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=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 F2474C433ED for ; Wed, 7 Apr 2021 09:43:29 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 973EA6135D for ; Wed, 7 Apr 2021 09:43:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 973EA6135D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=2R5Iffzzt9UCEWf8J7Zro0E4ZF4rbbKH4Ue/0l0UMx4=; b=WHEjXVHaZBKJp7FBRIMNg387W ooWjFT20DMsEIe0jgmW8gwroyl1hbnBs3WO+PCnQ03qEB1mMiTKyjVo9O/4HriNNINsBAO0j90rzI 0Y6Lt39zPzM/a11m74S5bJp+rHQqRYNRBfSd7tb1y2eJ5ALgcH8p/rJ1vfLlWX/Fx/xv1n/UAXXSi 5yZGNZI6smzxfpqJSaelZuaRQArVPhFPySa+FXzjf1+UnnAgR2WaxhaPFqBa3q/xxFU7FVQwLHQJX nDPgvj2tobW5ku8Sn7mEyz8spwWkfI34hYr0kO/8xVHkxlV5+R4BIQ7M237tG/NXOJbnp/UyL9b/6 CPQAWt4qg==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lU4iO-004doy-5r; Wed, 07 Apr 2021 09:43:12 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lU4iM-004doj-7G for linux-riscv@desiato.infradead.org; Wed, 07 Apr 2021 09:43:10 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=uHRRfQiUBlAZ+WTehIjctPz3UPqgqzr8MZeVhYIZJnY=; b=TiUqf7vIpHbIUyAQ2LLRGADfFO sXUzLx7KL6B+iS3V+LlPGebBQ+n2zSzcmzF4HoVj6LSDpw7kj7CZRMClGNuMmNk8EKkoJ5/Whf5Yg mpdjOxQxHEaKKIfcVprBXVDi1sxySzND4ACUgaRggQQJ1sBmr5MWj0lUTICjF5eoVV6lGhMEMuR6X YzQKXCvyVBM+LiR7KwHDVGI6jrRelZ6TEDdI857fL140/jbgSJ0NoHMjMriLTs8TUbhu7v5zi6ah/ KswtpdjjZMAwKlCMh55ch/rjKrXTOEb7dO3jl4tjEYq/+X5TGvWzI9a7UDmXTxGlx4lFejMoysRfx BGoFPCig==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lU4hc-00EFuS-3a; Wed, 07 Apr 2021 09:42:42 +0000 Date: Wed, 7 Apr 2021 10:42:24 +0100 From: Christoph Hellwig To: Peter Zijlstra Cc: Guo Ren , linux-riscv , Linux Kernel Mailing List , linux-csky@vger.kernel.org, linux-arch , Guo Ren , Will Deacon , Ingo Molnar , Waiman Long , Arnd Bergmann , Anup Patel Subject: Re: [PATCH v4 3/4] locking/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32 Message-ID: <20210407094224.GA3393992@infradead.org> References: <1616868399-82848-1-git-send-email-guoren@kernel.org> <1616868399-82848-4-git-send-email-guoren@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue, Apr 06, 2021 at 09:15:50AM +0200, Peter Zijlstra wrote: > Anyway, given you have such a crap architecture (and here I thought > RISC-V was supposed to be a modern design *sigh*), you had better go > look at the sparc64 atomic implementation which has a software backoff > for failed CAS in order to make fwd progress. It wasn't supposed to be modern. It was supposed to use boring old ideas. Where it actually did that it is a great ISA, in parts where academics actually tried to come up with cool or state of the art ideas (interrupt handling, tlb shootdowns, the totally fucked up memory model) it turned into a trainwreck. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv