The patch titled
Subject: mm/balloon_compaction.c: avoid duplicate page removal
has been added to the -mm tree. Its filename is
mm-balloon_compaction-avoid-duplicate-page-removal.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-balloon_compaction-avoid-duplicate-page-removal.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-balloon_compaction-avoid-duplicate-page-removal.patch
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------------------------------------------------------
From: Wei Wang <wei.w.wang@xxxxxxxxx>
Subject: mm/balloon_compaction.c: avoid duplicate page removal
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() from balloon_page_enqueue_one, and update some
comments as a reminder.
Link: http://lkml.kernel.org/r/1563442040-13510-1-git-send-email-wei.w.wang@xxxxxxxxx
Fixes: 418a3ab1e778 (mm/balloon_compaction: List interfaces)
Signed-off-by: Wei Wang <wei.w.wang@xxxxxxxxx>
Acked-by: Nadav Amit <namit@xxxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Xavier Deguillard <xdeguillard@xxxxxxxxxx>
Cc: Pankaj Gupta <pagupta@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Yang Zhang <yang.zhang.wz@xxxxxxxxx>
Cc: Luiz Capitulino <lcapitulino@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/balloon_compaction.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
--- a/mm/balloon_compaction.c~mm-balloon_compaction-avoid-duplicate-page-removal
+++ a/mm/balloon_compaction.c
@@ -21,7 +21,6 @@ static void balloon_page_enqueue_one(str
* 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(str
* @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
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.
*/
_
Patches currently in -mm which might be from wei.w.wang@xxxxxxxxx are
mm-balloon_compaction-avoid-duplicate-page-removal.patch
