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=-0.8 required=3.0 tests=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 C7537C10F25 for ; Sat, 7 Mar 2020 00:34:29 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 9E758206D5 for ; Sat, 7 Mar 2020 00:34:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="KSaI3l6Y"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="puvFN+Oa" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9E758206D5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lca.pw Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+infradead-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=bombadil.20170209; h=Sender:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:To:In-Reply-To: References:Message-Id:Date:Subject:Mime-Version:From: Content-Transfer-Encoding:Content-Type:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=Llth3MhUyFBOi7p0WfyKRqezwCMBh50m9NEH4AtRH1U=; b=KSaI3l6YD8CTZSOMX2NPs+fVad NKGGfqFHPg10YYe8jXMA9Am46yfmNR0Puqwn7ASFbJV0Mhu/IRvWiop6TK5Q/aEluXHiqMFlpva2e n1wJoSHTb/RULdd4mx44rqYwAMzZwONE19fSWuSU5tP18WufpV0w4TV31L2up1Dk2nfB3TjJ2dnfu qvFLG16+mAixab+52wQpZ6E0QLem4V62bvSUY0UouXO0R1PlxvIUM4gGLjfvieyevtkO65hogn0s+ ybM8YaXqjFddEsWRhkWJKAtEOtvMmL5xpZdAFlkIjwA8qCCikUfBUV688Hpsq4J7CZV3/wHWPWaB9 MvTsTXlA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jANQA-0004VF-6P; Sat, 07 Mar 2020 00:34:26 +0000 Received: from mail-qt1-x842.google.com ([2607:f8b0:4864:20::842]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jANQ7-0004UE-PX for linux-riscv@lists.infradead.org; Sat, 07 Mar 2020 00:34:25 +0000 Received: by mail-qt1-x842.google.com with SMTP id x21so3080333qto.13 for ; Fri, 06 Mar 2020 16:34:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=content-transfer-encoding:from:mime-version:subject:date:message-id :references:cc:in-reply-to:to; bh=Llth3MhUyFBOi7p0WfyKRqezwCMBh50m9NEH4AtRH1U=; b=puvFN+Oa4Vsque2ZZFahxBROstqlUCh6OUM3IAJz/PpFxOEwXVBDL1w614Lf5OgLn5 ZzOKj9HWOalPOfhv3WAYO45FNOPCCJIbnU41PCb5bB2Jpfed/n8m6G0z5zQoTE4+Y2y9 3QJpAM3ou6c7EdgrRsfCmCg49mhT4wc3UBudKo0M3IjKzr4rlUXBE2NlETbQYMK6HNXK FaW2q4McGhTj2NCjdx0Iunur4hGozNvUDxm9RmqprWgyakpEZ4US8GkH1ltbTWFsHiOw CwD/p2KKStXpzjgcBMWXRzzvBYt1qmOtcsAsjRrYeh1r/v9yIBxJhh+Vq48gTXYafbjW E5Vw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:content-transfer-encoding:from:mime-version :subject:date:message-id:references:cc:in-reply-to:to; bh=Llth3MhUyFBOi7p0WfyKRqezwCMBh50m9NEH4AtRH1U=; b=fMCwMuK6G+w8AIWeQa2NHwlyJeNIGGj+gXl7Cr9I4L7o1rLt8p46AJoh1hmZAiyBWh XTtvxsnmyaRXeJry5SB6x/hW4AbPEob6efYeN7G9X3h5MinYPiLYobsapoERDdnMxAbZ yZPTvAbrY1wowJGE5SAinnyKyKu/MAs3ViF1P1ooBIwpQCBdmCvVwEecsKNnhczk0Mdk KNcRpVJvEp/gzG9Mvy3ZrJREX6d6Z41EniaiMfSo5tn4+/zevNLGVEkKp9LUwLFNZorM Dz6GyBfgKmWBUZY5Ifvzhe2SSeo/VzQyZ+3zLjgRmRl/aTKlCAcVKBoWSawMq6f8fgvC QihQ== X-Gm-Message-State: ANhLgQ3x8qQkJZvuShW3xkbmjwGKPdJtBb0sn0lxMJiJEzQMnOa6pz5K mdeSHLpSkDccoGOaqAPKL6qP8gZct8X1bA== X-Google-Smtp-Source: ADFU+vtIXuLKAhOxSRwmQknHK6gBQTO4ffulLvuvjqolLxIBY8IQ/C9gOq1OdEnF0L6YkCCsmh/eQw== X-Received: by 2002:ac8:7b94:: with SMTP id p20mr5546904qtu.122.1583541260735; Fri, 06 Mar 2020 16:34:20 -0800 (PST) Received: from [192.168.1.183] (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id 202sm18088610qkg.132.2020.03.06.16.34.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 06 Mar 2020 16:34:19 -0800 (PST) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable From: Qian Cai Mime-Version: 1.0 (1.0) Subject: Re: [PATCH V15] mm/debug: Add tests validating architecture page table helpers Date: Fri, 6 Mar 2020 19:34:18 -0500 Message-Id: References: <61250cdc-f80b-2e50-5168-2ec67ec6f1e6@arm.com> In-Reply-To: <61250cdc-f80b-2e50-5168-2ec67ec6f1e6@arm.com> To: Anshuman Khandual X-Mailer: iPhone Mail (17D50) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200306_163423_971983_8303AB78 X-CRM114-Status: GOOD ( 10.33 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Benjamin Herrenschmidt , Heiko Carstens , linux-mm@kvack.org, Paul Mackerras , "H. Peter Anvin" , linux-riscv@lists.infradead.org, Will Deacon , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Michael Ellerman , x86@kernel.org, Mike Rapoport , Christian Borntraeger , Ingo Molnar , Catalin Marinas , linux-snps-arc@lists.infradead.org, Vasily Gorbik , Borislav Petkov , Paul Walmsley , "Kirill A . Shutemov" , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Christophe Leroy , Vineet Gupta , linux-kernel@vger.kernel.org, Palmer Dabbelt , Andrew Morton , linuxppc-dev@lists.ozlabs.org Sender: "linux-riscv" Errors-To: linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.org > On Mar 6, 2020, at 7:03 PM, Anshuman Khandual w= rote: >=20 > Hmm, set_pte_at() function is not preferred here for these tests. The idea= > is to avoid or atleast minimize TLB/cache flushes triggered from these sor= t > of 'static' tests. set_pte_at() is platform provided and could/might trigg= er > these flushes or some other platform specific synchronization stuff. Just Why is that important for this debugging option? > wondering is there specific reason with respect to the soft lock up proble= m > making it necessary to use set_pte_at() rather than a simple WRITE_ONCE() ?= Looks at the s390 version of set_pte_at(), it has this comment, vmaddr); /* * Certain architectures need to do special things when PTEs * within a page table are directly modified. Thus, the following * hook is made available. */ I can only guess that powerpc could be the same here.=