Messages in this thread | | | Date | Mon, 30 Oct 2023 19:41:23 -0400 | From | Gregory Price <> | Subject | Re: [PATCH v2] kpageflags: respect folio head-page flag placement |
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On Mon, Oct 30, 2023 at 11:22:18PM +0000, Matthew Wilcox wrote: > On Mon, Oct 30, 2023 at 02:00:05PM -0400, Gregory Price wrote: > > kpageflags reads page-flags directly from the page, even when the > > respective flag is only updated on the headpage of a folio. > > > > Update bitchecks to use PAGEFLAG() interfaces to check folio for the > > referenced, dirty, lru, active, and unevictable bits. > > But uptodate, writeback and reclaim (amongst others) are also defined > only on the head page. >
Ah yes i was only looking at the things defined w/ PAGEFLAG defines in page-flags.h. I'll give it full once over can collect them all, my bad.
(also i forgot to update my commit message)
Quick question here since i have your attention: any recommendation on what to do for ONLY_HEAD flags? If the provided page is not the head, should the flag report 0... or whatever the head says?
> > u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate); > > u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback); > > > > u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim); > > > > if (PageSwapCache(page)) > > u |= 1 << KPF_SWAPCACHE; > > u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked); > > > > u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked); >
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