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Wong" , Christoph Hellwig , David Howells References: From: Vlastimil Babka In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 97F013000105 X-Stat-Signature: qdrkboy5ggjkm8r9m7zr4zgw8fkcjq3e Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b="Ye7n1C/G"; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=HzQWu9YF; spf=pass (imf09.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none X-Rspamd-Server: rspam06 X-HE-Tag: 1632768838-98900 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: On 9/27/2021 8:16 PM, David Hildenbrand wrote: > On 27.09.21 20:12, Matthew Wilcox wrote: >> >> But the thing we're allocating is at least PAGE_SIZE bytes in size. >> Why is "We should avoid storing anything in the free page itself" true? >> > > Immediately comes to mind: > * Free page reporting via virtio-balloon > * CMA on s390x (see arch_free_page()) > * Free page poisoning > * init_on_free I was thinking of debug_pagealloc (unmaps free pages from direct map) but yeah, the list is longer.