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 BCEA33EFFB3; Fri, 24 Jul 2026 11:50:01 +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=1784893807; cv=none; b=SLm7lwZ5nm2KG6fkZt0pLJsDjJpeu/LRkRHn7RD+i6hvQb2jMo76J2/Yg5TFYDtdhX23nWZUPZoR08Ufg8WVwKsrvEYD4cMnMe+Xe0SFJgqd8tbHHaXGvAn/g+a/9qNiTmA+WLzyRzX7ardVB81i7GXombm4V2wO4KTuE7rWxOc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784893807; c=relaxed/simple; bh=lSGi/T62Qz3zkTtfJoxDSfari9OyrmBQakjPywG4Wwg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=s6YBvk8PbCt007xYdm1uxISkdZnaW4dLDErCz8ncq0R6qdW5nsjf+oZ7lM3/pQbj2X7xRH+g2EcXTvTJRCXlathWqro1bRLHnWrfkAXuuKOls6+EvfN0q5xxhu6yJEqEXMl4JIncPx7wEdx1IiWHEZPiwYT4r9c4RIqCS8b8kXc= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=onlJqJS2; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="onlJqJS2" 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 BB13C1595; Fri, 24 Jul 2026 04:49:55 -0700 (PDT) Received: from e129823.arm.com (e129823.arm.com [10.2.213.3]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0F2463F59E; Fri, 24 Jul 2026 04:49:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1784893799; bh=lSGi/T62Qz3zkTtfJoxDSfari9OyrmBQakjPywG4Wwg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=onlJqJS22YoDsKaG6SiKSkuKsNv+WmGR0K4ecfdNyqZf1u/+3JEGvSxKfGGrvm5nJ MXCh4HNavE1AO8qDTOoQLnL6W10waJKQJvwWm9dJxKiy7ypA0biilE7i0COMFUcgAZ cBx7VbhxE8imKHXZsbg7suIUPJzdyNKYFStD+n4k= Date: Fri, 24 Jul 2026 12:49:45 +0100 From: Yeoreum Yun To: Dave Hansen Cc: Yeoreum Yun , Russell King , Huacai Chen , WANG Xuerui , Thomas Bogendoerfer , Catalin Marinas , Will Deacon , Arnd Bergmann , Andrew Morton , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Johannes Weiner , David Hildenbrand , Michal Hocko , Lorenzo Stoakes , Tianrui Zhao , Bibo Mao , Anup Patel , Atish Patra , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonas Bonn , Stefan Kristiansson , Stafford Horne , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-openrisc@vger.kernel.org Subject: Re: [PATCH RFC v2 14/20] x86: mm: skip pud setup when using generic compile-time folded pagetable Message-ID: References: <20260722-dummy_ptxp3-v2-0-d9e4bad31e0a@arm.com> <20260722-dummy_ptxp3-v2-14-d9e4bad31e0a@arm.com> <0ea931f1-4801-4d32-b6ce-4787a8d3daa9@intel.com> <6f5060a7-0a64-49fc-81a3-ae88729ef794@intel.com> <3620750c-54d7-45a0-b067-bc813dd3cd9b@intel.com> Precedence: bulk X-Mailing-List: linux-mips@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3620750c-54d7-45a0-b067-bc813dd3cd9b@intel.com> On Wed, Jul 22, 2026 at 01:22:04PM -0700, Dave Hansen wrote: > On 7/22/26 13:18, Yeoreum Yun wrote: > > Sorry. But do you mean check with cpu_feature_enabled() not with > > boot_cpu_has()? > > IIRC, the boot_cpu_has() doesn't use the DISABLE_MASK_BIT_SET() but > > uses REQUIRED_MASK_BIT_SET() and I don't expect it wouldn't make > > an optimisation to constant check which is contrast to DISABLE_MASK_BIT_SET(). > > Ahh, yes. I forgot about that nuance! Moving to cpu_feature_enabled() > would be great! When I see again, using cpu_feature_enabled(), this would give a chance to optimisation when the feature disabled and there would be no harm for when feature enabled since cpu_feature_enabbled() also fallback to boot_cpu_has(). So, it might be good to change with cpu_feature_enabled() as we discussed. @Dave, Should I send above change separately or include it in this patch? -- Sincerely, Yeoreum Yun