* [PATCH 01/20] block, bfq: fix typo in comment
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
@ 2022-11-01 9:33 ` Kemeng Shi
2022-11-01 9:33 ` [PATCH 02/20] block, bfq: Update bfqd->max_budget with bfqd->lock held Kemeng Shi
` (18 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:33 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
IO/ -> I/0
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 7ea427817f7f..25a88ffd997e 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5633,7 +5633,7 @@ bfq_do_early_stable_merge(struct bfq_data *bfqd, struct bfq_queue *bfqq,
*
* Putting these two facts together, this commits merges stably the
* bfq_queues associated with these I/O flows, i.e., with the
- * processes that generate these IO/ flows, regardless of how many the
+ * processes that generate these I/O flows, regardless of how many the
* involved processes are.
*
* To decide whether a set of bfq_queues is actually associated with
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 02/20] block, bfq: Update bfqd->max_budget with bfqd->lock held
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
2022-11-01 9:33 ` [PATCH 01/20] block, bfq: fix typo in comment Kemeng Shi
@ 2022-11-01 9:33 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 03/20] block, bfq: correct bfq_max_budget and bfq_min_budget Kemeng Shi
` (17 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:33 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
bfq_max_budget and bfq_user_max_budget maybe be in inconsisten state if
bfq_max_budget configuration and bfq_max_budget auto-update happen
concurrently.
Example sequence:
config auto-update
bfqd->bfq_max_budget =
__data
if (bfqd->bfq_user_max_budget == 0)
bfqd->bfq_max_budget =
bfq_calc_max_budget(bfqd);
bfqd->bfq_user_max_budget =
__data;
bfq_max_budget is only update in update_thr_responsiveness_params and
configuration code. As update_thr_responsiveness_params is always called
under bfqd->lock, fix this by holding lock in configuration code.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 25a88ffd997e..13370c41ad36 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -7328,6 +7328,7 @@ static ssize_t bfq_max_budget_store(struct elevator_queue *e,
if (ret)
return ret;
+ spin_lock_irq(&bfqd->lock);
if (__data == 0)
bfqd->bfq_max_budget = bfq_calc_max_budget(bfqd);
else {
@@ -7337,6 +7338,7 @@ static ssize_t bfq_max_budget_store(struct elevator_queue *e,
}
bfqd->bfq_user_max_budget = __data;
+ spin_unlock_irq(&bfqd->lock);
return count;
}
@@ -7362,8 +7364,11 @@ static ssize_t bfq_timeout_sync_store(struct elevator_queue *e,
__data = INT_MAX;
bfqd->bfq_timeout = msecs_to_jiffies(__data);
+
+ spin_lock_irq(&bfqd->lock);
if (bfqd->bfq_user_max_budget == 0)
bfqd->bfq_max_budget = bfq_calc_max_budget(bfqd);
+ spin_unlock_irq(&bfqd->lock);
return count;
}
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 03/20] block, bfq: correct bfq_max_budget and bfq_min_budget
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
2022-11-01 9:33 ` [PATCH 01/20] block, bfq: fix typo in comment Kemeng Shi
2022-11-01 9:33 ` [PATCH 02/20] block, bfq: Update bfqd->max_budget with bfqd->lock held Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 04/20] block, bfq: simpfy computation of bfqd->budgets_assigned Kemeng Shi
` (16 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
The budgets_assigned is checked to make sure enough samples have been
computed for auto-tuning. Ignore budgets_assigned if auto-tuning is
disabled as bfq_default_max_budget is set by user.
