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b=skHak3je481fNw0ayYjO7y493PFx2ce5kzqQ9HAm1wcGlEKvhLSW2DL58/l9c1Mor g0n7Nw5zEEI0y/NdCN+rV+jldL+a4jYxLwRjdckEBxVowHltqTSZFGxpgDCkXe1F9E FK61DrzQSfd83p7KvlzAquTCZQHtR1LRcjxFA9bADMfn45DVVZtkt13dElB3tnKiw4 2yxrniX7u1ExsegzmUB8dezBfJ7c0bJWftmHWBm9QL8XyLTz2x1YZ7X1gOKKUdAkM9 +DruqvmZJovjkyoZME9LhOoWvKm4qDTF+0LzY08iDR8FvH35iIxHCw0RISHY824STm RUrUPyKfd7skQ== Date: Thu, 29 Jan 2026 10:05:16 +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 v2 0/3] Convert 64-bit x86/mm/pat to ptdescs Message-ID: References: <20260128224049.385013-1-vishal.moola@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260128224049.385013-1-vishal.moola@gmail.com> X-Rspamd-Queue-Id: BC18F40012 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: gctbdgkuygf19qnr1zs5k6qwyxdhh6at X-HE-Tag: 1769673924-818573 X-HE-Meta: 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 9jJJ6Wpj YMrJaItMs8C6p+k9Q1bygd2R/iCM5UHFh+nmM90enmxlboP0yiky0pGEQ3jk47Ehx/OHSX7Ij+Hs7/7q9eF2DhraUViNFBb/qRYcs/BAns7yaEGI3gfaqe22YAgUGPo6quE86y/OChPyFM0Qyr/KeYrjNUmaJouyh/05BeiP1mocpSNHuDePtCU/MMqo6NIgqkegCKBog/SbSM0s3Mbs0WjwuMo+24TywP9ZRtjZa7A+HBShTIsLVp4ubH/uY5lsM/POWi1cwygPWPXzGeAImTKF8cY1TUjKi+euhvZGLODKpW6TDF+31i7TjQNQuM/Lh9bN4CkTW70MTeCGeCjWtjFelYyikg0AKjhiMfXmba+XF6tvoR/+O51RfKwGW81lSzLG6qhOvWWT2FyeA7LaKcgWIhw== 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: Hi Vishal, On Wed, Jan 28, 2026 at 02:40:46PM -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. > > [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. Since Andrew merges cover-letter text into the first commit changelog, some explanation about pgd_list should be a part of that combined changelog. > 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 > -- Sincerely yours, Mike.