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b=umP7ldLW1m+GF85JZqxyEuuOLUb1h9mCQmDzKwZnrLKraN0WoXYL/1EVjHchIjzNi 0EYgu0oTZkxDRRI0C/+454BgBCgu6Wp1xaBiO1psabHDO+DVSl06T+0+KmSX8LKwrR jrvg7uZujTiRZGfAtk5Vp16S0TECDoHWQJdL+vdqSuKODi1li1JujZTSCkme3ilZ03 DJQwIa7PPVlTdeESBd9x+fbDtbMZE3vlRUKmeWFWG7cqIjFvPxdpQysNR3RcA1D55z KBVyUhIHai5T1wt9w9qkpNFzkXFgek1AKaTqZ5Z16Z6W0LmZmj0YT1OK6FXYhjcHrd tMFW218IYwAWQ== Date: Thu, 3 Apr 2025 16:58:27 +0300 From: Mike Rapoport To: Jason Gunthorpe Cc: Pratyush Yadav , Changyuan Lyu , linux-kernel@vger.kernel.org, graf@amazon.com, akpm@linux-foundation.org, luto@kernel.org, anthony.yznaga@oracle.com, arnd@arndb.de, ashish.kalra@amd.com, benh@kernel.crashing.org, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, dwmw2@infradead.org, ebiederm@xmission.com, mingo@redhat.com, jgowans@amazon.com, corbet@lwn.net, krzk@kernel.org, mark.rutland@arm.com, pbonzini@redhat.com, pasha.tatashin@soleen.com, hpa@zytor.com, peterz@infradead.org, robh+dt@kernel.org, robh@kernel.org, saravanak@google.com, skinsburskii@linux.microsoft.com, rostedt@goodmis.org, tglx@linutronix.de, thomas.lendacky@amd.com, usama.arif@bytedance.com, will@kernel.org, devicetree@vger.kernel.org, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org Subject: Re: [PATCH v5 09/16] kexec: enable KHO support for memory preservation Message-ID: References: <20250320015551.2157511-1-changyuanl@google.com> <20250320015551.2157511-10-changyuanl@google.com> <20250403114209.GE342109@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250403114209.GE342109@nvidia.com> X-Rspamd-Queue-Id: 3C3EC180009 X-Stat-Signature: 65pp4k8w7qncce17hmkyeww4oi6fk4zw X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1743688724-676563 X-HE-Meta: U2FsdGVkX1/3jJS/Mp2ZpjH1h7m5ZYSqItYEJD+zpPvMrY4x1uoAyVST8T+VALoqdggfv6moJEF8eAMvxqW5ACjVZ8IIHW4eeZmosygD0FYZnPAAaeMmNiw1Lgg47zKltnhpwSOgcjfbmX9GRJGGIvEFkwSHnVvSIbx4DhklMWT7wPHYEgrW4/lAvHjh6qoaj0fpuQnCTUo0uGHbfnDfZlkKcZx+vSalzYnZfxMtQbhPiYJHQdNEP1tZUlva+tsZgUMLbP0FK21hsbaYPfYPgzlTF0GFxnZEaKhKv+CBoZX4NinnE7uNhg1XPdJbIkCyubp8fcWjnVf8PMVK7cGnuaTO/vYWBNE+Jssp9BO7ai2fK9L3ZhQehaPEy5bqReDWN2YcK3B7dRGTuAfWatJS+XBc2lP6Z/FZuTNXEG5x+mBpQkgHXnnfctHiJtS9C2tyqGkH+wWqVy1/4/CCgCMF0cn9Wpmi5CYouo73AbwLsencBc1YNs5hVQlwrGrvhL7nAGismavBtpkAZJCE6Rp5nfbyY0twcs7dUZQ2pbUBx2UmKNKvhu9/NT/wc2SMiBRiEY0aYChnVJHFHeJchDxlgyLSNGwrvxVlISeM6f6jvo2NCx+Lnq0+RSE0NtLwHEAJxMAKuFSF17v07SL3Suij/UQz00F+8GD+Ty7StQbOpTIQDSreTx/pKNMoTJJugHyAhKWuxzFnjtpK8JJh2TqH8eanu4PUsIOR2vFBwpsOXusAPH7yK+j6qDnMtwIf1BFHT9KqizIJK39H7+EyXlX2c7g52oXEBX3V7TEcXtpn+6V/rseFcCj+p473DHFc4BBF/fbvuaXIXSRs1tDljV9K0kZ+3LUPZbvPUt/UG6bRZCApIzCAx6xt283qMGEjP0a59OfohroeeIVRrJM19rXZr3q58T6sMrlEHUPTPkSnwMSVFKcZvMFqKQVUGsiy/6+CrBaPiW/m7EfNiRrPRSZ MZ4Z80hL 7TbEhkfws90xdukmr4I04Z0+lsLm364ww+UCzlRoDMbs4tK+HA0lbYW2N+YgrHVM2iS36z4S4AC92sVd5ToHjgAdD6CrOGzycuzEhb1WELbxDXy6SaZcOgYTm144z1B9P0dtz7vArPc2dvc+/su8y0cPyH470I7LseyOB8qf3IBF/Rben1eaLE+doOIOLmQLjnhVcQJ7gB/fW1csA2F3E81wmCJ57BsPmvmH9Biz3jW5WspaIeAyXSpeDAozRSaQKNg6N6biZRnk0iTrd8GfVlvCVp/j7N7Eouk3o1pYrSj9JZ4Rn4cD75/qwO7FH218SxibQk6Dx/TqBzTGgjra6Zw0j2jNeAVWAgNmL 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 Thu, Apr 03, 2025 at 08:42:09AM -0300, Jason Gunthorpe wrote: > On Wed, Apr 02, 2025 at 07:16:27PM +0000, Pratyush Yadav wrote: > > > +int kho_preserve_phys(phys_addr_t phys, size_t size) > > > +{ > > > + unsigned long pfn = PHYS_PFN(phys), end_pfn = PHYS_PFN(phys + size); > > > + unsigned int order = ilog2(end_pfn - pfn); > > > > This caught my eye when playing around with the code. It does not put > > any limit on the order, so it can exceed NR_PAGE_ORDERS. Also, when > > initializing the page after KHO, we pass the order directly to > > prep_compound_page() without sanity checking it. The next kernel might > > not support all the orders the current one supports. Perhaps something > > to fix? > > IMHO we should delete the phys functions until we get a user of them The only user of memory tracker in this series uses kho_preserve_phys() > Jason -- Sincerely yours, Mike.