From: Anshuman Khandual <anshuman.khandual@xxxxxxx> Subject: mm/vma: append unlikely() while testing VMA access permissions It is unlikely that an inaccessible VMA without required permission flags will get a page fault. Hence lets just append unlikely() directive to such checks in order to improve performance while also standardizing it across various platforms. Link: http://lkml.kernel.org/r/1582525304-32113-1-git-send-email-anshuman.khandual@xxxxxxx Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Guo Ren <guoren@xxxxxxxxxx> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Cc: Paul Burton <paulburton@xxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/csky/mm/fault.c | 2 +- arch/m68k/mm/fault.c | 2 +- arch/mips/mm/fault.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) --- a/arch/csky/mm/fault.c~mm-vma-append-unlikely-while-testing-vma-access-permissions +++ a/arch/csky/mm/fault.c @@ -141,7 +141,7 @@ good_area: if (!(vma->vm_flags & VM_WRITE)) goto bad_area; } else { - if (!vma_is_accessible(vma)) + if (unlikely(!vma_is_accessible(vma))) goto bad_area; } --- a/arch/m68k/mm/fault.c~mm-vma-append-unlikely-while-testing-vma-access-permissions +++ a/arch/m68k/mm/fault.c @@ -125,7 +125,7 @@ good_area: case 1: /* read, present */ goto acc_err; case 0: /* read, not present */ - if (!vma_is_accessible(vma)) + if (unlikely(!vma_is_accessible(vma))) goto acc_err; } --- a/arch/mips/mm/fault.c~mm-vma-append-unlikely-while-testing-vma-access-permissions +++ a/arch/mips/mm/fault.c @@ -142,7 +142,7 @@ good_area: goto bad_area; } } else { - if (!vma_is_accessible(vma)) + if (unlikely(!vma_is_accessible(vma))) goto bad_area; } } _
