* [PATCH] net/sched/sch_htb: clamp xstats tokens to fit into 32-bit int
@ 2016-07-16 14:08 Konstantin Khlebnikov
2016-07-18 18:29 ` Cong Wang
2016-07-19 5:45 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Konstantin Khlebnikov @ 2016-07-16 14:08 UTC (permalink / raw)
To: David S. Miller; +Cc: netdev, Eric Dumazet, Jamal Hadi Salim, linux-kernel
In kernel HTB keeps tokens in signed 64-bit in nanoseconds. In netlink
protocol these values are converted into pshed ticks (64ns for now) and
truncated to 32-bit. In struct tc_htb_xstats fields "tokens" and "ctokens"
are declared as unsigned 32-bit but they could be negative thus tool 'tc'
prints them as signed. Big values loose higher bits and/or become negative.
This patch clamps tokens in xstat into range from INT_MIN to INT_MAX.
In this way it's easier to understand what's going on here.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
net/sched/sch_htb.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 62f9d8100c6e..052f84d6cc23 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1140,8 +1140,10 @@ htb_dump_class_stats(struct Qdisc *sch, unsigned long arg, struct gnet_dump *d)
if (!cl->level && cl->un.leaf.q)
qlen = cl->un.leaf.q->q.qlen;
- cl->xstats.tokens = PSCHED_NS2TICKS(cl->tokens);
- cl->xstats.ctokens = PSCHED_NS2TICKS(cl->ctokens);
+ cl->xstats.tokens = clamp_t(s64, PSCHED_NS2TICKS(cl->tokens),
+ INT_MIN, INT_MAX);
+ cl->xstats.ctokens = clamp_t(s64, PSCHED_NS2TICKS(cl->ctokens),
+ INT_MIN, INT_MAX);
if (gnet_stats_copy_basic(d, NULL, &cl->bstats) < 0 ||
gnet_stats_copy_rate_est(d, NULL, &cl->rate_est) < 0 ||
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] net/sched/sch_htb: clamp xstats tokens to fit into 32-bit int
2016-07-16 14:08 [PATCH] net/sched/sch_htb: clamp xstats tokens to fit into 32-bit int Konstantin Khlebnikov
@ 2016-07-18 18:29 ` Cong Wang
2016-07-19 5:45 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Cong Wang @ 2016-07-18 18:29 UTC (permalink / raw)
To: Konstantin Khlebnikov
Cc: David S. Miller, Linux Kernel Network Developers, Eric Dumazet,
Jamal Hadi Salim, LKML
On Sat, Jul 16, 2016 at 7:08 AM, Konstantin Khlebnikov
<khlebnikov@yandex-team.ru> wrote:
> In kernel HTB keeps tokens in signed 64-bit in nanoseconds. In netlink
> protocol these values are converted into pshed ticks (64ns for now) and
> truncated to 32-bit. In struct tc_htb_xstats fields "tokens" and "ctokens"
> are declared as unsigned 32-bit but they could be negative thus tool 'tc'
> prints them as signed. Big values loose higher bits and/or become negative.
>
> This patch clamps tokens in xstat into range from INT_MIN to INT_MAX.
> In this way it's easier to understand what's going on here.
Makes sense to me, I don't know why we didn't use signed int in
the beginning, interpreting an unsigned int as signed is confusing.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] net/sched/sch_htb: clamp xstats tokens to fit into 32-bit int
2016-07-16 14:08 [PATCH] net/sched/sch_htb: clamp xstats tokens to fit into 32-bit int Konstantin Khlebnikov
2016-07-18 18:29 ` Cong Wang
@ 2016-07-19 5:45 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2016-07-19 5:45 UTC (permalink / raw)
To: khlebnikov; +Cc: netdev, edumazet, jhs, linux-kernel
From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Date: Sat, 16 Jul 2016 17:08:56 +0300
> In kernel HTB keeps tokens in signed 64-bit in nanoseconds. In netlink
> protocol these values are converted into pshed ticks (64ns for now) and
> truncated to 32-bit. In struct tc_htb_xstats fields "tokens" and "ctokens"
> are declared as unsigned 32-bit but they could be negative thus tool 'tc'
> prints them as signed. Big values loose higher bits and/or become negative.
>
> This patch clamps tokens in xstat into range from INT_MIN to INT_MAX.
> In this way it's easier to understand what's going on here.
>
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Applied.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-07-16 14:08 [PATCH] net/sched/sch_htb: clamp xstats tokens to fit into 32-bit int Konstantin Khlebnikov
2016-07-18 18:29 ` Cong Wang
2016-07-19 5:45 ` David Miller
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