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Commit 0578edc5 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

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: default avatarDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: default avatarDavid 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;