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[67.164.59.41]) by smtp.googlemail.com with ESMTPSA id 5a478bee46e88-2b7a1abe57csm5439115eec.22.2026.01.28.14.41.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Jan 2026 14:41:00 -0800 (PST) From: "Vishal Moola (Oracle)" To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, "Mike Rapoport (Microsoft)" Cc: akpm@linux-foundation.org, "Matthew Wilcox (Oracle)" , Dave Hansen , Andy Lutomirski , Peter Zijlstra , "Vishal Moola (Oracle)" Subject: [PATCH v2 0/3] Convert 64-bit x86/mm/pat to ptdescs Date: Wed, 28 Jan 2026 14:40:46 -0800 Message-ID: <20260128224049.385013-1-vishal.moola@gmail.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit x86/mm/pat should be using ptdescs. One line has already been converted to pagetable_free(), while the allocation sites use get_free_pages(). This causes issues separately allocating ptdescs from struct page. These patches convert the allocation/free sites to use ptdescs. In the short term, this helps enable Matthew's work to allocate frozen pagetables[1]. And in the long term, this will help us cleanly split ptdesc allocations from struct page. [1] https://lore.kernel.org/linux-mm/20251113140448.1814860-1-willy@infradead.org/ [2] https://lore.kernel.org/linux-mm/20251020001652.2116669-1-willy@infradead.org/T/#u ------ I've also tested this on a tree that separately allocates ptdescs. That didn't find any lingering alloc/free issues. I've realized that the pgd_list should also be using ptdescs (for 32bit in this file). This can be done in a different patchset since there's other users of pgd_list that still need to be converted. Based on current mm-new. v2: - Use pagetable_alloc() in populate_pgd() - in patch 2 - Rename subject line to specify 64-bit (i.e. 32-bit wasn't converted) - Added reference links to the projects mentioned in the cover letter Vishal Moola (Oracle) (3): x86/mm/pat: Convert pte code to use ptdescs x86/mm/pat: Convert pmd code to use ptdescs x86/mm/pat: Convert split_large_page() to use ptdescs arch/x86/mm/pat/set_memory.c | 43 ++++++++++++++++++++---------------- 1 file changed, 24 insertions(+), 19 deletions(-) -- 2.52.0