The patch titled
Subject: mm/pagewalk: don't trigger test_walk() in walk_page_vma()
has been added to the -mm mm-unstable branch. Its filename is
mm-pagewalk-dont-trigger-test_walk-in-walk_page_vma.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-pagewalk-dont-trigger-test_walk-in-walk_page_vma.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm/pagewalk: don't trigger test_walk() in walk_page_vma()
Date: Fri, 21 Oct 2022 12:11:38 +0200
As Peter points out, the caller passes a single VMA and can just do that
check itself.
And in fact, no existing users rely on test_walk() getting called. So
let's just remove it and make the implementation slightly more efficient.
Link: https://lkml.kernel.org/r/20221021101141.84170-7-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/pagewalk.h | 2 ++
mm/pagewalk.c | 7 -------
2 files changed, 2 insertions(+), 7 deletions(-)
--- a/include/linux/pagewalk.h~mm-pagewalk-dont-trigger-test_walk-in-walk_page_vma
+++ a/include/linux/pagewalk.h
@@ -27,6 +27,8 @@ struct mm_walk;
* "do page table walk over the current vma", returning
* a negative value means "abort current page table walk
* right now" and returning 1 means "skip the current vma"
+ * Note that this callback is not called when the caller
+ * passes in a single VMA as for walk_page_vma().
* @pre_vma: if set, called before starting walk on a non-null vma.
* @post_vma: if set, called after a walk on a non-null vma, provided
* that @pre_vma and the vma walk succeeded.
--- a/mm/pagewalk.c~mm-pagewalk-dont-trigger-test_walk-in-walk_page_vma
+++ a/mm/pagewalk.c
@@ -526,18 +526,11 @@ int walk_page_vma(struct vm_area_struct
.vma = vma,
.private = private,
};
- int err;
if (!walk.mm)
return -EINVAL;
mmap_assert_locked(walk.mm);
-
- err = walk_page_test(vma->vm_start, vma->vm_end, &walk);
- if (err > 0)
- return 0;
- if (err < 0)
- return err;
return __walk_page_range(vma->vm_start, vma->vm_end, &walk);
}
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
selftests-vm-anon_cow-test-cow-handling-of-anonymous-memory.patch
selftests-vm-factor-out-pagemap_is_populated-into-vm_util.patch
selftests-vm-anon_cow-thp-tests.patch
selftests-vm-anon_cow-hugetlb-tests.patch
selftests-vm-anon_cow-add-liburing-test-cases.patch
mm-gup_test-start-stop-read-functionality-for-pin-longterm-test.patch
mm-gup_test-start-stop-read-functionality-for-pin-longterm-test-fix.patch
selftests-vm-anon_cow-add-r-o-longterm-tests-via-gup_test.patch
selftests-vm-add-ksm-unmerge-tests.patch
mm-pagewalk-dont-trigger-test_walk-in-walk_page_vma.patch
selftests-vm-add-test-to-measure-madv_unmergeable-performance.patch
mm-ksm-simplify-break_ksm-to-not-rely-on-vm_fault_write.patch
mm-remove-vm_fault_write.patch
mm-ksm-fix-ksm-cow-breaking-with-userfaultfd-wp-via-fault_flag_unshare.patch
mm-pagewalk-add-walk_page_range_vma.patch
mm-ksm-convert-break_ksm-to-use-walk_page_range_vma.patch
mm-gup-remove-foll_migration.patch
