The patch titled
Subject: mm/mmap.c: rb_parent is not necessary in __vma_link_list()
has been added to the -mm tree. Its filename is
mm-mmapc-rb_parent-is-not-necessary-in-__vma_link_list.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-mmapc-rb_parent-is-not-necessary-in-__vma_link_list.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-mmapc-rb_parent-is-not-necessary-in-__vma_link_list.patch
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------------------------------------------------------
From: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Subject: mm/mmap.c: rb_parent is not necessary in __vma_link_list()
Now we use rb_parent to get next, while this is not necessary.
When prev is NULL, this means vma should be the first element in the list.
Then next should be current first one (mm->mmap), no matter whether we
have parent or not.
After removing it, the code shows the beauty of symmetry.
Link: http://lkml.kernel.org/r/20190813032656.16625-1-richardw.yang@xxxxxxxxxxxxxxx
Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/internal.h | 2 +-
mm/mmap.c | 2 +-
mm/nommu.c | 2 +-
mm/util.c | 8 ++------
4 files changed, 5 insertions(+), 9 deletions(-)
--- a/mm/internal.h~mm-mmapc-rb_parent-is-not-necessary-in-__vma_link_list
+++ a/mm/internal.h
@@ -290,7 +290,7 @@ static inline bool is_data_mapping(vm_fl
/* mm/util.c */
void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
- struct vm_area_struct *prev, struct rb_node *rb_parent);
+ struct vm_area_struct *prev);
void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma);
#ifdef CONFIG_MMU
--- a/mm/mmap.c~mm-mmapc-rb_parent-is-not-necessary-in-__vma_link_list
+++ a/mm/mmap.c
@@ -641,7 +641,7 @@ __vma_link(struct mm_struct *mm, struct
struct vm_area_struct *prev, struct rb_node **rb_link,
struct rb_node *rb_parent)
{
- __vma_link_list(mm, vma, prev, rb_parent);
+ __vma_link_list(mm, vma, prev);
__vma_link_rb(mm, vma, rb_link, rb_parent);
}
--- a/mm/nommu.c~mm-mmapc-rb_parent-is-not-necessary-in-__vma_link_list
+++ a/mm/nommu.c
@@ -637,7 +637,7 @@ static void add_vma_to_mm(struct mm_stru
if (rb_prev)
prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
- __vma_link_list(mm, vma, prev, parent);
+ __vma_link_list(mm, vma, prev);
}
/*
--- a/mm/util.c~mm-mmapc-rb_parent-is-not-necessary-in-__vma_link_list
+++ a/mm/util.c
@@ -271,7 +271,7 @@ void *memdup_user_nul(const void __user
EXPORT_SYMBOL(memdup_user_nul);
void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
- struct vm_area_struct *prev, struct rb_node *rb_parent)
+ struct vm_area_struct *prev)
{
struct vm_area_struct *next;
@@ -280,12 +280,8 @@ void __vma_link_list(struct mm_struct *m
next = prev->vm_next;
prev->vm_next = vma;
} else {
+ next = mm->mmap;
mm->mmap = vma;
- if (rb_parent)
- next = rb_entry(rb_parent,
- struct vm_area_struct, vm_rb);
- else
- next = NULL;
}
vma->vm_next = next;
if (next)
_
Patches currently in -mm which might be from richardw.yang@xxxxxxxxxxxxxxx are
mm-mmapc-remove-a-never-trigger-warning-in-__vma_adjust.patch
mm-rmapc-reuse-mergeable-anon_vma-as-parent-when-fork.patch
mm-mmapc-prev-could-be-retrieved-from-vma-vm_prev.patch
mm-mmapc-__vma_unlink_prev-is-not-necessary-now.patch
mm-mmapc-extract-__vma_unlink_list-as-counter-part-for-__vma_link_list.patch
mm-mmapc-rb_parent-is-not-necessary-in-__vma_link_list.patch
hugetlb-remove-unused-hstate-in-hugetlb_fault_mutex_hash.patch
userfaultfd-use-vma_pagesize-for-all-huge-page-size-calculation.patch
userfaultfd-remove-unnecessary-warn_on-in-__mcopy_atomic_hugetlb.patch
userfaultfd-wrap-the-common-dst_vma-check-into-an-inlined-function.patch
mm-fix-typo-in-the-comment-when-calling-function-__setpageuptodate.patch
