diff mbox series

[V2,2/3] blk-throttle: Delete unnecessary carryover-related fields from throtl_grp

Message ID 20250417132054.2866409-3-wozizhi@huaweicloud.com (mailing list archive)
State New
Headers show
Series blk-throttle: Some bugfixes and modifications | expand

Commit Message

Zizhi Wo April 17, 2025, 1:20 p.m. UTC 
From: Zizhi Wo <wozizhi@huawei.com>

We no longer need carryover_[bytes/ios] in tg, so it is removed. The
related comments about carryover in tg are also merged into
[bytes/io]_disp, and modify other related comments.

Signed-off-by: Zizhi Wo <wozizhi@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
---
 block/blk-throttle.c |  8 ++++----
 block/blk-throttle.h | 19 ++++++++-----------
 2 files changed, 12 insertions(+), 15 deletions(-)
diff mbox series

Patch

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 8ac8db116520..66a9044a5207 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -658,9 +658,9 @@  static void __tg_update_carryover(struct throtl_grp *tg, bool rw,
 
 	/*
 	 * 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
-	 * configuration.
+	 * accumulate how many bytes/ios are waited across changes. And use the
+	 * calculated carryover (@bytes/@ios) to update [bytes/io]_disp, which
+	 * will be used to calculate new wait time under new configuration.
 	 */
 	if (bps_limit != U64_MAX)
 		*bytes = calculate_bytes_allowed(bps_limit, jiffy_elapsed) -
@@ -680,7 +680,7 @@  static void tg_update_carryover(struct throtl_grp *tg)
 	__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. */
+	/* see comments in struct throtl_grp for meaning of carryover. */
 	throtl_log(&tg->service_queue, "%s: %lld %lld %d %d\n", __func__,
 		   bytes[READ], bytes[WRITE], ios[READ], ios[WRITE]);
 }
diff --git a/block/blk-throttle.h b/block/blk-throttle.h
index 7964cc041e06..8bd16535302c 100644
--- a/block/blk-throttle.h
+++ b/block/blk-throttle.h
@@ -101,19 +101,16 @@  struct throtl_grp {
 	/* IOPS limits */
 	unsigned int iops[2];
 
-	/* Number of bytes dispatched in current slice */
-	int64_t bytes_disp[2];
-	/* Number of bio's dispatched in current slice */
-	int io_disp[2];
-
 	/*
-	 * The following two fields are updated when new configuration is
-	 * submitted while some bios are still throttled, they record how many
-	 * bytes/ios are waited already in previous configuration, and they will
-	 * be used to calculate wait time under new configuration.
+	 * Number of bytes/bio's dispatched in current slice.
+	 * When new configuration is submitted while some bios are still throttled,
+	 * first calculate the carryover: the amount of bytes/IOs already waited
+	 * under the previous configuration. Then, [bytes/io]_disp are represented
+	 * as the negative of the carryover, and they will be used to calculate the
+	 * wait time under the new configuration.
 	 */
-	long long carryover_bytes[2];
-	int carryover_ios[2];
+	int64_t bytes_disp[2];
+	int io_disp[2];
 
 	unsigned long last_check_time;