* [PATCH 1/2] mm/mmap: not necessary to check mapping separately
@ 2020-09-13 13:36 Wei Yang
2020-09-13 13:36 ` [PATCH 2/2] mm/mmap: check on file instead of the rb_root_cached of its address_space Wei Yang
0 siblings, 1 reply; 2+ messages in thread
From: Wei Yang @ 2020-09-13 13:36 UTC (permalink / raw)
To: akpm; +Cc: linux-mm, linux-kernel, Wei Yang
*root* with type of struct rb_root_cached is an element of *mapping*
with type of struct address_space. This implies when we have a valid
*root* it must be a part of valid *mapping*.
So we can merge these two checks together to make the code more easy to
read and to save some cpu cycles.
Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
---
mm/mmap.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 1922e6fce9e7..30b155098606 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -895,10 +895,9 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
anon_vma_interval_tree_post_update_vma(next);
anon_vma_unlock_write(anon_vma);
}
- if (mapping)
- i_mmap_unlock_write(mapping);
if (root) {
+ i_mmap_unlock_write(mapping);
uprobe_mmap(vma);
if (adjust_next)
--
2.20.1 (Apple Git-117)
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH 2/2] mm/mmap: check on file instead of the rb_root_cached of its address_space
2020-09-13 13:36 [PATCH 1/2] mm/mmap: not necessary to check mapping separately Wei Yang
@ 2020-09-13 13:36 ` Wei Yang
0 siblings, 0 replies; 2+ messages in thread
From: Wei Yang @ 2020-09-13 13:36 UTC (permalink / raw)
To: akpm; +Cc: linux-mm, linux-kernel, Wei Yang
In __vma_adjust(), we do the check on *root* to decide whether to adjust
the address_space. While it seems to be more meaningful to do the check
on *file* itself. This means we are adjust some data because it is a
file backed vma.
Since we seems to assume the address_space is valid if it is a file
backed vma, let's just replace *root* with *file* here.
Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
---
mm/mmap.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 30b155098606..829897646a9c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -823,7 +823,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
anon_vma_interval_tree_pre_update_vma(next);
}
- if (root) {
+ if (file) {
flush_dcache_mmap_lock(mapping);
vma_interval_tree_remove(vma, root);
if (adjust_next)
@@ -844,7 +844,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
next->vm_pgoff += adjust_next >> PAGE_SHIFT;
}
- if (root) {
+ if (file) {
if (adjust_next)
vma_interval_tree_insert(next, root);
vma_interval_tree_insert(vma, root);
@@ -896,7 +896,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
anon_vma_unlock_write(anon_vma);
}
- if (root) {
+ if (file) {
i_mmap_unlock_write(mapping);
uprobe_mmap(vma);
--
2.20.1 (Apple Git-117)
^ permalink raw reply related [flat|nested] 2+ messages in thread
end of thread, other threads:[~2020-09-13 13:42 UTC | newest]
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