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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC3B1C6FD18 for ; Wed, 29 Mar 2023 08:09:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230059AbjC2IJU (ORCPT ); Wed, 29 Mar 2023 04:09:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37322 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229750AbjC2IJS (ORCPT ); Wed, 29 Mar 2023 04:09:18 -0400 Received: from mail-pj1-x1030.google.com (mail-pj1-x1030.google.com [IPv6:2607:f8b0:4864:20::1030]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0FC9210D for ; Wed, 29 Mar 2023 01:08:55 -0700 (PDT) Received: by mail-pj1-x1030.google.com with SMTP id e15-20020a17090ac20f00b0023d1b009f52so17796014pjt.2 for ; Wed, 29 Mar 2023 01:08:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1680077335; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=mVRpG2dAr/nWYNSNRqghl5EEZFHlwrwTvwCgPASuUmU=; b=fjjwB2zFeG+SwWg0X1rPzwBGeccQqbojBL/azxEx/VC8yg0Qm5Sb+t0NfVOmibaucZ xCgCSTAIberX+90M1I05lsnIAWZKnB9rzQvEI+zmLP7W6dQiMeldn5j/30ESU917A/WM M2GmpY7IWQv5hQ/xwVyvv5I7gclcVvyIFEgTQzrHMxoWyew0bdrXRzjjgHy4jT+Wb9xQ jhWoxfiaJE+omv3VTH98A/tO9knUn3mdNKnpogad+NtkOsQmhW0NzBJWE4hOwd3sZ1G2 hxIXxoA+eJranOTs/dIbHJr/Ou4JCMK7MpqYQkOj3ZMsr7b/0+6HdBldsI8pWLe8CIwl rgig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680077335; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=mVRpG2dAr/nWYNSNRqghl5EEZFHlwrwTvwCgPASuUmU=; b=Fi3bXVVQw16ysTqQf579Q7UthZ5/T5ogHCxTfTN35SazV+6GfLYRZu1Kb3K9DoSsmT NXK+T/GAFijDSUkVVZc/HjQGbBlsw2Ifcz46vZvKUIFVwAkVzVoX+QHsa1nzESaWEOtJ cqrxD3CuC9FhDGQv1ObSs149dltxQHu7CpyaZNrATP9rcootESS/f7yW90ASxYKN8D6g 1IFk0pLhzgV7Ky0z6RBKaliA52X8GExtNH39kJo7zrVXUmVoU6pNM/7wQcPf8z2CUZO3 IrDOJQSwMieMmJ8Z0tLcwBrPNKLDFQz7g/q+nWSEasVKq5aSWOgypMR9QM0Egtc2BqeD g/mQ== X-Gm-Message-State: AAQBX9c/9dKztzojRW6MGOmGyx2ArN1HcQGtKG1mztKM13fDim3on+xC RBz8aSsIvw0XmuzUHkFmmBoXkQ== X-Google-Smtp-Source: AKy350YkuPVOI4SkoYUmjVLLsU+g0OQwvsA0hoKkKc7WLUm0Sa5StE4Ydf+KVToEOuvk5LGwIcWN8g== X-Received: by 2002:a17:90b:3ece:b0:23f:6edd:41da with SMTP id rm14-20020a17090b3ece00b0023f6edd41damr20304030pjb.29.1680077335048; Wed, 29 Mar 2023 01:08:55 -0700 (PDT) Received: from [10.3.144.50] ([61.213.176.11]) by smtp.gmail.com with ESMTPSA id b15-20020a17090ae38f00b002369e16b276sm859568pjz.32.2023.03.29.01.08.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Mar 2023 01:08:54 -0700 (PDT) Message-ID: <2a39ced1-05f1-d696-1905-4ff5199fa41b@bytedance.com> Date: Wed, 29 Mar 2023 16:08:49 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [External] Re: [PATCH V4 4/5] cachefiles: narrow the scope of triggering EPOLLIN events in ondemand mode To: David Howells Cc: linux-cachefs@redhat.com, linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Xin Yin , Jingbo Xu , zhujia.zj@bytedance.com References: <20230111052515.53941-5-zhujia.zj@bytedance.com> <20230111052515.53941-1-zhujia.zj@bytedance.com> <133078.1680013145@warthog.procyon.org.uk> From: Jia Zhu In-Reply-To: <133078.1680013145@warthog.procyon.org.uk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2023/3/28 22:19, David Howells 写道: > Jia Zhu wrote: > >> + if (!xa_empty(xa)) { >> + xa_lock(xa); >> + xa_for_each_marked(xa, index, req, CACHEFILES_REQ_NEW) { >> + if (!cachefiles_ondemand_is_reopening_read(req)) { >> + mask |= EPOLLIN; >> + break; >> + } >> + } >> + xa_unlock(xa); >> + } > > I wonder if there's a more efficient way to do this. I guess it depends on > how many reqs you expect to get in a queue. It might be worth taking the > rcu_read_lock before calling xa_lock() and holding it over the whole loop. > Thanks for the advice, will use rcu_read_lock（unlock） to replace it. > David >