lkml.org 
[lkml]   [2014]   [May]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 05/10 V2] workqueue: separate iteration role from worker_idr
Date
worker_idr has the iteration(iterating for attached workers) and worker ID
duties. These two duties are not necessary tied together. We can separate
them and use a list for tracking attached workers and iteration

After separation, we can add the rescuer workers to the list for iteration
in future. worker_idr can't add rescuer workers due to rescuer workers
can't allocate id from worker_idr.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
kernel/workqueue.c | 39 +++++++++++++--------------------------
kernel/workqueue_internal.h | 1 +
2 files changed, 14 insertions(+), 26 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 95695c3..b6cf4d9 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -161,7 +161,8 @@ struct worker_pool {
/* see manage_workers() for details on the two manager mutexes */
struct mutex manager_arb; /* manager arbitration */
struct mutex manager_mutex; /* manager exclusion */
- struct idr worker_idr; /* M: worker IDs and iteration */
+ struct idr worker_idr; /* M: worker IDs */
+ struct list_head workers; /* M: attached workers */
struct completion *detach_completion; /* all workers detached */

struct workqueue_attrs *attrs; /* I: worker attributes */
@@ -361,22 +362,6 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to,
else

/**
- * for_each_pool_worker - iterate through all workers of a worker_pool
- * @worker: iteration cursor
- * @wi: integer used for iteration
- * @pool: worker_pool to iterate workers of
- *
- * This must be called with @pool->manager_mutex.
- *
- * The if/else clause exists only for the lockdep assertion and can be
- * ignored.
- */
-#define for_each_pool_worker(worker, wi, pool) \
- idr_for_each_entry(&(pool)->worker_idr, (worker), (wi)) \
- if (({ lockdep_assert_held(&pool->manager_mutex); false; })) { } \
- else
-
-/**
* for_each_pwq - iterate through all pool_workqueues of the specified workqueue
* @pwq: iteration cursor
* @wq: the target workqueue
@@ -1674,6 +1659,7 @@ static struct worker *alloc_worker(void)
if (worker) {
INIT_LIST_HEAD(&worker->entry);
INIT_LIST_HEAD(&worker->scheduled);
+ INIT_LIST_HEAD(&worker->node);
/* on creation a worker is in !idle && prep state */
worker->flags = WORKER_PREP;
}
@@ -1696,7 +1682,8 @@ static void worker_detach_from_pool(struct worker *worker,

mutex_lock(&pool->manager_mutex);
idr_remove(&pool->worker_idr, worker->id);
- if (idr_is_empty(&pool->worker_idr))
+ list_del(&worker->node);
+ if (list_empty(&pool->workers))
detach_completion = pool->detach_completion;
mutex_unlock(&pool->manager_mutex);

@@ -1772,6 +1759,8 @@ static struct worker *create_worker(struct worker_pool *pool)

/* successful, commit the pointer to idr */
idr_replace(&pool->worker_idr, worker, worker->id);
+ /* successful, attach the worker to the pool */
+ list_add_tail(&worker->node, &pool->workers);

return worker;

@@ -3481,6 +3470,7 @@ static int init_worker_pool(struct worker_pool *pool)
mutex_init(&pool->manager_arb);
mutex_init(&pool->manager_mutex);
idr_init(&pool->worker_idr);
+ INIT_LIST_HEAD(&pool->workers);

INIT_HLIST_NODE(&pool->hash_node);
pool->refcnt = 1;
@@ -3545,7 +3535,7 @@ static void put_unbound_pool(struct worker_pool *pool)
spin_unlock_irq(&pool->lock);

mutex_lock(&pool->manager_mutex);
- if (!idr_is_empty(&pool->worker_idr))
+ if (!list_empty(&pool->workers))
pool->detach_completion = &detach_completion;
mutex_unlock(&pool->manager_mutex);

@@ -4530,7 +4520,6 @@ static void wq_unbind_fn(struct work_struct *work)
int cpu = smp_processor_id();
struct worker_pool *pool;
struct worker *worker;
- int wi;

for_each_cpu_worker_pool(pool, cpu) {
WARN_ON_ONCE(cpu != smp_processor_id());
@@ -4545,7 +4534,7 @@ static void wq_unbind_fn(struct work_struct *work)
* before the last CPU down must be on the cpu. After
* this, they may become diasporas.
*/
- for_each_pool_worker(worker, wi, pool)
+ list_for_each_entry(worker, &pool->workers, node)
worker->flags |= WORKER_UNBOUND;

pool->flags |= POOL_DISASSOCIATED;
@@ -4591,7 +4580,6 @@ static void wq_unbind_fn(struct work_struct *work)
static void rebind_workers(struct worker_pool *pool)
{
struct worker *worker;
- int wi;

lockdep_assert_held(&pool->manager_mutex);

@@ -4602,13 +4590,13 @@ static void rebind_workers(struct worker_pool *pool)
* of all workers first and then clear UNBOUND. As we're called
* from CPU_ONLINE, the following shouldn't fail.
*/
- for_each_pool_worker(worker, wi, pool)
+ list_for_each_entry(worker, &pool->workers, node)
WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
pool->attrs->cpumask) < 0);

spin_lock_irq(&pool->lock);

- for_each_pool_worker(worker, wi, pool) {
+ list_for_each_entry(worker, &pool->workers, node) {
unsigned int worker_flags = worker->flags;

/*
@@ -4660,7 +4648,6 @@ static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu)
{
static cpumask_t cpumask;
struct worker *worker;
- int wi;

lockdep_assert_held(&pool->manager_mutex);

@@ -4674,7 +4661,7 @@ static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu)
return;

/* as we're called from CPU_ONLINE, the following shouldn't fail */
- for_each_pool_worker(worker, wi, pool)
+ list_for_each_entry(worker, &pool->workers, node)
WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task,
pool->attrs->cpumask) < 0);
}
diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h
index 7e2204d..c44abc3 100644
--- a/kernel/workqueue_internal.h
+++ b/kernel/workqueue_internal.h
@@ -37,6 +37,7 @@ struct worker {
struct task_struct *task; /* I: worker task */
struct worker_pool *pool; /* I: the associated pool */
/* L: for rescuers */
+ struct list_head node; /* M: attached to the pool */

unsigned long last_active; /* L: last active timestamp */
unsigned int flags; /* X: flags */
--
1.7.4.4


\
 
 \ /
  Last update: 2014-05-12 09:21    [W:1.449 / U:0.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site