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-rw-r--r--mm/page_alloc.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 727751219003..48eb0f1410d4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8285,6 +8285,19 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
if ((flags & MEMORY_OFFLINE) && PageHWPoison(page))
continue;
+ /*
+ * We treat all PageOffline() pages as movable when offlining
+ * to give drivers a chance to decrement their reference count
+ * in MEM_GOING_OFFLINE in order to indicate that these pages
+ * can be offlined as there are no direct references anymore.
+ * For actually unmovable PageOffline() where the driver does
+ * not support this, we will fail later when trying to actually
+ * move these pages that still have a reference count > 0.
+ * (false negatives in this function only)
+ */
+ if ((flags & MEMORY_OFFLINE) && PageOffline(page))
+ continue;
+
if (__PageMovable(page) || PageLRU(page))
continue;
@@ -8516,6 +8529,7 @@ done:
pfn_max_align_up(end), migratetype);
return ret;
}
+EXPORT_SYMBOL(alloc_contig_range);
static int __alloc_contig_pages(unsigned long start_pfn,
unsigned long nr_pages, gfp_t gfp_mask)
@@ -8631,6 +8645,7 @@ void free_contig_range(unsigned long pfn, unsigned int nr_pages)
}
WARN(count != 0, "%d pages are still in use!\n", count);
}
+EXPORT_SYMBOL(free_contig_range);
/*
* The zone indicated has a new number of managed_pages; batch sizes and percpu
@@ -8703,6 +8718,17 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
offlined_pages++;
continue;
}
+ /*
+ * At this point all remaining PageOffline() pages have a
+ * reference count of 0 and can simply be skipped.
+ */
+ if (PageOffline(page)) {
+ BUG_ON(page_count(page));
+ BUG_ON(PageBuddy(page));
+ pfn++;
+ offlined_pages++;
+ continue;
+ }
BUG_ON(page_count(page));
BUG_ON(!PageBuddy(page));