Commit 0578edc5 authored Apr 19, 2013 by Daniel Borkmann Committed by David S. Miller Apr 25, 2013

packet: reorder a member in packet_ring_buffer



There's a 4 byte hole in packet_ring_buffer structure before
prb_bdqc, that can be filled with 'pending' member, thus we can
reduce the overall structure size from 224 bytes to 216 bytes.
This also has the side-effect, that in struct packet_sock 2*4 byte
holes after the embedded packet_ring_buffer members are removed,
and overall, packet_sock can be reduced by 1 cacheline:

Before: size: 1344, cachelines: 21, members: 24
After:  size: 1280, cachelines: 20, members: 24

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 660f7d22

net/packet/internal.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -54,6 +54,7 @@ struct pgv {

		struct packet_ring_buffer {
		struct pgv *pg_vec;

		unsigned int head;
		unsigned int frames_per_block;
		unsigned int frame_size;
		@@ -63,8 +64,9 @@ struct packet_ring_buffer {
		unsigned int pg_vec_pages;
		unsigned int pg_vec_len;

		struct tpacket_kbdq_core prb_bdqc;
		atomic_t pending;

		struct tpacket_kbdq_core prb_bdqc;
		};

		extern struct mutex fanout_mutex;

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