Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces)
A #GP is reported in the guest when requesting balloon inflation via
virtio-balloon. The reason is that the virtio-balloon driver has
removed the page from its internal page list (via balloon_page_pop),
but balloon_page_enqueue_one also calls "list_del" to do the removal.
This is necessary when it's used from balloon_page_enqueue_list, but
not from balloon_page_enqueue_one.
So remove the list_del balloon_page_enqueue_one, and update some
comments as a reminder.
Signed-off-by: Wei Wang <[email protected]>
---
ChangeLong:
v1->v2: updated some comments
mm/balloon_compaction.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 83a7b61..8639bfc 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -21,7 +21,6 @@ static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info,
* memory corruption is possible and we should stop execution.
*/
BUG_ON(!trylock_page(page));
- list_del(&page->lru);
balloon_page_insert(b_dev_info, page);
unlock_page(page);
__count_vm_event(BALLOON_INFLATE);
@@ -33,7 +32,7 @@ static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info,
* @b_dev_info: balloon device descriptor where we will insert a new page to
* @pages: pages to enqueue - allocated using balloon_page_alloc.
*
- * Driver must call it to properly enqueue a balloon pages before definitively
+ * Driver must call it to properly enqueue balloon pages before definitively
* removing it from the guest system.
*
* Return: number of pages that were enqueued.
@@ -47,6 +46,7 @@ size_t balloon_page_list_enqueue(struct balloon_dev_info *b_dev_info,
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
list_for_each_entry_safe(page, tmp, pages, lru) {
+ list_del(&page->lru);
balloon_page_enqueue_one(b_dev_info, page);
n_pages++;
}
@@ -128,13 +128,19 @@ struct page *balloon_page_alloc(void)
EXPORT_SYMBOL_GPL(balloon_page_alloc);
/*
- * balloon_page_enqueue - allocates a new page and inserts it into the balloon
- * page list.
+ * balloon_page_enqueue - inserts a new page into the balloon page list.
+ *
* @b_dev_info: balloon device descriptor where we will insert a new page to
* @page: new page to enqueue - allocated using balloon_page_alloc.
*
* Driver must call it to properly enqueue a new allocated balloon page
* before definitively removing it from the guest system.
+ *
+ * Drivers must not call balloon_page_enqueue on pages that have been
+ * pushed to a list with balloon_page_push before removing them with
+ * balloon_page_pop. To all pages on a list, use balloon_page_list_enqueue
+ * instead.
+ *
* This function returns the page address for the recently enqueued page or
* NULL in the case we fail to allocate a new page this turn.
*/
--
2.7.4
OK almost. Bunch of typos but I fixed them. Thanks!
On Thu, Jul 18, 2019 at 05:27:20PM +0800, Wei Wang wrote:
> Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces)
>
> A #GP is reported in the guest when requesting balloon inflation via
> virtio-balloon. The reason is that the virtio-balloon driver has
> removed the page from its internal page list (via balloon_page_pop),
> but balloon_page_enqueue_one also calls "list_del" to do the removal.
> This is necessary when it's used from balloon_page_enqueue_list, but
> not from balloon_page_enqueue_one.
>
> So remove the list_del balloon_page_enqueue_one, and update some
> comments as a reminder.
>
> Signed-off-by: Wei Wang <[email protected]>
> ---
> ChangeLong:
> v1->v2: updated some comments
>
> mm/balloon_compaction.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
> index 83a7b61..8639bfc 100644
> --- a/mm/balloon_compaction.c
> +++ b/mm/balloon_compaction.c
> @@ -21,7 +21,6 @@ static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info,
> * memory corruption is possible and we should stop execution.
> */
> BUG_ON(!trylock_page(page));
> - list_del(&page->lru);
> balloon_page_insert(b_dev_info, page);
> unlock_page(page);
> __count_vm_event(BALLOON_INFLATE);
> @@ -33,7 +32,7 @@ static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info,
> * @b_dev_info: balloon device descriptor where we will insert a new page to
> * @pages: pages to enqueue - allocated using balloon_page_alloc.
> *
> - * Driver must call it to properly enqueue a balloon pages before definitively
> + * Driver must call it to properly enqueue balloon pages before definitively
> * removing it from the guest system.
> *
> * Return: number of pages that were enqueued.
> @@ -47,6 +46,7 @@ size_t balloon_page_list_enqueue(struct balloon_dev_info *b_dev_info,
>
> spin_lock_irqsave(&b_dev_info->pages_lock, flags);
> list_for_each_entry_safe(page, tmp, pages, lru) {
> + list_del(&page->lru);
> balloon_page_enqueue_one(b_dev_info, page);
> n_pages++;
> }
> @@ -128,13 +128,19 @@ struct page *balloon_page_alloc(void)
> EXPORT_SYMBOL_GPL(balloon_page_alloc);
>
> /*
> - * balloon_page_enqueue - allocates a new page and inserts it into the balloon
> - * page list.
