blk-throttle: implement sq_to_tg(), sq_to_td() and throtl_log()
Now that both throtl_data and throtl_grp embed throtl_service_queue,
we can unify throtl_log() and throtl_log_tg().
* sq_to_tg() is added. This returns the throtl_grp a service_queue is
embedded in. If the service_queue is the top-level one embedded in
throtl_data, NULL is returned.
* sq_to_td() is added. A service_queue is always associated with a
throtl_data. This function finds the associated td and returns it.
* throtl_log() is updated to take throtl_service_queue instead of
throtl_data. If the service_queue is one embedded in throtl_grp, it
prints the same header as throtl_log_tg() did. If it's one embedded
in throtl_data, it behaves the same as before. This renders
throtl_log_tg() unnecessary. Removed.
This change is necessary for hierarchy support as we're gonna be using
the same code paths to dispatch bios to intermediate service_queues
embedded in throtl_grps and the top-level service_queue embedded in
throtl_data.
This patch doesn't make any behavior changes.
v2: throtl_log() didn't print a space after blkg path. Updated so
that it prints a space after throtl_grp path. Spotted by Vivek.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 00cfdd0..2875ff6 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -151,15 +151,64 @@
return blkg_to_tg(td->queue->root_blkg);
}
-#define throtl_log_tg(tg, fmt, args...) do { \
- char __pbuf[128]; \
- \
- blkg_path(tg_to_blkg(tg), __pbuf, sizeof(__pbuf)); \
- blk_add_trace_msg((tg)->td->queue, "throtl %s " fmt, __pbuf, ##args); \
-} while (0)
+/**
+ * sq_to_tg - return the throl_grp the specified service queue belongs to
+ * @sq: the throtl_service_queue of interest
+ *
+ * Return the throtl_grp @sq belongs to. If @sq is the top-level one
+ * embedded in throtl_data, %NULL is returned.
+ */
+static struct throtl_grp *sq_to_tg(struct throtl_service_queue *sq)
+{
+ if (sq && sq->parent_sq)
+ return container_of(sq, struct throtl_grp, service_queue);
+ else
+ return NULL;
+}
-#define throtl_log(td, fmt, args...) \
- blk_add_trace_msg((td)->queue, "throtl " fmt, ##args)
+/**
+ * sq_to_td - return throtl_data the specified service queue belongs to
+ * @sq: the throtl_service_queue of interest
+ *
+ * A service_queue can be embeded in either a throtl_grp or throtl_data.
+ * Determine the associated throtl_data accordingly and return it.
+ */
+static struct throtl_data *sq_to_td(struct throtl_service_queue *sq)
+{
+ struct throtl_grp *tg = sq_to_tg(sq);
+
+ if (tg)
+ return tg->td;
+ else
+ return container_of(sq, struct throtl_data, service_queue);
+}
+
+/**
+ * throtl_log - log debug message via blktrace
+ * @sq: the service_queue being reported
+ * @fmt: printf format string
+ * @args: printf args
+ *
+ * The messages are prefixed with "throtl BLKG_NAME" if @sq belongs to a
+ * throtl_grp; otherwise, just "throtl".
+ *
+ * TODO: this should be made a function and name formatting should happen
+ * after testing whether blktrace is enabled.
