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Date: Thu, 17 Sep 2015 16:37:13 -0700
From: Eric Dumazet <eric.dumazet@...il.com>
To: David Miller <davem@...emloft.net>
Cc: netdev <netdev@...r.kernel.org>,
Jamal Hadi Salim <jhs@...atatu.com>
Subject: [PATCH net-next] sch_dsmark: improve memory locality
From: Eric Dumazet <edumazet@...gle.com>
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: Eric Dumazet <edumazet@...gle.com>
---
net/sched/sch_dsmark.c | 63 ++++++++++++++++++++-------------------
1 file changed, 33 insertions(+), 30 deletions(-)
diff --git a/net/sched/sch_dsmark.c b/net/sched/sch_dsmark.c
index c4d45fd8c551..f357f34d02d2 100644
--- a/net/sched/sch_dsmark.c
+++ b/net/sched/sch_dsmark.c
@@ -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);
--
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