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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D352DCCFA05 for ; Fri, 7 Nov 2025 12:31:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1872E8E000C; Fri, 7 Nov 2025 07:31:53 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 15EFE8E0002; Fri, 7 Nov 2025 07:31:53 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 09BA48E000C; Fri, 7 Nov 2025 07:31:53 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id EFD8E8E0002 for ; Fri, 7 Nov 2025 07:31:52 -0500 (EST) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 0796E1A0469 for ; Fri, 7 Nov 2025 12:31:51 +0000 (UTC) X-FDA: 84083747664.16.9071AE0 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf06.hostedemail.com (Postfix) with ESMTP id F3937180013 for ; Fri, 7 Nov 2025 12:31:49 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf06.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1762518710; 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=riGlcmndbsVNq1RBdZCHUXalg5T8zJw1ELQJ4dXOoec=; b=ohSlGt6NuZu3wjzpvFGddILbxGXXdXWpiRDJjrb3vShbp5ioVpYh7TXB0DUelH8dnDl8j2 vpSAr/Wa4mVy3XCfY81VEqpqsgK9kwW+dr24aN/p+xY9My7ska4cLA+Uk7/umt1j2XOD2F 1nphlKhVcWURUbnI9xWFCUKsvCRIzNw= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf06.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1762518710; a=rsa-sha256; cv=none; b=HaFFNriU3yj9u2rCxTyiLPjp9E8mmIwc0ufsNfc8JA7mVYBc3mjNLSa0/ARRnR7DCubUJs /oa+eZg0QIuER/M66JPU8utXUX6s5H6z5OWeqMPEXKIW1Yr+ww/lU8DwinwvCswfPIR0Aj vOR6RAHl5myPOoklvck9N3M5qTiZuZA= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2C3C81516; Fri, 7 Nov 2025 04:31:41 -0800 (PST) Received: from [10.57.86.134] (unknown [10.57.86.134]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 412D63F66E; Fri, 7 Nov 2025 04:31:44 -0800 (PST) Message-ID: Date: Fri, 7 Nov 2025 12:31:42 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 02/12] x86/xen: simplify flush_lazy_mmu() Content-Language: en-GB To: Kevin Brodsky , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Alexander Gordeev , Andreas Larsson , Andrew Morton , Boris Ostrovsky , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , David Hildenbrand , "David S. Miller" , David Woodhouse , "H. Peter Anvin" , Ingo Molnar , Jann Horn , Juergen Gross , "Liam R. Howlett" , Lorenzo Stoakes , Madhavan Srinivasan , Michael Ellerman , Michal Hocko , Mike Rapoport , Nicholas Piggin , Peter Zijlstra , Suren Baghdasaryan , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org References: <20251029100909.3381140-1-kevin.brodsky@arm.com> <20251029100909.3381140-3-kevin.brodsky@arm.com> From: Ryan Roberts In-Reply-To: <20251029100909.3381140-3-kevin.brodsky@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: F3937180013 X-Stat-Signature: rt4g3p3m87cziyi18wnxamu8h5g1kjjg X-Rspam-User: X-HE-Tag: 1762518709-807033 X-HE-Meta: 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 vX0OFgNF LXMLpI//gmpJzl90ZM/MTbK9RoK0qj7VYeCOE/5ngoARGMEblDtQOHy5kHCZnu/Z0ag6pI2PFJcY/iHEwiOVY4jOpYK2hc53h19CtKY42dpDB81/5uarD7NB9zkZTbbQntlGmK8SgqadbBN6EkCz4YPrvpp78VwRO6rtyR/nH+r02uxlTBZtcMVjEH6+JfVzOFHXAwrCt8mHolxs1ob+vZ3G836hyan/5eBGfWQhEwby3w/RMg1k9fo1+5Q== 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: On 29/10/2025 10:08, Kevin Brodsky wrote: > arch_flush_lazy_mmu_mode() is called when outstanding batched > pgtable operations must be completed immediately. There should > however be no need to leave and re-enter lazy MMU completely. The > only part of that sequence that we really need is xen_mc_flush(); > call it directly. > > Signed-off-by: Kevin Brodsky This looks functionally equivalent to me, so: Reviewed-by: Ryan Roberts But I don't think this tidy up is strictly necessary for your series to work? (perhaps I'll change my mind on that as I go through it). > --- > arch/x86/xen/mmu_pv.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c > index 2a4a8deaf612..7a35c3393df4 100644 > --- a/arch/x86/xen/mmu_pv.c > +++ b/arch/x86/xen/mmu_pv.c > @@ -2139,10 +2139,8 @@ static void xen_flush_lazy_mmu(void) > { > preempt_disable(); > > - if (xen_get_lazy_mode() == XEN_LAZY_MMU) { > - arch_leave_lazy_mmu_mode(); > - arch_enter_lazy_mmu_mode(); > - } > + if (xen_get_lazy_mode() == XEN_LAZY_MMU) > + xen_mc_flush(); > > preempt_enable(); > }