On 2/2/26 12:36, Jordan Niethe wrote: > A future change will remove device private pages from the physical > address space. This will mean that device private pages no longer have > normal pfns and must be handled separately. > > Add a new flag PAGE_SNAPSHOT_DEVICE_PRIVATE to track when the pfn of a > page snapshot is a device private page. > > Signed-off-by: Jordan Niethe <[email protected]> > Signed-off-by: Alistair Popple <[email protected]> > --- > v1: > - No change > v2: > - No change > v3: > - No change > v4: > - Move logical continuation to previous line > --- > fs/proc/page.c | 6 ++++-- > include/linux/mm.h | 7 ++++--- > mm/util.c | 3 +++ > 3 files changed, 11 insertions(+), 5 deletions(-) > > diff --git a/fs/proc/page.c b/fs/proc/page.c > index f9b2c2c906cd..bc14f7ebc369 100644 > --- a/fs/proc/page.c > +++ b/fs/proc/page.c > @@ -191,10 +191,12 @@ u64 stable_page_flags(const struct page *page) > folio_test_large_rmappable(folio)) { > /* Note: we indicate any THPs here, not just PMD-sized ones */ > u |= 1 << KPF_THP; > - } else if (is_huge_zero_pfn(ps.pfn)) { > + } else if (!(ps.flags & PAGE_SNAPSHOT_DEVICE_PRIVATE) && > + is_huge_zero_pfn(ps.pfn)) { > u |= 1 << KPF_ZERO_PAGE; > u |= 1 << KPF_THP; > - } else if (is_zero_pfn(ps.pfn)) { > + } else if (!(ps.flags & PAGE_SNAPSHOT_DEVICE_PRIVATE) && > + is_zero_pfn(ps.pfn)) { > u |= 1 << KPF_ZERO_PAGE; > } > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index f0d5be9dc736..a52979536a5e 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -4627,9 +4627,10 @@ static inline bool page_pool_page_is_pp(const struct > page *page) > } > #endif > > -#define PAGE_SNAPSHOT_FAITHFUL (1 << 0) > -#define PAGE_SNAPSHOT_PG_BUDDY (1 << 1) > -#define PAGE_SNAPSHOT_PG_IDLE (1 << 2) > +#define PAGE_SNAPSHOT_FAITHFUL (1 << 0) > +#define PAGE_SNAPSHOT_PG_BUDDY (1 << 1) > +#define PAGE_SNAPSHOT_PG_IDLE (1 << 2) > +#define PAGE_SNAPSHOT_DEVICE_PRIVATE (1 << 3) > > struct page_snapshot { > struct folio folio_snapshot; > diff --git a/mm/util.c b/mm/util.c > index 97cae40c0209..65e3f1a97d76 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -1218,6 +1218,9 @@ static void set_ps_flags(struct page_snapshot *ps, > const struct folio *folio, > > if (folio_test_idle(folio)) > ps->flags |= PAGE_SNAPSHOT_PG_IDLE; > + > + if (is_device_private_page(page)) > + ps->flags |= PAGE_SNAPSHOT_DEVICE_PRIVATE;
stable_page_flags() has access to the page and can simply test that instead? -- Cheers, David
