[PATCH] proc: export page young and skip_kasan_poison flag via kpageflags

[PATCH] proc: export page young and skip_kasan_poison flag via kpageflags

[Xin Hao]

Now the young and skip_kasan_poison flag are supported in
show_page_flags(), but we can not get them from /proc/kpageflags,
So there add them.

Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
---
 fs/proc/page.c                    | 6 ++++++
 include/linux/kernel-page-flags.h | 2 ++
 tools/vm/page-types.c             | 4 ++++
 3 files changed, 12 insertions(+)

diff --git a/fs/proc/page.c b/fs/proc/page.c
index 9f1077d94cde..fd28e1d92c5c 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -220,6 +220,12 @@ u64 stable_page_flags(struct page *page)
 #ifdef CONFIG_64BIT
 	u |= kpf_copy_bit(k, KPF_ARCH_2,	PG_arch_2);
 #endif
+#if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
+	u |= kpf_copy_bit(k, KPF_YOUNG, PG_young);
+#endif
+#ifdef CONFIG_KASAN_HW_TAGS
+	u |= kpf_copy_bit(k, KPF_SKIP_KASAN_POSION, PG_skip_kasan_poison);
+#endif
 
 	return u;
 };
diff --git a/include/linux/kernel-page-flags.h b/include/linux/kernel-page-flags.h
index eee1877a354e..30aaa0ee4ca9 100644
--- a/include/linux/kernel-page-flags.h
+++ b/include/linux/kernel-page-flags.h
@@ -18,5 +18,7 @@
 #define KPF_UNCACHED		39
 #define KPF_SOFTDIRTY		40
 #define KPF_ARCH_2		41
+#define KPF_YOUNG		42
+#define KPF_SKIP_KASAN_POSION	43
 
 #endif /* LINUX_KERNEL_PAGE_FLAGS_H */
diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c
index b1ed76d9a979..2671b746d11f 100644
--- a/tools/vm/page-types.c
+++ b/tools/vm/page-types.c
@@ -79,6 +79,8 @@
 #define KPF_UNCACHED		39
 #define KPF_SOFTDIRTY		40
 #define KPF_ARCH_2		41
+#define KPF_YOUNG		42
+#define KPF_SKIP_KASAN_POSION	43
 
 /* [48-] take some arbitrary free slots for expanding overloaded flags
  * not part of kernel API
@@ -137,6 +139,8 @@ static const char * const page_flag_names[] = {
 	[KPF_UNCACHED]		= "c:uncached",
 	[KPF_SOFTDIRTY]		= "f:softdirty",
 	[KPF_ARCH_2]		= "H:arch_2",
+	[KPF_YOUNG]		= "y:young",
+	[KPF_SKIP_KASAN_POSION]	= "K:skip_kasan_posion",
 
 	[KPF_READAHEAD]		= "I:readahead",
 	[KPF_SLOB_FREE]		= "P:slob_free",
-- 
2.31.0

Re: [PATCH] proc: export page young and skip_kasan_poison flag via kpageflags

[Andrew Morton]

On Thu,  2 Jun 2022 23:43:02 +0800 Xin Hao <xhao@linux.alibaba.com> wrote:

> Now the young and skip_kasan_poison flag are supported in
> show_page_flags(), but we can not get them from /proc/kpageflags,
> So there add them.

Can we have a documentation update please?

hp2:/usr/src/25> grep -rl kpageflags Documentation 
Documentation/admin-guide/mm/idle_page_tracking.rst
Documentation/admin-guide/mm/pagemap.rst
Documentation/filesystems/proc.rst
Documentation/translations/zh_CN/vm/hwpoison.rst
Documentation/vm/hwpoison.rst

Re: [PATCH] proc: export page young and skip_kasan_poison flag via kpageflags

[Matthew Wilcox]

On Thu, Jun 02, 2022 at 11:43:02PM +0800, Xin Hao wrote:
> Now the young and skip_kasan_poison flag are supported in

Why do we want userspace to know about whether skip_kasan_poison is set?
That seems like a kernel-internal detail to me.

