On 09/08/2024 09:58, David Hildenbrand wrote: > On 09.08.24 10:42, David Hildenbrand wrote: >>>> Not sure I fully understand why David prefers to do the unaccounting at >>>> free-time though? It feels unbalanced to me to increment when first mapped but >>>> decrement when freed. Surely its safer to either use alloc/free or use first >>>> map/last map? >>>> >>>> If using alloc/free isn't there a THP constructor/destructor that prepares the >>>> deferred list? (My memory may be failing me). Could we use that? >>> >>> Additionally, if we wanted to extend (eventually) to track the number of shmem >>> and file mthps in additional counters, could we also account using similar folio >>> free-time hooks? If not, it might be an argument to account in rmap_unmap to be >>> consistent for all? >> >> Again, see NR_FILE_THPS handling. No rmap over-complication please. > > ... not to mention that it is non-sensical to only count pageache folios that > are mapped to user space ;) Yes, good point. I'll get back in my box. :)
