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Date: Tue, 1 Nov 2022 17:34:10 +0800
From: Kemeng Shi <shikemeng@...wei.com>
To: <paolo.valente@...aro.org>, <axboe@...nel.dk>
CC: <linux-block@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<shikemeng@...wei.com>
Subject: [PATCH 13/20] block,bfq: remove redundant nonrot_with_queueing check in bfq_setup_cooperator
Commit 430a67f9d6169 ("block, bfq: merge bursts of newly-created queues")
add stable merge logic in bfq_setup_cooperator and will only be executed
for !nonrot_with_queueing device. Actually, bfq_setup_cooperator is
designed for only !nonrot_with_queueing and has already returned NULL
before doing real work if device is nonrot_with_queueing. We can add
stable merge after existing nonrot_with_queueing check and no need to
re-check nonrot_with_queueing.
Signed-off-by: Kemeng Shi <shikemeng@...wei.com>
---
block/bfq-iosched.c | 97 ++++++++++++++++++++++-----------------------
1 file changed, 47 insertions(+), 50 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index a46e49de895a..b8af0bb98d66 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2886,56 +2886,6 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq,
if (bfqq->new_bfqq)
return bfqq->new_bfqq;
- /*
- * Check delayed stable merge for rotational or non-queueing
- * devs. For this branch to be executed, bfqq must not be
- * currently merged with some other queue (i.e., bfqq->bic
- * must be non null). If we considered also merged queues,
- * then we should also check whether bfqq has already been
- * merged with bic->stable_merge_bfqq. But this would be
- * costly and complicated.
- */
- if (unlikely(!bfqd->nonrot_with_queueing)) {
- /*
- * Make sure also that bfqq is sync, because
- * bic->stable_merge_bfqq may point to some queue (for
- * stable merging) also if bic is associated with a
- * sync queue, but this bfqq is async
- */
- if (bfq_bfqq_sync(bfqq) && bic->stable_merge_bfqq &&
- !bfq_bfqq_just_created(bfqq) &&
- time_is_before_jiffies(bfqq->split_time +
- msecs_to_jiffies(bfq_late_stable_merging)) &&
- time_is_before_jiffies(bfqq->creation_time +
- msecs_to_jiffies(bfq_late_stable_merging))) {
- struct bfq_queue *stable_merge_bfqq =
- bic->stable_merge_bfqq;
- int proc_ref = min(bfqq_process_refs(bfqq),
- bfqq_process_refs(stable_merge_bfqq));
-
- /* deschedule stable merge, because done or aborted here */
- bfq_put_stable_ref(stable_merge_bfqq);
-
- bic->stable_merge_bfqq = NULL;
-
- if (!idling_boosts_thr_without_issues(bfqd, bfqq) &&
- proc_ref > 0) {
- /* next function will take at least one ref */
- struct bfq_queue *new_bfqq =
- bfq_setup_merge(bfqq, stable_merge_bfqq);
-
- if (new_bfqq) {
- bic->stably_merged = true;
- if (new_bfqq->bic)
- new_bfqq->bic->stably_merged =
- true;
- }
- return new_bfqq;
- } else
- return NULL;
- }
- }
-
/*
* Do not perform queue merging if the device is non
* rotational and performs internal queueing. In fact, such a
@@ -2976,6 +2926,53 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq,
if (likely(bfqd->nonrot_with_queueing))
return NULL;
+ /*
+ * Check delayed stable merge for rotational or non-queueing
+ * devs. For this branch to be executed, bfqq must not be
+ * currently merged with some other queue (i.e., bfqq->bic
+ * must be non null). If we considered also merged queues,
+ * then we should also check whether bfqq has already been
+ * merged with bic->stable_merge_bfqq. But this would be
+ * costly and complicated.
+ * Make sure also that bfqq is sync, because
+ * bic->stable_merge_bfqq may point to some queue (for
+ * stable merging) also if bic is associated with a
+ * sync queue, but this bfqq is async
+ */
+ if (bfq_bfqq_sync(bfqq) && bic->stable_merge_bfqq &&
+ !bfq_bfqq_just_created(bfqq) &&
+ time_is_before_jiffies(bfqq->split_time +
+ msecs_to_jiffies(bfq_late_stable_merging)) &&
+ time_is_before_jiffies(bfqq->creation_time +
+ msecs_to_jiffies(bfq_late_stable_merging))) {
+ struct bfq_queue *stable_merge_bfqq =
+ bic->stable_merge_bfqq;
+ int proc_ref = min(bfqq_process_refs(bfqq),
+ bfqq_process_refs(stable_merge_bfqq));
+
+ /* deschedule stable merge, because done or aborted here */
+ bfq_put_stable_ref(stable_merge_bfqq);
+
+ bic->stable_merge_bfqq = NULL;
+
+ if (!idling_boosts_thr_without_issues(bfqd, bfqq) &&
+ proc_ref > 0) {
+ /* next function will take at least one ref */
+ struct bfq_queue *new_bfqq =
+ bfq_setup_merge(bfqq, stable_merge_bfqq);
+
+ if (new_bfqq) {
+ bic->stably_merged = true;
+ if (new_bfqq->bic)
+ new_bfqq->bic->stably_merged =
+ true;
+ }
+ return new_bfqq;
+ } else
+ return NULL;
+ }
+
+
/*
* Prevent bfqq from being merged if it has been created too
* long ago. The idea is that true cooperating processes, and
--
2.30.0
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