| Message ID | 1563442040-13510-1-git-send-email-wei.w.wang@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] mm/balloon_compaction: avoid duplicate page removal | expand |
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 <wei.w.wang@intel.com> > --- > 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 <wei.w.wang@intel.com> 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 <mst@redhat.com> 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 <wei.w.wang@intel.com> > > > 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 <namit@vmware.com>
On Thu, 18 Jul 2019 08:26:11 -0400 "Michael S. Tsirkin" <mst@redhat.com> 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 <wei.w.wang@intel.com> > > > 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" <mst@redhat.com> 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 <wei.w.wang@intel.com> > > > > > > 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" <mst@redhat.com> 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 <wei.w.wang@intel.com> > > > > > > > > > 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.
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. */
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 <wei.w.wang@intel.com> --- ChangeLong: v1->v2: updated some comments mm/balloon_compaction.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)