Signed-off-by: Cyrill Gorcunov <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Matt Mackall <[email protected]>
Cc: Xiao Guangrong <[email protected]>
Cc: Marcelo Tosatti <[email protected]>
Cc: KOSAKI Motohiro <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: "Aneesh Kumar K.V" <[email protected]>
---
Documentation/vm/soft-dirty.txt | 7 +++++++
1 file changed, 7 insertions(+)
Index: linux-2.6.git/Documentation/vm/soft-dirty.txt
===================================================================
--- linux-2.6.git.orig/Documentation/vm/soft-dirty.txt
+++ linux-2.6.git/Documentation/vm/soft-dirty.txt
@@ -28,6 +28,13 @@ This is so, since the pages are still ma
the kernel does is finds this fact out and puts both writable and soft-dirty
bits on the PTE.
+ While in most cases tracking memory changes by #PF-s is more than enough
+there is still a scenario when we can loose soft dirty bit -- a task does
+unmap previously mapped memory region and then maps new one exactly at the
+same place. When unmap called the kernel internally clears PTEs values
+including soft dirty bit. To notify user space application about such
+memory region renewal the kernel always mark new memory regions (and
+expanded regions) as soft dirtified.
This feature is actively used by the checkpoint-restore project. You
can find more details about it on http://criu.org
On 08/20/13 08:31, Cyrill Gorcunov wrote:
> Signed-off-by: Cyrill Gorcunov <[email protected]>
> Cc: Pavel Emelyanov <[email protected]>
> Cc: Andy Lutomirski <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: Matt Mackall <[email protected]>
> Cc: Xiao Guangrong <[email protected]>
> Cc: Marcelo Tosatti <[email protected]>
> Cc: KOSAKI Motohiro <[email protected]>
> Cc: Stephen Rothwell <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: "Aneesh Kumar K.V" <[email protected]>
> ---
> Documentation/vm/soft-dirty.txt | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> Index: linux-2.6.git/Documentation/vm/soft-dirty.txt
> ===================================================================
> --- linux-2.6.git.orig/Documentation/vm/soft-dirty.txt
> +++ linux-2.6.git/Documentation/vm/soft-dirty.txt
> @@ -28,6 +28,13 @@ This is so, since the pages are still ma
> the kernel does is finds this fact out and puts both writable and soft-dirty
> bits on the PTE.
>
> + While in most cases tracking memory changes by #PF-s is more than enough
enough,
> +there is still a scenario when we can loose soft dirty bit -- a task does
lose soft dirty bits -- a task
> +unmap previously mapped memory region and then maps new one exactly at the
unmaps a previously mapped memory region and then maps a new one at exactly the
> +same place. When unmap called the kernel internally clears PTEs values
When unmap is called, the kernel internally clears PTE values
> +including soft dirty bit. To notify user space application about such
bits.
> +memory region renewal the kernel always mark new memory regions (and
marks
> +expanded regions) as soft dirtified.
or: as soft dirty.
>
> This feature is actively used by the checkpoint-restore project. You
> can find more details about it on http://criu.org
> --
--
~Randy
On Tue, Aug 20, 2013 at 09:57:38AM -0700, Randy Dunlap wrote:
> >
> > + While in most cases tracking memory changes by #PF-s is more than enough
> enough,
?
For the rest -- thanks a LOT Randy, I'll update.
Here is updated one, thanks again.
---
From: Cyrill Gorcunov <[email protected]>
Subject: [PATCH] docs: Document soft dirty behaviour for freshly created memory regions
Signed-off-by: Cyrill Gorcunov <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Matt Mackall <[email protected]>
Cc: Xiao Guangrong <[email protected]>
Cc: Marcelo Tosatti <[email protected]>
Cc: KOSAKI Motohiro <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: "Aneesh Kumar K.V" <[email protected]>
Cc: Randy Dunlap <[email protected]>
---
Documentation/vm/soft-dirty.txt | 7 +++++++
1 file changed, 7 insertions(+)
Index: linux-2.6.git/Documentation/vm/soft-dirty.txt
===================================================================
--- linux-2.6.git.orig/Documentation/vm/soft-dirty.txt
+++ linux-2.6.git/Documentation/vm/soft-dirty.txt
@@ -28,6 +28,13 @@ This is so, since the pages are still ma
the kernel does is finds this fact out and puts both writable and soft-dirty
bits on the PTE.