The bfq_default_max_budget check is added after budgets_assigned check,
so no extra cost is added for normal branch to return bfqd->bfq_max_budget.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 13370c41ad36..b21c3711d69d 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1485,7 +1485,8 @@ static int bfq_bfqq_budget_left(struct bfq_queue *bfqq)
*/
static int bfq_max_budget(struct bfq_data *bfqd)
{
- if (bfqd->budgets_assigned < bfq_stats_min_budgets)
+ if (bfqd->budgets_assigned < bfq_stats_min_budgets &&
+ bfqd->bfq_user_max_budget == 0)
return bfq_default_max_budget;
else
return bfqd->bfq_max_budget;
@@ -1497,7 +1498,8 @@ static int bfq_max_budget(struct bfq_data *bfqd)
*/
static int bfq_min_budget(struct bfq_data *bfqd)
{
- if (bfqd->budgets_assigned < bfq_stats_min_budgets)
+ if (bfqd->budgets_assigned < bfq_stats_min_budgets &&
+ bfqd->bfq_user_max_budget == 0)
return bfq_default_max_budget / 32;
else
return bfqd->bfq_max_budget / 32;
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 04/20] block, bfq: simpfy computation of bfqd->budgets_assigned
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (2 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 03/20] block, bfq: correct bfq_max_budget and bfq_min_budget Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 05/20] block, bfq: recover the "service hole" if enough budget is left Kemeng Shi
` (15 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
The computation of budgets_assigned is a little confusing as we only need
to check if it's updated more than 10 times. Simpfy the computation to
improve readability.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index b21c3711d69d..be69b0e061f7 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -175,7 +175,7 @@ static const int bfq_back_penalty = 2;
static u64 bfq_slice_idle = NSEC_PER_SEC / 125;
/* Minimum number of assigned budgets for which stats are safe to compute. */
-static const int bfq_stats_min_budgets = 194;
+static const int bfq_stats_min_budgets = 11;
/* Default maximum budget values, in sectors and number of requests. */
static const int bfq_default_max_budget = 16 * 1024;
@@ -3288,7 +3288,7 @@ static void __bfq_set_in_service_queue(struct bfq_data *bfqd,
if (bfqq) {
bfq_clear_bfqq_fifo_expire(bfqq);
- bfqd->budgets_assigned = (bfqd->budgets_assigned * 7 + 256) / 8;
+ bfqd->budgets_assigned++;
if (time_is_before_jiffies(bfqq->last_wr_start_finish) &&
bfqq->wr_coeff > 1 &&
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 05/20] block, bfq: recover the "service hole" if enough budget is left
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (3 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 04/20] block, bfq: simpfy computation of bfqd->budgets_assigned Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 06/20] block, bfq: correct interactive weight-raise check in bfq_set_budget_timeout Kemeng Shi
` (14 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
If budget left is less than budget need by next request, the activated bfqq
will be expired if it preempts the in-service queue. Avoid to cause useless
overhead to check budget left is enough for next request.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index be69b0e061f7..f4b4ba05f804 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1623,7 +1623,7 @@ static bool bfq_bfqq_update_budg_for_activation(struct bfq_data *bfqd,
* service. This would only cause useless overhead.
*/
if (bfq_bfqq_non_blocking_wait_rq(bfqq) && arrived_in_time &&
- bfq_bfqq_budget_left(bfqq) > 0) {
+ bfq_bfqq_budget_left(bfqq) >= bfq_serv_to_charge(bfqq->next_rq, bfqq)) {
/*
* We do not clear the flag non_blocking_wait_rq here, as
* the latter is used in bfq_activate_bfqq to signal
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 06/20] block, bfq: correct interactive weight-raise check in bfq_set_budget_timeout
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (4 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 05/20] block, bfq: recover the "service hole" if enough budget is left Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 07/20] block, bfq: simpfy check for interactive bfqq in bfq_update_wr_data Kemeng Shi
` (13 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
After weight-raise finished, bfqq->wr_coeff is reset to 1 while
bfqq->wr_cur_max_time may not be reset. For example,
Function bfq_update_bfqq_wr_on_rq_arrival will only reset wr_coeff to 1 if
bfqq is created in burst creation. Function bfq_set_budget_timeout will be
called when bfqq is selected while it's wr_cur_max_time is set and wr_coeff
is 1. Fix this by check wr_coeff > 1 before check wr_cur_max_time.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index f4b4ba05f804..20ae52882235 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -3271,7 +3271,8 @@ static void bfq_set_budget_timeout(struct bfq_data *bfqd,
{
unsigned int timeout_coeff;
- if (bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time)
+ if (bfqq->wr_coeff > 1 &&
+ bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time)
timeout_coeff = 1;
else
timeout_coeff = bfqq->entity.weight / bfqq->entity.orig_weight;
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 07/20] block, bfq: simpfy check for interactive bfqq in bfq_update_wr_data
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (5 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 06/20] block, bfq: correct interactive weight-raise check in bfq_set_budget_timeout Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 08/20] block, bfq: do srt filtering for interactive queues in bfq_completed_request Kemeng Shi
` (12 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
The bfqq->wr_coeff will be set to bfqd->bfq_wr_coeff if bfqq is in
interactive weight raising. So we can simpfy interactive weight raising
check in function bfq_update_wr_data.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 20ae52882235..15e7d6c6fa83 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -4997,8 +4997,7 @@ static void bfq_update_wr_data(struct bfq_data *bfqd, struct bfq_queue *bfqq)
bfqq->entity.prio_changed = 1;
}
}
- if (bfqq->wr_coeff > 1 &&
- bfqq->wr_cur_max_time != bfqd->bfq_wr_rt_max_time &&
+ if (bfqq->wr_coeff == bfqd->bfq_wr_coeff &&
bfqq->service_from_wr > max_service_from_wr) {
/* see comments on max_service_from_wr */
bfq_bfqq_end_wr(bfqq);
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 08/20] block, bfq: do srt filtering for interactive queues in bfq_completed_request
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (6 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 07/20] block, bfq: simpfy check for interactive bfqq in bfq_update_wr_data Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 09/20] block, bfq: remove redundant check if (bfqq->dispatched > 0) Kemeng Shi
` (11 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
Commit 20cd32450bcbec ("block, bfq: do not consider interactive queues in
srt filtering") remove the updating of soft_rt_next_start for bfq_queues
in interactive weight raising.
