* [PATCH] xen/balloon: Set balloon's initial state to number of existing RAM pages
@ 2013-11-06 20:37 Boris Ostrovsky
2013-11-06 21:29 ` Konrad Rzeszutek Wilk
2013-11-07 0:41 ` [Xen-devel] " Bob Liu
0 siblings, 2 replies; 6+ messages in thread
From: Boris Ostrovsky @ 2013-11-06 20:37 UTC (permalink / raw)
To: konrad.wilk, david.vrabel; +Cc: xen-devel, linux-kernel, boris.ostrovsky
Currently balloon's initial value is set to max_pfn which includes
non-RAM ranges such as MMIO hole. As result, initial memory target
(specified by guest's configuration file) will appear smaller than
what balloon driver perceives to be the current number of available
pages. Thus it will balloon down "extra" pages, decreasing amount of
available memory for no good reason.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
drivers/xen/balloon.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index b232908..1b62304 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -641,7 +641,7 @@ static int __init balloon_init(void)
balloon_stats.current_pages = xen_pv_domain()
? min(xen_start_info->nr_pages - xen_released_pages, max_pfn)
- : max_pfn;
+ : get_num_physpages();
balloon_stats.target_pages = balloon_stats.current_pages;
balloon_stats.balloon_low = 0;
balloon_stats.balloon_high = 0;
--
1.8.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] xen/balloon: Set balloon's initial state to number of existing RAM pages
2013-11-06 20:37 [PATCH] xen/balloon: Set balloon's initial state to number of existing RAM pages Boris Ostrovsky
@ 2013-11-06 21:29 ` Konrad Rzeszutek Wilk
2013-11-07 0:41 ` [Xen-devel] " Bob Liu
1 sibling, 0 replies; 6+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-11-06 21:29 UTC (permalink / raw)
To: Boris Ostrovsky; +Cc: david.vrabel, xen-devel, linux-kernel
On Wed, Nov 06, 2013 at 03:37:40PM -0500, Boris Ostrovsky wrote:
> Currently balloon's initial value is set to max_pfn which includes
> non-RAM ranges such as MMIO hole. As result, initial memory target
> (specified by guest's configuration file) will appear smaller than
> what balloon driver perceives to be the current number of available
> pages. Thus it will balloon down "extra" pages, decreasing amount of
> available memory for no good reason.
Duh!
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> ---
> drivers/xen/balloon.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index b232908..1b62304 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -641,7 +641,7 @@ static int __init balloon_init(void)
>
> balloon_stats.current_pages = xen_pv_domain()
> ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn)
> - : max_pfn;
> + : get_num_physpages();
> balloon_stats.target_pages = balloon_stats.current_pages;
> balloon_stats.balloon_low = 0;
> balloon_stats.balloon_high = 0;
> --
> 1.8.1.4
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Xen-devel] [PATCH] xen/balloon: Set balloon's initial state to number of existing RAM pages
2013-11-06 20:37 [PATCH] xen/balloon: Set balloon's initial state to number of existing RAM pages Boris Ostrovsky
2013-11-06 21:29 ` Konrad Rzeszutek Wilk
@ 2013-11-07 0:41 ` Bob Liu
2013-11-07 1:25 ` Konrad Rzeszutek Wilk
1 sibling, 1 reply; 6+ messages in thread
From: Bob Liu @ 2013-11-07 0:41 UTC (permalink / raw)
To: Boris Ostrovsky; +Cc: konrad.wilk, david.vrabel, xen-devel, linux-kernel
On 11/07/2013 04:37 AM, Boris Ostrovsky wrote:
> Currently balloon's initial value is set to max_pfn which includes
> non-RAM ranges such as MMIO hole. As result, initial memory target
> (specified by guest's configuration file) will appear smaller than
> what balloon driver perceives to be the current number of available
> pages. Thus it will balloon down "extra" pages, decreasing amount of
> available memory for no good reason.
>
This fix the strange behavior I mentioned yesterday, every time after
guest started balloon driver will be triggered unreasonably.
