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From: Tejun Heo <tj@kernel.org>
To: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	alexander.deucher@amd.com, christian.koenig@amd.com
Subject: Re: [PATCH] gpu: drm: amd: amdkfd: Remove create_workqueue()
Date: Thu, 26 May 2016 14:50:29 -0400	[thread overview]
Message-ID: <20160526185029.GA23194@mtj.duckdns.org> (raw)
In-Reply-To: <20160526184517.GA8758@Karyakshetra>

On Fri, May 27, 2016 at 12:15:17AM +0530, Bhaktipriya Shridhar wrote:
> alloc_workqueue replaces deprecated create_workqueue().
> 
> 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.

create_workqueue(NAME) maps to alloc_workqueue(NAME, WQ_MEM_RECLAIM, 1),
so the change is effectively dropping WQ_MEM_RECLAIM and changing
concurrency value from 1 to WQ_DFL_ACTIVE.  It'd be nice to explain
why these changes are safe and I think they're. It just needs
explanations.

> Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>

Other than that, Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun
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dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj@kernel.org>
To: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Cc: oded.gabbay@gmail.com, alexander.deucher@amd.com,
	christian.koenig@amd.com, airlied@linux.ie,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] gpu: drm: amd: amdkfd: Remove create_workqueue()
Date: Thu, 26 May 2016 14:50:29 -0400	[thread overview]
Message-ID: <20160526185029.GA23194@mtj.duckdns.org> (raw)
In-Reply-To: <20160526184517.GA8758@Karyakshetra>

On Fri, May 27, 2016 at 12:15:17AM +0530, Bhaktipriya Shridhar wrote:
> alloc_workqueue replaces deprecated create_workqueue().
> 
> 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.

create_workqueue(NAME) maps to alloc_workqueue(NAME, WQ_MEM_RECLAIM, 1),
so the change is effectively dropping WQ_MEM_RECLAIM and changing
concurrency value from 1 to WQ_DFL_ACTIVE.  It'd be nice to explain
why these changes are safe and I think they're. It just needs
explanations.

> Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>

Other than that, Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun

  reply	other threads:[~2016-05-26 18:50 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-26 18:45 [PATCH] gpu: drm: amd: amdkfd: Remove create_workqueue() Bhaktipriya Shridhar
2016-05-26 18:45 ` Bhaktipriya Shridhar
2016-05-26 18:50 ` Tejun Heo [this message]
2016-05-26 18:50   ` Tejun Heo

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