Commit 3c337690d2ebb7 ("block, bfq: avoid spurious switches to soft_rt of
interactive queues") try to revert the first commit to add back updating of
soft_rt_next_start for bfq_queues in interactive weight raising and fix
original problem by reset consumed bandwidth if a bfq_queue switches from
interactive to normal mode.
The problem this patch fixes is that first commit is not fully reverted as
updating of soft_rt_next_start for bfq_queues in interactive weight
raising is still removed in bfq_completed_request. Fix this by updating
soft_rt_next_start for bfq_queues in interactive weight raising in
bfq_completed_request.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 15e7d6c6fa83..fa96cbca7814 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -6317,14 +6317,11 @@ static void bfq_completed_request(struct bfq_queue *bfqq, struct bfq_data *bfqd)
* isochronous, and both requisites for this condition to hold
* are now satisfied, then compute soft_rt_next_start (see the
* comments on the function bfq_bfqq_softrt_next_start()). We
- * do not compute soft_rt_next_start if bfqq is in interactive
- * weight raising (see the comments in bfq_bfqq_expire() for
- * an explanation). We schedule this delayed update when bfqq
- * expires, if it still has in-flight requests.
+ * schedule this delayed update when bfqq expires, if it still
+ * has in-flight requests.
*/
if (bfq_bfqq_softrt_update(bfqq) && bfqq->dispatched == 0 &&
- RB_EMPTY_ROOT(&bfqq->sort_list) &&
- bfqq->wr_coeff != bfqd->bfq_wr_coeff)
+ RB_EMPTY_ROOT(&bfqq->sort_list))
bfqq->soft_rt_next_start =
bfq_bfqq_softrt_next_start(bfqd, bfqq);
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 09/20] block, bfq: remove redundant check if (bfqq->dispatched > 0)
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (7 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 08/20] block, bfq: do srt filtering for interactive queues in bfq_completed_request Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 10/20] block, bfq: define and use soft_rt, in_burst and wr_or_deserves_wr only low_latency is enable Kemeng Shi
` (10 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
Commit 3c337690d2ebb7 ("block, bfq: avoid spurious switches to soft_rt of
interactive queues") remove bfqq->wr_coeff != bfqd->bfq_wr_coeff check
along with bfqq->dispatched == 0 to update soft_rt_next_start for
interactive bfq_queues. So we can remove redundant bfqq->dispatched > 0
in else branch with current bfqq->dispatched == 0 check.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index fa96cbca7814..8f6d05258f22 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -4375,7 +4375,7 @@ void bfq_bfqq_expire(struct bfq_data *bfqd,
if (bfqq->dispatched == 0)
bfqq->soft_rt_next_start =
bfq_bfqq_softrt_next_start(bfqd, bfqq);
- else if (bfqq->dispatched > 0) {
+ else {
/*
* Schedule an update of soft_rt_next_start to when
* the task may be discovered to be isochronous.
