From: Lai Jiangshan <laijs@linux.alibaba.com>
To: linux-kernel@vger.kernel.org
Cc: Lai Jiangshan <laijs@linux.alibaba.com>,
Tejun Heo <tj@kernel.org>, Lai Jiangshan <jiangshanlai@gmail.com>
Subject: [PATCH 2/4] workqueue: don't check wq->rescuer in rescuer
Date: Fri, 29 May 2020 06:59:00 +0000 [thread overview]
Message-ID: <20200529065903.1758-3-laijs@linux.alibaba.com> (raw)
In-Reply-To: <20200529065903.1758-1-laijs@linux.alibaba.com>
Now rescuer checks pwq->nr_active before requeues the pwq,
it is a more robust check and the rescuer must be still valid.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
kernel/workqueue.c | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index b2b15f1f0c8d..8d017727bfbc 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -248,7 +248,7 @@ struct workqueue_struct {
struct list_head flusher_overflow; /* WQ: flush overflow list */
struct list_head maydays; /* MD: pwqs requesting rescue */
- struct worker *rescuer; /* MD: rescue worker */
+ struct worker *rescuer; /* I: rescue worker */
int nr_drainers; /* WQ: drain in progress */
int saved_max_active; /* WQ: saved pwq max_active */
@@ -2532,12 +2532,13 @@ static int rescuer_thread(void *__rescuer)
if (pwq->nr_active && need_to_create_worker(pool)) {
spin_lock(&wq_mayday_lock);
/*
- * Queue iff we aren't racing destruction
- * and somebody else hasn't queued it already.
+ * Queue iff somebody else hasn't queued it
+ * already.
*/
- if (wq->rescuer && list_empty(&pwq->mayday_node)) {
+ if (list_empty(&pwq->mayday_node)) {
get_pwq(pwq);
- list_add_tail(&pwq->mayday_node, &wq->maydays);
+ list_add_tail(&pwq->mayday_node,
+ &wq->maydays);
}
spin_unlock(&wq_mayday_lock);
}
@@ -4356,16 +4357,10 @@ void destroy_workqueue(struct workqueue_struct *wq)
/* kill rescuer, if sanity checks fail, leave it w/o rescuer */
if (wq->rescuer) {
- struct worker *rescuer = wq->rescuer;
-
- /* this prevents new queueing */
- spin_lock_irq(&wq_mayday_lock);
- wq->rescuer = NULL;
- spin_unlock_irq(&wq_mayday_lock);
-
/* rescuer will empty maydays list before exiting */
- kthread_stop(rescuer->task);
- kfree(rescuer);
+ kthread_stop(wq->rescuer->task);
+ kfree(wq->rescuer);
+ wq->rescuer = NULL;
}
/*
--
2.20.1
next prev parent reply other threads:[~2020-05-29 6:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-29 6:58 [PATCH 0/4] workqueue: simple cleanups Lai Jiangshan
2020-05-29 6:58 ` [PATCH 1/4] workqueue: void unneeded requeuing the pwq in rescuer thread Lai Jiangshan
2020-05-29 14:22 ` Tejun Heo
2020-05-29 6:59 ` Lai Jiangshan [this message]
2020-05-29 14:14 ` [PATCH 2/4] workqueue: don't check wq->rescuer in rescuer Tejun Heo
2020-05-29 14:58 ` Lai Jiangshan
2020-05-29 15:04 ` Tejun Heo
2020-05-29 6:59 ` [PATCH 3/4] workqueue: free wq->unbound_attrs earlier Lai Jiangshan
2020-05-29 14:23 ` Tejun Heo
2020-05-29 6:59 ` [PATCH 4/4] workqueue: remove useless unlock() and lock() in series Lai Jiangshan
2020-05-29 14:26 ` Tejun Heo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200529065903.1758-3-laijs@linux.alibaba.com \
--to=laijs@linux.alibaba.com \
--cc=jiangshanlai@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).