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workqueue: use new hashtable implementation

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Switch workqueues to use the new hashtable implementation. This reduces the
amount of generic unrelated code in the workqueues.

This patch depends on d9b482c ("hashtable: introduce a small and naive
hashtable") which was merged in v3.6.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Sasha Levin 2012-12-17 10:01:23 -05:00 • committed by Tejun Heo
commit 42f8570f43
1 changed files with 15 additions and 71 deletions
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86
kernel/workqueue.c
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@ -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];
DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
/* L: hash of busy workers */
struct worker_pool pools[NR_WORKER_POOLS];
@ -285,8 +284,7 @@ EXPORT_SYMBOL_GPL(system_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, i, pos, worker, hentry)
static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask,
unsigned int sw)
@ -858,63 +856,6 @@ static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
atomic_inc(get_pool_nr_running(pool));
}
/**
* 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
@ -934,8 +875,14 @@ 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, tmp, hentry, (unsigned long)work)
if (worker->current_work == work)
return worker;
return NULL;
}
/**
@ -2166,7 +2113,6 @@ __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;
@ -2198,7 +2144,7 @@ __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;
@ -2206,7 +2152,7 @@ __acquires(&gcwq->lock)
/* claim and dequeue */
debug_work_deactivate(work);
hlist_add_head(&worker->hentry, bwh);
hash_add(gcwq->busy_hash, &worker->hentry, (unsigned long)worker);
worker->current_work = work;
worker->current_cwq = cwq;
work_color = get_work_color(work);
@ -2264,7 +2210,7 @@ __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);
@ -3831,7 +3777,6 @@ out_unlock:
static int __init init_workqueues(void)
{
unsigned int cpu;
int i;
/* make sure we have enough bits for OFFQ CPU number */
BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_CPU_SHIFT)) <
@ -3849,8 +3794,7 @@ 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);
for_each_worker_pool(pool, gcwq) {
pool->gcwq = gcwq;