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X-CSE-ConnectionGUID: JCY5YHNuTRmg/GAUJolDtQ== X-CSE-MsgGUID: CMVCY50ETgi4OgC21asL4A== X-IronPort-AV: E=McAfee;i="6800,10657,11735"; a="85442852" X-IronPort-AV: E=Sophos;i="6.23,130,1770624000"; d="scan'208";a="85442852" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by orvoesa103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Mar 2026 12:47:06 -0700 X-CSE-ConnectionGUID: r2V4PA5UTweUfGTFBq68dw== X-CSE-MsgGUID: v8VAW6WFRv66cG/HLAQlWA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,130,1770624000"; d="scan'208";a="228112168" Received: from dnelso2-mobl.amr.corp.intel.com (HELO [10.125.109.109]) ([10.125.109.109]) by fmviesa005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Mar 2026 12:47:04 -0700 Message-ID: <17e58542-1221-48dd-88b9-236128515ed2@intel.com> Date: Fri, 20 Mar 2026 12:47:02 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 02/22] x86/mm: Generalize LDT remap into "mm-local region" To: Brendan Jackman , Borislav Petkov , Dave Hansen , Peter Zijlstra , Andrew Morton , David Hildenbrand , Vlastimil Babka , Wei Xu , Johannes Weiner , Zi Yan , Lorenzo Stoakes Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, rppt@kernel.org, Sumit Garg , derkling@google.com, reijiw@google.com, Will Deacon , rientjes@google.com, "Kalyazin, Nikita" , patrick.roy@linux.dev, "Itazuri, Takahiro" , Andy Lutomirski , David Kaplan , Thomas Gleixner , Yosry Ahmed References: <20260320-page_alloc-unmapped-v2-0-28bf1bd54f41@google.com> <20260320-page_alloc-unmapped-v2-2-28bf1bd54f41@google.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/20/26 11:23, Brendan Jackman wrote: > > +#ifdef CONFIG_MM_LOCAL_REGION > +static inline void mm_local_region_free(struct mm_struct *mm) > +{ > + if (mm_local_region_used(mm)) { > + struct mmu_gather tlb; > + unsigned long start = MM_LOCAL_BASE_ADDR; > + unsigned long end = MM_LOCAL_END_ADDR; > + > + /* > + * Although free_pgd_range() is intended for freeing user > + * page-tables, it also works out for kernel mappings on x86. > + * We use tlb_gather_mmu_fullmm() to avoid confusing the > + * range-tracking logic in __tlb_adjust_range(). > + */ > + tlb_gather_mmu_fullmm(&tlb, mm); These are superficial nits and I need to go through this series in actual detail, but here are the nits: Indentation is bad. What you have here double-indents the whole function. Do this: struct mmu_gather tlb; unsigned long start = MM_LOCAL_BASE_ADDR; unsigned long end = MM_LOCAL_END_ADDR; if (!mm_local_region_used(mm)) return; ... rest of code here > + * We use tlb_gather_mmu_fullmm() to avoid confusing the > + * range-tracking logic in __tlb_adjust_range(). > + */ Imperative voice, please. And a meta-comment: > Documentation/arch/x86/x86_64/mm.rst | 4 +- > arch/x86/Kconfig | 2 + > arch/x86/include/asm/mmu_context.h | 119 ++++++++++++++++++++++++++++- > arch/x86/include/asm/page.h | 32 ++++++++ > arch/x86/include/asm/pgtable_32_areas.h | 9 ++- > arch/x86/include/asm/pgtable_64_types.h | 12 ++- > arch/x86/kernel/ldt.c | 130 +++++--------------------------- This is too big and there's too much going on here. This is doing a few logical things like both introducing mm-local regions *and* making the LDT remap one of them.