Hello, Paul.
Applied the following two patches to allow early init of
WQ_MEM_RECLAIM workqueues to the following git branch.
git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-4.16
The branch won't be rebased and currently only contains these two
patches. Please feel free to pull and put further RCU changes on top.
Thanks.
------ 8< ------
>From 983c751532738b83c4c5b51192ebc6fbfe9330f7 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@xxxxxxxxxx>
Date: Mon, 8 Jan 2018 05:38:32 -0800
Separate out init_rescuer() from __alloc_workqueue_key() to prepare
for early init support for WQ_MEM_RECLAIM. This patch doesn't
introduce any functional changes.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Paul McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/workqueue.c | 56 ++++++++++++++++++++++++++++++++----------------------
1 file changed, 33 insertions(+), 23 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 43d18cb..5baac7c 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3939,6 +3939,37 @@ static int wq_clamp_max_active(int max_active, unsigned int flags,
return clamp_val(max_active, 1, lim);
}
+/*
+ * Workqueues which may be used during memory reclaim should have a rescuer
+ * to guarantee forward progress.
+ */
+static int init_rescuer(struct workqueue_struct *wq)
+{
+ struct worker *rescuer;
+ int ret;
+
+ if (!(wq->flags & WQ_MEM_RECLAIM))
+ return 0;
+
+ rescuer = alloc_worker(NUMA_NO_NODE);
+ if (!rescuer)
+ return -ENOMEM;
+
+ rescuer->rescue_wq = wq;
+ rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", wq->name);
+ ret = PTR_ERR_OR_ZERO(rescuer->task);
+ if (ret) {
+ kfree(rescuer);
+ return ret;
+ }
+
+ wq->rescuer = rescuer;
+ kthread_bind_mask(rescuer->task, cpu_possible_mask);
+ wake_up_process(rescuer->task);
+
+ return 0;
+}
+
struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
unsigned int flags,
int max_active,
@@ -4001,29 +4032,8 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
if (alloc_and_link_pwqs(wq) < 0)
goto err_free_wq;
- /*
- * Workqueues which may be used during memory reclaim should
- * have a rescuer to guarantee forward progress.
- */
- if (flags & WQ_MEM_RECLAIM) {
- struct worker *rescuer;
-
- rescuer = alloc_worker(NUMA_NO_NODE);
- if (!rescuer)
- goto err_destroy;
-
- rescuer->rescue_wq = wq;
- rescuer->task = kthread_create(rescuer_thread, rescuer, "%s",
- wq->name);
- if (IS_ERR(rescuer->task)) {
- kfree(rescuer);
- goto err_destroy;
- }
-
- wq->rescuer = rescuer;
- kthread_bind_mask(rescuer->task, cpu_possible_mask);
- wake_up_process(rescuer->task);
- }
+ if (init_rescuer(wq) < 0)
+ goto err_destroy;
if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
goto err_destroy;
--
2.9.5
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