Xen devel - Feb 2007 - [PATCH][TOOLS] Reducing impact of domain save/restore/dump on Dom0

Attached is a patch to unstable that stops save/restore/dump from hosing
Dom0 when dealing with large domains - I''m actually resubmitting the
dump patch I previously submitted in addition as it hasn''t been
incorporated yet; this is based on using fadvise64(DONTNEED) to throw
the page cache away once it has been written to disk -- with this in
place, memory usage does go up somewhat but then immediately drops again
when the action is done and this change, in conjunction with setting the
vm.dirty_ratio sysctl parameter seems to gives very good results.

Simon

-----------------------------------
Reduce impact of saving/restoring/dumping large domains on Dom0 memory
usage by means of fadvise64() to tell the OS to discard the cache pages
used for the save/dump file.

Signed-off-by: Simon Graham <Simon.Graham@stratus.com>


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

On Mon, Feb 12, 2007 at 04:48:09PM -0500, Graham, Simon wrote:
> Attached is a patch to unstable that stops save/restore/dump from hosing
> Dom0 when dealing with large domains - I''m actually resubmitting
the
There''s no fadvise at all on Solaris, so could you make this
conditional
please?

thanks
john

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

On Mon, Feb 12, 2007 at 04:48:09PM -0500, Graham, Simon
wrote:
> Attached is a patch to unstable that stops save/restore/dump from hosing
> Dom0 when dealing with large domains - I''m actually resubmitting
the
> dump patch I previously submitted in addition as it hasn''t been
> incorporated yet; this is based on using fadvise64(DONTNEED) to throw
> the page cache away once it has been written to disk -- with this in
> place, memory usage does go up somewhat but then immediately drops again
> when the action is done and this change, in conjunction with setting the
> vm.dirty_ratio sysctl parameter seems to gives very good results.
Question - why fadvise64 and not posix_fadvise? posix_fadvise complies
to some posix standard, according to the man page, whereas the fadvise64
seems to be some glibc internal definition.

Just a thought.

Iustin

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

Sure -- sorry about that; I definitely google''d and thought
I''d seen
that it does exist.

Simon
> -----Original Message-----
> From: John Levon [mailto:levon@movementarian.org]
> Sent: Monday, February 12, 2007 5:40 PM
> To: Graham, Simon
> Cc: xen-devel@lists.xensource.com
> Subject: Re: [Xen-devel] [PATCH][TOOLS] Reducing impact of domain
> save/restore/dump on Dom0
> 
> On Mon, Feb 12, 2007 at 04:48:09PM -0500, Graham, Simon wrote:
> 
> > Attached is a patch to unstable that stops save/restore/dump from
> hosing
> > Dom0 when dealing with large domains - I''m actually
resubmitting the
> 
> There''s no fadvise at all on Solaris, so could you make this
> conditional
> please?
> 
> thanks
> john
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

> Question - why fadvise64 and not posix_fadvise? posix_fadvise complies
> to some posix standard, according to the man page, whereas the
> fadvise64
> seems to be some glibc internal definition.
>
It seemed to me (and I am prepared to be wrong) that posix_fadvise64 is
a Linux only thing and the real official name is fadvise64 (although man
fadvise64 on Linux claims that it''s either fadvise64_64 or
sys_fadvise64). Given that Solaris doesn''t have fadvise, I''ll
make this
conditional on being built on linux and use posix_fadvise64 directly.

Simon
 

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

On Tue, 13 Feb 2007 08:01:39 -0500
"Graham, Simon" <Simon.Graham@stratus.com> wrote:
> > Question - why fadvise64 and not posix_fadvise? posix_fadvise complies
> > to some posix standard, according to the man page, whereas the
> > fadvise64
> > seems to be some glibc internal definition.
> >
> 
> It seemed to me (and I am prepared to be wrong) that posix_fadvise64 is
> a Linux only thing and the real official name is fadvise64 (although man
> fadvise64 on Linux claims that it''s either fadvise64_64 or
> sys_fadvise64). Given that Solaris doesn''t have fadvise,
I''ll make this
> conditional on being built on linux and use posix_fadvise64 directly.
Linux man(2) documents system calls. Glibc provides POSIX interfaces for
the OS

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel