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=-11.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 13049C4338F for ; Thu, 29 Jul 2021 01:30:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DFAAF60F43 for ; Thu, 29 Jul 2021 01:30:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233197AbhG2BaI (ORCPT ); Wed, 28 Jul 2021 21:30:08 -0400 Received: from mailout4.samsung.com ([203.254.224.34]:27919 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233142AbhG2BaH (ORCPT ); Wed, 28 Jul 2021 21:30:07 -0400 Received: from epcas3p1.samsung.com (unknown [182.195.41.19]) by mailout4.samsung.com (KnoxPortal) with ESMTP id 20210729013003epoutp0437b5824f1715caec745c5b389a7c5adb~WHtJDOC2o1475714757epoutp04z for ; Thu, 29 Jul 2021 01:30:03 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout4.samsung.com 20210729013003epoutp0437b5824f1715caec745c5b389a7c5adb~WHtJDOC2o1475714757epoutp04z DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1627522203; bh=nc411u8xYr70oG2ZWOibXBg/rWcbdAtPphHBq1O5BD8=; h=Subject:Reply-To:From:To:CC:In-Reply-To:Date:References:From; b=gGNlc+Uj6+1TRjjDXOYrTeJ5meZMe/j1cFQX8hi7GnBNAMyfApxfY7sxCZvlOa45i 9e+M4GIr7LU1qjADTH05ZCWUCI8GTfCSpsFKEMrALfnL9l/nzJgE3xazVB8D6cwsB0 gXmOQAZgq+zQ/s0UifQd1SSK4l2wZksW1UdAOMCU= Received: from epsnrtp1.localdomain (unknown [182.195.42.162]) by epcas3p3.samsung.com (KnoxPortal) with ESMTP id 20210729013002epcas3p3ed64fe50b4770c37fbabf4e0ade934f1~WHtH5vLdT3174231742epcas3p3C; Thu, 29 Jul 2021 01:30:02 +0000 (GMT) Received: from epcpadp3 (unknown [182.195.40.17]) by epsnrtp1.localdomain (Postfix) with ESMTP id 4GZtHt2qXxz4x9Pr; Thu, 29 Jul 2021 01:30:02 +0000 (GMT) Mime-Version: 1.0 Subject: RE: [PATCH v3 13/18] scsi: ufs: Optimize SCSI command processing Reply-To: daejun7.park@samsung.com Sender: Daejun Park From: Daejun Park To: "Martin K . Petersen" CC: "linux-scsi@vger.kernel.org" , Jaegeuk Kim , Bart Van Assche , Adrian Hunter , Stanley Chu , Can Guo , Asutosh Das , Avri Altman , "James E.J. Bottomley" , Matthias Brugger , Bean Huo , Kiwoong Kim , Keoseong Park X-Priority: 3 X-Content-Kind-Code: NORMAL In-Reply-To: <20210722033439.26550-14-bvanassche@acm.org> X-CPGS-Detection: blocking_info_exchange X-Drm-Type: N,general X-Msg-Generator: Mail X-Msg-Type: PERSONAL X-Reply-Demand: N Message-ID: <1891546521.01627522202382.JavaMail.epsvc@epcpadp3> Date: Thu, 29 Jul 2021 10:25:02 +0900 X-CMS-MailID: 20210729012502epcms2p1b7b0f63eed6c4f8a73a1d086e8d22631 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: AUTO_CONFIDENTIAL X-CPGSPASS: Y X-CPGSPASS: Y X-Hop-Count: 3 X-CMS-RootMailID: 20210722033553epcas2p2818d9c1f046e8514415a72a4ddddc3db References: <20210722033439.26550-14-bvanassche@acm.org> <20210722033439.26550-1-bvanassche@acm.org> Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Hi Bart, >Use a spinlock to protect hba->outstanding_reqs instead of using atomic >operations to update this member variable. > >This patch is a performance improvement because it reduces the number of >atomic operations in the hot path (test_and_clear_bit()) and because it >reduces the lock contention on the SCSI host lock. On my test setup this >patch improves IOPS by about 1%. Reviewed-by: Daejun Park Thanks, Daejun