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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0A7AC369C8 for ; Wed, 25 Sep 2024 10:12:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2208A6B0089; Wed, 25 Sep 2024 06:12:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1CF976B008C; Wed, 25 Sep 2024 06:12:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0985B6B0092; Wed, 25 Sep 2024 06:12:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id E04EE6B0089 for ; Wed, 25 Sep 2024 06:12:21 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 7EAD214098B for ; Wed, 25 Sep 2024 10:12:21 +0000 (UTC) X-FDA: 82602845682.26.E00D8E5 Received: from frasgout11.his.huawei.com (frasgout11.his.huawei.com [14.137.139.23]) by imf24.hostedemail.com (Postfix) with ESMTP id 0E069180005 for ; Wed, 25 Sep 2024 10:12:18 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=none; spf=pass (imf24.hostedemail.com: domain of jonas.oberhauser@huaweicloud.com designates 14.137.139.23 as permitted sender) smtp.mailfrom=jonas.oberhauser@huaweicloud.com; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1727259078; a=rsa-sha256; cv=none; b=pllIc65LA5Zvbwg/LblM/88Jg9Li2Zh2O3rvHXEeC6EpFfA0Ea9AJtAdAx/JMUkh/vO4W5 oOuDB9j2bE3qzUl9F45q9evTkoSCQUu1JaEm3N+KiX02SzdTrP6UVPTawaamg8lZFYhK9N Fm3wk2yFthcVT8SwgxlMuoAMIoIi5PE= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=none; spf=pass (imf24.hostedemail.com: domain of jonas.oberhauser@huaweicloud.com designates 14.137.139.23 as permitted sender) smtp.mailfrom=jonas.oberhauser@huaweicloud.com; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1727259078; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3xnKQWEHjLYJCWM2ah0X8xIo2oZ5GnKDtgm0guQWWoo=; b=dW3ZyxR2fd8iQ3ecMGO8QEVPgOihIi5IT9z/DN0IU/AoW7vQMZ7TBsJYdtnRPRc5U6fmro MUlscThtJhityeetGpi83Vhcl+En67OmgL0PA/tDz8Ih8HBGPrBMcIfL7jnoNbkmAyPb0o UTGJsuNb22NcT0NUeYNAI9aPAcGjYM0= Received: from mail.maildlp.com (unknown [172.18.186.29]) by frasgout11.his.huawei.com (SkyGuard) with ESMTP id 4XDBq127Dnz9v7Hp for ; Wed, 25 Sep 2024 17:52:29 +0800 (CST) Received: from mail02.huawei.com (unknown [7.182.16.47]) by mail.maildlp.com (Postfix) with ESMTP id 88F68140391 for ; Wed, 25 Sep 2024 18:12:10 +0800 (CST) Received: from [10.45.145.58] (unknown [10.45.145.58]) by APP1 (Coremail) with SMTP id LxC2BwBn+C_r4fNmunSaAQ--.25388S2; Wed, 25 Sep 2024 11:12:10 +0100 (CET) Message-ID: Date: Wed, 25 Sep 2024 12:11:52 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 1/4] hazptr: Add initial implementation of hazard pointers To: Boqun Feng Cc: linux-kernel@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, lkmm@vger.kernel.org, "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Uladzislau Rezki , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Mark Rutland , Thomas Gleixner , Kent Overstreet , Linus Torvalds , Vlastimil Babka , maged.michael@gmail.com, Neeraj Upadhyay References: <20240917143402.930114-1-boqun.feng@gmail.com> <20240917143402.930114-2-boqun.feng@gmail.com> <55975a55-302f-4c45-bfcc-192a8a1242e9@huaweicloud.com> From: Jonas Oberhauser In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CM-TRANSID:LxC2BwBn+C_r4fNmunSaAQ--.25388S2 X-Coremail-Antispam: 1UD129KBjDUn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7v73 VFW2AGmfu7bjvjm3AaLaJ3UjIYCTnIWjp_UUUYa7kC6x804xWl14x267AKxVWrJVCq3wAF c2x0x2IEx4CE42xK8VAvwI8IcIk0rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII 0Yj41l84x0c7CEw4AK67xGY2AK021l84ACjcxK6xIIjxv20xvE14v26r1j6r1xM28EF7xv wVC0I7IYx2IY6xkF7I0E14v26F4j6r4UJwA2z4x0Y4vEx4A2jsIE14v26r4j6F4UM28EF7 xvwVC2z280aVCY1x0267AKxVW8Jr0_Cr1UM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8C rVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r106r15McIj6I8E87Iv67AKxV WUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lFIxGxcIEc7CjxVA2Y2ka 0xkIwI1l42xK82IYc2Ij64vIr41l4c8EcI0Ec7CjxVAaw2AFwI0_GFv_Wryl4I8I3I0E4I kC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWU WwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr 0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26F4j6r4UJwCI42IY6xAIw20EY4v20xvaj40_ Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8Jr UvcSsGvfC2KfnxnUUI43ZEXa7IUbHa0PUUUUU== X-CM-SenderInfo: 5mrqt2oorev25kdx2v3u6k3tpzhluzxrxghudrp/ X-Stat-Signature: d4mm6ycfe5xi4s8faikhrakdgbqi56bk X-Rspamd-Queue-Id: 0E069180005 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1727259138-334126 X-HE-Meta: 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 TYUGdUrl 1ng7Uw3EowvqsXGlKScnpVMi4U1Cy71oU7Tz1YXQVbDOT80oGDCDCVRiTRWSFL0Mdt3YzyvTbKoyhCJBeaG5HUI+/AaSf8oBjPKPq9dXiC1gPA/PgsZruFbQDePxppG8NmzJQQpc/iYLfrutzbP30uQQcS/887DGuHwyWvo1wE+XOPsEW3nLM8O+pYldi63YcY9crPhpIeIO4/eV2RdS8t+DLi2YDcjyJij7hgde07dFoXQA= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Am 9/25/2024 um 12:02 PM schrieb Boqun Feng: > Hi Jonas, > > Of > course, if we are really worried about compilers being too "smart" Ah, I see you know me better and better... > we can always do the comparison in asm code, then compilers don't know > anything of the equality between 'ptr' and 'head - head_offset'. Yes, but then a simple compiler barrier between the comparison and returning ptr would also do the trick, right? And maybe easier on the eyes. Have fun, jonas