This is a note to let you know that I've just added the patch titled
blk-throttle: use calculate_io/bytes_allowed() for throtl_trim_slice()
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
blk-throttle-use-calculate_io-bytes_allowed-for-thro.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 82db798047fc17d422ce6348e87c3f2a46b4cf89
Author: Yu Kuai <yukuai3@xxxxxxxxxx>
Date: Wed Aug 16 09:27:07 2023 +0800
blk-throttle: use calculate_io/bytes_allowed() for throtl_trim_slice()
[ Upstream commit e8368b57c006dc0e02dcd8a9dc9f2060ff5476fe ]
There are no functional changes, just make the code cleaner.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230816012708.1193747-4-yukuai1@xxxxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Stable-dep-of: eead0056648c ("blk-throttle: consider 'carryover_ios/bytes' in throtl_trim_slice()")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index f1bc600c4ded6..931795da4d65d 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -697,11 +697,40 @@ static bool throtl_slice_used(struct throtl_grp *tg, bool rw)
return true;
}
+static unsigned int calculate_io_allowed(u32 iops_limit,
+ unsigned long jiffy_elapsed)
+{
+ unsigned int io_allowed;
+ u64 tmp;
+
+ /*
+ * jiffy_elapsed should not be a big value as minimum iops can be
+ * 1 then at max jiffy elapsed should be equivalent of 1 second as we
+ * will allow dispatch after 1 second and after that slice should
+ * have been trimmed.
+ */
+
+ tmp = (u64)iops_limit * jiffy_elapsed;
+ do_div(tmp, HZ);
+
+ if (tmp > UINT_MAX)
+ io_allowed = UINT_MAX;
+ else
+ io_allowed = tmp;
+
+ return io_allowed;
+}
+
+static u64 calculate_bytes_allowed(u64 bps_limit, unsigned long jiffy_elapsed)
+{
+ return mul_u64_u64_div_u64(bps_limit, (u64)jiffy_elapsed, (u64)HZ);
+}
+
/* Trim the used slices and adjust slice start accordingly */
static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw)
{
- unsigned long nr_slices, time_elapsed, io_trim;
- u64 bytes_trim, tmp;
+ unsigned long time_elapsed, io_trim;
+ u64 bytes_trim;
BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw]));
@@ -723,19 +752,14 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw)
throtl_set_slice_end(tg, rw, jiffies + tg->td->throtl_slice);
- time_elapsed = jiffies - tg->slice_start[rw];
-
- nr_slices = time_elapsed / tg->td->throtl_slice;
-
- if (!nr_slices)
+ time_elapsed = rounddown(jiffies - tg->slice_start[rw],
+ tg->td->throtl_slice);
+ if (!time_elapsed)
return;
- tmp = tg_bps_limit(tg, rw) * tg->td->throtl_slice * nr_slices;
- do_div(tmp, HZ);
- bytes_trim = tmp;
-
- io_trim = (tg_iops_limit(tg, rw) * tg->td->throtl_slice * nr_slices) /
- HZ;
+ bytes_trim = calculate_bytes_allowed(tg_bps_limit(tg, rw),
+ time_elapsed);
+ io_trim = calculate_io_allowed(tg_iops_limit(tg, rw), time_elapsed);
if (!bytes_trim && !io_trim)
return;
@@ -749,41 +773,13 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw)
else
tg->io_disp[rw] = 0;
- tg->slice_start[rw] += nr_slices * tg->td->throtl_slice;
+ tg->slice_start[rw] += time_elapsed;
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 unsigned int calculate_io_allowed(u32 iops_limit,
- unsigned long jiffy_elapsed)
-{
- unsigned int io_allowed;
- u64 tmp;
-
- /*
- * jiffy_elapsed should not be a big value as minimum iops can be
- * 1 then at max jiffy elapsed should be equivalent of 1 second as we
- * will allow dispatch after 1 second and after that slice should
- * have been trimmed.
- */
-
- tmp = (u64)iops_limit * jiffy_elapsed;
- do_div(tmp, HZ);
-
- if (tmp > UINT_MAX)
- io_allowed = UINT_MAX;
- else
- io_allowed = tmp;
-
- return io_allowed;
-}
-
-static u64 calculate_bytes_allowed(u64 bps_limit, unsigned long jiffy_elapsed)
-{
- return mul_u64_u64_div_u64(bps_limit, (u64)jiffy_elapsed, (u64)HZ);
+ rw == READ ? 'R' : 'W', time_elapsed / tg->td->throtl_slice,
+ bytes_trim, io_trim, tg->slice_start[rw], tg->slice_end[rw],
+ jiffies);
}
static void __tg_update_carryover(struct throtl_grp *tg, bool rw)
