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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Vishal Moola , Ingo Molnar , Lu Baolu , Jason Gunthorpe , Steven Rostedt , x86@kernel.org, linux-mm@kvack.org, regressions@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260924092307.22813-1-mikhail.v.gavrilov@gmail.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; keydata= xsFNBE6HMP0BEADIMA3XYkQfF3dwHlj58Yjsc4E5y5G67cfbt8dvaUq2fx1lR0K9h1bOI6fC oAiUXvGAOxPDsB/P6UEOISPpLl5IuYsSwAeZGkdQ5g6m1xq7AlDJQZddhr/1DC/nMVa/2BoY 2UnKuZuSBu7lgOE193+7Uks3416N2hTkyKUSNkduyoZ9F5twiBhxPJwPtn/wnch6n5RsoXsb ygOEDxLEsSk/7eyFycjE+btUtAWZtx+HseyaGfqkZK0Z9bT1lsaHecmB203xShwCPT49Blxz VOab8668QpaEOdLGhtvrVYVK7x4skyT3nGWcgDCl5/Vp3TWA4K+IofwvXzX2ON/Mj7aQwf5W iC+3nWC7q0uxKwwsddJ0Nu+dpA/UORQWa1NiAftEoSpk5+nUUi0WE+5DRm0H+TXKBWMGNCFn c6+EKg5zQaa8KqymHcOrSXNPmzJuXvDQ8uj2J8XuzCZfK4uy1+YdIr0yyEMI7mdh4KX50LO1 pmowEqDh7dLShTOif/7UtQYrzYq9cPnjU2ZW4qd5Qz2joSGTG9eCXLz5PRe5SqHxv6ljk8mb ApNuY7bOXO/A7T2j5RwXIlcmssqIjBcxsRRoIbpCwWWGjkYjzYCjgsNFL6rt4OL11OUF37wL QcTl7fbCGv53KfKPdYD5hcbguLKi/aCccJK18ZwNjFhqr4MliQARAQABzUVEYXZpZCBDaHJp c3RvcGhlciBIYW5zZW4gKEludGVsIFdvcmsgQWRkcmVzcykgPGRhdmUuaGFuc2VuQGludGVs LmNvbT7CwXgEEwECACIFAlQ+9J0CGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEGg1 lTBwyZKwLZUP/0dnbhDc229u2u6WtK1s1cSd9WsflGXGagkR6liJ4um3XCfYWDHvIdkHYC1t MNcVHFBwmQkawxsYvgO8kXT3SaFZe4ISfB4K4CL2qp4JO+nJdlFUbZI7cz/Td9z8nHjMcWYF IQuTsWOLs/LBMTs+ANumibtw6UkiGVD3dfHJAOPNApjVr+M0P/lVmTeP8w0uVcd2syiaU5jB aht9CYATn+ytFGWZnBEEQFnqcibIaOrmoBLu2b3fKJEd8Jp7NHDSIdrvrMjYynmc6sZKUqH2 I1qOevaa8jUg7wlLJAWGfIqnu85kkqrVOkbNbk4TPub7VOqA6qG5GCNEIv6ZY7HLYd/vAkVY E8Plzq/NwLAuOWxvGrOl7OPuwVeR4hBDfcrNb990MFPpjGgACzAZyjdmYoMu8j3/MAEW4P0z F5+EYJAOZ+z212y1pchNNauehORXgjrNKsZwxwKpPY9qb84E3O9KYpwfATsqOoQ6tTgr+1BR CCwP712H+E9U5HJ0iibN/CDZFVPL1bRerHziuwuQuvE0qWg0+0SChFe9oq0KAwEkVs6ZDMB2 P16MieEEQ6StQRlvy2YBv80L1TMl3T90Bo1UUn6ARXEpcbFE0/aORH/jEXcRteb+vuik5UGY 5TsyLYdPur3TXm7XDBdmmyQVJjnJKYK9AQxj95KlXLVO38lczsFNBFRjzmoBEACyAxbvUEhd GDGNg0JhDdezyTdN8C9BFsdxyTLnSH31NRiyp1QtuxvcqGZjb2trDVuCbIzRrgMZLVgo3upr MIOx1CXEgmn23Zhh0EpdVHM8IKx9Z7V0r+rrpRWFE8/wQZngKYVi49PGoZj50ZEifEJ5qn/H Nsp2+Y+bTUjDdgWMATg9DiFMyv8fvoqgNsNyrrZTnSgoLzdxr89FGHZCoSoAK8gfgFHuO54B lI8QOfPDG9WDPJ66HCodjTlBEr/Cwq6GruxS5i2Y33YVqxvFvDa1tUtl+iJ2SWKS9kCai2DR 3BwVONJEYSDQaven/EHMlY1q8Vln3lGPsS11vSUK3QcNJjmrgYxH5KsVsf6PNRj9mp8Z1kIG qjRx08+nnyStWC0gZH6NrYyS9rpqH3j+hA2WcI7De51L4Rv9pFwzp161mvtc6eC/GxaiUGuH