+ While in most cases tracking memory changes by #PF-s is more than enough
+there is still a scenario when we can lose soft dirty bits -- a task
+unmaps a previously mapped memory region and then maps a new one at exactly
+the same place. When unmap is called, the kernel internally clears PTE values
+including soft dirty bits. To notify user space application about such
+memory region renewal the kernel always marks new memory regions (and
+expanded regions) as soft dirty.
This feature is actively used by the checkpoint-restore project. You
can find more details about it on http://criu.org
On 08/20/13 10:01, Cyrill Gorcunov wrote:
> On Tue, Aug 20, 2013 at 09:57:38AM -0700, Randy Dunlap wrote:
>>>
>>> + While in most cases tracking memory changes by #PF-s is more than enough
>> enough,
>
> ?
Long introductory phrases usually merit a comma after them.
>
> For the rest -- thanks a LOT Randy, I'll update.
> --
--
~Randy
On Tue, Aug 20, 2013 at 10:25:11AM -0700, Randy Dunlap wrote:
>
> Long introductory phrases usually merit a comma after them.
Ah, I see, thanks!
---
From: Cyrill Gorcunov <[email protected]>
Subject: [PATCH] docs: Document soft dirty behaviour for freshly created memory regions
Signed-off-by: Cyrill Gorcunov <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Matt Mackall <[email protected]>
Cc: Xiao Guangrong <[email protected]>
Cc: Marcelo Tosatti <[email protected]>
Cc: KOSAKI Motohiro <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: "Aneesh Kumar K.V" <[email protected]>
Cc: Randy Dunlap <[email protected]>
---
Documentation/vm/soft-dirty.txt | 7 +++++++
1 file changed, 7 insertions(+)
Index: linux-2.6.git/Documentation/vm/soft-dirty.txt
===================================================================
--- linux-2.6.git.orig/Documentation/vm/soft-dirty.txt
+++ linux-2.6.git/Documentation/vm/soft-dirty.txt
@@ -28,6 +28,13 @@ This is so, since the pages are still ma
the kernel does is finds this fact out and puts both writable and soft-dirty
bits on the PTE.
+ While in most cases tracking memory changes by #PF-s is more than enough,
+there is still a scenario when we can lose soft dirty bits -- a task
+unmaps a previously mapped memory region and then maps a new one at exactly
+the same place. When unmap is called, the kernel internally clears PTE values
+including soft dirty bits. To notify user space application about such
+memory region renewal the kernel always marks new memory regions (and
+expanded regions) as soft dirty.
This feature is actively used by the checkpoint-restore project. You
can find more details about it on http://criu.org
On 08/20/2013 10:31:32 AM, Cyrill Gorcunov wrote:
> Signed-off-by: Cyrill Gorcunov <[email protected]>
> Cc: Pavel Emelyanov <[email protected]>
> Cc: Andy Lutomirski <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: Matt Mackall <[email protected]>
> Cc: Xiao Guangrong <[email protected]>
> Cc: Marcelo Tosatti <[email protected]>
> Cc: KOSAKI Motohiro <[email protected]>
> Cc: Stephen Rothwell <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: "Aneesh Kumar K.V" <[email protected]>
With that cc: list, I'll assume you do _not_ want the Documentation
maintainer paying attention to it.
Rob-
On Tue, Aug 20, 2013 at 04:15:53PM -0500, Rob Landley wrote:
> On 08/20/2013 10:31:32 AM, Cyrill Gorcunov wrote:
> >Signed-off-by: Cyrill Gorcunov <[email protected]>
> >Cc: Pavel Emelyanov <[email protected]>
> >Cc: Andy Lutomirski <[email protected]>
> >Cc: Andrew Morton <[email protected]>
> >Cc: Matt Mackall <[email protected]>
> >Cc: Xiao Guangrong <[email protected]>
> >Cc: Marcelo Tosatti <[email protected]>
> >Cc: KOSAKI Motohiro <[email protected]>
> >Cc: Stephen Rothwell <[email protected]>
> >Cc: Peter Zijlstra <[email protected]>
> >Cc: "Aneesh Kumar K.V" <[email protected]>
>
> With that cc: list, I'll assume you do _not_ want the Documentation
> maintainer paying attention to it.
Hmm, I must admit I don't know whis else list should be CC'ed.