From 54d5b7d079dffa74597715a892473b474babd5b5 Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Thu, 7 Feb 2013 13:14:20 -0800 Subject: [PATCH] workqueue: make get_work_pool_id() cheaper get_work_pool_id() currently first obtains pool using get_work_pool() and then return pool->id. For an off-queue work item, this involves obtaining pool ID from worker->data, performing idr_find() to find the matching pool and then returning its pool->id which of course is the same as the one which went into idr_find(). Just open code WORK_STRUCT_CWQ case and directly return pool ID from work->data. tj: The original patch dropped on-queue work item handling and renamed the function to offq_work_pool_id(). There isn't much benefit in doing so. Handling it only requires a single if() and we need at least BUG_ON(), which is also a branch, even if we drop on-queue handling. Open code WORK_STRUCT_CWQ case and keep the function in line with get_work_pool(). Rewrote the description. Signed-off-by: Lai Jiangshan Signed-off-by: Tejun Heo --- kernel/workqueue.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 91ce7a984c22..1801c37b28c4 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -611,9 +611,13 @@ static struct worker_pool *get_work_pool(struct work_struct *work) */ static int get_work_pool_id(struct work_struct *work) { - struct worker_pool *pool = get_work_pool(work); + unsigned long data = atomic_long_read(&work->data); + + if (data & WORK_STRUCT_CWQ) + return ((struct cpu_workqueue_struct *) + (data & WORK_STRUCT_WQ_DATA_MASK))->pool->id; - return pool ? pool->id : WORK_OFFQ_POOL_NONE; + return data >> WORK_OFFQ_POOL_SHIFT; } static void mark_work_canceling(struct work_struct *work) -- 2.20.1