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authorJustin TerAvest <teravest@google.com>2011-07-12 08:31:45 +0200
committerJens Axboe <jaxboe@fusionio.com>2011-07-12 08:35:10 +0200
commit4aede84b33d6beb401136a3deca0651ae07c5e99 (patch)
tree831266dbb15227584da5011ae4bb1e5038a69677 /block
parenta07405b7802691d29ab3b23bdc76ee6d006aad0b (diff)
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fixlet: Remove fs_excl from struct task.
fs_excl is a poor man's priority inheritance for filesystems to hint to the block layer that an operation is important. It was never clearly specified, not widely adopted, and will not prevent starvation in many cases (like across cgroups). fs_excl was introduced with the time sliced CFQ IO scheduler, to indicate when a process held FS exclusive resources and thus needed a boost. It doesn't cover all file systems, and it was never fully complete. Lets kill it. Signed-off-by: Justin TerAvest <teravest@google.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block')
-rw-r--r--block/cfq-iosched.c28
1 files changed, 1 insertions, 27 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 762bd509b71..d8b108737b7 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -134,7 +134,7 @@ struct cfq_queue {
/* io prio of this group */
unsigned short ioprio, org_ioprio;
- unsigned short ioprio_class, org_ioprio_class;
+ unsigned short ioprio_class;
pid_t pid;
@@ -2869,7 +2869,6 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
* elevate the priority of this queue
*/
cfqq->org_ioprio = cfqq->ioprio;
- cfqq->org_ioprio_class = cfqq->ioprio_class;
cfq_clear_cfqq_prio_changed(cfqq);
}
@@ -3593,30 +3592,6 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
cfq_schedule_dispatch(cfqd);
}
-/*
- * we temporarily boost lower priority queues if they are holding fs exclusive
- * resources. they are boosted to normal prio (CLASS_BE/4)
- */
-static void cfq_prio_boost(struct cfq_queue *cfqq)
-{
- if (has_fs_excl()) {
- /*
- * boost idle prio on transactions that would lock out other
- * users of the filesystem
- */
- if (cfq_class_idle(cfqq))
- cfqq->ioprio_class = IOPRIO_CLASS_BE;
- if (cfqq->ioprio > IOPRIO_NORM)
- cfqq->ioprio = IOPRIO_NORM;
- } else {
- /*
- * unboost the queue (if needed)
- */
- cfqq->ioprio_class = cfqq->org_ioprio_class;
- cfqq->ioprio = cfqq->org_ioprio;
- }
-}
-
static inline int __cfq_may_queue(struct cfq_queue *cfqq)
{
if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) {
@@ -3647,7 +3622,6 @@ static int cfq_may_queue(struct request_queue *q, int rw)
cfqq = cic_to_cfqq(cic, rw_is_sync(rw));
if (cfqq) {
cfq_init_prio_data(cfqq, cic->ioc);
- cfq_prio_boost(cfqq);
return __cfq_may_queue(cfqq);
}