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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 70FB9C4727D for ; Wed, 23 Sep 2020 06:19:24 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1FC9F21D43 for ; Wed, 23 Sep 2020 06:19:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="mrhkeExx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1FC9F21D43 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amazon.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kKy7R-00070n-7C; Wed, 23 Sep 2020 06:19:09 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kKy7Q-00070i-Ao for xen-devel@lists.xenproject.org; Wed, 23 Sep 2020 06:19:08 +0000 X-Inumbo-ID: c72d138c-31dd-4152-8458-9d1cf4bce7ec Received: from smtp-fw-6001.amazon.com (unknown [52.95.48.154]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id c72d138c-31dd-4152-8458-9d1cf4bce7ec; Wed, 23 Sep 2020 06:19:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1600841947; x=1632377947; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=Hhec5BYj6RypLE3xumu+lmtnfCoV4fVGGtCtUQZxGR8=; b=mrhkeExxT6f1G1EdeNyOUezHVTAFBy7jslRDHxS9yg+BoJUM83r7ZanV 4yGOo6lB/8PzZdMcth/uDxqajCw6tQSltNF5SNVtA/LSBcssIYJB2tu7h dzEhCLpfMji7XLUaYYa2J0uk22Le8bq+S5bp1lNsdismYpR09l4KEgvbL E=; X-IronPort-AV: E=Sophos;i="5.77,293,1596499200"; d="scan'208";a="57152334" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2b-baacba05.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-6001.iad6.amazon.com with ESMTP; 23 Sep 2020 06:19:06 +0000 Received: from EX13D31EUA004.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan2.pdx.amazon.com [10.170.41.162]) by email-inbound-relay-2b-baacba05.us-west-2.amazon.com (Postfix) with ESMTPS id 1BB94A1C8B; Wed, 23 Sep 2020 06:19:03 +0000 (UTC) Received: from u3f2cd687b01c55.ant.amazon.com (10.43.162.85) by EX13D31EUA004.ant.amazon.com (10.43.165.161) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Wed, 23 Sep 2020 06:18:57 +0000 From: SeongJae Park To: , , CC: SeongJae Park , , , , , , , , Subject: [PATCH v4 0/3] xen-blk(back|front): Let users disable persistent grants Date: Wed, 23 Sep 2020 08:18:38 +0200 Message-ID: <20200923061841.20531-1-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.43.162.85] X-ClientProxiedBy: EX13D10UWB001.ant.amazon.com (10.43.161.111) To EX13D31EUA004.ant.amazon.com (10.43.165.161) Precedence: Bulk X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" From: SeongJae Park Persistent grants feature provides high scalability. On some small systems, however, it could incur data copy overheads[1] and thus it is required to be disabled. But, there is no option to disable it. For the reason, this commit adds module parameters for disabling of the feature. [1] https://wiki.xen.org/wiki/Xen_4.3_Block_Protocol_Scalability Baseline and Complete Git Trees =============================== The patches are based on the v5.9-rc6. You can also clone the complete git tree: $ git clone git://github.com/sjp38/linux -b pgrants_disable_v4 The web is also available: https://github.com/sjp38/linux/tree/pgrants_disable_v4 Patch History ============= Changes from v3 (https://lore.kernel.org/xen-devel/20200922141549.26154-2-sjpark@amazon.com/) - Remove unnecessary ternary operation (Jürgen Groß) - Add 'Reviewed-by: Juergen Gross ' and 'Acked-by: Roger Pau Monné ' Changes from v2 (https://lore.kernel.org/linux-block/20200922105209.5284-1-sjpark@amazon.com/) - Avoid a race condition (Roger Pau Monné) Because the option value is written twice, there could be a race if the user change the value meanwhile. This version fixes the problem by reading the value once when each (front|back)end is created. Changes from v1 (https://lore.kernel.org/linux-block/20200922070125.27251-1-sjpark@amazon.com/) - use 'bool' parameter type (Jürgen Groß) - Let blkfront can also disable the feature from its side (Roger Pau Monné) - Avoid unnecessary xenbus_printf (Roger Pau Monné) - Update frontend parameter doc SeongJae Park (3): xen-blkback: add a parameter for disabling of persistent grants xen-blkfront: add a parameter for disabling of persistent grants xen-blkfront: Apply changed parameter name to the document .../ABI/testing/sysfs-driver-xen-blkback | 9 ++++++++ .../ABI/testing/sysfs-driver-xen-blkfront | 11 +++++++++- drivers/block/xen-blkback/xenbus.c | 22 ++++++++++++++----- drivers/block/xen-blkfront.c | 20 ++++++++++++----- 4 files changed, 50 insertions(+), 12 deletions(-) -- 2.17.1