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b=RdxzCnvF9/9K4BIJpoa4VFdo4EKLFQj2KonO3t3fqpBr9IK0kXzCg6LjA/+5GGC2T CQFWYMMuYHqoTe+KyAXloSkpg5xjW1qvQamKc7clWJk17XPU4SESQ/zFYvHtWWM8Z+ 5/JEHZRh/JQCh2bbcBSJqinQi22QzstH+GvviE/nFDvvrdWYULyVvbsYFzLO5IapCO 6aMeCj4Lx4fPfKJ9/xcvYcgxpD5jlQ0rSbOBYJxlf2f3c24f/Yp0jfp7wGH886EjCi JdGkipBOLrN6nQZlGFssROtYbt4cXeXH58eaFpL28fYRKDRVXb0rKFMntOkiaG9mN2 7HMNlpf1YzyOQ== Date: Tue, 3 Feb 2026 19:03:39 +0200 From: Mike Rapoport To: "Vishal Moola (Oracle)" Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, akpm@linux-foundation.org, "Matthew Wilcox (Oracle)" , Dave Hansen , Andy Lutomirski , Peter Zijlstra Subject: Re: [PATCH v3 0/3] Convert 64-bit x86/mm/pat to ptdescs Message-ID: References: <20260202172005.683870-1-vishal.moola@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260202172005.683870-1-vishal.moola@gmail.com> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: A9C2D100003 X-Stat-Signature: rajbd3bzy99nz9k887iwgx7pat731rqe X-HE-Tag: 1770138227-946672 X-HE-Meta: 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 UNP308B/ p3qeSoYzk/C+x1nSS5SncTe9H+FDCGZVXtwg45u8AR/Ti16ABIq10z0atU7mcHt8y4Js0mFEHDU35/UGQz/PeX57Slhxm2sDkxOcsMgvgnKKPdin7ktUN/wV5ajlCGNSJLiIkv9iDJbDoYzv1gymeBFDb2ECJuHXeCc0KiBNHZBIo2O26CSl1CUiVXt4tqZrHtMAGKm/EJsyLBqVSZYrlTrqRjPVONGMy6QV9aLo0fvyDo4US/6p8m4VIYdBSLMxLyWLYomcwSfGqnS19RgTU/TYURaC3LkL7AM0kgjUKn8n6VcSID9Ge2XE7gRyYPRyR4rZu5gqxBAk+UZOWlbpAqXMNCTYDPq342Hki7XW8AG8vcEk7rD6u7PI8grbFFsSCMdCYF6Sq0ih2qINRcctnqxpjUQ== 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 Mon, Feb 02, 2026 at 09:20:02AM -0800, Vishal Moola (Oracle) wrote: > 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. > > 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. > > [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/ > > ------ > > I've also tested this on a tree that separately allocates ptdescs. That > didn't find any lingering alloc/free issues. > > Based on current mm-new. > > v3: > - Move comment regarding 32-bit conversions into the cover letter > - Correct the handling for the pagetable_alloc() error path > > 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 Acked-by: Mike Rapoport (Microsoft) With some minor comments in patch 1/3 > arch/x86/mm/pat/set_memory.c | 56 +++++++++++++++++++++--------------- > 1 file changed, 33 insertions(+), 23 deletions(-) > > -- > 2.52.0 > -- Sincerely yours, Mike.