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> ---
> drivers/xen/balloon.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index b232908..1b62304 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -641,7 +641,7 @@ static int __init balloon_init(void)
>
> balloon_stats.current_pages = xen_pv_domain()
> ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn)
> - : max_pfn;
> + : get_num_physpages();
By the way, should the other places using max_pfn also be changed with
get_num_physpages()?
> balloon_stats.target_pages = balloon_stats.current_pages;
> balloon_stats.balloon_low = 0;
> balloon_stats.balloon_high = 0;
>
--
Regards,
-Bob
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Xen-devel] [PATCH] xen/balloon: Set balloon's initial state to number of existing RAM pages
2013-11-07 0:41 ` [Xen-devel] " Bob Liu
@ 2013-11-07 1:25 ` Konrad Rzeszutek Wilk
2013-11-07 14:38 ` Daniel Kiper
0 siblings, 1 reply; 6+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-11-07 1:25 UTC (permalink / raw)
To: Bob Liu, Boris Ostrovsky; +Cc: david.vrabel, xen-devel, linux-kernel
Bob Liu <bob.liu@oracle.com> wrote:
>
>On 11/07/2013 04:37 AM, Boris Ostrovsky wrote:
>> Currently balloon's initial value is set to max_pfn which includes
>> non-RAM ranges such as MMIO hole. As result, initial memory target
>> (specified by guest's configuration file) will appear smaller than
>> what balloon driver perceives to be the current number of available
>> pages. Thus it will balloon down "extra" pages, decreasing amount of
>> available memory for no good reason.
>>
>
>This fix the strange behavior I mentioned yesterday, every time after
>guest started balloon driver will be triggered unreasonably.
>
>> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>> ---
>> drivers/xen/balloon.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
>> index b232908..1b62304 100644
>> --- a/drivers/xen/balloon.c
>> +++ b/drivers/xen/balloon.c
>> @@ -641,7 +641,7 @@ static int __init balloon_init(void)
>>
>> balloon_stats.current_pages = xen_pv_domain()
>> ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn)
>> - : max_pfn;
>> + : get_num_physpages();
>
>By the way, should the other places using max_pfn also be changed with
>get_num_physpages()?
No. In PV that calculation is correct as it gets the amount of RAM pages - which is a exactly what you need.
>
>> balloon_stats.target_pages = balloon_stats.current_pages;
>> balloon_stats.balloon_low = 0;
>> balloon_stats.balloon_high = 0;
>>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Xen-devel] [PATCH] xen/balloon: Set balloon's initial state to number of existing RAM pages
2013-11-07 1:25 ` Konrad Rzeszutek Wilk
@ 2013-11-07 14:38 ` Daniel Kiper
2013-11-07 17:37 ` Konrad Rzeszutek Wilk
0 siblings, 1 reply; 6+ messages in thread
From: Daniel Kiper @ 2013-11-07 14:38 UTC (permalink / raw)
To: Konrad Rzeszutek Wilk
Cc: Bob Liu, Boris Ostrovsky, xen-devel, david.vrabel, linux-kernel,
daniel.kiper
On Wed, Nov 06, 2013 at 08:25:04PM -0500, Konrad Rzeszutek Wilk wrote:
> Bob Liu <bob.liu@oracle.com> wrote:
> >
> >On 11/07/2013 04:37 AM, Boris Ostrovsky wrote:
> >> Currently balloon's initial value is set to max_pfn which includes
> >> non-RAM ranges such as MMIO hole. As result, initial memory target
> >> (specified by guest's configuration file) will appear smaller than
> >> what balloon driver perceives to be the current number of available
> >> pages. Thus it will balloon down "extra" pages, decreasing amount of
> >> available memory for no good reason.
> >>
> >
> >This fix the strange behavior I mentioned yesterday, every time after
> >guest started balloon driver will be triggered unreasonably.
> >
> >> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> >> ---
> >> drivers/xen/balloon.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> >> index b232908..1b62304 100644
> >> --- a/drivers/xen/balloon.c
> >> +++ b/drivers/xen/balloon.c
> >> @@ -641,7 +641,7 @@ static int __init balloon_init(void)
> >>
> >> balloon_stats.current_pages = xen_pv_domain()
> >> ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn)
> >> - : max_pfn;
> >> + : get_num_physpages();
> >
> >By the way, should the other places using max_pfn also be changed with
> >get_num_physpages()?
