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=-5.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,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 D17C3C33C8C for ; Mon, 6 Jan 2020 16:22:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A542520731 for ; Mon, 6 Jan 2020 16:22:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=toxicpanda-com.20150623.gappssmtp.com header.i=@toxicpanda-com.20150623.gappssmtp.com header.b="WFOIT7AG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726612AbgAFQWX (ORCPT ); Mon, 6 Jan 2020 11:22:23 -0500 Received: from mail-qk1-f195.google.com ([209.85.222.195]:45124 "EHLO mail-qk1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726448AbgAFQWX (ORCPT ); Mon, 6 Jan 2020 11:22:23 -0500 Received: by mail-qk1-f195.google.com with SMTP id x1so39859913qkl.12 for ; Mon, 06 Jan 2020 08:22:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=toxicpanda-com.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=dvhh6ogEj5AuzRcV1dw4Yh6p7jo5MomIDIIqYgaDkYQ=; b=WFOIT7AGa1gnof18zVWSpKGikUrNH9ezMOVEP0fUeJcOFlQwZXTPA2NAP0kXsO0xO2 ajlyiEx8Muz7r4TrZn7jr0hA9dRXkVbpXRUCCEyfb8O3Rdz1bWC7Rrsj4ixCxbg0rLd/ /3GCSlwRLiX7aT0lWlDWJsJ3SsH56IDpUMd3xXdn2u+9Nn7fy3OkFvc+WQGyfbgpTBjI H9KkbRPVQ7WoX5a/Cc8AfoXUL//wtk5tGIqOjeYPyKhuiMz8AqG30c2+CQl0smL3jafa fy9IdWNGJeWbYnc54Ts6iR4Chkjecho71Y8mTlg1EQLfc4xenfvts9y38MQtS/zZf7rM My9g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=dvhh6ogEj5AuzRcV1dw4Yh6p7jo5MomIDIIqYgaDkYQ=; b=j14UNUBjVD/aJi4fJYc3mQuQRuPi1ATJUE4EijcvxGqjUtSRtek4Q9+ROdQVJHVjo5 wS5QZ/hx9MhjFcbB/cxTj2WOs7JRvBbMxlN3EpHXZ1U7+IEQDA8TF5r7LzCy6BFWMpGd fmF3/f2lRRHEvhxbP8FN6JEz2MBWBvRrjh4UqnjAB3+UJQRIkdcA2Y+OeIsQXyrMyNRw yu3WOpM/aNdd2h7SN539FKPupJ5TEncG1dSySojYAvMwOQXDGJ3BKoCMYRJTUrKm80SH F8Yujj+H/CUYV2pC9rDBGRBycvXg1HnE7vRfGSoUzwvVY5GW9YZ5lJ0y7Z0yZT1s1tte M4fA== X-Gm-Message-State: APjAAAUzMkJiHjqeV9hQ5l4vxj0Ml2V5geoWRcAuGGPQnDMQE9BxQ78T dvSQwCZ6+O9Fdi7xrBs86IJfUw== X-Google-Smtp-Source: APXvYqzUNz2kmEEFMZw8SAIfzejI4fJSgmAJS/lTbnjyHy6FZUiaL5u0XN0jKVV4RU+PS2z+Slrafg== X-Received: by 2002:a37:684b:: with SMTP id d72mr85218255qkc.293.1578327742490; Mon, 06 Jan 2020 08:22:22 -0800 (PST) Received: from ?IPv6:2620:10d:c0a8:1102:ce0:3629:8daa:1271? ([2620:10d:c091:480::6941]) by smtp.gmail.com with ESMTPSA id k1sm19855769qtq.86.2020.01.06.08.22.21 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 06 Jan 2020 08:22:21 -0800 (PST) Subject: Re: [PATCH 1/2] btrfs: add read_policy framework To: Anand Jain , linux-btrfs@vger.kernel.org Cc: btrfs-list@steev.me.uk References: <20200105151402.1440-1-anand.jain@oracle.com> <20200105151402.1440-2-anand.jain@oracle.com> From: Josef Bacik Message-ID: <5331bb6f-4c95-9afd-ab98-23d22b71fd3b@toxicpanda.com> Date: Mon, 6 Jan 2020 11:22:20 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: <20200105151402.1440-2-anand.jain@oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 1/5/20 10:14 AM, Anand Jain wrote: > As of now we use %pid method to read stripped mirrored data, which means > application's process id determines the stripe id to be read. This type > of read IO routing typically helps in a system with many small > independent applications tying to read random data. On the other hand > the %pid based read IO distribution policy is inefficient because if > there is a single application trying to read large data the overall disk > bandwidth remains under-utilized. > > So this patch introduces read policy framework so that we could add more > read policies, such as IO routing based on device's wait-queue or manual > when we have a read-preferred device or a policy based on the target > storage caching. > > Signed-off-by: Anand Jain Reviewed-by: Josef Bacik Thanks, Josef