Commit 0e56acae4b4dd4a9 ("mm: initialize MAX_ORDER_NR_PAGES at a time
instead of doing larger sections") is causing a regression on some
systems when the kernel is booted as Xen dom0.
The system will just hang in early boot.
Reason is an endless loop in get_page_from_freelist() in case the first
zone looked at has no free memory. deferred_grow_zone() is always
returning true due to the following code snipplet:
/* If the zone is empty somebody else may have cleared out the zone */
if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
first_deferred_pfn)) {
pgdat->first_deferred_pfn = ULONG_MAX;
pgdat_resize_unlock(pgdat, &flags);
return true;
}
This in turn results in the loop as get_page_from_freelist() is
assuming forward progress can be made by doing some more struct page
initialization.
Cc: Alexander Duyck <[email protected]>
Fixes: 0e56acae4b4dd4a9 ("mm: initialize MAX_ORDER_NR_PAGES at a time instead
of doing larger sections")
Suggested-by: Alexander Duyck <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>
---
mm/page_alloc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d66bc8abe0af..8e3bc949ebcc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1826,7 +1826,8 @@ deferred_grow_zone(struct zone *zone, unsigned int order)
first_deferred_pfn)) {
pgdat->first_deferred_pfn = ULONG_MAX;
pgdat_resize_unlock(pgdat, &flags);
- return true;
+ /* Retry only once. */
+ return first_deferred_pfn != ULONG_MAX;
}
/*
--
2.16.4