> + * balloon_page_enqueue - inserts a new page into the balloon page list.
> + *
> * @b_dev_info: balloon device descriptor where we will insert a new page to
> * @page: new page to enqueue - allocated using balloon_page_alloc.
> *
> * Driver must call it to properly enqueue a new allocated balloon page
> * before definitively removing it from the guest system.
> + *
> + * Drivers must not call balloon_page_enqueue on pages that have been
> + * pushed to a list with balloon_page_push before removing them with
> + * balloon_page_pop. To all pages on a list, use balloon_page_list_enqueue
> + * instead.
> + *
> * This function returns the page address for the recently enqueued page or
> * NULL in the case we fail to allocate a new page this turn.
> */
> --
> 2.7.4
On Thu, Jul 18, 2019 at 05:27:20PM +0800, Wei Wang wrote:
> Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces)
>
> A #GP is reported in the guest when requesting balloon inflation via
> virtio-balloon. The reason is that the virtio-balloon driver has
> removed the page from its internal page list (via balloon_page_pop),
> but balloon_page_enqueue_one also calls "list_del" to do the removal.
> This is necessary when it's used from balloon_page_enqueue_list, but
> not from balloon_page_enqueue_one.
>
> So remove the list_del balloon_page_enqueue_one, and update some
> comments as a reminder.
>
> Signed-off-by: Wei Wang <[email protected]>
ok I posted v3 with typo fixes. 1/2 is this patch with comment changes. Pls take a look.
> ---
> ChangeLong:
> v1->v2: updated some comments
>
> mm/balloon_compaction.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
> index 83a7b61..8639bfc 100644
> --- a/mm/balloon_compaction.c
> +++ b/mm/balloon_compaction.c
> @@ -21,7 +21,6 @@ static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info,
> * memory corruption is possible and we should stop execution.
> */
> BUG_ON(!trylock_page(page));
> - list_del(&page->lru);
> balloon_page_insert(b_dev_info, page);
> unlock_page(page);
> __count_vm_event(BALLOON_INFLATE);
> @@ -33,7 +32,7 @@ static void balloon_page_enqueue_one(struct balloon_dev_info *b_dev_info,
> * @b_dev_info: balloon device descriptor where we will insert a new page to
> * @pages: pages to enqueue - allocated using balloon_page_alloc.
> *
> - * Driver must call it to properly enqueue a balloon pages before definitively
> + * Driver must call it to properly enqueue balloon pages before definitively
> * removing it from the guest system.
> *
> * Return: number of pages that were enqueued.
> @@ -47,6 +46,7 @@ size_t balloon_page_list_enqueue(struct balloon_dev_info *b_dev_info,
>
> spin_lock_irqsave(&b_dev_info->pages_lock, flags);
> list_for_each_entry_safe(page, tmp, pages, lru) {
> + list_del(&page->lru);
> balloon_page_enqueue_one(b_dev_info, page);
> n_pages++;
> }
> @@ -128,13 +128,19 @@ struct page *balloon_page_alloc(void)
> EXPORT_SYMBOL_GPL(balloon_page_alloc);
>
> /*
> - * balloon_page_enqueue - allocates a new page and inserts it into the balloon
> - * page list.
> + * balloon_page_enqueue - inserts a new page into the balloon page list.
> + *
> * @b_dev_info: balloon device descriptor where we will insert a new page to
> * @page: new page to enqueue - allocated using balloon_page_alloc.
> *
> * Driver must call it to properly enqueue a new allocated balloon page
> * before definitively removing it from the guest system.
> + *
> + * Drivers must not call balloon_page_enqueue on pages that have been
> + * pushed to a list with balloon_page_push before removing them with
> + * balloon_page_pop. To all pages on a list, use balloon_page_list_enqueue
> + * instead.
> + *
> * This function returns the page address for the recently enqueued page or
> * NULL in the case we fail to allocate a new page this turn.
> */
> --
> 2.7.4
> On Jul 18, 2019, at 5:26 AM, Michael S. Tsirkin <[email protected]> wrote:
>
> On Thu, Jul 18, 2019 at 05:27:20PM +0800, Wei Wang wrote:
>> Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces)
>>
>> A #GP is reported in the guest when requesting balloon inflation via
>> virtio-balloon. The reason is that the virtio-balloon driver has
>> removed the page from its internal page list (via balloon_page_pop),
>> but balloon_page_enqueue_one also calls "list_del" to do the removal.
