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Message-ID: <20230811102250.GA7959@didi-ThinkCentre-M930t-N000>
Date: Fri, 11 Aug 2023 18:23:07 +0800
From: Tio Zhang <tiozhang@...iglobal.com>
To: <tj@...nel.org>
CC: <jiangshanlai@...il.com>, <linux-kernel@...r.kernel.org>,
<zyhtheonly@...il.com>, <zyhtheonly@...h.net>,
<tiozhang@...iglobal.com>
Subject: [PATCH] workqueue: let WORKER_CPU_INTENSIVE be included in watchdog
When a pool has a worker with WORKER_CPU_INTENSIVE set but other workers
are not that busy, the pool->worklist will mostly be empty, which leads
the intensive work always having a chance of escaping from the watchdog's
check. This may cause watchdog miss finding out a forever running work
in WQ_CPU_INTENSIVE.
Also, after commit '616db8779b1e3f93075df691432cccc5ef3c3ba0',
workers with potentially intensive works will automatically be converted
into WORKER_CPU_INTENSIVE. This might let watchdog to miss all work
potentially running forever.
Signed-off-by: Tio Zhang <tiozhang@...iglobal.com>
---
kernel/workqueue.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 02a8f402eeb5..29875b680f5b 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -6280,10 +6280,23 @@ static void wq_watchdog_timer_fn(struct timer_list *unused)
rcu_read_lock();
for_each_pool(pool, pi) {
+ struct worker *worker;
unsigned long pool_ts, touched, ts;
+ bool check_intensive = false;
pool->cpu_stall = false;
- if (list_empty(&pool->worklist))
+
+ /* Not sure if we should let WORKER_UNBOUND to
+ * be included? Since let a unbound work to last
+ * more than e,g, 30 seconds seem also unacceptable.
+ */
+ for_each_pool_worker(worker, pool) {
+ if (worker->flags & WORKER_CPU_INTENSIVE) {
+ check_intensive = true;
+ break;
+ }
+ }
+ if (list_empty(&pool->worklist) && !check_intensive)
continue;
/*
--
2.17.1
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