Commit dab48dab authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
Browse files

page-allocator: warn if __GFP_NOFAIL is used for a large allocation

__GFP_NOFAIL is a bad fiction.  Allocations _can_ fail, and callers should
detect and suitably handle this (and not by lamely moving the infinite
loop up to the caller level either).

Attempting to use __GFP_NOFAIL for a higher-order allocation is even
worse, so add a once-off runtime check for this to slap people around for
even thinking about trying it.

Cc: David Rientjes <>
Acked-by: default avatarMel Gorman <>
Acked-by: default avatarPeter Zijlstra <>
Cc: KOSAKI Motohiro <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 720b17e7
...@@ -1128,6 +1128,19 @@ struct page *buffered_rmqueue(struct zone *preferred_zone, ...@@ -1128,6 +1128,19 @@ struct page *buffered_rmqueue(struct zone *preferred_zone,
list_del(&page->lru); list_del(&page->lru);
pcp->count--; pcp->count--;
} else { } else {
if (unlikely(gfp_flags & __GFP_NOFAIL)) {
* __GFP_NOFAIL is not to be used in new code.
* All __GFP_NOFAIL callers should be fixed so that they
* properly detect and handle allocation failures.
* We most definitely don't want callers attempting to
* allocate greater than single-page units with
WARN_ON_ONCE(order > 0);
spin_lock_irqsave(&zone->lock, flags); spin_lock_irqsave(&zone->lock, flags);
page = __rmqueue(zone, order, migratetype); page = __rmqueue(zone, order, migratetype);
__mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order)); __mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
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