The commit is pushed to "branch-rh7-3.10.0-693.17.1.vz7.43.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.17.1.vz7.43.4
------>
commit 497a0449ec62f49bc2f29f2e1a90154c6b536fa3
Author: Shaohua Li <s...@fb.com>
Date: Wed Feb 14 13:17:33 2018 +0300
ms/net: don't wait for order-3 page allocation
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 <eduma...@google.com>
Cc: Chris Mason <c...@fb.com>
Cc: Debabrata Banerjee <dbava...@gmail.com>
Signed-off-by: Shaohua Li <s...@fb.com>
Acked-by: Eric Dumazet <eduma...@google.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
https://jira.sw.ru/browse/PSBM-81488
(cherry picked from commit fb05e7a89f500cfc06ae277bdc911b281928995d)
Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
---
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
header_len,
while (order) {
if (npages >= 1 << order) {
- page = alloc_pages(gfp_mask |
+ page = alloc_pages((gfp_mask & ~__GFP_WAIT) |
__GFP_COMP |
__GFP_NOWARN |
__GFP_NORETRY,
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