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 10/20] block, bfq: define and use soft_rt, in_burst and wr_or_deserves_wr only low_latency is enable
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (8 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 09/20] block, bfq: remove redundant check if (bfqq->dispatched > 0) Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 11/20] block, bfq: remove unnecessary "wr" part of wr_or_deserves_wr Kemeng Shi
` (9 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
The soft_rt, in_burst and wr_or_deserves_wr are only used when low_latency
is enable. Currently, these variables are computed even low_latency is
disable. Define these variables in successful branch of bfqd->low_latency
check and compute them if needed to remove redundant computation and
improve readability.
The interactive parameter will be used only if low_latency is enabled
outside bfq_bfqq_handle_idle_busy_switch, so it's safe to move
interactive assignment inside branch where low_latency is true.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 77 ++++++++++++++++++++++-----------------------
1 file changed, 38 insertions(+), 39 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 8f6d05258f22..0ecb3640d715 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1822,8 +1822,7 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd,
struct request *rq,
bool *interactive)
{
- bool soft_rt, in_burst, wr_or_deserves_wr,
- bfqq_wants_to_preempt,
+ bool bfqq_wants_to_preempt,
idle_for_long_time = bfq_bfqq_idle_for_long_time(bfqd, bfqq),
/*
* See the comments on
@@ -1834,43 +1833,6 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd,
bfqq->ttime.last_end_request +
bfqd->bfq_slice_idle * 3;
-
- /*
- * bfqq deserves to be weight-raised if:
- * - it is sync,
- * - it does not belong to a large burst,
- * - it has been idle for enough time or is soft real-time,
- * - is linked to a bfq_io_cq (it is not shared in any sense),
- * - has a default weight (otherwise we assume the user wanted
- * to control its weight explicitly)
- */
- in_burst = bfq_bfqq_in_large_burst(bfqq);
- soft_rt = bfqd->bfq_wr_max_softrt_rate > 0 &&
- !BFQQ_TOTALLY_SEEKY(bfqq) &&
- !in_burst &&
- time_is_before_jiffies(bfqq->soft_rt_next_start) &&
- bfqq->dispatched == 0 &&
- bfqq->entity.new_weight == 40;
- *interactive = !in_burst && idle_for_long_time &&
- bfqq->entity.new_weight == 40;
- /*
- * Merged bfq_queues are kept out of weight-raising
- * (low-latency) mechanisms. The reason is that these queues
- * are usually created for non-interactive and
- * non-soft-real-time tasks. Yet this is not the case for
- * stably-merged queues. These queues are merged just because
- * they are created shortly after each other. So they may
- * easily serve the I/O of an interactive or soft-real time
- * application, if the application happens to spawn multiple
- * processes. So let also stably-merged queued enjoy weight
- * raising.
- */
- wr_or_deserves_wr = bfqd->low_latency &&
- (bfqq->wr_coeff > 1 ||
- (bfq_bfqq_sync(bfqq) &&
- (bfqq->bic || RQ_BIC(rq)->stably_merged) &&
- (*interactive || soft_rt)));
-
/*
* Using the last flag, update budget and check whether bfqq
* may want to preempt the in-service queue.
@@ -1904,6 +1866,20 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd,
bfq_clear_bfqq_just_created(bfqq);
if (bfqd->low_latency) {
+ bool soft_rt, in_burst, wr_or_deserves_wr;
+ /*
+ * bfqq deserves to be weight-raised if:
+ * - it is sync,
+ * - it does not belong to a large burst,
+ * - it has been idle for enough time or is soft real-time,
+ * - is linked to a bfq_io_cq (it is not shared in any sense),
+ * - has a default weight (otherwise we assume the user wanted
+ * to control its weight explicitly)
+ */
+ in_burst = bfq_bfqq_in_large_burst(bfqq);
+ *interactive = !in_burst && idle_for_long_time &&
+ bfqq->entity.new_weight == 40;
+
if (unlikely(time_is_after_jiffies(bfqq->split_time)))
/* wraparound */
bfqq->split_time =
@@ -1911,6 +1887,29 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd,
if (time_is_before_jiffies(bfqq->split_time +
bfqd->bfq_wr_min_idle_time)) {
+ soft_rt = bfqd->bfq_wr_max_softrt_rate > 0 &&
+ !BFQQ_TOTALLY_SEEKY(bfqq) &&
+ !in_burst &&
+ time_is_before_jiffies(bfqq->soft_rt_next_start) &&
+ bfqq->dispatched == 0 &&
+ bfqq->entity.new_weight == 40;
+ /*
+ * Merged bfq_queues are kept out of weight-raising
+ * (low-latency) mechanisms. The reason is that these queues
+ * are usually created for non-interactive and
+ * non-soft-real-time tasks. Yet this is not the case for
+ * stably-merged queues. These queues are merged just because
+ * they are created shortly after each other. So they may
+ * easily serve the I/O of an interactive or soft-real time
+ * application, if the application happens to spawn multiple
+ * processes. So let also stably-merged queued enjoy weight
+ * raising.
