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charset="UTF-8" X-Rspamd-Queue-Id: 3C3A7100015 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: by6tddqwgcskmxqibjg6y3t3zst59tm3 X-HE-Tag: 1689889149-172497 X-HE-Meta: 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 ag3MgLrG HfT+S3B+/bDlBv0DPpXNk1/iwdKYKZoj6CuHQpraQjTh2rSXK6mjt1pMQUWZVaxBIEQJXaODPMF1FUDV/PIY+yc6CTllE7VVgGsbq0/hn2rgNPBjfVYuddrG9Nvwydke7Tyb5tcDiBkceh/HoMR2873eVKdPpZT/ANh44QHayePXTJ1BwIIf4sIzqRUAKRGsdNzCgc0knlTkZTmD262R4QoQj5IgaHz4O5KUdjDqw7A1TNwhIjp6D4V9lm2BIpb185e+zcJCvdiP2GhSLwlYKi2gEzkl+nRq6fZ5VJFxPCMxlDbc= 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: > > > > > It seems to me though the sizeof(zsdesc) is actually 56 bytes (on > > > > 64-bit), so sizeof(zsdesc) + sizeof(memdesc) would be equal to the > > > > current size of struct page. If that's true, then there is no loss, > > > > > > Yeah, zsdesc would be 56 bytes on 64 bit CPUs as memcg_data field is > > > not used in zsmalloc. > > > More fields in the current struct page might not be needed in the > > > future, although it's hard to say at the moment. > > > but it's not a loss. > > > > Is page->memcg_data something that we can drop? Aren't there code > > paths that will check page->memcg_data even for kernel pages (e.g. > > __folio_put() -> __folio_put_small() -> mem_cgroup_uncharge() ) ? > > zsmalloc pages are not accounted for via __GFP_ACCOUNT, Yeah, but the code in the free path above will check page->memcg_data nonetheless to check if it is charged. I think to drop memcg_data we need to enlighten the code that some pages do not even have memcg_data at all, no? > and IIUC the current implementation of zswap memcg charging does not > use memcg_data > either - so I think it can be dropped. My question is more about the generic mm code expecting to see page->memcg_data in every page, even if it is not actually used (zero). > > I think we don't want to increase memdesc to 16 bytes by adding memcg_data. > It should be in use-case specific descriptors if it can be charged to memcg? >