The patch titled
Subject: mm/vma: append unlikely() while testing VMA access permissions
has been added to the -mm tree. Its filename is
mm-vma-append-unlikely-while-testing-vma-access-permissions.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-vma-append-unlikely-while-testing-vma-access-permissions.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-vma-append-unlikely-while-testing-vma-access-permissions.patch
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------------------------------------------------------
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
@@ -137,7 +137,7 @@ 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;
}
}
_
Patches currently in -mm which might be from anshuman.khandual@xxxxxxx are
mm-debug-add-tests-validating-architecture-page-table-helpers.patch
mm-vma-add-missing-vma-flag-readable-name-for-vm_sync.patch
mm-vma-make-vma_is_accessible-available-for-general-use.patch
mm-vma-replace-all-remaining-open-encodings-with-is_vm_hugetlb_page.patch
mm-vma-replace-all-remaining-open-encodings-with-vma_is_anonymous.patch
mm-vma-append-unlikely-while-testing-vma-access-permissions.patch
