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authorDivyesh Shah <dpshah@google.com>2010-03-25 15:45:03 +0100
committerJens Axboe <jens.axboe@oracle.com>2010-03-25 15:45:03 +0100
commitb1ffe737f5b743115ee46ffb59e338e580c54902 (patch)
treefb069889c4832ff90adc63bfe422e607c9b0ebc8 /block
parent8a6d9b149f105f8bdfa8e42dd9753e45a1887a16 (diff)
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cfq-iosched: Add additional blktrace log messages in CFQ for easier debugging
These have helped us debug some issues we've noticed in earlier IO controller versions and should be useful now as well. The extra logging covers: - idling behavior. Since there are so many conditions based on which we decide to idle or not, this patch adds a log message for some conditions that we've found useful. - workload slices and current prio and workload type Changelog from v1: o moved log message from cfq_set_active_queue() to __cfq_set_active_queue() o changed queue_count to st->count Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
-rw-r--r--block/cfq-iosched.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 8d5a2f2f7fb..2f91c535194 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1518,7 +1518,8 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd,
struct cfq_queue *cfqq)
{
if (cfqq) {
- cfq_log_cfqq(cfqd, cfqq, "set_active");
+ cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d",
+ cfqd->serving_prio, cfqd->serving_type);
cfqq->slice_start = 0;
cfqq->dispatch_start = jiffies;
cfqq->allocated_slice = 0;
@@ -1788,7 +1789,11 @@ static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq)
* Otherwise, we do only if they are the last ones
* in their service tree.
*/
- return service_tree->count == 1 && cfq_cfqq_sync(cfqq);
+ if (service_tree->count == 1 && cfq_cfqq_sync(cfqq))
+ return 1;
+ cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d",
+ service_tree->count);
+ return 0;
}
static void cfq_arm_slice_timer(struct cfq_data *cfqd)
@@ -1833,8 +1838,11 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
* time slice.
*/
if (sample_valid(cic->ttime_samples) &&
- (cfqq->slice_end - jiffies < cic->ttime_mean))
+ (cfqq->slice_end - jiffies < cic->ttime_mean)) {
+ cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%d",
+ cic->ttime_mean);
return;
+ }
cfq_mark_cfqq_wait_request(cfqq);
@@ -2042,6 +2050,7 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
slice = max(slice, 2 * cfqd->cfq_slice_idle);
slice = max_t(unsigned, slice, CFQ_MIN_TT);
+ cfq_log(cfqd, "workload slice:%d", slice);
cfqd->workload_expires = jiffies + slice;
cfqd->noidle_tree_requires_idle = false;
}
@@ -3308,6 +3317,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
if (cfq_should_wait_busy(cfqd, cfqq)) {
cfqq->slice_end = jiffies + cfqd->cfq_slice_idle;
cfq_mark_cfqq_wait_busy(cfqq);
+ cfq_log_cfqq(cfqd, cfqq, "will busy wait");
}
/*