
if (count && !time_after(jiffies, cfqd->workload_expires))
/* otherwise select new workload type */
cfqd->serving_type =
cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio);