From: Shaohua Li <>

We saw excessive direct memory compaction triggered by skb_page_frag_refill.
This causes performance issues and add latency. Commit 5640f7685831e0
introduces the order-3 allocation. According to the changelog, the order-3
allocation isn't a must-have but to improve performance. But direct memory
compaction has high overhead. The benefit of order-3 allocation can't
compensate the overhead of direct memory compaction.

This patch makes the order-3 page allocation atomic. If there is no memory
pressure and memory isn't fragmented, the alloction will still success, so we
don't sacrifice the order-3 benefit here. If the atomic allocation fails,
direct memory compaction will not be triggered, skb_page_frag_refill will
fallback to order-0 immediately, hence the direct memory compaction overhead is
avoided. In the allocation failure case, kswapd is waken up and doing
compaction, so chances are allocation could success next time.

alloc_skb_with_frags is the same.

The mellanox driver does similar thing, if this is accepted, we must fix
the driver too.

V3: fix the same issue in alloc_skb_with_frags as pointed out by Eric
V2: make the changelog clearer

Cc: Eric Dumazet <>
Cc: Chris Mason <>
Cc: Debabrata Banerjee <>
Signed-off-by: Shaohua Li <>
Acked-by: Eric Dumazet <>
Signed-off-by: David S. Miller <>
(cherry picked from commit fb05e7a89f500cfc06ae277bdc911b281928995d)
Signed-off-by: Andrey Ryabinin <>
 net/core/skbuff.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 4147d7219589..dca9d1d9676b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4360,7 +4360,7 @@ struct sk_buff *alloc_skb_with_frags(unsigned long 
                while (order) {
                        if (npages >= 1 << order) {
-                               page = alloc_pages(gfp_mask |
+                               page = alloc_pages((gfp_mask & ~__GFP_WAIT) |
                                                   __GFP_COMP |
                                                   __GFP_NOWARN |

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