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b=i2jp9z9RcjWmzfTFdI2o0RKgNd5lHBSExqJbfVUWMOO3Hqtg8Ocr3XnH8AjA1rE+8 4JOg3mOL71xU17oyCOVQS5D3nzPIUBu7SzLxVt96CbTNjdvz6IUMxyGYg8frUbyE62 Ms9bTFfLVQPNoq4JbZ9vTDdpJB8/5/biHLFU9tXDLucmpQc5I05+e4jZru9aTEpCn4 DjPR2z/M8mfvz1R/8ekpZy+0etF37VzorR8WK8iwKd0M7AftHzPSuvsJHmIJ0WEj3F 5AqSWH/YNaidOXVDE7d+knZY7phLDP9/OtWpltqn9ir8Xnwjns3+7I71a2hISoySxd SICGxvBZK0p1g== From: Pratyush Yadav To: Mike Rapoport Cc: Pratyush Yadav , Pasha Tatashin , Alexander Graf , kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Bing Jiao Subject: Re: [PATCH] kho: do not reserve empty per-node bootmem areas In-Reply-To: (Mike Rapoport's message of "Thu, 15 Oct 2026 11:36:58 +0300") References: <20261014131547.259138-1-pratyush@kernel.org> Date: Thu, 15 Oct 2026 13:08:59 +0200 Message-ID: <2vxz8q3zi5kk.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Rspamd-Queue-Id: C7543C000A X-Rspam-User: X-Rspamd-Server: rspam12 X-Stat-Signature: aex4433bbkzj9or3g9k9mbtqi7h85jp5 X-HE-Tag: 1792062543-116616 X-HE-Meta: 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 Xk3Ws11g x+8V/eufFAlss9jhfxAvmvtPeZxR3AnrJyVMnfwgehpxBp6iNgK/FXrJU5nbSMUDmhsnO6e8w8YvGVDfTEr6QYEpe9ZKlhw4pmesjsw7f4sfbwihsJ6mDa7CQH3wsf014al+NnUm0IOBYbBnCkuatXwekB2kCh6z095Ie8JW7+w5ba2HCufeFYTEALYPg6Ifu/7KM5r8p4E/C1Whe9JIlN44ECoh357L3lQzzgMgxhJx/vyQ= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Oct 15 2026, Mike Rapoport wrote: > On Wed, Oct 14, 2026 at 03:15:44PM +0200, Pratyush Yadav wrote: >> From: "Pratyush Yadav (Google)" >> >> Some nodes do not allocate any early boot memory. An example is >> hotpluggable nodes with movable_node enabled. So the scratch size for > > Let's use the new naming please ^ ;-) Argh, muscle memory... > > I'll fix it up when applying. Thanks! > >> them ends up being zero. Zero size allocations normally don't play well >> with memblock. Memblock returns an address, but then doesn't actually >> reserve anything. This address ends up being recorded in kho_bootmem >> with a size of 0. In case of hotpluggable nodes with movable_nodes, the >> allocation on the node actually fails because memblock refuses to >> allocate there, and so KHO fails to initialize. >> >> Skip bootmem reservation for such nodes entirely. >> >> To keep the code more robust, avoid overloading kho_bootmem_cnt. use >> max_nr_bootmem to store the size of kho_bootmem array. This ensures that >> the location of kho_bootmem_cnt assignment does not affect the cleanup >> paths. [...] -- Regards, Pratyush Yadav