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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,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 5C6B9C388F9 for ; Thu, 19 Nov 2020 06:30:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECE85246AD for ; Thu, 19 Nov 2020 06:30:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="RCnXMMIT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726122AbgKSGaC (ORCPT ); Thu, 19 Nov 2020 01:30:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725944AbgKSGaC (ORCPT ); Thu, 19 Nov 2020 01:30:02 -0500 Received: from mail-qk1-x736.google.com (mail-qk1-x736.google.com [IPv6:2607:f8b0:4864:20::736]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DE27DC0613D4 for ; Wed, 18 Nov 2020 22:30:01 -0800 (PST) Received: by mail-qk1-x736.google.com with SMTP id q22so4419359qkq.6 for ; Wed, 18 Nov 2020 22:30:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=from:references:in-reply-to:mime-version:thread-index:date :message-id:subject:to:cc; bh=tHGoV4Zvy8mFULKy+/iaTp5F4KB48kx3Th06KdtFJ+k=; b=RCnXMMITVd4fV8gZKbXMUL8qCNDK3TWlzaiYv8ZtN6zMSc2lMHd/TW1/lATp/Nv4xr WmIRK7B68CbS2TSFfZtzMV4ThIcP60e/AEXGknEp9O/H6AY3m7zXEWuqdsGgohm8iE2H Qe4CWWfeZrnJbGVKdTwXT17Vo2jTIeJ5LUuNE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:references:in-reply-to:mime-version :thread-index:date:message-id:subject:to:cc; bh=tHGoV4Zvy8mFULKy+/iaTp5F4KB48kx3Th06KdtFJ+k=; b=BEBCkiI6yS20i68HGfsj+L8lQS+90lGnHxINld7fEvlIvcd7dqsYpPg1K8QA0/xyFv N1IAF6mUJYQqRf7/KdkEPfkCDLWRg1pBxjySDAlE0qgpxMhNQFlYbwwv8iB6TzYPU6nc zRMs/EeIMlp9/H536G0Nj8z4tPb2xydDkhdz3OzYw3Dry0ZTFw2+6uLiWCLly15hBJLS 3JeO4IzouUysxkmjmu2K5FEIopm368vxmFVVZ128v5Qbv3AWzmTpYh5j8BGlUu+G77hJ x2nl4u9QRu7r8m7TCsinAt9bIAcyKBz+P4VrtBI+7YfrNsmgXdLvaxy72xvZzTHqmMqY vbGQ== X-Gm-Message-State: AOAM533Uf4J4e0fDIFQsCpdlnZFwZnNY7eT9g/ns8KiVjV3odmudv9Df Hp3lEQ97R3UrEzzSDMlP6SU8QA61i3iZgCYDPSz0wA== X-Google-Smtp-Source: ABdhPJyzV2D/qpLhcBGGbFW9nwsVykZgLieXwP+5RtqpuVOv4K1oHEVxYs+XEX3ffFxlpXjfBP++t61g+cAZKLEB+JY= X-Received: by 2002:a37:7f03:: with SMTP id a3mr9549191qkd.72.1605767400793; Wed, 18 Nov 2020 22:30:00 -0800 (PST) From: Kashyap Desai References: <20201116090737.50989-13-ming.lei@redhat.com> <202011161944.U7XHrbsd-lkp@intel.com> <20201118023507.GA92339@T590> <99089c7f-422b-3a61-a9c5-677a1e629862@suse.de> <20201118074405.GA111852@T590> In-Reply-To: <20201118074405.GA111852@T590> MIME-Version: 1.0 X-Mailer: Microsoft Outlook 15.0 Thread-Index: AQIS9sCgRF18gKjqcruTOMh+o2IV3QHxSRdOAbmfafcBi0xdtQICciWJqRzGZbA= Date: Thu, 19 Nov 2020 11:59:58 +0530 Message-ID: <4214ad35c463dccb26cc261a7d1fbb9e@mail.gmail.com> Subject: RE: [PATCH V4 12/12] scsi: replace sdev->device_busy with sbitmap To: Ming Lei , Hannes Reinecke Cc: kernel test robot , Sumanesh Samanta , Jens Axboe , linux-block@vger.kernel.org, "Martin K . Petersen" , linux-scsi@vger.kernel.org, kbuild-all@lists.01.org, clang-built-linux@googlegroups.com, Omar