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 <[email protected]>
---
fs/proc/page.c | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
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
--
2.39.1
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?
--
All Rights Reversed.
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().