2019-12-12 14:19:03

by Jürgen Groß

Subject: [PATCH] xen/balloon: fix ballooned page accounting without hotplug enabled

When CONFIG_XEN_BALLOON_MEMORY_HOTPLUG is not defined
reserve_additional_memory() will set balloon_stats.target_pages to a
wrong value in case there are still some ballooned pages allocated via
alloc_xenballooned_pages().

This will result in balloon_process() no longer be triggered when
ballooned pages are freed in batches.

Reported-by: Nicholas Tsirakis <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>
---
drivers/xen/balloon.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 4f2e78a5e4db..0c142bcab79d 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -394,7 +394,8 @@ static struct notifier_block xen_memory_nb = {
#else
static enum bp_state reserve_additional_memory(void)
{
- balloon_stats.target_pages = balloon_stats.current_pages;
+ balloon_stats.target_pages = balloon_stats.current_pages +
+ balloon_stats.target_unpopulated;
return BP_ECANCELED;
}
#endif /* CONFIG_XEN_BALLOON_MEMORY_HOTPLUG */
--
2.16.4

2019-12-12 18:31:18

by Boris Ostrovsky

Subject: Re: [PATCH] xen/balloon: fix ballooned page accounting without hotplug enabled

On 12/12/19 9:17 AM, Juergen Gross wrote:
> When CONFIG_XEN_BALLOON_MEMORY_HOTPLUG is not defined
> reserve_additional_memory() will set balloon_stats.target_pages to a
> wrong value in case there are still some ballooned pages allocated via
> alloc_xenballooned_pages().
>
> This will result in balloon_process() no longer be triggered when
> ballooned pages are freed in batches.
>
> Reported-by: Nicholas Tsirakis <[email protected]>
> Signed-off-by: Juergen Gross <[email protected]>

Reviewed-by: Boris Ostrovsky <[email protected]>