This is a note to let you know that I've just added the patch titled
Revert "workqueue: Move nr_active handling into helpers"
to the 6.8-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:
revert-workqueue-move-nr_active-handling-into-helpers.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c7cb60780ff4256313fc047682cfd498e2b5a3e7 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Date: Wed, 3 Apr 2024 16:29:20 +0200
Subject: Revert "workqueue: Move nr_active handling into helpers"
From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
This reverts commit 6584970ff38fc8f875c683dbb47bb38d4132a528 which is
commit 1c270b79ce0b8290f146255ea9057243f6dd3c17 upstream.
The workqueue patches backported to 6.8.y caused some reported
regressions, so revert them for now.
Reported-by: Thorsten Leemhuis <regressions@xxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Sasha Levin <sashal@xxxxxxxxxx>
Cc: Audra Mitchell <audra@xxxxxxxxxx>
Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@xxxxxxxxxxxxx/
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/workqueue.c | 86 +++++++++++------------------------------------------
1 file changed, 19 insertions(+), 67 deletions(-)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1464,14 +1464,11 @@ static bool pwq_is_empty(struct pool_wor
static void __pwq_activate_work(struct pool_workqueue *pwq,
struct work_struct *work)
{
- unsigned long *wdb = work_data_bits(work);
-
- WARN_ON_ONCE(!(*wdb & WORK_STRUCT_INACTIVE));
trace_workqueue_activate_work(work);
if (list_empty(&pwq->pool->worklist))
pwq->pool->watchdog_ts = jiffies;
move_linked_works(work, &pwq->pool->worklist, NULL);
- __clear_bit(WORK_STRUCT_INACTIVE_BIT, wdb);
+ __clear_bit(WORK_STRUCT_INACTIVE_BIT, work_data_bits(work));
}
/**
@@ -1496,66 +1493,12 @@ static bool pwq_activate_work(struct poo
return true;
}
-/**
- * pwq_tryinc_nr_active - Try to increment nr_active for a pwq
- * @pwq: pool_workqueue of interest
- *
- * Try to increment nr_active for @pwq. Returns %true if an nr_active count is
- * successfully obtained. %false otherwise.
- */
-static bool pwq_tryinc_nr_active(struct pool_workqueue *pwq)
-{
- struct workqueue_struct *wq = pwq->wq;
- struct worker_pool *pool = pwq->pool;
- bool obtained;
-
- lockdep_assert_held(&pool->lock);
-
- obtained = pwq->nr_active < READ_ONCE(wq->max_active);
-
- if (obtained)
- pwq->nr_active++;
- return obtained;
-}
-
-/**
- * pwq_activate_first_inactive - Activate the first inactive work item on a pwq
- * @pwq: pool_workqueue of interest
- *
- * Activate the first inactive work item of @pwq if available and allowed by
- * max_active limit.
- *
- * Returns %true if an inactive work item has been activated. %false if no
- * inactive work item is found or max_active limit is reached.
- */
-static bool pwq_activate_first_inactive(struct pool_workqueue *pwq)
-{
- struct work_struct *work =
- list_first_entry_or_null(&pwq->inactive_works,
- struct work_struct, entry);
-
- if (work && pwq_tryinc_nr_active(pwq)) {
- __pwq_activate_work(pwq, work);
- return true;
- } else {
- return false;
- }
-}
-
-/**
- * pwq_dec_nr_active - Retire an active count
- * @pwq: pool_workqueue of interest
- *
- * Decrement @pwq's nr_active and try to activate the first inactive work item.
- */
-static void pwq_dec_nr_active(struct pool_workqueue *pwq)
+static void pwq_activate_first_inactive(struct pool_workqueue *pwq)
{
- struct worker_pool *pool = pwq->pool;
+ struct work_struct *work = list_first_entry(&pwq->inactive_works,
+ struct work_struct, entry);
- lockdep_assert_held(&pool->lock);
-
- pwq->nr_active--;
- pwq_activate_first_inactive(pwq);
+ pwq_activate_work(pwq, work);
}
/**
@@ -1573,8 +1516,14 @@ static void pwq_dec_nr_in_flight(struct
{
int color = get_work_color(work_data);
- if (!(work_data & WORK_STRUCT_INACTIVE))
- pwq_dec_nr_active(pwq);
+ if (!(work_data & WORK_STRUCT_INACTIVE)) {
+ pwq->nr_active--;
+ if (!list_empty(&pwq->inactive_works)) {
+ /* one down, submit an inactive one */
+ if (pwq->nr_active < READ_ONCE(pwq->wq->max_active))
+ pwq_activate_first_inactive(pwq);
+ }
+ }
pwq->nr_in_flight[color]--;
@@ -1876,11 +1825,13 @@ retry:
* @work must also queue behind existing inactive work items to maintain
* ordering when max_active changes. See wq_adjust_max_active().
*/
- if (list_empty(&pwq->inactive_works) && pwq_tryinc_nr_active(pwq)) {
+ if (list_empty(&pwq->inactive_works) &&
+ pwq->nr_active < READ_ONCE(pwq->wq->max_active)) {
if (list_empty(&pool->worklist))
pool->watchdog_ts = jiffies;
trace_workqueue_activate_work(work);
+ pwq->nr_active++;
insert_work(pwq, work, &pool->worklist, work_flags);
kick_pool(pool);
} else {
@@ -4729,8 +4680,9 @@ static void wq_adjust_max_active(struct
/* this function can be called during early boot w/ irq disabled */
raw_spin_lock_irqsave(&pwq->pool->lock, flags);
- while (pwq_activate_first_inactive(pwq))
- ;
+ while (!list_empty(&pwq->inactive_works) &&
+ pwq->nr_active < wq->max_active)
+ pwq_activate_first_inactive(pwq);
kick_pool(pwq->pool);
Patches currently in stable-queue which might be from gregkh@xxxxxxxxxxxxxxxxxxx are
queue-6.8/revert-workqueue-move-pwq-max_active-to-wq-max_active.patch
queue-6.8/revert-workqueue-replace-pwq_activate_inactive_work-with-pwq_activate_work.patch
queue-6.8/revert-workqueue-implement-system-wide-nr_active-enforcement-for-unbound-workqueues.patch
queue-6.8/revert-workqueue-introduce-struct-wq_node_nr_active.patch
queue-6.8/revert-workqueue-rcu-protect-wq-dfl_pwq-and-implement-accessors-for-it.patch
queue-6.8/revert-workqueue-don-t-call-cpumask_test_cpu-with-1-cpu-in-wq_update_node_max_active.patch
queue-6.8/revert-workqueue-factor-out-pwq_is_empty.patch
queue-6.8/revert-workqueue-shorten-events_freezable_power_efficient-name.patch
queue-6.8/revert-workqueue-make-wq_adjust_max_active-round-robin-pwqs-while-activating.patch
queue-6.8/revert-workqueue.c-increase-workqueue-name-length.patch
queue-6.8/revert-workqueue-move-nr_active-handling-into-helpers.patch
