From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756252Ab2C0VpH (ORCPT ); Tue, 27 Mar 2012 17:45:07 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:38446 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753913Ab2C0VpF (ORCPT ); Tue, 27 Mar 2012 17:45:05 -0400 From: "Rafael J. Wysocki" To: Stephen Boyd Subject: Re: [PATCH 2/2] firmware_class: Move request_firmware_nowait() to workqueues Date: Tue, 27 Mar 2012 23:49:24 +0200 User-Agent: KMail/1.13.6 (Linux/3.3.0+; KDE/4.6.0; x86_64; ; ) Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Saravana Kannan , Kay Sievers , Greg KH , Christian Lamparter , "Srivatsa S. Bhat" , alan@lxorguk.ukuu.org.uk, Linux PM mailing list , Tejun Heo References: <1332883710-7486-1-git-send-email-sboyd@codeaurora.org> <1332883710-7486-2-git-send-email-sboyd@codeaurora.org> In-Reply-To: <1332883710-7486-2-git-send-email-sboyd@codeaurora.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Message-Id: <201203272349.24291.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, March 27, 2012, Stephen Boyd wrote: > Oddly enough a work_struct was already part of the firmware_work > structure but nobody was using it. Instead of creating a new > kthread for each request_firmware_nowait() call just schedule the > work on the long system workqueue. This should avoid some overhead > in forking new threads when they're not strictly necessary. > > Signed-off-by: Stephen Boyd > --- > > Is it better to use alloc_workqueue() and not put these on the system > long workqueue? I think if that happens to interfere destructively with something, we can always use a new workqueue. For now, let's try to avoid adding yet another one if possible. Thanks, Rafael > drivers/base/firmware_class.c | 27 +++++++-------------------- > 1 file changed, 7 insertions(+), 20 deletions(-) > > diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c > index ae00a2f..4d8cb8b 100644 > --- a/drivers/base/firmware_class.c > +++ b/drivers/base/firmware_class.c > @@ -16,10 +16,11 @@ > #include > #include > #include > -#include > +#include > #include > #include > #include > +#include > > #define to_dev(obj) container_of(obj, struct device, kobj) > > @@ -630,19 +631,15 @@ struct firmware_work { > bool uevent; > }; > > -static int request_firmware_work_func(void *arg) > +static void request_firmware_work_func(struct work_struct *work) > { > - struct firmware_work *fw_work = arg; > + struct firmware_work *fw_work; > const struct firmware *fw; > struct firmware_priv *fw_priv; > long timeout; > int ret; > > - if (!arg) { > - WARN_ON(1); > - return 0; > - } > - > + fw_work = container_of(work, struct firmware_work, work); > fw_priv = _request_firmware_prepare(&fw, fw_work->name, fw_work->device, > fw_work->uevent, true); > if (IS_ERR_OR_NULL(fw_priv)) { > @@ -667,8 +664,6 @@ static int request_firmware_work_func(void *arg) > > module_put(fw_work->module); > kfree(fw_work); > - > - return ret; > } > > /** > @@ -694,7 +689,6 @@ request_firmware_nowait( > const char *name, struct device *device, gfp_t gfp, void *context, > void (*cont)(const struct firmware *fw, void *context)) > { > - struct task_struct *task; > struct firmware_work *fw_work; > > fw_work = kzalloc(sizeof (struct firmware_work), gfp); > @@ -713,15 +707,8 @@ request_firmware_nowait( > return -EFAULT; > } > > - task = kthread_run(request_firmware_work_func, fw_work, > - "firmware/%s", name); > - if (IS_ERR(task)) { > - fw_work->cont(NULL, fw_work->context); > - module_put(fw_work->module); > - kfree(fw_work); > - return PTR_ERR(task); > - } > - > + INIT_WORK(&fw_work->work, request_firmware_work_func); > + queue_work(system_long_wq, &fw_work->work); > return 0; > } > >