From patchwork Tue Jun 13 18:24:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: SeongJae Park X-Patchwork-Id: 107505 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp746891vqr; Tue, 13 Jun 2023 11:27:41 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ6mIyA6XsszWoDo/R4o16TRh6WHBskzFpJDcnWbJjj+VNqnfvuoumBnHj0LVinlJJiU3JqX X-Received: by 2002:a17:906:58c5:b0:974:5e8b:fc28 with SMTP id e5-20020a17090658c500b009745e8bfc28mr13875469ejs.9.1686680861603; Tue, 13 Jun 2023 11:27:41 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1686680861; cv=none; d=google.com; s=arc-20160816; b=jvO2Fp/EKQmeuBmdwJ3+35tFnGQETmQ+c7szJt4ypchNBIW1KMEoiSKqinANY8x78V t+d1Ipyajw59bqouuAACbNyi2mhzC7fWZlZF5WxOecBsV1cPMNCj7B/teC+FchD3EbOR NdHLoVJeosP9/Ho5uJxDqzzvY65IqNTuJMtUTjrvHSvfuZuRsS0y4+LDn+iXuv6XQiG/ Rr2eyn8mhqQNLT93AYpBzk5RxZCY8g8jLt1t5UBXgVenKXvH7r5EFFyHfCgvXAN1YJsB Oig+4iA6zEezAI3hVubNF77nJ+/L9yjExWZwvdywda6sFoq7B0oPubWnjz+fgmVppBqI biQw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=5Awvwvnf2Yio6gduOGwuv1jP6KBOIsfXhpavq3jscoI=; b=u/02ilcZIFHMelzp7DlhI/YwLTg2ZIgxvrQbmIquH99CTRVvXpACCD1u6DwntmFDBj 9CpZRrzYhy+AM9Mr8rkxQvulwTdY7cu2ZyJ81WPo5zlL4h5Ghp8yAWpITaBlWyBAt4Mc o6nU/FwoLPz5ssOMnqi4U5zDg4aRkw3YlrdDatF6jIV+9ZaMA2AZgUZXwFvi1+eFfkcl gw/wjeh0TF3nN8Do8/ia2iRzhxhuZCKs9BeUrwFeCCgSAGFeVzXRUXA7UB//IAOZgQXY lOpE/293OAbEXMLpDDqXKGCBdLLTQuMLioAkM12IefDY8JcWymj4OtGh9E4+ZO2C6Mdj TTAw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=BhJ2cluN; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id p22-20020a170906499600b00977cb7af75asi6721919eju.719.2023.06.13.11.27.16; Tue, 13 Jun 2023 11:27:41 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=BhJ2cluN; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240430AbjFMSZT (ORCPT + 99 others); Tue, 13 Jun 2023 14:25:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239370AbjFMSYn (ORCPT ); Tue, 13 Jun 2023 14:24:43 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9A54DE41; Tue, 13 Jun 2023 11:24:42 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2F36063365; Tue, 13 Jun 2023 18:24:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 125D1C433F1; Tue, 13 Jun 2023 18:24:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686680681; bh=tKaE0feCA4Misffydrf5UR6uG+RXTeYv2hshyi6erLw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BhJ2cluNI4psNgHorBPau3CpVT1R9LA6maOtkq4Jg7r+eOP1b9SBvIOw2gL4U1U+p sJTDHRyT0xThUGQQ3SLFPV51kBaQry3fG6EpHHmfpVx6TLUEBMwzHlrlcuav0vhQaV BtJbiA9mYF3TaUyVgC1XDtp32cQR+GRJ5jE5SXiqkHGYF9M9LCMyC1VBaVAdeE8YB6 rbd54j5/RMZflfPPq/WfFhiV2g7HBVbkOaX4veNpewafKHPPILbiiNeVGRg4OX1rSp 24wcRcOPE9R4POUba/uQafK1PW/ggSSCEq1vPrrhTKW4g84QbMBGLbMau12YYQpZpk ouVO+GoDJhOzg== From: SeongJae Park To: paulmck@kernel.org Cc: SeongJae Park , joel@joelfernandes.org, mmpgouride@gmail.com, corbet@lwn.net, rcu@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 4/4] Docs/RCU/rculist_nulls: Fix wrong text about atomic_set_release() Date: Tue, 13 Jun 2023 18:24:34 +0000 Message-Id: <20230613182434.88317-5-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230613182434.88317-1-sj@kernel.org> References: <20230613182434.88317-1-sj@kernel.org> MIME-Version: 1.0 X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1768613071024068310?= X-GMAIL-MSGID: =?utf-8?q?1768613071024068310?= The document says we can avoid extra _release() in insert function when hlist_nulls is used, but that's not true[1]. Drop it. [1] https://lore.kernel.org/rcu/46440869-644a-4982-b790-b71b43976c66@paulmck-laptop/ Signed-off-by: SeongJae Park --- Documentation/RCU/rculist_nulls.rst | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/Documentation/RCU/rculist_nulls.rst b/Documentation/RCU/rculist_nulls.rst index 5cd6f3f8810f..018cc100d19b 100644 --- a/Documentation/RCU/rculist_nulls.rst +++ b/Documentation/RCU/rculist_nulls.rst @@ -129,8 +129,7 @@ very very fast (before the end of RCU grace period) Avoiding extra smp_rmb() ======================== -With hlist_nulls we can avoid extra smp_rmb() in lockless_lookup() -and extra _release() in insert function. +With hlist_nulls we can avoid extra smp_rmb() in lockless_lookup(). For example, if we choose to store the slot number as the 'nulls' end-of-list marker for each slot of the hash table, we can detect @@ -182,6 +181,9 @@ scan the list again without harm. 2) Insert algorithm ------------------- +Same to the above one, but uses hlist_nulls_add_head_rcu() instead of +hlist_add_head_rcu(). + :: /*