Sandoval , "Ewan D . Milne" Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-256; boundary="0000000000008a210e05b46fdb36" Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org --0000000000008a210e05b46fdb36 Content-Type: text/plain; charset="UTF-8" > > From: Hannes Reinecke > > Date: Wed, 18 Nov 2020 08:08:41 +0100 > > Subject: [PATCH] megaraid_sas: use scsi_device_busy() instead of > > direct access to atomic counter > > > > It's always a bad style to access structure internals, especially if > > there is an accessor for it. So convert to use scsi_device_busy() > > intead of accessing the atomic counter directly. > > > > Cc: Kashyap Desai > > Cc: Sumanesh Samanta > > Signed-off-by: Hannes Reinecke > > --- > > drivers/scsi/megaraid/megaraid_sas_fusion.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c > > b/drivers/scsi/megaraid/megaraid_sas_fusion.c > > index fd607287608e..272ff123bc6b 100644 > > --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c > > +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c > > @@ -362,7 +362,7 @@ megasas_get_msix_index(struct megasas_instance > *instance, > > /* TBD - if sml remove device_busy in future, driver > > * should track counter in internal structure. > > */ > > - sdev_busy = atomic_read(&scmd->device->device_busy); > > + sdev_busy = scsi_device_busy(scmd->device); > > megasas_get_msix_index() is called in .queuecommand() path, > scsi_device_busy() might take more cycles since it has to iterate over each > sbitmap words, especially when the sbitmap depth is high. > > I'd suggest Kashyap/Sumanesh to check if there is better way to deal with it. If > not, scsi_device_busy() should be fine. Scsi_device_busy() add significant amount of overhead which will be visible in terms of reduced IOPS and high CPU cycle. I tested it earlier and noticed regression in performance. I posted megaraid_sas driver patch which will use internal per sdev outstanding similar to legacy sdev_busy counter. Kashyap > > > Thanks, > Ming --0000000000008a210e05b46fdb36 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIIQRQYJKoZIhvcNAQcCoIIQNjCCEDICAQExDzANBglghkgBZQMEAgEFADALBgkqhkiG9w0BBwGg gg2aMIIE6DCCA9CgAwIBAgIOSBtqCRO9gCTKXSLwFPMwDQYJKoZIhvcNAQELBQAwTDEgMB4GA1UE CxMXR2xvYmFsU2lnbiBSb290IENBIC0gUjMxEzARBgNVBAoTCkdsb2JhbFNpZ24xEzARBgNVBAMT Ckdsb2JhbFNpZ24wHhcNMTYwNjE1MDAwMDAwWhcNMjQwNjE1MDAwMDAwWjBdMQswCQYDVQQGEwJC RTEZMBcGA1UEChMQR2xvYmFsU2lnbiBudi1zYTEzMDEGA1UEAxMqR2xvYmFsU2lnbiBQZXJzb25h bFNpZ24gMiBDQSAtIFNIQTI1NiAtIEczMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA tpZok2X9LAHsYqMNVL+Ly6RDkaKar7GD8rVtb9nw6tzPFnvXGeOEA4X5xh9wjx9sScVpGR5wkTg1 fgJIXTlrGESmaqXIdPRd9YQ+Yx9xRIIIPu3Jp/bpbiZBKYDJSbr/2Xago7sb9nnfSyjTSnucUcIP ZVChn6hKneVGBI2DT9yyyD3PmCEJmEzA8Y96qT83JmVH2GaPSSbCw0C+Zj1s/zqtKUbwE5zh8uuZ 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