>
> No. In PV that calculation is correct as it gets the amount of RAM pages - which is a exactly what you need.
What about PCI passthrough case?
Daniel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Xen-devel] [PATCH] xen/balloon: Set balloon's initial state to number of existing RAM pages
2013-11-07 14:38 ` Daniel Kiper
@ 2013-11-07 17:37 ` Konrad Rzeszutek Wilk
0 siblings, 0 replies; 6+ messages in thread
From: Konrad Rzeszutek Wilk @ 2013-11-07 17:37 UTC (permalink / raw)
To: Daniel Kiper
Cc: Konrad Rzeszutek Wilk, daniel.kiper, linux-kernel, Bob Liu,
david.vrabel, xen-devel, Boris Ostrovsky
On Thu, Nov 07, 2013 at 03:38:32PM +0100, Daniel Kiper wrote:
> On Wed, Nov 06, 2013 at 08:25:04PM -0500, Konrad Rzeszutek Wilk wrote:
> > Bob Liu <bob.liu@oracle.com> wrote:
> > >
> > >On 11/07/2013 04:37 AM, Boris Ostrovsky wrote:
> > >> Currently balloon's initial value is set to max_pfn which includes
> > >> non-RAM ranges such as MMIO hole. As result, initial memory target
> > >> (specified by guest's configuration file) will appear smaller than
> > >> what balloon driver perceives to be the current number of available
> > >> pages. Thus it will balloon down "extra" pages, decreasing amount of
> > >> available memory for no good reason.
> > >>
> > >
> > >This fix the strange behavior I mentioned yesterday, every time after
> > >guest started balloon driver will be triggered unreasonably.
> > >
> > >> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> > >> ---
> > >> drivers/xen/balloon.c | 2 +-
> > >> 1 file changed, 1 insertion(+), 1 deletion(-)
> > >>
> > >> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> > >> index b232908..1b62304 100644
> > >> --- a/drivers/xen/balloon.c
> > >> +++ b/drivers/xen/balloon.c
> > >> @@ -641,7 +641,7 @@ static int __init balloon_init(void)
> > >>
> > >> balloon_stats.current_pages = xen_pv_domain()
> > >> ? min(xen_start_info->nr_pages - xen_released_pages, max_pfn)
> > >> - : max_pfn;
> > >> + : get_num_physpages();
> > >
> > >By the way, should the other places using max_pfn also be changed with
> > >get_num_physpages()?
> >
> > No. In PV that calculation is correct as it gets the amount of RAM pages - which is a exactly what you need.
>
> What about PCI passthrough case?
That is still valid. The nr_pages will have the amount of
RAM pages. If the user is using e820_host=1 option
the E820 in an PV guest looks like the host one - and
the Linux kernel ends up ballooning in/out to make the
P2M look like the E820. If not using the e820_host=1
you end up with a big giant E820_RAM - at which point
the 'max_pfn' is the end of the E820_RAM and
nr_pages - xen_relesed_pages is smaller, or equal.
The end result is that the nr_pages is the amount of
RAM pages that are right now available.
The max_pfn can be different - either bigger or the same.
I guess what you are thinking of is that we have:
min(nr_pages - xen_released_pages, max_pfn).
And we could just get rid of the 'min' and just use
nr_pages - xen_released_page. And since the
'nr_pages - xen_released_page' should be equal to
'get_num_physpages()' so - why not do that.
But that sounds to me like a new patch - lets not
try to fix too many things at once.
>
> Daniel
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
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2013-11-06 20:37 [PATCH] xen/balloon: Set balloon's initial state to number of existing RAM pages Boris Ostrovsky
2013-11-06 21:29 ` Konrad Rzeszutek Wilk
2013-11-07 0:41 ` [Xen-devel] " Bob Liu
2013-11-07 1:25 ` Konrad Rzeszutek Wilk
2013-11-07 14:38 ` Daniel Kiper
2013-11-07 17:37 ` Konrad Rzeszutek Wilk
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