+ */
+#define throtl_log(sq, fmt, args...) do { \
+ struct throtl_grp *__tg = sq_to_tg((sq)); \
+ struct throtl_data *__td = sq_to_td((sq)); \
+ \
+ (void)__td; \
+ if ((__tg)) { \
+ char __pbuf[128]; \
+ \
+ blkg_path(tg_to_blkg(__tg), __pbuf, sizeof(__pbuf)); \
+ blk_add_trace_msg(__td->queue, "throtl %s " fmt, __pbuf, ##args); \
+ } else { \
+ blk_add_trace_msg(__td->queue, "throtl " fmt, ##args); \
+ } \
+} while (0)
/*
* Worker for allocating per cpu stat for tgs. This is scheduled on the
@@ -402,9 +451,10 @@
unsigned long delay)
{
struct delayed_work *dwork = &td->dispatch_work;
+ struct throtl_service_queue *sq = &td->service_queue;
mod_delayed_work(kthrotld_workqueue, dwork, delay);
- throtl_log(td, "schedule work. delay=%lu jiffies=%lu", delay, jiffies);
+ throtl_log(sq, "schedule work. delay=%lu jiffies=%lu", delay, jiffies);
}
static void throtl_schedule_next_dispatch(struct throtl_data *td)
@@ -429,9 +479,10 @@
tg->io_disp[rw] = 0;
tg->slice_start[rw] = jiffies;
tg->slice_end[rw] = jiffies + throtl_slice;
- throtl_log_tg(tg, "[%c] new slice start=%lu end=%lu jiffies=%lu",
- rw == READ ? 'R' : 'W', tg->slice_start[rw],
- tg->slice_end[rw], jiffies);
+ throtl_log(&tg->service_queue,
+ "[%c] new slice start=%lu end=%lu jiffies=%lu",
+ rw == READ ? 'R' : 'W', tg->slice_start[rw],
+ tg->slice_end[rw], jiffies);
}
static inline void throtl_set_slice_end(struct throtl_grp *tg, bool rw,
@@ -444,9 +495,10 @@
unsigned long jiffy_end)
{
tg->slice_end[rw] = roundup(jiffy_end, throtl_slice);
- throtl_log_tg(tg, "[%c] extend slice start=%lu end=%lu jiffies=%lu",
- rw == READ ? 'R' : 'W', tg->slice_start[rw],
- tg->slice_end[rw], jiffies);
+ throtl_log(&tg->service_queue,
+ "[%c] extend slice start=%lu end=%lu jiffies=%lu",
+ rw == READ ? 'R' : 'W', tg->slice_start[rw],
+ tg->slice_end[rw], jiffies);
}
/* Determine if previously allocated or extended slice is complete or not */
@@ -511,10 +563,10 @@
tg->slice_start[rw] += nr_slices * throtl_slice;
- throtl_log_tg(tg, "[%c] trim slice nr=%lu bytes=%llu io=%lu"
- " start=%lu end=%lu jiffies=%lu",
- rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim,
- tg->slice_start[rw], tg->slice_end[rw], jiffies);
+ throtl_log(&tg->service_queue,
+ "[%c] trim slice nr=%lu bytes=%llu io=%lu start=%lu end=%lu jiffies=%lu",
+ rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim,
+ tg->slice_start[rw], tg->slice_end[rw], jiffies);
}
static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio,
@@ -852,7 +904,7 @@
bio_list_init(&bio_list_on_stack);
- throtl_log(td, "dispatch nr_queued=%u read=%u write=%u",
+ throtl_log(sq, "dispatch nr_queued=%u read=%u write=%u",
td->nr_queued[READ] + td->nr_queued[WRITE],
td->nr_queued[READ], td->nr_queued[WRITE]);
@@ -863,7 +915,7 @@
bio_list_merge(&bio_list_on_stack, &sq->bio_lists[rw]);
bio_list_init(&sq->bio_lists[rw]);
}
- throtl_log(td, "bios disp=%u", nr_disp);
+ throtl_log(sq, "bios disp=%u", nr_disp);
}
throtl_schedule_next_dispatch(td);
@@ -972,9 +1024,10 @@
else
*(unsigned int *)((void *)tg + cft->private) = ctx.v;
- throtl_log_tg(tg, "limit change rbps=%llu wbps=%llu riops=%u wiops=%u",
- tg->bps[READ], tg->bps[WRITE],
- tg->iops[READ], tg->iops[WRITE]);
+ throtl_log(&tg->service_queue,
+ "limit change rbps=%llu wbps=%llu riops=%u wiops=%u",
+ tg->bps[READ], tg->bps[WRITE],
+ tg->iops[READ], tg->iops[WRITE]);
/*
* We're already holding queue_lock and know @tg is valid. Let's
@@ -1131,12 +1184,11 @@
}
queue_bio:
- throtl_log_tg(tg, "[%c] bio. bdisp=%llu sz=%u bps=%llu"
- " iodisp=%u iops=%u queued=%d/%d",
- rw == READ ? 'R' : 'W',
- tg->bytes_disp[rw], bio->bi_size, tg->bps[rw],
- tg->io_disp[rw], tg->iops[rw],
- sq->nr_queued[READ], sq->nr_queued[WRITE]);
+ throtl_log(sq, "[%c] bio. bdisp=%llu sz=%u bps=%llu iodisp=%u iops=%u queued=%d/%d",
+ rw == READ ? 'R' : 'W',
+ tg->bytes_disp[rw], bio->bi_size, tg->bps[rw],
+ tg->io_disp[rw], tg->iops[rw],
+ sq->nr_queued[READ], sq->nr_queued[WRITE]);
bio_associate_current(bio);
throtl_add_bio_tg(bio, tg);