From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 251022E2DFE; Wed, 15 Oct 2025 08:27:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760516875; cv=none; b=KlpA7I/PBLLCiE0tpElw0h0ZBaAcaIXEU1XOzJiBNKYg80Q86Y1sz32nnk/YqAjwhOgTOmhBPSnzZc0jUI20BhFmGhc1pZ7dpuINdWJZAQbtDWssnM7A/vjsB709pw+yfyAmyaoiACEHbiIqlrOA+z9DsXFFTn+3//FB746Lddo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760516875; c=relaxed/simple; bh=25flPjRMXR8LYUKwJe0iy9R5OTqX6GUkNayOQ1le2Y8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nsVATBndNdWagk96g3fKZl44ieOqk5CkfZQsRJthttfsfR0rOviB7gwXBXAAaL9GGAoXt5fDTsESYrFAzS0fUOZVRN+1RYxQxclFjVq3ZaF9pnBpBeD0sGlBYnvAOo0xKfRbzNDwUq8NsYNBRYdfsAE3Fy2uNDjv/N7OQf8NkLk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 968DD22EA; Wed, 15 Oct 2025 01:27:45 -0700 (PDT) Received: from e123572-lin.arm.com (e123572-lin.cambridge.arm.com [10.1.194.54]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 400C13F66E; Wed, 15 Oct 2025 01:27:48 -0700 (PDT) From: Kevin Brodsky To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Kevin Brodsky , Alexander Gordeev , Andreas Larsson , Andrew Morton , Boris Ostrovsky , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , David Hildenbrand , "David S. Miller" , "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 , Ryan Roberts , 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 Subject: [PATCH v3 02/13] x86/xen: simplify flush_lazy_mmu() Date: Wed, 15 Oct 2025 09:27:16 +0100 Message-ID: <20251015082727.2395128-3-kevin.brodsky@arm.com> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20251015082727.2395128-1-kevin.brodsky@arm.com> References: <20251015082727.2395128-1-kevin.brodsky@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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. While at it, we can also avoid preempt_disable() if we are not in lazy MMU mode - xen_get_lazy_mode() should tolerate preemption. Signed-off-by: Kevin Brodsky --- arch/x86/xen/mmu_pv.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index 2a4a8deaf612..dcb7b0989c32 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -2137,14 +2137,11 @@ static void xen_enter_lazy_mmu(void) 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(); + preempt_disable(); + xen_mc_flush(); + preempt_enable(); } - - preempt_enable(); } static void __init xen_post_allocator_init(void) -- 2.47.0