BNAVP0PY0fqvIC68p3rLIAW3f97uv4ce2RSQ7LbsPsimOeCo/5vgS6YQsj83E+AipPr09Caj 0hloj+hFoqiticNpmsxdWKoOsV0PftcQvBCCYuhKbZV9s5hjt9qn8CE86A5g5KqDf83Fxqm/ vXKgHNFHE5zgXGZnrmaf6resQzbvJHO0Fb0CcIohzrpPaL3YepcLDoCCgElGMGQjdCcSQ+Ci FCRl0Bvyj1YZUql+ZkptgGjikQARAQABwsFfBBgBAgAJBQJUY85qAhsMAAoJEGg1lTBwyZKw l4IQAIKHs/9po4spZDFyfDjunimEhVHqlUt7ggR1Hsl/tkvTSze8pI1P6dGp2XW6AnH1iayn yRcoyT0ZJ+Zmm4xAH1zqKjWplzqdb/dO28qk0bPso8+1oPO8oDhLm1+tY+cOvufXkBTm+whm +AyNTjaCRt6aSMnA/QHVGSJ8grrTJCoACVNhnXg/R0g90g8iV8Q+IBZyDkG0tBThaDdw1B2l asInUTeb9EiVfL/Zjdg5VWiF9LL7iS+9hTeVdR09vThQ/DhVbCNxVk+DtyBHsjOKifrVsYep WpRGBIAu3bK8eXtyvrw1igWTNs2wazJ71+0z2jMzbclKAyRHKU9JdN6Hkkgr2nPb561yjcB8 sIq1pFXKyO+nKy6SZYxOvHxCcjk2fkw6UmPU6/j/nQlj2lfOAgNVKuDLothIxzi8pndB8Jju KktE5HJqUUMXePkAYIxEQ0mMc8Po7tuXdejgPMwgP7x65xtfEqI0RuzbUioFltsp1jUaRwQZ MTsCeQDdjpgHsj+P2ZDeEKCbma4m6Ez/YWs4+zDm1X8uZDkZcfQlD9NldbKDJEXLIjYWo1PH hYepSffIWPyvBMBTW2W5FRjJ4vLRrJSUoEfJuPQ3vW9Y73foyo/qFoURHO48AinGPZ7PC7TF vUaNOTjKedrqHkaOcqB185ahG2had0xnFsDPlx5y In-Reply-To: <20260924092307.22813-1-mikhail.v.gavrilov@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 9xxybqeiieeq8y6hzg88jz9o9fg9ambm X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: D477BC0005 X-HE-Tag: 1790272630-578331 X-HE-Meta: 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 9ljhSEQG 6kJn3keVAPAgeUB1eteweiwfXfV/1N+kFPGEBy7Nu9CFd9H8zY0VJKlh7Z7rAytW3CQZVIemKZb2eoaUvNljHX0tQNW8N3mzgXDXYOQJhxHOw86pGUE5bCJVRHJe/j/HvP9R/BZiAZdyeMFvm0H4wABDyFZmfoJUJIPxAnItxbeBbqD/AjNTu8m11vq08ji9kIqglcxCNfA3KlX8CZjenTT1wuYx5HR253wNAquoBl/V8fOujxpfqsJX1aGKuUwJtdjyVmHSwLiQczEVA8wL9I8ac7g== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/24/26 02:23, Mikhail Gavrilov wrote: > Keep putting the table on the list, but don't schedule the work while > the system is still booting. The next kernel page table freed after > boot schedules it, and the work then frees the early table too, after > the same IOMMU flush as any other. If no kernel page table is freed > after boot, the ones freed during boot stay on the list. There seems to be an awful lot of chit chat about how and when the boot-time tables might get freed. Like: > So on this box the early tables wait until the first module is > loaded, and no separate drain is needed. Wouldn't a "separate drain" be all of 5 lines of code? /* Take care of deferred freeing from boot: */ static __init int free_boot_kernel_pgtables(void) { schedule_work(&kernel_pgtable_work.work); } late_initcall(free_boot_kernel_pgtables); Then we don't have to reason about it at all.