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Subject[PATCH 1/2] cfq-iosched: Get rid of cfqq wait_busy_done flag
Date
o Get rid of wait_busy_done flag. This flag only tells we were doing wait
busy on a queue and that queue got request so expire it. That information
can easily be obtained by (cfq_cfqq_wait_busy() && queue_is_not_empty). So
remove this flag and keep code simple.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
block/cfq-iosched.c | 17 ++++++++---------
1 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index cfb0b2f..276d765 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -319,7 +319,6 @@ enum cfqq_state_flags {
CFQ_CFQQ_FLAG_coop, /* cfqq is shared */
CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */
CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */
- CFQ_CFQQ_FLAG_wait_busy_done, /* Got new request. Expire the queue */
};

#define CFQ_CFQQ_FNS(name) \
@@ -348,7 +347,6 @@ CFQ_CFQQ_FNS(sync);
CFQ_CFQQ_FNS(coop);
CFQ_CFQQ_FNS(deep);
CFQ_CFQQ_FNS(wait_busy);
-CFQ_CFQQ_FNS(wait_busy_done);
#undef CFQ_CFQQ_FNS

#ifdef CONFIG_DEBUG_CFQ_IOSCHED
@@ -1574,7 +1572,6 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,

cfq_clear_cfqq_wait_request(cfqq);
cfq_clear_cfqq_wait_busy(cfqq);
- cfq_clear_cfqq_wait_busy_done(cfqq);

/*
* store what was left of this slice, if the queue idled/timed out
@@ -2128,11 +2125,17 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)

if (!cfqd->rq_queued)
return NULL;
+
+ /*
+ * We were waiting for group to get backlogged. Expire the queue
+ */
+ if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list))
+ goto expire;
+
/*
* The active queue has run out of time, expire it and select new.
*/
- if ((cfq_slice_used(cfqq) || cfq_cfqq_wait_busy_done(cfqq))
- && !cfq_cfqq_must_dispatch(cfqq))
+ if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq))
goto expire;

/*
@@ -3165,10 +3168,6 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);

if (cfqq == cfqd->active_queue) {
- if (cfq_cfqq_wait_busy(cfqq)) {
- cfq_clear_cfqq_wait_busy(cfqq);
- cfq_mark_cfqq_wait_busy_done(cfqq);
- }
/*
* Remember that we saw a request from this process, but
* don't start queuing just yet. Otherwise we risk seeing lots
--
1.6.2.5


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