cfq-iosched: add message logging through blktrace
Now that blktrace has the ability to carry arbitrary messages in
its stream, use that for some CFQ logging.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 32aa367..0ebb626 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -11,6 +11,7 @@
#include <linux/elevator.h>
#include <linux/rbtree.h>
#include <linux/ioprio.h>
+#include <linux/blktrace_api.h>
/*
* tunables
@@ -41,7 +42,7 @@
#define RQ_CIC(rq) \
((struct cfq_io_context *) (rq)->elevator_private)
-#define RQ_CFQQ(rq) ((rq)->elevator_private2)
+#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2)
static struct kmem_cache *cfq_pool;
static struct kmem_cache *cfq_ioc_pool;
@@ -156,6 +157,7 @@
unsigned short ioprio, org_ioprio;
unsigned short ioprio_class, org_ioprio_class;
+ pid_t pid;
};
enum cfqq_state_flags {
@@ -199,6 +201,11 @@
CFQ_CFQQ_FNS(sync);
#undef CFQ_CFQQ_FNS
+#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
+ blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args)
+#define cfq_log(cfqd, fmt, args...) \
+ blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
+
static void cfq_dispatch_insert(struct request_queue *, struct request *);
static struct cfq_queue *cfq_get_queue(struct cfq_data *, int,
struct io_context *, gfp_t);
@@ -235,8 +242,10 @@
*/
static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
{
- if (cfqd->busy_queues)
+ if (cfqd->busy_queues) {
+ cfq_log(cfqd, "schedule dispatch");
kblockd_schedule_work(&cfqd->unplug_work);
+ }
}
static int cfq_queue_empty(struct request_queue *q)
@@ -271,6 +280,7 @@
cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
+ cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies);
}
/*
@@ -540,6 +550,7 @@
*/
static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
+ cfq_log_cfqq(cfqd, cfqq, "add_to_rr");
BUG_ON(cfq_cfqq_on_rr(cfqq));
cfq_mark_cfqq_on_rr(cfqq);
cfqd->busy_queues++;
@@ -553,6 +564,7 @@
*/
static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
+ cfq_log_cfqq(cfqd, cfqq, "del_from_rr");
BUG_ON(!cfq_cfqq_on_rr(cfqq));
cfq_clear_cfqq_on_rr(cfqq);
@@ -639,6 +651,8 @@
struct cfq_data *cfqd = q->elevator->elevator_data;
cfqd->rq_in_driver++;
+ cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d",
+ cfqd->rq_in_driver);
/*
* If the depth is larger 1, it really could be queueing. But lets
@@ -658,6 +672,8 @@
WARN_ON(!cfqd->rq_in_driver);
cfqd->rq_in_driver--;
+ cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d",
+ cfqd->rq_in_driver);
}
static void cfq_remove_request(struct request *rq)
@@ -747,6 +763,7 @@
struct cfq_queue *cfqq)
{
if (cfqq) {
+ cfq_log_cfqq(cfqd, cfqq, "set_active");
cfqq->slice_end = 0;
cfq_clear_cfqq_must_alloc_slice(cfqq);
cfq_clear_cfqq_fifo_expire(cfqq);
@@ -764,6 +781,8 @@
__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
int timed_out)
{
+ cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out);
+
if (cfq_cfqq_wait_request(cfqq))
del_timer(&cfqd->idle_slice_timer);
@@ -773,8 +792,10 @@
/*
* store what was left of this slice, if the queue idled/timed out
*/
- if (timed_out && !cfq_cfqq_slice_new(cfqq))
+ if (timed_out && !cfq_cfqq_slice_new(cfqq)) {
cfqq->slice_resid = cfqq->slice_end - jiffies;
+ cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid);
+ }
cfq_resort_rr_list(cfqd, cfqq);
@@ -867,6 +888,12 @@
return;
/*
+ * still requests with the driver, don't idle
+ */
+ if (cfqd->rq_in_driver)
+ return;
+
+ /*
* task has exited, don't wait
*/
cic = cfqd->active_cic;
@@ -893,6 +920,7 @@
sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));
mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
+ cfq_log(cfqd, "arm_idle: %lu", sl);
}
/*
@@ -903,6 +931,8 @@
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
+ cfq_log_cfqq(cfqd, cfqq, "dispatch_insert");
+
cfq_remove_request(rq);
cfqq->dispatched++;
elv_dispatch_sort(q, rq);
@@ -932,8 +962,9 @@
rq = rq_entry_fifo(cfqq->fifo.next);
if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
- return NULL;
+ rq = NULL;
+ cfq_log_cfqq(cfqd, cfqq, "fifo=%p", rq);
return rq;
}
@@ -1073,6 +1104,7 @@
BUG_ON(cfqd->busy_queues);
+ cfq_log(cfqd, "forced_dispatch=%d\n", dispatched);
return dispatched;
}
@@ -1113,6 +1145,7 @@
dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
}
+ cfq_log(cfqd, "dispatched=%d", dispatched);
return dispatched;
}
@@ -1131,6 +1164,7 @@
if (!atomic_dec_and_test(&cfqq->ref))
return;
+ cfq_log_cfqq(cfqd, cfqq, "put_queue");
BUG_ON(rb_first(&cfqq->sort_list));
BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
BUG_ON(cfq_cfqq_on_rr(cfqq));
@@ -1439,6 +1473,8 @@
cfq_mark_cfqq_idle_window(cfqq);
cfq_mark_cfqq_sync(cfqq);
}
+ cfqq->pid = current->pid;
+ cfq_log_cfqq(cfqd, cfqq, "alloced");
}
if (new_cfqq)
@@ -1687,7 +1723,7 @@
cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_io_context *cic)
{
- int enable_idle;
+ int old_idle, enable_idle;
/*
* Don't idle for async or idle io prio class
@@ -1695,7 +1731,7 @@
if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq))
return;
- enable_idle = cfq_cfqq_idle_window(cfqq);
+ old_idle = cfq_cfqq_idle_window(cfqq);
if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
(cfqd->hw_tag && CIC_SEEKY(cic)))
@@ -1707,10 +1743,13 @@
enable_idle = 1;
}
- if (enable_idle)
- cfq_mark_cfqq_idle_window(cfqq);
- else
- cfq_clear_cfqq_idle_window(cfqq);
+ if (old_idle != enable_idle) {
+ cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle);
+ if (enable_idle)
+ cfq_mark_cfqq_idle_window(cfqq);
+ else
+ cfq_clear_cfqq_idle_window(cfqq);
+ }
}
/*
@@ -1769,6 +1808,7 @@
*/
static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
+ cfq_log_cfqq(cfqd, cfqq, "preempt");
cfq_slice_expired(cfqd, 1);
/*
@@ -1830,6 +1870,7 @@
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
+ cfq_log_cfqq(cfqd, cfqq, "insert_request");
cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc);
cfq_add_rq_rb(rq);
@@ -1847,6 +1888,7 @@
unsigned long now;
now = jiffies;
+ cfq_log_cfqq(cfqd, cfqq, "complete");
WARN_ON(!cfqd->rq_in_driver);
WARN_ON(!cfqq->dispatched);
@@ -2016,6 +2058,7 @@
cfq_schedule_dispatch(cfqd);
spin_unlock_irqrestore(q->queue_lock, flags);
+ cfq_log(cfqd, "set_request fail");
return 1;
}
@@ -2041,6 +2084,8 @@
unsigned long flags;
int timed_out = 1;
+ cfq_log(cfqd, "idle timer fired");
+
spin_lock_irqsave(cfqd->queue->queue_lock, flags);
cfqq = cfqd->active_queue;