We encounter warning messages when failing to create a new slab like this: page allocation failure: order:0, mode:0x1004000(GFP_NOWAIT|__GFP_COMP), nodemask=(null) It's a bit confusing for users because __GFP_COMP flag is used to create compound page which implies the order should not be 0. This is because minimum order will be tried if higher-order allocation fails and the minimum order is 0. It's pointless to allocate 0 order page with __GFP_COMP flag. Therefore, clear the __GFP_COMP flag when falling back to 0 order allocation which makes the order and gfp flags matched. Signed-off-by: Haifeng Xu <haifeng.xu@xxxxxxxxxx> --- mm/slub.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/slub.c b/mm/slub.c index a307d319e82c..d3e03dcb9ff2 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1875,6 +1875,13 @@ static inline struct slab *alloc_slab_page(gfp_t flags, int node, struct slab *slab; unsigned int order = oo_order(oo); + /* + * If fallback to the minimum order allocation and the order is 0, + * clear the __GFP_COMP flag. + */ + if (order == 0) + flags = flags & ~__GFP_COMP; + if (node == NUMA_NO_NODE) folio = (struct folio *)alloc_pages(flags, order); else -- 2.25.1
