Add a bit to vm_flags to indicate a vma shares PTEs with others. Add a function to determine if a vma shares PTE by checking this flag. This is to be used to find the shared page table entries on page fault for vmas sharing PTE. Signed-off-by: Khalid Aziz <khalid.aziz@xxxxxxxxxx> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> --- include/linux/mm.h | 8 ++++++++ include/trace/events/mmflags.h | 3 ++- mm/internal.h | 5 +++++ 3 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index bc8f326be0ce..0ddc3057f73b 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -310,11 +310,13 @@ extern unsigned int kobjsize(const void *objp); #define VM_HIGH_ARCH_BIT_2 34 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_3 35 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_BIT_4 36 /* bit only usable on 64-bit architectures */ +#define VM_HIGH_ARCH_BIT_5 37 /* bit only usable on 64-bit architectures */ #define VM_HIGH_ARCH_0 BIT(VM_HIGH_ARCH_BIT_0) #define VM_HIGH_ARCH_1 BIT(VM_HIGH_ARCH_BIT_1) #define VM_HIGH_ARCH_2 BIT(VM_HIGH_ARCH_BIT_2) #define VM_HIGH_ARCH_3 BIT(VM_HIGH_ARCH_BIT_3) #define VM_HIGH_ARCH_4 BIT(VM_HIGH_ARCH_BIT_4) +#define VM_HIGH_ARCH_5 BIT(VM_HIGH_ARCH_BIT_5) #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */ #ifdef CONFIG_ARCH_HAS_PKEYS @@ -356,6 +358,12 @@ extern unsigned int kobjsize(const void *objp); # define VM_MTE_ALLOWED VM_NONE #endif +#ifdef CONFIG_ARCH_USES_HIGH_VMA_FLAGS +#define VM_SHARED_PT VM_HIGH_ARCH_5 +#else +#define VM_SHARED_PT 0 +#endif + #ifndef VM_GROWSUP # define VM_GROWSUP VM_NONE #endif diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h index e87cb2b80ed3..30e56cbac99b 100644 --- a/include/trace/events/mmflags.h +++ b/include/trace/events/mmflags.h @@ -194,7 +194,8 @@ IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY, "softdirty" ) \ {VM_MIXEDMAP, "mixedmap" }, \ {VM_HUGEPAGE, "hugepage" }, \ {VM_NOHUGEPAGE, "nohugepage" }, \ - {VM_MERGEABLE, "mergeable" } \ + {VM_MERGEABLE, "mergeable" }, \ + {VM_SHARED_PT, "sharedpt" } \ #define show_vma_flags(flags) \ (flags) ? __print_flags(flags, "|", \ diff --git a/mm/internal.h b/mm/internal.h index c0f8fbe0445b..3f2790aea918 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -861,4 +861,9 @@ struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags); DECLARE_PER_CPU(struct per_cpu_nodestat, boot_nodestats); +static inline bool vma_is_shared(const struct vm_area_struct *vma) +{ + return vma->vm_flags & VM_SHARED_PT; +} + #endif /* __MM_INTERNAL_H */ -- 2.32.0