From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8C907C4360C for ; Wed, 25 Sep 2019 13:46:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 647A7222BD for ; Wed, 25 Sep 2019 13:46:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406961AbfIYNqb (ORCPT ); Wed, 25 Sep 2019 09:46:31 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:2721 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2406887AbfIYNqa (ORCPT ); Wed, 25 Sep 2019 09:46:30 -0400 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 837F7C084E2234E37D0C; Wed, 25 Sep 2019 21:46:26 +0800 (CST) Received: from [127.0.0.1] (10.177.251.225) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.439.0; Wed, 25 Sep 2019 21:46:25 +0800 Subject: Re: [PATCH] async: Let kfree() out of the critical area of the lock To: "gregkh@linuxfoundation.org" CC: , , , "tglx@linutronix.de" , , , "linux-kernel@vger.kernel.org" References: <216356b1-38c1-8477-c4e8-03f497dd6ac8@huawei.com> <20190925133826.GA1496885@kroah.com> From: Yunfeng Ye Message-ID: Date: Wed, 25 Sep 2019 21:45:44 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190925133826.GA1496885@kroah.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.251.225] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/9/25 21:38, gregkh@linuxfoundation.org wrote: > On Wed, Sep 25, 2019 at 08:52:26PM +0800, Yunfeng Ye wrote: >> It's not necessary to put kfree() in the critical area of the lock, so >> let it out. >> >> Signed-off-by: Yunfeng Ye >> --- >> kernel/async.c | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/kernel/async.c b/kernel/async.c >> index 4f9c1d6..1de270d 100644 >> --- a/kernel/async.c >> +++ b/kernel/async.c >> @@ -135,12 +135,12 @@ static void async_run_entry_fn(struct work_struct *work) >> list_del_init(&entry->domain_list); >> list_del_init(&entry->global_list); >> >> - /* 3) free the entry */ >> - kfree(entry); >> atomic_dec(&entry_count); >> - >> spin_unlock_irqrestore(&async_lock, flags); >> >> + /* 3) free the entry */ >> + kfree(entry); >> + >> /* 4) wake up any waiters */ >> wake_up(&async_done); >> } >> -- >> 2.7.4 >> > > Does this result any any measurable performance changes? > No performance has been Measured at present, I just want the critical area to be as short as possible. I think it's good to put it outside. thanks > thanks, > > greg k-h > > . >