| Message ID | 20231025201237.948993-1-gregory.price@memverge.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | kpageflags: respect folio head-page flag placement | expand |
On Wed, 2023-10-25 at 16:12 -0400, Gregory Price wrote: > > +++ b/fs/proc/page.c > @@ -188,20 +188,31 @@ u64 stable_page_flags(struct page *page) > u |= 1 << KPF_SLAB; > > u |= kpf_copy_bit(k, KPF_ERROR, PG_error); > - u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty); > + > + if (PageDirty(page)) > + u |= 1 << KPF_DIRTY; > + > u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate); > u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback); > > - u |= kpf_copy_bit(k, KPF_LRU, PG_lru); > - u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced); > - u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active); > + if (PageLRU(page)) > + u |= 1 << KPF_LRU; > + > + if (PageReferenced(page)) > + u |= 1 << KPF_REFERENCED; > + > + if (PageActive(page)) > + u |= 1 << KPF_ACTIVE; > + > 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); > Aren't PG_locked, PG_reclaim, and PG_swapbacked also maintained only on the folio/head? Would it make sense to convert those over as well?
On Wed, Oct 25, 2023 at 09:34:15PM -0400, Rik van Riel wrote: > On Wed, 2023-10-25 at 16:12 -0400, Gregory Price wrote: > > u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked); > > > > Aren't PG_locked, PG_reclaim, and PG_swapbacked also maintained only on > the folio/head? > > Would it make sense to convert those over as well? > I see them registered as PF_NO_TAIL in include/linux/page-flags.h Certainly i think there are other updates that are likely needed, but I wasn't quite sure how to handle ONLY_HEAD and NO_TAIL and other conditionals. Should the bits always be 0 or should it refer to HEAD? Just not sure at the moment. ~Gregory
On Wed, Oct 25, 2023 at 04:12:37PM -0400, Gregory Price wrote: > +++ b/fs/proc/page.c > @@ -188,20 +188,31 @@ u64 stable_page_flags(struct page *page) > u |= 1 << KPF_SLAB; > > u |= kpf_copy_bit(k, KPF_ERROR, PG_error); > - u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty); > + > + if (PageDirty(page)) > + u |= 1 << KPF_DIRTY; This is not the way to do it. At the beginning of the function, add: struct folio *folio = page_folio(page); Then use folio_test_XXX istead of PageXXX().
diff --git a/fs/proc/page.c b/fs/proc/page.c index 195b077c0fac..958fb2311108 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -188,20 +188,31 @@ u64 stable_page_flags(struct page *page) u |= 1 << KPF_SLAB; u |= kpf_copy_bit(k, KPF_ERROR, PG_error); - u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty); + + if (PageDirty(page)) + u |= 1 << KPF_DIRTY; + u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate); u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback); - u |= kpf_copy_bit(k, KPF_LRU, PG_lru); - u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced); - u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active); + if (PageLRU(page)) + u |= 1 << KPF_LRU; + + if (PageReferenced(page)) + u |= 1 << KPF_REFERENCED; + + if (PageActive(page)) + u |= 1 << KPF_ACTIVE; + 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_UNEVICTABLE, PG_unevictable); + if (PageUnevictable(page)) + u |= 1 << KPF_UNEVICTABLE; + u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked); #ifdef CONFIG_MEMORY_FAILURE
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. Signed-off-by: Gregory Price <gregory.price@memverge.com> --- fs/proc/page.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-)