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-rw-r--r--block/blk-throttle.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index d6dd2e047874..7437de947120 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -645,6 +645,18 @@ static void __tg_update_carryover(struct throtl_grp *tg, bool rw,
u32 iops_limit = tg_iops_limit(tg, rw);
/*
+ * If the queue is empty, carryover handling is not needed. In such cases,
+ * tg->[bytes/io]_disp should be reset to 0 to avoid impacting the dispatch
+ * of subsequent bios. The same handling applies when the previous BPS/IOPS
+ * limit was set to max.
+ */
+ if (tg->service_queue.nr_queued[rw] == 0) {
+ tg->bytes_disp[rw] = 0;
+ tg->io_disp[rw] = 0;
+ return;
+ }
+
+ /*
* If config is updated while bios are still throttled, calculate and
* accumulate how many bytes/ios are waited across changes. And
* carryover_bytes/ios will be used to calculate new wait time under new
@@ -656,8 +668,8 @@ static void __tg_update_carryover(struct throtl_grp *tg, bool rw,
if (iops_limit != UINT_MAX)
*ios = calculate_io_allowed(iops_limit, jiffy_elapsed) -
tg->io_disp[rw];
- tg->bytes_disp[rw] -= *bytes;
- tg->io_disp[rw] -= *ios;
+ tg->bytes_disp[rw] = -*bytes;
+ tg->io_disp[rw] = -*ios;
}
static void tg_update_carryover(struct throtl_grp *tg)
@@ -665,10 +677,8 @@ static void tg_update_carryover(struct throtl_grp *tg)
long long bytes[2] = {0};
int ios[2] = {0};
- if (tg->service_queue.nr_queued[READ])
- __tg_update_carryover(tg, READ, &bytes[READ], &ios[READ]);
- if (tg->service_queue.nr_queued[WRITE])
- __tg_update_carryover(tg, WRITE, &bytes[WRITE], &ios[WRITE]);
+ __tg_update_carryover(tg, READ, &bytes[READ], &ios[READ]);
+ __tg_update_carryover(tg, WRITE, &bytes[WRITE], &ios[WRITE]);
/* see comments in struct throtl_grp for meaning of these fields. */
throtl_log(&tg->service_queue, "%s: %lld %lld %d %d\n", __func__,