Re: [PATCH] proc: export page young and skip_kasan_poison flag via kpageflags

[Xin Hao]

On 6/3/22 2:28 AM, Matthew Wilcox wrote:
> On Thu, Jun 02, 2022 at 11:43:02PM +0800, Xin Hao wrote:
>> Now the young and skip_kasan_poison flag are supported in
> Why do we want userspace to know about whether skip_kasan_poison is set?
> That seems like a kernel-internal detail to me.

the  skip_kasan_poison also a page flags, we use page_types tool to 
display them not only include user-internal,

but also  kernel-internal, add them, the page-types tool can more detail 
display the kernel-internal page flags,

just in case we don't miss some page flags when check the whole memory.

-
Best Regards!
Xin Hao

Re: [PATCH] proc: export page young and skip_kasan_poison flag via kpageflags

[Xin Hao]

On 6/3/22 2:04 AM, Andrew Morton wrote:
> On Thu,  2 Jun 2022 23:43:02 +0800 Xin Hao <xhao@linux.alibaba.com> wrote:
>
>> Now the young and skip_kasan_poison flag are supported in
>> show_page_flags(), but we can not get them from /proc/kpageflags,
>> So there add them.
> Can we have a documentation update please?
>
> hp2:/usr/src/25> grep -rl kpageflags Documentation
> Documentation/admin-guide/mm/idle_page_tracking.rst
> Documentation/admin-guide/mm/pagemap.rst
> Documentation/filesystems/proc.rst
> Documentation/translations/zh_CN/vm/hwpoison.rst
> Documentation/vm/hwpoison.rst
OK, will do in the next version, thanks

-- 
Best Regards!
Xin Hao

Re: [PATCH] proc: export page young and skip_kasan_poison flag via kpageflags

[Matthew Wilcox]

On Sat, Jun 04, 2022 at 05:50:31PM +0800, Xin Hao wrote:
> 
> On 6/3/22 2:28 AM, Matthew Wilcox wrote:
> > On Thu, Jun 02, 2022 at 11:43:02PM +0800, Xin Hao wrote:
> > > Now the young and skip_kasan_poison flag are supported in
> > Why do we want userspace to know about whether skip_kasan_poison is set?
> > That seems like a kernel-internal detail to me.
> 
> the  skip_kasan_poison also a page flags, we use page_types tool to display
> them not only include user-internal,
> 
> but also  kernel-internal, add them, the page-types tool can more detail
> display the kernel-internal page flags,
> 
> just in case we don't miss some page flags when check the whole memory.

So you're just being completist?  You don't have a reason to expose this
information?

Re: [PATCH] proc: export page young and skip_kasan_poison flag via kpageflags

[Xin Hao]

Hi, Matthew:

On 6/4/22 11:08 PM, Matthew Wilcox wrote:
> On Sat, Jun 04, 2022 at 05:50:31PM +0800, Xin Hao wrote:
>> On 6/3/22 2:28 AM, Matthew Wilcox wrote:
>>> On Thu, Jun 02, 2022 at 11:43:02PM +0800, Xin Hao wrote:
>>>> Now the young and skip_kasan_poison flag are supported in
>>> Why do we want userspace to know about whether skip_kasan_poison is set?
>>> That seems like a kernel-internal detail to me.
>> the  skip_kasan_poison also a page flags, we use page_types tool to display
>> them not only include user-internal,
>>
>> but also  kernel-internal, add them, the page-types tool can more detail
>> display the kernel-internal page flags,
>>
>> just in case we don't miss some page flags when check the whole memory.
> So you're just being completist?  You don't have a reason to expose this
> information?

Yes, about the skip_kasan_poison, i just want the kpageflags to support 
it,  i think it should be included,

the mainly  region is i want get the page node info from the kpageflags 
in my next patch,  when i check these

codes,  i see there lost some info about the skip_kasan_poison and young 
flags,  the page_types tool also check

the kasan pages, so i think it should be included.

Thanks.

-- 
Best Regards!
Xin Hao