>> This is necessary when it's used from balloon_page_enqueue_list, but
>> not from balloon_page_enqueue_one.
>>
>> So remove the list_del balloon_page_enqueue_one, and update some
>> comments as a reminder.
>>
>> Signed-off-by: Wei Wang <[email protected]>
>
>
> ok I posted v3 with typo fixes. 1/2 is this patch with comment changes. Pls take a look.
Thanks (Wei, Michael) for taking care of it. Please cc me on future
iterations of the patch.
Acked-by: Nadav Amit <[email protected]>
On Thu, 18 Jul 2019 08:26:11 -0400 "Michael S. Tsirkin" <[email protected]> wrote:
> On Thu, Jul 18, 2019 at 05:27:20PM +0800, Wei Wang wrote:
> > Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces)
> >
> > A #GP is reported in the guest when requesting balloon inflation via
> > virtio-balloon. The reason is that the virtio-balloon driver has
> > removed the page from its internal page list (via balloon_page_pop),
> > but balloon_page_enqueue_one also calls "list_del" to do the removal.
> > This is necessary when it's used from balloon_page_enqueue_list, but
> > not from balloon_page_enqueue_one.
> >
> > So remove the list_del balloon_page_enqueue_one, and update some
> > comments as a reminder.
> >
> > Signed-off-by: Wei Wang <[email protected]>
>
>
> ok I posted v3 with typo fixes. 1/2 is this patch with comment changes. Pls take a look.
I really have no idea what you're talking about here :(. Some other
discussion and patch thread, I suppose.
You're OK with this patch?
Should this patch have cc:stable?
On Thu, Jul 18, 2019 at 01:36:26PM -0700, Andrew Morton wrote:
> On Thu, 18 Jul 2019 08:26:11 -0400 "Michael S. Tsirkin" <[email protected]> wrote:
>
> > On Thu, Jul 18, 2019 at 05:27:20PM +0800, Wei Wang wrote:
> > > Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces)
> > >
> > > A #GP is reported in the guest when requesting balloon inflation via
> > > virtio-balloon. The reason is that the virtio-balloon driver has
> > > removed the page from its internal page list (via balloon_page_pop),
> > > but balloon_page_enqueue_one also calls "list_del" to do the removal.
> > > This is necessary when it's used from balloon_page_enqueue_list, but
> > > not from balloon_page_enqueue_one.
> > >
> > > So remove the list_del balloon_page_enqueue_one, and update some
> > > comments as a reminder.
> > >
> > > Signed-off-by: Wei Wang <[email protected]>
> >
> >
> > ok I posted v3 with typo fixes. 1/2 is this patch with comment changes. Pls take a look.
>
> I really have no idea what you're talking about here :(. Some other
> discussion and patch thread, I suppose.
>
> You're OK with this patch?
Not exactly. I will send v5 soon, you will be CC'd.
> Should this patch have cc:stable?
Yes. Sorry.
On Thu, Jul 18, 2019 at 04:42:50PM -0400, Michael S. Tsirkin wrote:
> On Thu, Jul 18, 2019 at 01:36:26PM -0700, Andrew Morton wrote:
> > On Thu, 18 Jul 2019 08:26:11 -0400 "Michael S. Tsirkin" <[email protected]> wrote:
> >
> > > On Thu, Jul 18, 2019 at 05:27:20PM +0800, Wei Wang wrote:
> > > > Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces)
> > > >
> > > > A #GP is reported in the guest when requesting balloon inflation via
> > > > virtio-balloon. The reason is that the virtio-balloon driver has
> > > > removed the page from its internal page list (via balloon_page_pop),
> > > > but balloon_page_enqueue_one also calls "list_del" to do the removal.
> > > > This is necessary when it's used from balloon_page_enqueue_list, but
> > > > not from balloon_page_enqueue_one.
> > > >
> > > > So remove the list_del balloon_page_enqueue_one, and update some
> > > > comments as a reminder.
> > > >
> > > > Signed-off-by: Wei Wang <[email protected]>
> > >
> > >
> > > ok I posted v3 with typo fixes. 1/2 is this patch with comment changes. Pls take a look.
> >
> > I really have no idea what you're talking about here :(. Some other
> > discussion and patch thread, I suppose.
> >
> > You're OK with this patch?
>
> Not exactly. I will send v5 soon, you will be CC'd.
Just done. Do you see it?
> > Should this patch have cc:stable?
>
> Yes. Sorry.
Actually no - 418a3ab1e778 is new since 5.2.