[PATCH v3 8/8] cfq: Don't allow preemption across cgroups

From: Justin TerAvest
Date: Wed Mar 30 2011 - 12:52:51 EST


Previously, a sync queue in can preempt an async queue in another
cgroup. This changes that behavior to disallow such preemption.

Signed-off-by: Justin TerAvest <teravest@xxxxxxxxxx>
---
block/cfq-iosched.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 23caa79..0d0189b 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3430,6 +3430,9 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
if (!cfqq)
return false;

+ if (new_cfqq->cfqg != cfqq->cfqg)
+ return false;
+
if (cfq_class_idle(new_cfqq))
return false;

@@ -3449,9 +3452,6 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
return true;

- if (new_cfqq->cfqg != cfqq->cfqg)
- return false;
-
if (cfq_slice_used(cfqq))
return true;

--
1.7.3.1

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