+ */
+ wr_or_deserves_wr = (bfqq->wr_coeff > 1 ||
+ (bfq_bfqq_sync(bfqq) &&
+ (bfqq->bic || RQ_BIC(rq)->stably_merged) &&
+ (*interactive || soft_rt)));
+
bfq_update_bfqq_wr_on_rq_arrival(bfqd, bfqq,
old_wr_coeff,
wr_or_deserves_wr,
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 11/20] block, bfq: remove unnecessary "wr" part of wr_or_deserves_wr
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (9 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 10/20] block, bfq: define and use soft_rt, in_burst and wr_or_deserves_wr only low_latency is enable Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 12/20] block, bfq: start/restart service_from_wr accumulating correctly Kemeng Shi
` (8 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
Before commit 96a291c38c3299 ("block, bfq: preempt lower-weight or
lower-priority queues"), wr_or_deserves_wr is used to check if
preempt is wanted. Currently, wr_or_deserves_wr is only used in
bfq_update_bfqq_wr_on_rq_arrival to check if weight raising is
needed, so the "wr" part of wr_or_deserves_wr is not needed
anymore. Rename wr_or_deserves_wr to deserves_wr and remove
unnecessary bfqq->wr_coeff > 1 for original wr_or_deserves_wr.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 0ecb3640d715..261ba2d63925 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1681,12 +1681,12 @@ static unsigned long bfq_smallest_from_now(void)
static void bfq_update_bfqq_wr_on_rq_arrival(struct bfq_data *bfqd,
struct bfq_queue *bfqq,
unsigned int old_wr_coeff,
- bool wr_or_deserves_wr,
+ bool deserves_wr,
bool interactive,
bool in_burst,
bool soft_rt)
{
- if (old_wr_coeff == 1 && wr_or_deserves_wr) {
+ if (old_wr_coeff == 1 && deserves_wr) {
/* start a weight-raising period */
if (interactive) {
bfqq->service_from_wr = 0;
@@ -1866,7 +1866,7 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd,
bfq_clear_bfqq_just_created(bfqq);
if (bfqd->low_latency) {
- bool soft_rt, in_burst, wr_or_deserves_wr;
+ bool soft_rt, in_burst, deserves_wr;
/*
* bfqq deserves to be weight-raised if:
* - it is sync,
@@ -1905,14 +1905,13 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd,
* processes. So let also stably-merged queued enjoy weight
* raising.
*/
- wr_or_deserves_wr = (bfqq->wr_coeff > 1 ||
- (bfq_bfqq_sync(bfqq) &&
+ deserves_wr = (bfq_bfqq_sync(bfqq) &&
(bfqq->bic || RQ_BIC(rq)->stably_merged) &&
- (*interactive || soft_rt)));
+ (*interactive || soft_rt));
bfq_update_bfqq_wr_on_rq_arrival(bfqd, bfqq,
old_wr_coeff,
- wr_or_deserves_wr,
+ deserves_wr,
*interactive,
in_burst,
soft_rt);
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 12/20] block, bfq: start/restart service_from_wr accumulating correctly
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (10 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 11/20] block, bfq: remove unnecessary "wr" part of wr_or_deserves_wr Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 13/20] block,bfq: remove redundant nonrot_with_queueing check in bfq_setup_cooperator Kemeng Shi
` (7 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
1. Start accumulating service_from_wr when async queues are weight raised.
The service_from_wr for async queues is accumulated and checked to finish
weight-raise as sync queues. We need to charge service_from_wr for async
queues about to weight-raise.
