linux-kernel - [PATCH v2] gpu: drm: amd: amdkfd: Remove create

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Date:	Fri, 27 May 2016 01:07:33 +0530
From:	Bhaktipriya Shridhar <bhaktipriya96@...il.com>
To:	tj@...nel.org, oded.gabbay@...il.com, alexander.deucher@....com,
	christian.koenig@....com, airlied@...ux.ie
Cc:	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] gpu: drm: amd: amdkfd: Remove create_workqueue()

alloc_workqueue replaces deprecated create_workqueue().

create_workqueue has been replaced with alloc_workqueue with max_active
as 0 since there is no need for throttling the number of active work items.

WQ_MEM_RECLAIM has not been set to because kfd_process_wq will not be used in
memory reclaim path.

kfd_process_wq is used for delay destruction. A work item embedded in
kfd_process gets queued to kfd_process_wq and when it executes it
destroys and frees the containing kfd_process and thus itself.

This requires a dedicated workqueue because a work item once queued, may
get freed at any point of time and any external entity cannot
flush the work item. So, in order to wait for such a work item,
it needs to be put on a dedicated workqueue.

kfd_module_exit() calls kfd_process_destroy_wq which ensures that all
pending work items are finished before the module is removed.

flush_workqueue is unnecessary since destroy_workqueue() itself calls
drain_workqueue() which flushes repeatedly till the workqueue becomes empty.

Hence flush_workqueue has been removed.

Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@...il.com>
---
 Changes in v2:
	- added explanation for setting concurrency value to
	  WQ_DFL_ACTIVE
	- added explanation for dropping WQ_MEM_RECLAIM

 drivers/gpu/drm/amd/amdkfd/kfd_process.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index ac00579..b21d3fc8 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -63,13 +63,12 @@ static struct kfd_process *create_process(const struct task_struct *thread);
 void kfd_process_create_wq(void)
 {
 	if (!kfd_process_wq)
-		kfd_process_wq = create_workqueue("kfd_process_wq");
+		kfd_process_wq = alloc_workqueue("kfd_process_wq",0,0);
 }

 void kfd_process_destroy_wq(void)
 {
 	if (kfd_process_wq) {
-		flush_workqueue(kfd_process_wq);
 		destroy_workqueue(kfd_process_wq);
 		kfd_process_wq = NULL;
 	}
--
2.1.4