[PATCH] mm: page_alloc: __GFP_NOWARN shouldn't suppress stall warnings

[Johannes Weiner]

__GFP_NOWARN, which is usually added to avoid warnings from callsites
that expect to fail and have fallbacks, currently also suppresses
allocation stall warnings. These trigger when an allocation is stuck
inside the allocator for 10 seconds or longer.

But there is no class of allocations that can get legitimately stuck
in the allocator for this long. This always indicates a problem.

Always emit stall warnings. Restrict __GFP_NOWARN to alloc failures.

Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
 mm/page_alloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f3e0c69a97b7..7ce051d1d575 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3704,7 +3704,7 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
 
 	/* Make sure we know about allocations which stall for too long */
 	if (time_after(jiffies, alloc_start + stall_timeout)) {
-		warn_alloc(gfp_mask,
+		warn_alloc(gfp_mask & ~__GFP_NOWARN,
 			"page allocation stalls for %ums, order:%u",
 			jiffies_to_msecs(jiffies-alloc_start), order);
 		stall_timeout += 10 * HZ;
-- 
2.11.0