2. Restart accumulating service_from_wr when queues are deemed interactive
again The weight-raising period is restarted when queues are deemed
interactive again in bfq_add_request. It's more reasonable to restart
service_from_wr accumulating too.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 261ba2d63925..a46e49de895a 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1726,6 +1726,7 @@ static void bfq_update_bfqq_wr_on_rq_arrival(struct bfq_data *bfqd,
2 * bfq_min_budget(bfqd));
} else if (old_wr_coeff > 1) {
if (interactive) { /* update wr coeff and duration */
+ bfqq->service_from_wr = 0;
bfqq->wr_coeff = bfqd->bfq_wr_coeff;
bfqq->wr_cur_max_time = bfq_wr_duration(bfqd);
} else if (in_burst)
@@ -2311,6 +2312,7 @@ static void bfq_add_request(struct request *rq)
time_is_before_jiffies(
bfqq->last_wr_start_finish +
bfqd->bfq_wr_min_inter_arr_async)) {
+ bfqq->service_from_wr = 0;
bfqq->wr_coeff = bfqd->bfq_wr_coeff;
bfqq->wr_cur_max_time = bfq_wr_duration(bfqd);
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 13/20] block,bfq: remove redundant nonrot_with_queueing check in bfq_setup_cooperator
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (11 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 12/20] block, bfq: start/restart service_from_wr accumulating correctly Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 14/20] block, bfq: remove redundant oom_bfqq check for bfqq from bfq_find_close_cooperator Kemeng Shi
` (6 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
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@huawei.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
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 14/20] block, bfq: remove redundant oom_bfqq check for bfqq from bfq_find_close_cooperator
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (12 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 13/20] block,bfq: remove redundant nonrot_with_queueing check in bfq_setup_cooperator Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 15/20] block, bfq: some cleanups for function bfq_pos_tree_add_move Kemeng Shi
` (5 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
The oom_bfqq is never added to tree in bfq_pos_tree_add_move, so bfqq
returned from bfq_find_close_cooperator is no need to be checked if it's
oom_bfqq.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index b8af0bb98d66..776951156fbc 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -3014,8 +3014,7 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq,
new_bfqq = bfq_find_close_cooperator(bfqd, bfqq,
bfq_io_struct_pos(io_struct, request));
- if (new_bfqq && likely(new_bfqq != &bfqd->oom_bfqq) &&
- bfq_may_be_close_cooperator(bfqq, new_bfqq))
+ if (new_bfqq && bfq_may_be_close_cooperator(bfqq, new_bfqq))
return bfq_setup_merge(bfqq, new_bfqq);
return NULL;
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 15/20] block, bfq: some cleanups for function bfq_pos_tree_add_move
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (13 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 14/20] block, bfq: remove redundant oom_bfqq check for bfqq from bfq_find_close_cooperator Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 16/20] block, bfq: remove unnecessary goto tag in __bfq_weights_tree_remove Kemeng Shi
` (4 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
There are three cleanups in this patch:
1. The oom_bfqq is never inserted to tree, so return immediately for
oom_bfqq before unnecessary NULL check of bfqq->pos_root.
2. Only set bfqq->pos_root after bfq_rq_pos_tree_lookup successes rather
than set bfqq->pos_root unconditionally and reset to NULL if
bfq_rq_pos_tree_lookup fails.
