[...] > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > index 2aa986a5cd1b..c73ad77fa33d 100644 > --- a/include/linux/huge_mm.h > +++ b/include/linux/huge_mm.h > @@ -72,14 +72,20 @@ extern struct kobj_attribute shmem_enabled_attr; > #define THP_ORDERS_ALL_ANON ((BIT(PMD_ORDER + 1) - 1) & ~(BIT(0) | BIT(1))) > > /* > - * Mask of all large folio orders supported for file THP. > + * Mask of all large folio orders supported for file THP. Folios in a DAX > + * file is never split and the MAX_PAGECACHE_ORDER limit does not apply to > + * it. > */ > -#define THP_ORDERS_ALL_FILE (BIT(PMD_ORDER) | BIT(PUD_ORDER)) > +#define THP_ORDERS_ALL_FILE_DAX \ > + (BIT(PMD_ORDER) | BIT(PUD_ORDER)) Appologies if this was already discussed, but if changing _FILE_DEFAULT to advertise all orders 1-MAX_PAGECACHE_ORDER, shouldn't we also change _FILE_DAX to advertise all orders 1-PUD_ORDER ? Or is DAX literally limited to PTE/PMD/PUD? > +#define THP_ORDERS_ALL_FILE_DEFAULT \ > + ((BIT(MAX_PAGECACHE_ORDER + 1) - 1) & ~BIT(0)) > > /* > * Mask of all large folio orders supported for THP. > */ > -#define THP_ORDERS_ALL (THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE) > +#define THP_ORDERS_ALL \ > + (THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE_DAX | THP_ORDERS_ALL_FILE_DEFAULT) > > #define TVA_SMAPS (1 << 0) /* Will be used for procfs */ > #define TVA_IN_PF (1 << 1) /* Page fault handler */ > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 2120f7478e55..4690f33afaa6 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -88,9 +88,17 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma, > bool smaps = tva_flags & TVA_SMAPS; > bool in_pf = tva_flags & TVA_IN_PF; > bool enforce_sysfs = tva_flags & TVA_ENFORCE_SYSFS; > + unsigned long supported_orders; > + > /* Check the intersection of requested and supported orders. */ > - orders &= vma_is_anonymous(vma) ? > - THP_ORDERS_ALL_ANON : THP_ORDERS_ALL_FILE; > + if (vma_is_anonymous(vma)) > + supported_orders = THP_ORDERS_ALL_ANON; > + else if (vma_is_dax(vma)) > + supported_orders = THP_ORDERS_ALL_FILE_DAX; > + else > + supported_orders = THP_ORDERS_ALL_FILE_DEFAULT; > + > + orders &= supported_orders; > if (!orders) > return 0; >
