Eric Dumazet d35c99ff77 netlink: do not enter direct reclaim from netlink_dump() ... Since linux-3.15, netlink_dump() can use up to 16384 bytes skb allocations. Due to struct skb_shared_info ~320 bytes overhead, we end up using order-3 (on x86) page allocations, that might trigger direct reclaim and add stress. The intent was really to attempt a large allocation but immediately fallback to a smaller one (order-1 on x86) in case of memory stress. On recent kernels (linux-4.4), we can remove __GFP_DIRECT_RECLAIM to meet the goal. Old kernels would need to remove __GFP_WAIT While we are at it, since we do an order-3 allocation, allow to use all the allocated bytes instead of 16384 to reduce syscalls during large dumps. iproute2 already uses 32KB recvmsg() buffer sizes. Alexei provided an initial patch downsizing to SKB_WITH_OVERHEAD(16384) Fixes: 9063e21fb0 ("netlink: autosize skb lengthes") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Alexei Starovoitov <ast@kernel.org> Cc: Greg Thelen <gthelen@google.com> Reviewed-by: Greg Rose <grose@lightfleet.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>		2016-10-06 20:53:13 -04:00
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af_netlink.c	netlink: do not enter direct reclaim from netlink_dump()	2016-10-06 20:53:13 -04:00
af_netlink.h	net/netlink/af_netlink.h: Remove unused structure.	2016-06-09 22:26:24 -07:00
diag.c	netlink: don't forget to release a rhashtable_iter structure	2016-09-07 17:29:38 -07:00
genetlink.c	net: make genetlink ctrl ops const	2016-09-01 14:09:00 -07:00
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