From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH] gpu: drm: amd: amdkfd: Remove create_workqueue() Date: Thu, 26 May 2016 14:50:29 -0400 Message-ID: <20160526185029.GA23194@mtj.duckdns.org> References: <20160526184517.GA8758@Karyakshetra> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from mail-yw0-x243.google.com (mail-yw0-x243.google.com [IPv6:2607:f8b0:4002:c05::243]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2286E6EA44 for ; Thu, 26 May 2016 18:50:33 +0000 (UTC) Received: by mail-yw0-x243.google.com with SMTP id y6so3412906ywe.0 for ; Thu, 26 May 2016 11:50:33 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20160526184517.GA8758@Karyakshetra> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Bhaktipriya Shridhar Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, alexander.deucher@amd.com, christian.koenig@amd.com List-Id: dri-devel@lists.freedesktop.org T24gRnJpLCBNYXkgMjcsIDIwMTYgYXQgMTI6MTU6MTdBTSArMDUzMCwgQmhha3RpcHJpeWEgU2hy aWRoYXIgd3JvdGU6Cj4gYWxsb2Nfd29ya3F1ZXVlIHJlcGxhY2VzIGRlcHJlY2F0ZWQgY3JlYXRl X3dvcmtxdWV1ZSgpLgo+IAo+IGtmZF9wcm9jZXNzX3dxIGlzIHVzZWQgZm9yIGRlbGF5IGRlc3Ry dWN0aW9uLiBBIHdvcmsgaXRlbSBlbWJlZGRlZCBpbgo+IGtmZF9wcm9jZXNzIGdldHMgcXVldWVk IHRvIGtmZF9wcm9jZXNzX3dxIGFuZCB3aGVuIGl0IGV4ZWN1dGVzIGl0Cj4gZGVzdHJveXMgYW5k IGZyZWVzIHRoZSBjb250YWluaW5nIGtmZF9wcm9jZXNzIGFuZCB0aHVzIGl0c2VsZi4KPiAKPiBU aGlzIHJlcXVpcmVzIGEgZGVkaWNhdGVkIHdvcmtxdWV1ZSBiZWNhdXNlIGEgd29yayBpdGVtIG9u Y2UgcXVldWVkLCBtYXkKPiBnZXQgZnJlZWQgYXQgYW55IHBvaW50IG9mIHRpbWUgYW5kIGFueSBl eHRlcm5hbCBlbnRpdHkgY2Fubm90Cj4gZmx1c2ggdGhlIHdvcmsgaXRlbS4gU28sIGluIG9yZGVy IHRvIHdhaXQgZm9yIHN1Y2ggYSB3b3JrIGl0ZW0sCj4gaXQgbmVlZHMgdG8gYmUgcHV0IG9uIGEg ZGVkaWNhdGVkIHdvcmtxdWV1ZS4KPiAKPiBrZmRfbW9kdWxlX2V4aXQoKSBjYWxscyBrZmRfcHJv Y2Vzc19kZXN0cm95X3dxIHdoaWNoIGVuc3VyZXMgdGhhdCBhbGwKPiBwZW5kaW5nIHdvcmsgaXRl bXMgYXJlIGZpbmlzaGVkIGJlZm9yZSB0aGUgbW9kdWxlIGlzIHJlbW92ZWQuCj4gCj4gZmx1c2hf d29ya3F1ZXVlIGlzIHVubmVjZXNzYXJ5IHNpbmNlIGRlc3Ryb3lfd29ya3F1ZXVlKCkgaXRzZWxm IGNhbGxzCj4gZHJhaW5fd29ya3F1ZXVlKCkgd2hpY2ggZmx1c2hlcyByZXBlYXRlZGx5IHRpbGwg dGhlIHdvcmtxdWV1ZSBiZWNvbWVzIGVtcHR5Lgo+IAo+IEhlbmNlIGZsdXNoX3dvcmtxdWV1ZSBo YXMgYmVlbiByZW1vdmVkLgoKY3JlYXRlX3dvcmtxdWV1ZShOQU1FKSBtYXBzIHRvIGFsbG9jX3dv cmtxdWV1ZShOQU1FLCBXUV9NRU1fUkVDTEFJTSwgMSksCnNvIHRoZSBjaGFuZ2UgaXMgZWZmZWN0 aXZlbHkgZHJvcHBpbmcgV1FfTUVNX1JFQ0xBSU0gYW5kIGNoYW5naW5nCmNvbmN1cnJlbmN5IHZh bHVlIGZyb20gMSB0byBXUV9ERkxfQUNUSVZFLiAgSXQnZCBiZSBuaWNlIHRvIGV4cGxhaW4Kd2h5 IHRoZXNlIGNoYW5nZXMgYXJlIHNhZmUgYW5kIEkgdGhpbmsgdGhleSdyZS4gSXQganVzdCBuZWVk cwpleHBsYW5hdGlvbnMuCgo+IFNpZ25lZC1vZmYtYnk6IEJoYWt0aXByaXlhIFNocmlkaGFyIDxi aGFrdGlwcml5YTk2QGdtYWlsLmNvbT4KCk90aGVyIHRoYW4gdGhhdCwgQWNrZWQtYnk6IFRlanVu IEhlbyA8dGpAa2VybmVsLm9yZz4KClRoYW5rcy4KCi0tIAp0ZWp1bgpfX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fXwpkcmktZGV2ZWwgbWFpbGluZyBsaXN0CmRy aS1kZXZlbEBsaXN0cy5mcmVlZGVza3RvcC5vcmcKaHR0cHM6Ly9saXN0cy5mcmVlZGVza3RvcC5v cmcvbWFpbG1hbi9saXN0aW5mby9kcmktZGV2ZWwK From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755042AbcEZSuf (ORCPT ); Thu, 26 May 2016 14:50:35 -0400 Received: from mail-yw0-f195.google.com ([209.85.161.195]:34239 "EHLO mail-yw0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754692AbcEZSuc (ORCPT ); Thu, 26 May 2016 14:50:32 -0400 Date: Thu, 26 May 2016 14:50:29 -0400 From: Tejun Heo To: Bhaktipriya Shridhar 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() Message-ID: <20160526185029.GA23194@mtj.duckdns.org> References: <20160526184517.GA8758@Karyakshetra> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160526184517.GA8758@Karyakshetra> User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Other than that, Acked-by: Tejun Heo Thanks. -- tejun