From 47bbbb30b4331ec58a74a66a044341f0114b02b3 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 17 Sep 2015 16:37:13 -0700 Subject: [PATCH] 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: Eric Dumazet Signed-off-by: David S. Miller --- 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); -- 2.20.1