Commit 73dca124 authored Sep 29, 2016 by Xin Long Committed by David S. Miller Sep 30, 2016

sctp: move sent_count to the memory hole in sctp_chunk



Now pahole sctp_chunk, it has 2 memory holes:
   struct sctp_chunk {
	struct list_head           list;
	atomic_t                   refcnt;
	/* XXX 4 bytes hole, try to pack */
	...
	long unsigned int          prsctp_param;
	int                        sent_count;
	/* XXX 4 bytes hole, try to pack */

This patch is to move up sent_count to fill the 1st one and eliminate
the 2nd one.

It's not just another struct compaction, it also fixes the "netperf-
Throughput_Mbps -37.2% regression" issue when overloading the CPU.

Fixes: a6c2f792 ("sctp: implement prsctp TTL policy")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 1b0ff898

include/net/sctp/structs.h

+3 −3

Original line number	Diff line number	Diff line
		@@ -554,6 +554,9 @@ struct sctp_chunk {

		atomic_t refcnt;

		/* How many times this chunk have been sent, for prsctp RTX policy */
		int sent_count;

		/* This is our link to the per-transport transmitted list. */
		struct list_head transmitted_list;

		@@ -610,9 +613,6 @@ struct sctp_chunk {
		*/
		unsigned long prsctp_param;

		/* How many times this chunk have been sent, for prsctp RTX policy */
		int sent_count;

		/* Which association does this belong to? */
		struct sctp_association *asoc;