[PATCH 18/31] workqueue: remove unbound_std_worker_pools[] and related helpers

Tejun Heo
2013-03-02T03:30:09Z

Workqueue no longer makes use of unbound_std_worker_pools[]. All
unbound worker_pools are created dynamically and there's nothing
special about the standard ones. With unbound_std_worker_pools[]
unused, workqueue no longer has places where it needs to treat the
per-cpu pools-cpu and unbound pools together.

Remove unbound_std_worker_pools[] and the helpers wrapping it to
present unified per-cpu and unbound standard worker_pools.

* for_each_std_worker_pool() now only walks through per-cpu pools.

* for_each[_online]_wq_cpu() which don't have any users left are
removed.

* std_worker_pools() and std_worker_pool_pri() are unused and removed.

* get_std_worker_pool() is removed. Its only user -
alloc_and_link_pwqs() - only used it for per-cpu pools anyway. Open
code per_cpu access in alloc_and_link_pwqs() instead.

This patch doesn't introduce any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/workqueue.c | 66 +++++-------------------------------------------------
1 file changed, 6 insertions(+), 60 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index fb91b67..f7f627c 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -253,48 +253,13 @@ EXPORT_SYMBOL_GPL(system_freezable_wq);
"sched RCU or workqueue lock should be held")

#define for_each_std_worker_pool(pool, cpu) \
- for ((pool) = &std_worker_pools(cpu)[0]; \
- (pool) < &std_worker_pools(cpu)[NR_STD_WORKER_POOLS]; (pool)++)
+ for ((pool) = &per_cpu(cpu_std_worker_pools, cpu)[0]; \
+ (pool) < &per_cpu(cpu_std_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \
+ (pool)++)

#define for_each_busy_worker(worker, i, pos, pool) \
hash_for_each(pool->busy_hash, i, pos, worker, hentry)

-static inline int __next_wq_cpu(int cpu, const struct cpumask *mask,
- unsigned int sw)
-{
- if (cpu < nr_cpu_ids) {
- if (sw & 1) {
- cpu = cpumask_next(cpu, mask);
- if (cpu < nr_cpu_ids)
- return cpu;
- }
- if (sw & 2)
- return WORK_CPU_UNBOUND;
- }
- return WORK_CPU_END;
-}
-
-/*
- * CPU iterators
- *
- * An extra cpu number is defined using an invalid cpu number
- * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any
- * specific CPU. The following iterators are similar to for_each_*_cpu()
- * iterators but also considers the unbound CPU.
- *
- * for_each_wq_cpu() : possible CPUs + WORK_CPU_UNBOUND
- * for_each_online_wq_cpu() : online CPUs + WORK_CPU_UNBOUND
- */
-#define for_each_wq_cpu(cpu) \
- for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, 3); \
- (cpu) < WORK_CPU_END; \
- (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, 3))
-
-#define for_each_online_wq_cpu(cpu) \
- for ((cpu) = __next_wq_cpu(-1, cpu_online_mask, 3); \
- (cpu) < WORK_CPU_END; \
- (cpu) = __next_wq_cpu((cpu), cpu_online_mask, 3))
-
/**
* for_each_pool - iterate through all worker_pools in the system
* @pool: iteration cursor
@@ -452,7 +417,6 @@ static bool workqueue_freezing; /* W: have wqs started freezing? */
*/
static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS],
cpu_std_worker_pools);
-static struct worker_pool unbound_std_worker_pools[NR_STD_WORKER_POOLS];

/*
* idr of all pools. Modifications are protected by workqueue_lock. Read
@@ -462,19 +426,6 @@ static DEFINE_IDR(worker_pool_idr);

static int worker_thread(void *__worker);

-static struct worker_pool *std_worker_pools(int cpu)
-{
- if (cpu != WORK_CPU_UNBOUND)
- return per_cpu(cpu_std_worker_pools, cpu);
- else
- return unbound_std_worker_pools;
-}
-
-static int std_worker_pool_pri(struct worker_pool *pool)
-{
- return pool - std_worker_pools(pool->cpu);
-}
-
/* allocate ID and assign it to @pool */
static int worker_pool_assign_id(struct worker_pool *pool)
{
@@ -492,13 +443,6 @@ static int worker_pool_assign_id(struct worker_pool *pool)
return ret;
}

-static struct worker_pool *get_std_worker_pool(int cpu, bool highpri)
-{
- struct worker_pool *pools = std_worker_pools(cpu);
-
- return &pools[highpri];
-}
-
/**
* first_pwq - return the first pool_workqueue of the specified workqueue
* @wq: the target workqueue
@@ -3390,8 +3334,10 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq)
for_each_possible_cpu(cpu) {
struct pool_workqueue *pwq =
per_cpu_ptr(wq->cpu_pwqs, cpu);
+ struct worker_pool *cpu_pools =
+ per_cpu(cpu_std_worker_pools, cpu);

- pwq->pool = get_std_worker_pool(cpu, highpri);
+ pwq->pool = &cpu_pools[highpri];
list_add_tail_rcu(&pwq->pwqs_node, &wq->pwqs);
}
} else {
--
1.8.1.2