On Tue, Apr 06, 2021 at 10:43:01PM +0200, David Hildenbrand wrote:
> But not end_pfn as given in my version or what am I missing?
Nah, was my fault, I managed to see:
if (WARN_ON_ONCE(!nr_pages ||
!IS_ALIGNED(start_pfn, pageblock_nr_pages))
!IS_ALIGNED(start_pfn | nr_pages, PAGES_PER_SECTION)))
which would not work.
I agree that keeping the PAGES_PER_SECTION check maks this safer, so this all
should have been:
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 0cdbbfbc5757..25e59d5dc13c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -838,9 +838,14 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
int ret;
struct memory_notify arg;
- /* We can only online full sections (e.g., SECTION_IS_ONLINE) */
+ /* We can only offline full sections (e.g., SECTION_IS_ONLINE).
+ * However, when using e.g: memmap_on_memory, some pages are initialized
+ * prior to calling in here. The remaining amount of pages must be
+ * pageblock aligned.
+ */
if (WARN_ON_ONCE(!nr_pages ||
- !IS_ALIGNED(pfn | nr_pages, PAGES_PER_SECTION)))
+ !IS_ALIGNED(pfn, pageblock_nr_pages) ||
+ !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION)))
return -EINVAL;
mem_hotplug_begin();
@@ -1573,9 +1578,14 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
int ret, node;
char *reason;
- /* We can only offline full sections (e.g., SECTION_IS_ONLINE) */
+ /* We can only offline full sections (e.g., SECTION_IS_ONLINE).
+ * However, when using e.g: memmap_on_memory, some pages are initialized
+ * prior to calling in here. The remaining amount of pages must be
+ * pageblock aligned.
+ */
if (WARN_ON_ONCE(!nr_pages ||
- !IS_ALIGNED(start_pfn | nr_pages, PAGES_PER_SECTION)))
+ !IS_ALIGNED(start_pfn, pageblock_nr_pages) ||
+ !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)))
return -EINVAL;
mem_hotplug_begin();
--
Oscar Salvador
SUSE L3
