On 2024/1/23 08:18, Liam R. Howlett wrote:
* Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> [240122 18:40]:
On Mon, 22 Jan 2024 17:00:31 -0500 "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> wrote:
* Yajun Deng <yajun.deng@xxxxxxxxx> [240110 21:15]:
There is a lot of code needs to set the range of vma, introduce
vma_range_init() to initialize the range of vma.
Signed-off-by: Yajun Deng <yajun.deng@xxxxxxxxx>
---
include/linux/mm.h | 9 +++++++++
mm/mmap.c | 29 +++++++----------------------
2 files changed, 16 insertions(+), 22 deletions(-)
This isn't a whole lot of code, are there others? We're losing code
clarity in favour of saving 6 lines?
Oh. I thought it was a nice cleanup which made things more clear.
I'm not totally against it; that's why I suggested the changes below. I
think a name change would go a long way for clarity. It's not as much as
I though it would be though.
diff --git a/include/linux/mm.h b/include/linux/mm.h
index f5a97dec5169..abb4534be3cc 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3516,6 +3516,15 @@ static inline bool range_in_vma(struct vm_area_struct *vma,
return (vma && vma->vm_start <= start && end <= vma->vm_end);
}
+static inline void vma_range_init(struct vm_area_struct *vma,
Any reason this can't be in mm/internal.h ?
That would be good.
One other thing, do we trust this to be inlined correctly by the
compiler or should this be __always_inline? I'd expect it to be okay as
it is, but I've been proven wrong in a perf trace before..
Okay, I would take __always_inline and put it in mm/internal.h in v2.
vma_range_set(), vma_set_range(), or just vma_range() might be a better
name? My thinking is that some of these are actually modifying the vma
and not just initializing it, right?
I'd vote for vma_set_range().
Using vma_set_range() leaves vma_range() or vma_size(), which could be
added for the calculations of vma->vm_end - vma->vm_start. Davidlohr
suggested such a beast a few years ago, but that one would need to live
in the include/linux/mm.h as it occurs a lot more.
$ git grep "vma->vm_end - vma->vm_start" | wc -l
198
.. for just those named vma.
