2017-09-26 07:21:20

by Du, Changbin

[permalink] [raw]
Subject: [PATCH] mm: update comments for struct page.mapping

From: Changbin Du <[email protected]>

The struct page.mapping can NULL or points to one object of type
address_space, anon_vma or KSM private structure.

Signed-off-by: Changbin Du <[email protected]>
---
include/linux/mm_types.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 46f4ecf5..8dd6cb3 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -47,8 +47,8 @@ struct page {
* inode address_space, or NULL.
* If page mapped as anonymous
* memory, low bit is set, and
- * it points to anon_vma object:
- * see PAGE_MAPPING_ANON below.
+ * it points to anon_vma object
+ * or KSM private structure.
*/
void *s_mem; /* slab first object */
atomic_t compound_mapcount; /* first tail page */
--
2.7.4


2017-09-26 23:30:29

by Andrew Morton

[permalink] [raw]
Subject: Re: [PATCH] mm: update comments for struct page.mapping

On Tue, 26 Sep 2017 15:14:17 +0800 [email protected] wrote:

> From: Changbin Du <[email protected]>
>
> The struct page.mapping can NULL or points to one object of type
> address_space, anon_vma or KSM private structure.
>
> ...
>
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -47,8 +47,8 @@ struct page {
> * inode address_space, or NULL.
> * If page mapped as anonymous
> * memory, low bit is set, and
> - * it points to anon_vma object:
> - * see PAGE_MAPPING_ANON below.
> + * it points to anon_vma object
> + * or KSM private structure.
> */
> void *s_mem; /* slab first object */
> atomic_t compound_mapcount; /* first tail page */

Why did you remove the (useful) reference to PAGE_MAPPING_ANON?

2017-09-27 04:06:22

by Du, Changbin

[permalink] [raw]
Subject: Re: [PATCH] mm: update comments for struct page.mapping

On Tue, Sep 26, 2017 at 04:30:27PM -0700, Andrew Morton wrote:
> On Tue, 26 Sep 2017 15:14:17 +0800 [email protected] wrote:
>
> > From: Changbin Du <[email protected]>
> >
> > The struct page.mapping can NULL or points to one object of type
> > address_space, anon_vma or KSM private structure.
> >
> > ...
> >
> > --- a/include/linux/mm_types.h
> > +++ b/include/linux/mm_types.h
> > @@ -47,8 +47,8 @@ struct page {
> > * inode address_space, or NULL.
> > * If page mapped as anonymous
> > * memory, low bit is set, and
> > - * it points to anon_vma object:
> > - * see PAGE_MAPPING_ANON below.
> > + * it points to anon_vma object
> > + * or KSM private structure.
> > */
> > void *s_mem; /* slab first object */
> > atomic_t compound_mapcount; /* first tail page */
>
> Why did you remove the (useful) reference to PAGE_MAPPING_ANON?

There are two flags now, let me add them back. thanks.

--
Thanks,
Changbin Du

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