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Commit 47bbbb30 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
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sch_dsmark: improve memory locality 



Memory placement in sch_dsmark is silly : Better place mask/value
in the same cache line.

Also, we can embed small arrays in the first cache line and
remove a potential cache miss.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 25354001

net/sched/sch_dsmark.c

+33 −30
Original line number Diff line number Diff line
@@ -35,14 +35,20 @@ 


#define NO_DEFAULT_INDEX	(1 << 16)



struct mask_value {

	u8			mask;

	u8			value;

};



struct dsmark_qdisc_data {

	struct Qdisc		*q;

	struct tcf_proto __rcu	*filter_list;

	u8			*mask;	/* "owns" the array */

	u8			*value;

	struct mask_value	*mv;

	u16			indices;

	u8			set_tc_index;

	u32			default_index;	/* index range is 0...0xffff */

	int			set_tc_index;

#define DSMARK_EMBEDDED_SZ	16

	struct mask_value	embedded[DSMARK_EMBEDDED_SZ];

};



static inline int dsmark_valid_index(struct dsmark_qdisc_data *p, u16 index)
@@ -116,7 +122,6 @@ static int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent, 
	struct nlattr *opt = tca[TCA_OPTIONS];

	struct nlattr *tb[TCA_DSMARK_MAX + 1];

	int err = -EINVAL;

	u8 mask = 0;



	pr_debug("%s(sch %p,[qdisc %p],classid %x,parent %x), arg 0x%lx\n",

		 __func__, sch, p, classid, parent, *arg);
@@ -133,14 +138,11 @@ static int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent, 
	if (err < 0)

		goto errout;



	if (tb[TCA_DSMARK_MASK])

		mask = nla_get_u8(tb[TCA_DSMARK_MASK]);



	if (tb[TCA_DSMARK_VALUE])

		p->value[*arg - 1] = nla_get_u8(tb[TCA_DSMARK_VALUE]);

		p->mv[*arg - 1].value = nla_get_u8(tb[TCA_DSMARK_VALUE]);



	if (tb[TCA_DSMARK_MASK])

		p->mask[*arg - 1] = mask;

		p->mv[*arg - 1].mask = nla_get_u8(tb[TCA_DSMARK_MASK]);



	err = 0;
@@ -155,8 +157,8 @@ static int dsmark_delete(struct Qdisc *sch, unsigned long arg) 
	if (!dsmark_valid_index(p, arg))

		return -EINVAL;



	p->mask[arg - 1] = 0xff;

	p->value[arg - 1] = 0;

	p->mv[arg - 1].mask = 0xff;

	p->mv[arg - 1].value = 0;



	return 0;

}
@@ -173,7 +175,7 @@ static void dsmark_walk(struct Qdisc *sch, struct qdisc_walker *walker) 
		return;



	for (i = 0; i < p->indices; i++) {

		if (p->mask[i] == 0xff && !p->value[i])

		if (p->mv[i].mask == 0xff && !p->mv[i].value)

			goto ignore;

		if (walker->count >= walker->skip) {

			if (walker->fn(sch, i + 1, walker) < 0) {
@@ -291,12 +293,12 @@ static struct sk_buff *dsmark_dequeue(struct Qdisc *sch) 


	switch (tc_skb_protocol(skb)) {

	case htons(ETH_P_IP):

		ipv4_change_dsfield(ip_hdr(skb), p->mask[index],

				    p->value[index]);

		ipv4_change_dsfield(ip_hdr(skb), p->mv[index].mask,

				    p->mv[index].value);

			break;

	case htons(ETH_P_IPV6):

		ipv6_change_dsfield(ipv6_hdr(skb), p->mask[index],

				    p->value[index]);

		ipv6_change_dsfield(ipv6_hdr(skb), p->mv[index].mask,

				    p->mv[index].value);

			break;

	default:

		/*
@@ -304,7 +306,7 @@ static struct sk_buff *dsmark_dequeue(struct Qdisc *sch) 
		 * This way, we can send non-IP traffic through dsmark

		 * and don't need yet another qdisc as a bypass.

		 */

		if (p->mask[index] != 0xff || p->value[index])

		if (p->mv[index].mask != 0xff || p->mv[index].value)

			pr_warn("%s: unsupported protocol %d\n",

				__func__, ntohs(tc_skb_protocol(skb)));

		break;
@@ -346,7 +348,7 @@ static int dsmark_init(struct Qdisc *sch, struct nlattr *opt) 
	int err = -EINVAL;

	u32 default_index = NO_DEFAULT_INDEX;

	u16 indices;

	u8 *mask;

	int i;



	pr_debug("%s(sch %p,[qdisc %p],opt %p)\n", __func__, sch, p, opt);
@@ -366,18 +368,18 @@ static int dsmark_init(struct Qdisc *sch, struct nlattr *opt) 
	if (tb[TCA_DSMARK_DEFAULT_INDEX])

		default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);



	mask = kmalloc(indices * 2, GFP_KERNEL);

	if (mask == NULL) {

	if (indices <= DSMARK_EMBEDDED_SZ)

		p->mv = p->embedded;

	else

		p->mv = kmalloc_array(indices, sizeof(*p->mv), GFP_KERNEL);

	if (!p->mv) {

		err = -ENOMEM;

		goto errout;

	}



	p->mask = mask;

	memset(p->mask, 0xff, indices);



	p->value = p->mask + indices;

	memset(p->value, 0, indices);



	for (i = 0; i < indices; i++) {

		p->mv[i].mask = 0xff;

		p->mv[i].value = 0;

	}

	p->indices = indices;

	p->default_index = default_index;

	p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
@@ -410,7 +412,8 @@ static void dsmark_destroy(struct Qdisc *sch) 


	tcf_destroy_chain(&p->filter_list);

	qdisc_destroy(p->q);

	kfree(p->mask);

	if (p->mv != p->embedded)

		kfree(p->mv);

}



static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
@@ -430,8 +433,8 @@ static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl, 
	opts = nla_nest_start(skb, TCA_OPTIONS);

	if (opts == NULL)

		goto nla_put_failure;

	if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mask[cl - 1]) ||

	    nla_put_u8(skb, TCA_DSMARK_VALUE, p->value[cl - 1]))

	if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mv[cl - 1].mask) ||

	    nla_put_u8(skb, TCA_DSMARK_VALUE, p->mv[cl - 1].value))

		goto nla_put_failure;



	return nla_nest_end(skb, opts);