3. Remove unnecessary local variable __bfqq which is only used to check
return value of bfq_rq_pos_tree_lookup.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 776951156fbc..dd9a51255a0f 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -758,17 +758,16 @@ void __cold
bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq)
{
struct rb_node **p, *parent;
- struct bfq_queue *__bfqq;
+
+ /* oom_bfqq does not participate in queue merging */
+ if (bfqq == &bfqd->oom_bfqq)
+ return;
if (bfqq->pos_root) {
rb_erase(&bfqq->pos_node, bfqq->pos_root);
bfqq->pos_root = NULL;
}
- /* oom_bfqq does not participate in queue merging */
- if (bfqq == &bfqd->oom_bfqq)
- return;
-
/*
* bfqq cannot be merged any longer (see comments in
* bfq_setup_cooperator): no point in adding bfqq into the
@@ -782,14 +781,13 @@ bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq)
if (!bfqq->next_rq)
return;
+ if (bfq_rq_pos_tree_lookup(bfqd, &bfqq_group(bfqq)->rq_pos_tree,
+ blk_rq_pos(bfqq->next_rq), &parent, &p))
+ return;
+
bfqq->pos_root = &bfqq_group(bfqq)->rq_pos_tree;
- __bfqq = bfq_rq_pos_tree_lookup(bfqd, bfqq->pos_root,
- blk_rq_pos(bfqq->next_rq), &parent, &p);
- if (!__bfqq) {
- rb_link_node(&bfqq->pos_node, parent, p);
- rb_insert_color(&bfqq->pos_node, bfqq->pos_root);
- } else
- bfqq->pos_root = NULL;
+ rb_link_node(&bfqq->pos_node, parent, p);
+ rb_insert_color(&bfqq->pos_node, bfqq->pos_root);
}
/*
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 16/20] block, bfq: remove unnecessary goto tag in __bfq_weights_tree_remove
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (14 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 15/20] block, bfq: some cleanups for function bfq_pos_tree_add_move Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 17/20] block, bfq: remove unnecessary traverse in bfq_add_to_burst Kemeng Shi
` (3 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
Do free work if num_active == 0 and remove unnecessary tag
reset_entity_pointer.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index dd9a51255a0f..1402dfd9f448 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -950,13 +950,11 @@ void __bfq_weights_tree_remove(struct bfq_data *bfqd,
return;
bfqq->weight_counter->num_active--;
- if (bfqq->weight_counter->num_active > 0)
- goto reset_entity_pointer;
-
- rb_erase_cached(&bfqq->weight_counter->weights_node, root);
- kfree(bfqq->weight_counter);
+ if (bfqq->weight_counter->num_active == 0) {
+ rb_erase_cached(&bfqq->weight_counter->weights_node, root);
+ kfree(bfqq->weight_counter);
+ }
-reset_entity_pointer:
bfqq->weight_counter = NULL;
bfq_put_queue(bfqq);
}
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 17/20] block, bfq: remove unnecessary traverse in bfq_add_to_burst
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (15 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 16/20] block, bfq: remove unnecessary goto tag in __bfq_weights_tree_remove Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 18/20] block, bfq: remove unnecessary bfqq->next_rq = NULL in bfq_remove_request Kemeng Shi
` (2 subsequent siblings)
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
Do mark burst and remove from list in a single traverse to remove
unnecessary re-traverse.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 1402dfd9f448..0864254b8dcd 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -1255,7 +1255,7 @@ static void bfq_add_to_burst(struct bfq_data *bfqd, struct bfq_queue *bfqq)
bfqd->burst_size++;
if (bfqd->burst_size == bfqd->bfq_large_burst_thresh) {
- struct bfq_queue *pos, *bfqq_item;
+ struct bfq_queue *pos;
struct hlist_node *n;
/*
@@ -1267,13 +1267,6 @@ static void bfq_add_to_burst(struct bfq_data *bfqd, struct bfq_queue *bfqq)
/*
* We can now mark all queues in the burst list as
* belonging to a large burst.
- */
- hlist_for_each_entry(bfqq_item, &bfqd->burst_list,
- burst_list_node)
- bfq_mark_bfqq_in_large_burst(bfqq_item);
- bfq_mark_bfqq_in_large_burst(bfqq);
-
- /*
* From now on, and until the current burst finishes, any
* new queue being activated shortly after the last queue
* was inserted in the burst can be immediately marked as
@@ -1281,8 +1274,11 @@ static void bfq_add_to_burst(struct bfq_data *bfqd, struct bfq_queue *bfqq)
* needed any more. Remove it.
