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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 EF88EC3A59B for ; Sat, 31 Aug 2019 02:50:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE8FD2343B for ; Sat, 31 Aug 2019 02:50:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=sifive.com header.i=@sifive.com header.b="j28iqp/6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728386AbfHaCug (ORCPT ); Fri, 30 Aug 2019 22:50:36 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:37857 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728330AbfHaCug (ORCPT ); Fri, 30 Aug 2019 22:50:36 -0400 Received: by mail-pg1-f195.google.com with SMTP id d1so4434661pgp.4 for ; Fri, 30 Aug 2019 19:50:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; h=date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=pRGk1s9ftRrOgrFlJyIOUPDg0XINxHbTOG06p4KdZFQ=; b=j28iqp/6JSYiDZNbRISiYHb21g4mVidI5hA2fpwhhod9ip0yIepebDaVqaNC4NSZ6t F4sqJtg0aNnUBAJ4xvigwSkyU3d3BhU4fKyqFQwEEecpZb6omCOOgzbVZVdAwVudh8YS 6sAdCx1o8qqmfBIKwSjsLucJEbNfA+AnN8WTl8dWCKLDsa5HJRooFNeT9lMV7R87U2u9 KXmlf47JGDrH7ILcbodi08i+6ehVBoujXc6/cUx4HyJ5u93ZM3FF54VbS+qgGeIEXSfV n5I3UI6QXxv203AO8+D/lzpzXof1tsEkr9j37CEL5qafNFHR6QEo9dMi6UqQFn1zoh8l UWDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=pRGk1s9ftRrOgrFlJyIOUPDg0XINxHbTOG06p4KdZFQ=; b=Xw/MJctiNx58qhVr2M6wc+Ci5Q3HFSua6ePmi3A3GGLPNrV56nifkXfkre8OJPpqZn a32RuLZINHsPREppItXfuJyp0SF55TjM1k/V/N0aoZnafXqdA4wInN5SYwiDYklO82Re MhW5Ba0EtOLcKImgAq4uNn4Src6yF2sb79R5wTuzynIxR4zXLdiY8uUqKBjuotkgrGuY 5vgAZARJZ2paZC8ckN6Hn/J3oruXg5vtEbUr/GfRfwc5Q7wGa21RuI+roBnYyz1r+JWy 8bQZKHO8q5B0nD2DDi7FmXmS5VvTXiSBWpJG7ZZ0injKKZgjeovNws1SfpPTB2nLLvWE mfKQ== X-Gm-Message-State: APjAAAWa71/KqamIIyNSqCzeIjOxwDYN4ftfZ9VgxM7HTiXo9cvNJT9X CKe5fVQcA6AIAC5mKb4Ky2pT4g== X-Google-Smtp-Source: APXvYqyyIZTS2at8UaC2GBzO1HAEDcqCzwTOJ2eIeXn1Qqrvu+CLxM4PQ8fncDRODM0mD17f4WmUzQ== X-Received: by 2002:a63:f07:: with SMTP id e7mr16271558pgl.238.1567219835444; Fri, 30 Aug 2019 19:50:35 -0700 (PDT) Received: from localhost ([216.9.110.5]) by smtp.gmail.com with ESMTPSA id 195sm8287179pfu.75.2019.08.30.19.50.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Aug 2019 19:50:34 -0700 (PDT) Date: Fri, 30 Aug 2019 19:50:33 -0700 (PDT) From: Paul Walmsley X-X-Sender: paulw@viisi.sifive.com To: Atish Patra cc: linux-kernel@vger.kernel.org, Albert Ou , linux-riscv@lists.infradead.org, Palmer Dabbelt , Christoph Hellwig , Anup Patel Subject: Re: [PATCH v4 0/3] Optimize tlbflush path In-Reply-To: <20190822075151.24838-1-atish.patra@wdc.com> Message-ID: References: <20190822075151.24838-1-atish.patra@wdc.com> User-Agent: Alpine 2.21.9999 (DEB 301 2018-08-15) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Atish, On Thu, 22 Aug 2019, Atish Patra wrote: > This series adds few optimizations to reduce the trap cost in the tlb > flush path. We should only make SBI calls to remote tlb flush only if > absolutely required. The patches look great. My understanding is that these optimization patches may actually be a partial workaround for the TLB flushing bug that we've been looking at for the last month or so, which can corrupt memory or crash the system. If that's the case, let's first root-cause the underlying bug. Otherwise we'll just be papering over the actual issue, which probably could still occur even with this series, correct? Since it contains no explicit fixes? - Paul