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Message-Id: <1344300317-23189-6-git-send-email-levinsasha928@gmail.com>
Date: Tue, 7 Aug 2012 02:45:14 +0200
From: Sasha Levin <levinsasha928@...il.com>
To: torvalds@...ux-foundation.org
Cc: tj@...nel.org, akpm@...ux-foundation.org,
linux-kernel@...r.kernel.org, linux-mm@...ck.org,
paul.gortmaker@...driver.com, davem@...emloft.net,
rostedt@...dmis.org, mingo@...e.hu, ebiederm@...ssion.com,
aarcange@...hat.com, ericvh@...il.com, netdev@...r.kernel.org,
josh@...htriplett.org, eric.dumazet@...il.com,
mathieu.desnoyers@...icios.com,
Sasha Levin <sasha.levin@...cle.com>
Subject: [RFC v3 4/7] workqueue: use new hashtable implementation
From: Sasha Levin <sasha.levin@...cle.com>
Switch workqueues to use the new hashtable implementation. This reduces the amount of
generic unrelated code in the workqueues.
Signed-off-by: Sasha Levin <sasha.levin@...cle.com>
---
kernel/workqueue.c | 91 +++++++++++-----------------------------------------
1 files changed, 19 insertions(+), 72 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 692d976..edc7fd0 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -41,6 +41,7 @@
#include <linux/debug_locks.h>
#include <linux/lockdep.h>
#include <linux/idr.h>
+#include <linux/hashtable.h>
#include "workqueue_sched.h"
@@ -82,8 +83,6 @@ enum {
NR_WORKER_POOLS = 2, /* # worker pools per gcwq */
BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */
- BUSY_WORKER_HASH_SIZE = 1 << BUSY_WORKER_HASH_ORDER,
- BUSY_WORKER_HASH_MASK = BUSY_WORKER_HASH_SIZE - 1,
MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */
IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */
@@ -180,7 +179,7 @@ struct global_cwq {
unsigned int flags; /* L: GCWQ_* flags */
/* workers are chained either in busy_hash or pool idle_list */
- struct hlist_head busy_hash[BUSY_WORKER_HASH_SIZE];
+ DEFINE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
/* L: hash of busy workers */
struct worker_pool pools[2]; /* normal and highpri pools */
@@ -288,8 +287,8 @@ EXPORT_SYMBOL_GPL(system_nrt_freezable_wq);
(pool) < &(gcwq)->pools[NR_WORKER_POOLS]; (pool)++)
#define for_each_busy_worker(worker, i, pos, gcwq) \
- for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++) \
- hlist_for_each_entry(worker, pos, &gcwq->busy_hash[i], hentry)
+ hash_for_each(gcwq->busy_hash, BUSY_WORKER_HASH_ORDER, i, pos, \
+ worker, hentry)
static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask,
unsigned int sw)
@@ -822,63 +821,6 @@ static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
}
/**
- * busy_worker_head - return the busy hash head for a work
- * @gcwq: gcwq of interest
- * @work: work to be hashed
- *
- * Return hash head of @gcwq for @work.
- *
- * CONTEXT:
- * spin_lock_irq(gcwq->lock).
- *
- * RETURNS:
- * Pointer to the hash head.
- */
-static struct hlist_head *busy_worker_head(struct global_cwq *gcwq,
- struct work_struct *work)
-{
- const int base_shift = ilog2(sizeof(struct work_struct));
- unsigned long v = (unsigned long)work;
-
- /* simple shift and fold hash, do we need something better? */
- v >>= base_shift;
- v += v >> BUSY_WORKER_HASH_ORDER;
- v &= BUSY_WORKER_HASH_MASK;
-
- return &gcwq->busy_hash[v];
-}
-
-/**
- * __find_worker_executing_work - find worker which is executing a work
- * @gcwq: gcwq of interest
- * @bwh: hash head as returned by busy_worker_head()
- * @work: work to find worker for
- *
- * Find a worker which is executing @work on @gcwq. @bwh should be
- * the hash head obtained by calling busy_worker_head() with the same
- * work.
- *
- * CONTEXT:
- * spin_lock_irq(gcwq->lock).
- *
- * RETURNS:
- * Pointer to worker which is executing @work if found, NULL
- * otherwise.
- */
-static struct worker *__find_worker_executing_work(struct global_cwq *gcwq,
- struct hlist_head *bwh,
- struct work_struct *work)
-{
- struct worker *worker;
- struct hlist_node *tmp;
-
- hlist_for_each_entry(worker, tmp, bwh, hentry)
- if (worker->current_work == work)
- return worker;
- return NULL;
-}
-
-/**
* find_worker_executing_work - find worker which is executing a work
* @gcwq: gcwq of interest
* @work: work to find worker for
@@ -897,8 +839,15 @@ static struct worker *__find_worker_executing_work(struct global_cwq *gcwq,
static struct worker *find_worker_executing_work(struct global_cwq *gcwq,
struct work_struct *work)
{
- return __find_worker_executing_work(gcwq, busy_worker_head(gcwq, work),
- work);
+ struct worker *worker;
+ struct hlist_node *tmp;
+
+ hash_for_each_possible(gcwq->busy_hash, worker, BUSY_WORKER_HASH_ORDER,
+ tmp, hentry, work)
+ if (worker->current_work == work)
+ return worker;
+
+ return NULL;
}
/**
@@ -1916,7 +1865,7 @@ static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color,
* @worker: self
* @work: work to process
*
- * Process @work. This function contains all the logics necessary to
+ * Process @work. This? function contains all the logics necessary to
* process a single work including synchronization against and
* interaction with other workers on the same cpu, queueing and
* flushing. As long as context requirement is met, any worker can
@@ -1932,7 +1881,6 @@ __acquires(&gcwq->lock)
struct cpu_workqueue_struct *cwq = get_work_cwq(work);
struct worker_pool *pool = worker->pool;
struct global_cwq *gcwq = pool->gcwq;
- struct hlist_head *bwh = busy_worker_head(gcwq, work);
bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE;
work_func_t f = work->func;
int work_color;
@@ -1964,7 +1912,7 @@ __acquires(&gcwq->lock)
* already processing the work. If so, defer the work to the
* currently executing one.
*/
- collision = __find_worker_executing_work(gcwq, bwh, work);
+ collision = find_worker_executing_work(gcwq, work);
if (unlikely(collision)) {
move_linked_works(work, &collision->scheduled, NULL);
return;
@@ -1972,7 +1920,8 @@ __acquires(&gcwq->lock)
/* claim and process */
debug_work_deactivate(work);
- hlist_add_head(&worker->hentry, bwh);
+ hash_add(gcwq->busy_hash, BUSY_WORKER_HASH_ORDER, &worker->hentry,
+ (unsigned long)worker);
worker->current_work = work;
worker->current_cwq = cwq;
work_color = get_work_color(work);
@@ -2027,7 +1976,7 @@ __acquires(&gcwq->lock)
worker_clr_flags(worker, WORKER_CPU_INTENSIVE);
/* we're done with it, release */
- hlist_del_init(&worker->hentry);
+ hash_del(&worker->hentry);
worker->current_work = NULL;
worker->current_cwq = NULL;
cwq_dec_nr_in_flight(cwq, work_color, false);
@@ -3690,7 +3639,6 @@ out_unlock:
static int __init init_workqueues(void)
{
unsigned int cpu;
- int i;
cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP);
cpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN);
@@ -3704,8 +3652,7 @@ static int __init init_workqueues(void)
gcwq->cpu = cpu;
gcwq->flags |= GCWQ_DISASSOCIATED;
- for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++)
- INIT_HLIST_HEAD(&gcwq->busy_hash[i]);
+ hash_init(gcwq->busy_hash, BUSY_WORKER_HASH_ORDER);
for_each_worker_pool(pool, gcwq) {
pool->gcwq = gcwq;
--
1.7.8.6
--
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