On 2023/10/31 12:34, Gregory Price wrote:
On Tue, Oct 31, 2023 at 09:13:44AM +0000, Matthew Wilcox wrote:
On Mon, Oct 30, 2023 at 07:41:23PM -0400, Gregory Price wrote:
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?
Thinking about it some more, really almost all flags are per-folio, not
per-page. The only exceptions are HWPoison and AnonExclusive. So
probably the right way to do this is to make k = folio->flags, and
then just change a few places rather than changing all the places that
test 'k'.
Funny enough that's what i originally did but was confident it was
correct so walked it back. I'll take another crack at it.
Hi Gregory, any update?
I changed stable_page_flags[1] when try to remove page idle wrapper,
Matthew pointed it will conflict with this, I could redo my patch
based on your new version:)
[1]https://lore.kernel.org/linux-mm/20231103072906.2000381-5-wangkefeng.wang@xxxxxxxxxx/
Thanks.
~Gregory
