https://github.com/torvalds/linux
Revision fb05e7a89f500cfc06ae277bdc911b281928995d authored by Shaohua Li on 11 June 2015, 23:50:48 UTC, committed by David S. Miller on 12 June 2015, 00:33:44 UTC
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 <edumazet@google.com> Cc: Chris Mason <clm@fb.com> Cc: Debabrata Banerjee <dbavatar@gmail.com> Signed-off-by: Shaohua Li <shli@fb.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 0fae3bf
Tip revision: fb05e7a89f500cfc06ae277bdc911b281928995d authored by Shaohua Li on 11 June 2015, 23:50:48 UTC
net: don't wait for order-3 page allocation
net: don't wait for order-3 page allocation
Tip revision: fb05e7a
File | Mode | Size |
---|---|---|
Documentation | ||
arch | ||
block | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.gitignore | -rw-r--r-- | 1.2 KB |
.mailmap | -rw-r--r-- | 4.9 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 94.7 KB |
Kbuild | -rw-r--r-- | 2.1 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 303.1 KB |
Makefile | -rw-r--r-- | 53.1 KB |
README | -rw-r--r-- | 18.2 KB |
REPORTING-BUGS | -rw-r--r-- | 7.3 KB |
Computing file changes ...