On 17-04-20 09:59 AM, Jiri Pirko wrote:
Thu, Apr 20, 2017 at 03:06:21PM CEST, j...@mojatatu.com wrote:
From: Jamal Hadi Salim <j...@mojatatu.com>
When you dump hundreds of thousands of actions, getting only 32 per
dump batch even when the socket buffer and memory allocations allow
is inefficient.
With this change, the user will get as many as possibly fitting
within the given constraints available to the kernel.
A new top level TLV space is introduced. An attribute
TCAA_ACT_FLAGS is used to carry the flags indicating the user
is capable of processing these large dumps. Older user space which
doesn't set this flag doesn't get the large (than 32) batches.
The kernel uses the TCAA_ACT_COUNT attribute to tell the user how many
actions are put in a single batch. As such user space app knows how long
to iterate (independent of the type of action being dumped)
instead of hardcoded maximum of 32.
Some results dumping 1.5M actions, first unpatched tc which the
kernel doesn't help:
prompt$ time -p tc actions ls action gact | grep index | wc -l
1500000
real 1388.43
user 2.07
sys 1386.79
Now lets see a patched tc which sets the correct flags when requesting
a dump:
prompt$ time -p updatedtc actions ls action gact | grep index | wc -l
1500000
real 178.13
user 2.02
sys 176.96
Signed-off-by: Jamal Hadi Salim <j...@mojatatu.com>
---
include/uapi/linux/rtnetlink.h | 21 +++++++++++++++++--
net/sched/act_api.c | 46 +++++++++++++++++++++++++++++++++---------
2 files changed, 55 insertions(+), 12 deletions(-)
diff --git a/include/uapi/linux/rtnetlink.h b/include/uapi/linux/rtnetlink.h
index cce0613..d7d28ec 100644
--- a/include/uapi/linux/rtnetlink.h
+++ b/include/uapi/linux/rtnetlink.h
@@ -674,10 +674,27 @@ struct tcamsg {
unsigned char tca__pad1;
unsigned short tca__pad2;
};
+
+enum {
+ TCAA_UNSPEC,
TCAA stands for "traffic control action action". I don't get it :(
Prefix still sounds wrong to me, sorry :/
Should be:
TCA_SOMETHING_*
+ TCAA_ACT_TAB,
+#define TCA_ACT_TAB TCAA_ACT_TAB
+ TCAA_ACT_FLAGS,
+ TCAA_ACT_COUNT,
+ __TCAA_MAX,
+#define TCAA_MAX (__TCAA_MAX - 1)
+};
+
#define TA_RTA(r) ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct
tcamsg))))
#define TA_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct tcamsg))
-#define TCA_ACT_TAB 1 /* attr type must be >=1 */
-#define TCAA_MAX 1
+/* tcamsg flags stored in attribute TCAA_ACT_FLAGS
+ *
+ * ACT_LARGE_DUMP_ON user->kernel to request for larger than TCA_ACT_MAX_PRIO
+ * actions in a dump. All dump responses will contain the number of actions
+ * being dumped stored in for user app's consumption in TCAA_ACT_COUNT
+ *
+ */
+#define ACT_LARGE_DUMP_ON BIT(0)
Please put some prefix to the name, as I asked for in the previous
version.
Didnt mean to leave out but:
I cant seem to find it. Do you recall what you said it should be?
/* New extended info filters for IFLA_EXT_MASK */
#define RTEXT_FILTER_VF (1 << 0)
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 82b1d48..f85b8fd 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -83,6 +83,7 @@ static int tcf_dump_walker(struct tcf_hashinfo *hinfo, struct
sk_buff *skb,
struct netlink_callback *cb)
{
int err = 0, index = -1, i = 0, s_i = 0, n_i = 0;
+ unsigned short act_flags = cb->args[2];
struct nlattr *nest;
spin_lock_bh(&hinfo->lock);
@@ -111,14 +112,18 @@ static int tcf_dump_walker(struct tcf_hashinfo *hinfo,
struct sk_buff *skb,
}
nla_nest_end(skb, nest);
n_i++;
- if (n_i >= TCA_ACT_MAX_PRIO)
+ if (!(act_flags & ACT_LARGE_DUMP_ON) &&
+ n_i >= TCA_ACT_MAX_PRIO)
goto done;
}
}
done:
spin_unlock_bh(&hinfo->lock);
- if (n_i)
+ if (n_i) {
cb->args[0] += n_i;
+ if (act_flags & ACT_LARGE_DUMP_ON)
+ cb->args[1] = n_i;
+ }
return n_i;
nla_put_failure:
@@ -993,11 +998,15 @@ static int tcf_action_add(struct net *net, struct nlattr
*nla,
return tcf_add_notify(net, n, &actions, portid);
}
+static const struct nla_policy tcaa_policy[TCAA_MAX + 1] = {
+ [TCAA_ACT_FLAGS] = { .type = NLA_U32 },
+};
+
static int tc_ctl_action(struct sk_buff *skb, struct nlmsghdr *n,
struct netlink_ext_ack *extack)
{
struct net *net = sock_net(skb->sk);
- struct nlattr *tca[TCA_ACT_MAX + 1];
+ struct nlattr *tca[TCAA_MAX + 1];
u32 portid = skb ? NETLINK_CB(skb).portid : 0;
int ret = 0, ovr = 0;
@@ -1005,7 +1014,7 @@ static int tc_ctl_action(struct sk_buff *skb, struct
nlmsghdr *n,
!netlink_capable(skb, CAP_NET_ADMIN))
return -EPERM;
- ret = nlmsg_parse(n, sizeof(struct tcamsg), tca, TCA_ACT_MAX, NULL,
+ ret = nlmsg_parse(n, sizeof(struct tcamsg), tca, TCAA_MAX, tcaa_policy,
Please do this in a separate patch. It is an unrelated bug fix.
Ok, that is fair. Thanks. Ok, if this was patch 1/3 in next update.
"tcaa" again, now as a variable :/
Just use "tb" as the rest of the code does.
Sure.
+ if (tcaa[TCAA_ACT_FLAGS])
+ act_flags = nla_get_u32(tcaa[TCAA_ACT_FLAGS]);
I still believe this is wrong. Should be a separate attr per flag.
For user experience breakage reasons:
2 kernels should not behave differently on the exact same value passed
from userspace:
User passes 0x2. Now the kernel will ignore the set bit, the next kernel
will recognize it as a valid flag and do something.
Please let the discussion reach a consensus before pushing this again.
Jiri - I dont agree. There is no such breakage. Refer to my previous
email. Lets just move on.
cheers,
jamal
