[PATCH 04/31] workqueue: add workqueue_struct->pwqs list

Tejun Heo
2013-03-02T03:24:57Z

Add workqueue_struct->pwqs list and chain all pool_workqueues
belonging to a workqueue there. This will be used to implement
generic pool_workqueue iteration and handle multiple pool_workqueues
for the scheduled unbound pools with custom attributes.

This patch doesn't introduce any visible behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/workqueue.c | 33 +++++++++++++++++++++++++++------
1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 69f1268..d493293 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -169,6 +169,7 @@ struct pool_workqueue {
int nr_active; /* L: nr of active works */
int max_active; /* L: max active works */
struct list_head delayed_works; /* L: delayed works */
+ struct list_head pwqs_node; /* I: node on wq->pwqs */
} __aligned(1 << WORK_STRUCT_FLAG_BITS);

/*
@@ -212,6 +213,7 @@ struct workqueue_struct {
struct pool_workqueue *single;
unsigned long v;
} pool_wq; /* I: pwq's */
+ struct list_head pwqs; /* I: all pwqs of this wq */
struct list_head list; /* W: list of all workqueues */

struct mutex flush_mutex; /* protects wq flushing */
@@ -3098,14 +3100,32 @@ int keventd_up(void)
return system_wq != NULL;
}

-static int alloc_pwqs(struct workqueue_struct *wq)
+static int alloc_and_link_pwqs(struct workqueue_struct *wq)
{
- if (!(wq->flags & WQ_UNBOUND))
+ int cpu;
+
+ if (!(wq->flags & WQ_UNBOUND)) {
wq->pool_wq.pcpu = alloc_percpu(struct pool_workqueue);
- else
- wq->pool_wq.single = kmem_cache_zalloc(pwq_cache, GFP_KERNEL);
+ if (!wq->pool_wq.pcpu)
+ return -ENOMEM;
+
+ for_each_possible_cpu(cpu) {
+ struct pool_workqueue *pwq = get_pwq(cpu, wq);

- return wq->pool_wq.v ? 0 : -ENOMEM;
+ list_add_tail(&pwq->pwqs_node, &wq->pwqs);
+ }
+ } else {
+ struct pool_workqueue *pwq;
+
+ pwq = kmem_cache_zalloc(pwq_cache, GFP_KERNEL);
+ if (!pwq)
+ return -ENOMEM;
+
+ wq->pool_wq.single = pwq;
+ list_add_tail(&pwq->pwqs_node, &wq->pwqs);
+ }
+
+ return 0;
}

static void free_pwqs(struct workqueue_struct *wq)
@@ -3167,13 +3187,14 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
wq->saved_max_active = max_active;
mutex_init(&wq->flush_mutex);
atomic_set(&wq->nr_pwqs_to_flush, 0);
+ INIT_LIST_HEAD(&wq->pwqs);
INIT_LIST_HEAD(&wq->flusher_queue);
INIT_LIST_HEAD(&wq->flusher_overflow);

lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
INIT_LIST_HEAD(&wq->list);

- if (alloc_pwqs(wq) < 0)
+ if (alloc_and_link_pwqs(wq) < 0)
goto err;

for_each_pwq_cpu(cpu, wq) {
--
1.8.1.2