2023-07-12 14:30:02

by Kefeng Wang

Subject: [PATCH 2/5] mm: use vma_is_stack() and vma_is_heap()

Use the helpers to simplify code.

Signed-off-by: Kefeng Wang <[email protected]>
---
fs/proc/task_mmu.c | 24 ++++--------------------
fs/proc/task_nommu.c | 15 +--------------
2 files changed, 5 insertions(+), 34 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index cfab855fe7e9..05e9893552ce 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -236,21 +236,6 @@ static int do_maps_open(struct inode *inode, struct file *file,
sizeof(struct proc_maps_private));
}

-/*
- * Indicate if the VMA is a stack for the given task; for
- * /proc/PID/maps that is the stack of the main task.
- */
-static int is_stack(struct vm_area_struct *vma)
-{
- /*
- * We make no effort to guess what a given thread considers to be
- * its "stack". It's not even well-defined for programs written
- * languages like Go.
- */
- return vma->vm_start <= vma->vm_mm->start_stack &&
- vma->vm_end >= vma->vm_mm->start_stack;
-}
-
static void show_vma_header_prefix(struct seq_file *m,
unsigned long start, unsigned long end,
vm_flags_t flags, unsigned long long pgoff,
@@ -327,13 +312,12 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
goto done;
}

- if (vma->vm_start <= mm->brk &&
- vma->vm_end >= mm->start_brk) {
+ if (vma_is_heap(vma)) {
name = "[heap]";
goto done;
}

- if (is_stack(vma)) {
+ if (vma_is_stack(vma)) {
name = "[stack]";
goto done;
}
@@ -1974,9 +1958,9 @@ static int show_numa_map(struct seq_file *m, void *v)
if (file) {
seq_puts(m, " file=");
seq_file_path(m, file, "\n\t= ");
- } else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
+ } else if (vma_is_heap(vma)) {
seq_puts(m, " heap");
- } else if (is_stack(vma)) {
+ } else if (vma_is_stack(vma)) {
seq_puts(m, " stack");
}

diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 2c8b62265981..f42c84172b9e 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -121,19 +121,6 @@ unsigned long task_statm(struct mm_struct *mm,
return size;
}

-static int is_stack(struct vm_area_struct *vma)
-{
- struct mm_struct *mm = vma->vm_mm;
-
- /*
- * We make no effort to guess what a given thread considers to be
- * its "stack". It's not even well-defined for programs written
- * languages like Go.
- */
- return vma->vm_start <= mm->start_stack &&
- vma->vm_end >= mm->start_stack;
-}
-
/*
* display a single VMA to a sequenced file
*/
@@ -171,7 +158,7 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
if (file) {
seq_pad(m, ' ');
seq_file_path(m, file, "");
- } else if (mm && is_stack(vma)) {
+ } else if (mm && vma_is_stack(vma)) {
seq_pad(m, ' ');
seq_puts(m, "[stack]");
}
--
2.41.0

2023-07-17 10:36:43

by David Hildenbrand

Subject: Re: [PATCH 2/5] mm: use vma_is_stack() and vma_is_heap()

On 12.07.23 16:38, Kefeng Wang wrote:
> Use the helpers to simplify code.
>
> Signed-off-by: Kefeng Wang <[email protected]>
> ---
> fs/proc/task_mmu.c | 24 ++++--------------------
> fs/proc/task_nommu.c | 15 +--------------
> 2 files changed, 5 insertions(+), 34 deletions(-)
>

Please squash patch #1 and this patch and call it something like

"mm: factor out VMA stack and heap checks"

And then, maybe also keep the comments in these functions, they sound
reasonable to have.

--
Cheers,

David / dhildenb

2023-07-18 01:45:58

by Kefeng Wang

Subject: Re: [PATCH 2/5] mm: use vma_is_stack() and vma_is_heap()

On 2023/7/17 18:25, David Hildenbrand wrote:
> On 12.07.23 16:38, Kefeng Wang wrote:
>> Use the helpers to simplify code.
>>
>> Signed-off-by: Kefeng Wang <[email protected]>
>> ---
>>   fs/proc/task_mmu.c   | 24 ++++--------------------
>>   fs/proc/task_nommu.c | 15 +--------------
>>   2 files changed, 5 insertions(+), 34 deletions(-)
>>
>
> Please squash patch #1 and this patch and call it something like
>
> "mm: factor out VMA stack and heap checks"
>
> And then, maybe also keep the comments in these functions, they sound
> reasonable to have.

Thanks, will re-post them.
>