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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52278C433EF for ; Mon, 4 Oct 2021 19:24:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CABF661458 for ; Mon, 4 Oct 2021 19:24:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org CABF661458 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id EEE6094006A; Mon, 4 Oct 2021 15:24:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E9D4694000B; Mon, 4 Oct 2021 15:24:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D162E94006A; Mon, 4 Oct 2021 15:24:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0007.hostedemail.com [216.40.44.7]) by kanga.kvack.org (Postfix) with ESMTP id C39BF94000B for ; Mon, 4 Oct 2021 15:24:19 -0400 (EDT) Received: from smtpin34.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 6A65832609 for ; Mon, 4 Oct 2021 19:24:19 +0000 (UTC) X-FDA: 78659731038.34.65A3C11 Received: from mail-pj1-f45.google.com (mail-pj1-f45.google.com [209.85.216.45]) by imf12.hostedemail.com (Postfix) with ESMTP id 30F2E1000A8F for ; Mon, 4 Oct 2021 19:24:19 +0000 (UTC) Received: by mail-pj1-f45.google.com with SMTP id g13-20020a17090a3c8d00b00196286963b9so195497pjc.3 for ; Mon, 04 Oct 2021 12:24:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=0U7IBsrDQvR7BEZkcrW5Le/tFKp52n4Y9d5zqsAi/H4=; b=claLKin48dOn1KbAZAzFb4o1s0eZ9Wb63SspSgP12JgHcxAn8Qih6z262lCfMmRzdV 5X0yUvVCSoEt4/1WOCCFYg9je4A9dYGkPDem5bqo5DfhAQqzK5M83QqbYDeVqjVzbU2L Q+SSowd/MDouxXBq8Zk8kXk/Mc71A/DpGOnc0/h/soXMhD3bLLyPb9NrT3Cn3PTTSM57 zmYOqv69Kh2NB8PNbrpsCY0vuKDtupzAmKyKvj8sf6iEuFI3uacC1jotgWV0kFYqIz5Z nGEh8290vF/fIAjdPYOQV0Z8EP6B1FfE12H+xYBS0YTShzqqk4Tz5ZT2QkdumyxfjAA5 g3BQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=0U7IBsrDQvR7BEZkcrW5Le/tFKp52n4Y9d5zqsAi/H4=; b=Gb6mGythOn+CV0aOJFQk2aGZTHf1ujPF4qN+npRXFqz228OyS74zbPeBODFc90pIV9 asG32CY/ACgDegtvdqpMF6KXWj/Fo4mbxkmSQyx0DMDALmouxaTDjzn9FUdBBM6OdKUe XJSJgZ/qMz13jLhaFhVUtLFURghEV4Lz33X2WUlYrxkT/xrXRzYK2Tax/ciz2BnO2NvK OHmrt46hDIhCsKbEbi/mBUK+D8+913PmnPH7AFe4o7GWmLO39BvnUO8i8OBb8IWS/ZY1 9d4VWEU7owH8GGOLj1Sdt+SlJI0Nqr1cg9hILosEXbQfZCfXvBKqq4ynUcUpukmKOQvh L6tQ== X-Gm-Message-State: AOAM533AGJwUmMWVbw52cs8/o+kVfN1U+CNIWYHnLYMF/m4+bh6IRDl2 Vc5sfLgN3gyzuJ58K8zG38Q= X-Google-Smtp-Source: ABdhPJxrf3sEF71SLcFd8+fGSLjRiX07BYjC+i4DwK1KJQ3X5TUbLiWFjwBI+lhTrbs1XCykIZNtvw== X-Received: by 2002:a17:902:8543:b029:12d:461f:a6a8 with SMTP id d3-20020a1709028543b029012d461fa6a8mr1274421plo.1.1633375457875; Mon, 04 Oct 2021 12:24:17 -0700 (PDT) Received: from smtpclient.apple (c-24-6-216-183.hsd1.ca.comcast.net. [24.6.216.183]) by smtp.gmail.com with ESMTPSA id e6sm5125083pgf.59.2021.10.04.12.24.15 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 04 Oct 2021 12:24:16 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.120.0.1.13\)) Subject: Re: [PATCH 1/2] mm/mprotect: use mmu_gather From: Nadav Amit In-Reply-To: <20211003121019.GF4323@worktop.programming.kicks-ass.net> Date: Mon, 4 Oct 2021 12:24:14 -0700 Cc: Andrew Morton , LKML , Linux-MM , Peter Xu , Andrea Arcangeli , Andrew Cooper , Andy Lutomirski , Dave Hansen , Thomas Gleixner , Will Deacon , Yu Zhao , Nick Piggin , x86@kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: <620B1A38-1457-4F77-8666-E73A318392B6@gmail.com> References: <20210925205423.168858-1-namit@vmware.com> <20210925205423.168858-2-namit@vmware.com> <20211003121019.GF4323@worktop.programming.kicks-ass.net> To: Peter Zijlstra X-Mailer: Apple Mail (2.3654.120.0.1.13) X-Rspamd-Queue-Id: 30F2E1000A8F X-Stat-Signature: b5fs6aner9nqeazdfd8m17wmbungttcw Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=claLKin4; spf=pass (imf12.hostedemail.com: domain of nadav.amit@gmail.com designates 209.85.216.45 as permitted sender) smtp.mailfrom=nadav.amit@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspamd-Server: rspam06 X-HE-Tag: 1633375459-581857 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: > On Oct 3, 2021, at 5:10 AM, Peter Zijlstra = wrote: >=20 > On Sat, Sep 25, 2021 at 01:54:22PM -0700, Nadav Amit wrote: >=20 >> @@ -338,25 +344,25 @@ static unsigned long = change_protection_range(struct vm_area_struct *vma, >> struct mm_struct *mm =3D vma->vm_mm; >> pgd_t *pgd; >> unsigned long next; >> - unsigned long start =3D addr; >> unsigned long pages =3D 0; >> + struct mmu_gather tlb; >>=20 >> BUG_ON(addr >=3D end); >> pgd =3D pgd_offset(mm, addr); >> flush_cache_range(vma, addr, end); >> inc_tlb_flush_pending(mm); >=20 > That seems unbalanced... Bad rebase. Thanks for catching it! >=20 >> + tlb_gather_mmu(&tlb, mm); >> + tlb_start_vma(&tlb, vma); >> do { >> next =3D pgd_addr_end(addr, end); >> if (pgd_none_or_clear_bad(pgd)) >> continue; >> - pages +=3D change_p4d_range(vma, pgd, addr, next, = newprot, >> + pages +=3D change_p4d_range(&tlb, vma, pgd, addr, next, = newprot, >> cp_flags); >> } while (pgd++, addr =3D next, addr !=3D end); >>=20 >> - /* Only flush the TLB if we actually modified any entries: */ >> - if (pages) >> - flush_tlb_range(vma, start, end); >> - dec_tlb_flush_pending(mm); >=20 > ... seeing you do remove the extra decrement. Is it really needed? We do not put this comment elsewhere for tlb_finish_mmu(). But no problem, I=E2=80=99ll keep it.=