*/
hlist_for_each_entry_safe(pos, n, &bfqd->burst_list,
- burst_list_node)
+ burst_list_node) {
+ bfq_mark_bfqq_in_large_burst(pos);
hlist_del_init(&pos->burst_list_node);
+ }
+ bfq_mark_bfqq_in_large_burst(bfqq);
} else /*
* Burst not yet large: add bfqq to the burst list. Do
* not increment the ref counter for bfqq, because bfqq
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 18/20] block, bfq: remove unnecessary bfqq->next_rq = NULL in bfq_remove_request
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (16 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 17/20] block, bfq: remove unnecessary traverse in bfq_add_to_burst Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 19/20] block, bfq: remove unnecessary local variable __bfqq in bfq_setup_merge Kemeng Shi
2022-11-01 9:34 ` [PATCH 20/20] block, bfq: remove unncessary process_ref check for merged queue " Kemeng Shi
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
bfqq->next_rq is properly assigned at beginning of bfq_remove_request
for condition that bfq_queue will be empty as bfqq->next_rq will be
NULL only if bfqq->next_rq is removed and bfqq->next_rq is the last
request existing are both met.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 0864254b8dcd..d3f4d995f84a 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2410,8 +2410,6 @@ static void bfq_remove_request(struct request_queue *q,
q->last_merge = NULL;
if (RB_EMPTY_ROOT(&bfqq->sort_list)) {
- bfqq->next_rq = NULL;
-
if (bfq_bfqq_busy(bfqq) && bfqq != bfqd->in_service_queue) {
bfq_del_bfqq_busy(bfqq, false);
/*
@@ -2445,7 +2443,6 @@ static void bfq_remove_request(struct request_queue *q,
if (rq->cmd_flags & REQ_META)
bfqq->meta_pending--;
-
}
static bool bfq_bio_merge(struct request_queue *q, struct bio *bio,
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 19/20] block, bfq: remove unnecessary local variable __bfqq in bfq_setup_merge
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (17 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 18/20] block, bfq: remove unnecessary bfqq->next_rq = NULL in bfq_remove_request Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
2022-11-01 9:34 ` [PATCH 20/20] block, bfq: remove unncessary process_ref check for merged queue " Kemeng Shi
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
We could traversal bfqq->new_bfqq list without a local variable easily and
intuitively. So remove unnecessary local variable __bfqq.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index d3f4d995f84a..589ab59abcf5 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2741,7 +2741,6 @@ static struct bfq_queue *
bfq_setup_merge(struct bfq_queue *bfqq, struct bfq_queue *new_bfqq)
{
int process_refs, new_process_refs;
- struct bfq_queue *__bfqq;
/*
* If there are no process references on the new_bfqq, then it is
@@ -2753,10 +2752,9 @@ bfq_setup_merge(struct bfq_queue *bfqq, struct bfq_queue *new_bfqq)
return NULL;
/* Avoid a circular list and skip interim queue merges. */
- while ((__bfqq = new_bfqq->new_bfqq)) {
- if (__bfqq == bfqq)
+ while ((new_bfqq = new_bfqq->new_bfqq)) {
+ if (new_bfqq == bfqq)
return NULL;
- new_bfqq = __bfqq;
}
process_refs = bfqq_process_refs(bfqq);
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread* [PATCH 20/20] block, bfq: remove unncessary process_ref check for merged queue in bfq_setup_merge
2022-11-01 9:33 [PATCH 00/20] A few bugfix and cleanup patches for bfq-iosched Kemeng Shi
` (18 preceding siblings ...)
2022-11-01 9:34 ` [PATCH 19/20] block, bfq: remove unnecessary local variable __bfqq in bfq_setup_merge Kemeng Shi
@ 2022-11-01 9:34 ` Kemeng Shi
19 siblings, 0 replies; 21+ messages in thread
From: Kemeng Shi @ 2022-11-01 9:34 UTC (permalink / raw)
To: paolo.valente, axboe; +Cc: linux-block, linux-kernel, shikemeng
As we already check process_refs of original new_bfqq is not zero. The
later new_bfqq maybe the merged queue of original new_bfqq which inherit
the process_refs of original new_bfqq which is not zero, so process_refs
of merged queue will not be zero.
Remove unncessary check for merged queue and remove new_process_refs
which will not be used.
Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
---
block/bfq-iosched.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 589ab59abcf5..0736577bfbfe 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2740,7 +2740,7 @@ static struct bfq_queue *bfq_find_close_cooperator(struct bfq_data *bfqd,
static struct bfq_queue *
bfq_setup_merge(struct bfq_queue *bfqq, struct bfq_queue *new_bfqq)
{
- int process_refs, new_process_refs;
+ int process_refs;
/*
* If there are no process references on the new_bfqq, then it is
@@ -2758,12 +2758,11 @@ bfq_setup_merge(struct bfq_queue *bfqq, struct bfq_queue *new_bfqq)
}
process_refs = bfqq_process_refs(bfqq);
- new_process_refs = bfqq_process_refs(new_bfqq);
/*
* If the process for the bfqq has gone away, there is no
* sense in merging the queues.
*/
- if (process_refs == 0 || new_process_refs == 0)
+ if (process_refs == 0)
return NULL;
/*
--
2.30.0
^ permalink raw reply related [flat|nested] 21+ messages in thread