* [PATCH] net/sched: cbs: fix calculation error of idleslope credits
@ 2020-09-18 8:42 Xiaoyong Yan
2020-09-19 0:50 ` David Miller
2020-09-19 11:35 ` kernel test robot
0 siblings, 2 replies; 3+ messages in thread
From: Xiaoyong Yan @ 2020-09-18 8:42 UTC (permalink / raw)
To: jhs, xiyou.wangcong, jiri; +Cc: davem, netdev, linux-kernel, Xiaoyong Yan
in the function cbs_dequeue_soft, when q->credits< 0, (now- q->last)
should be accounted for sendslope, not idleslope.
so the solution is as follows: when q->credits is less than 0, directly
calculate delay time, activate hrtimer and when hrtimer fires, calculate
idleslope credits and update it to q->credits.
Signed-off-by: Xiaoyong Yan <yanxiaoyong5@gmail.com>
---
net/sched/sch_cbs.c | 71 ++++++++++++++++++++++++++++++---------------
1 file changed, 48 insertions(+), 23 deletions(-)
diff --git a/net/sched/sch_cbs.c b/net/sched/sch_cbs.c
index 2eaac2ff380f..b870576839d1 100644
--- a/net/sched/sch_cbs.c
+++ b/net/sched/sch_cbs.c
@@ -76,7 +76,9 @@ struct cbs_sched_data {
s32 hicredit; /* in bytes */
s64 sendslope; /* in bytes/s */
s64 idleslope; /* in bytes/s */
- struct qdisc_watchdog watchdog;
+ struct hrtimer timer;
+ struct Qdisc *sch;
+ u64 last_expires;
int (*enqueue)(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff **to_free);
struct sk_buff *(*dequeue)(struct Qdisc *sch);
@@ -84,6 +86,41 @@ struct cbs_sched_data {
struct list_head cbs_list;
};
+/* timediff is in ns, slope is in bytes/s */
+static s64 timediff_to_credits(s64 timediff, s64 slope)
+{
+ return div64_s64(timediff * slope, NSEC_PER_SEC);
+}
+
+static void cbs_timer_schedule(struct cbs_sched_data *q, u64 expires)
+{
+ if (test_bit(__QDISC_STATE_DEACTIVATED,
+ &qdisc_root_sleeping(q->sch)->state))
+ return;
+ if (q->last_expires == expires)
+ return;
+ q->last_expires = expires;
+ hrtimer_start(&q->timer,
+ ns_to_ktime(expires),
+ HRTIMER_MODE_ABS_PINNED);
+
+}
+static enum hrtimer_restart cbs_timer(struct hrtimer *timer)
+{
+ struct cbs_sched_data *q = container_of(timer, struct cbs_sched_data, timer);
+ s64 now = ktime_get_ns();
+ s64 credits;
+
+ credits = timediff_to_credits(now- q->last, q->idleslope);
+ credits = q->credits+ credits;
+ q->credits = clamp_t(s64, credits, q->locredit, q->hicredit);
+ q->last = now;
+ rcu_read_lock();
+ __netif_schedule(qdisc_root(q->sch));
+ rcu_read_unlock();
+
+ return HRTIMER_NORESTART;
+}
static int cbs_child_enqueue(struct sk_buff *skb, struct Qdisc *sch,
struct Qdisc *child,
struct sk_buff **to_free)
@@ -135,12 +172,6 @@ static int cbs_enqueue(struct sk_buff *skb, struct Qdisc *sch,
return q->enqueue(skb, sch, to_free);
}
-/* timediff is in ns, slope is in bytes/s */
-static s64 timediff_to_credits(s64 timediff, s64 slope)
-{
- return div64_s64(timediff * slope, NSEC_PER_SEC);
-}
-
static s64 delay_from_credits(s64 credits, s64 slope)
{
if (unlikely(slope == 0))
@@ -183,25 +214,17 @@ static struct sk_buff *cbs_dequeue_soft(struct Qdisc *sch)
/* The previous packet is still being sent */
if (now < q->last) {
- qdisc_watchdog_schedule_ns(&q->watchdog, q->last);
+ cbs_timer_schedule(q, q->last);
return NULL;
}
if (q->credits < 0) {
- credits = timediff_to_credits(now - q->last, q->idleslope);
-
- credits = q->credits + credits;
- q->credits = min_t(s64, credits, q->hicredit);
-
- if (q->credits < 0) {
- s64 delay;
-
- delay = delay_from_credits(q->credits, q->idleslope);
- qdisc_watchdog_schedule_ns(&q->watchdog, now + delay);
+ s64 delay;
- q->last = now;
+ delay = delay_from_credits(q->credits, q->idleslope);
+ cbs_timer_schedule(q, now+ delay);
+ q->last = now;
- return NULL;
- }
+ return NULL;
}
skb = cbs_child_dequeue(sch, qdisc);
if (!skb)
@@ -424,7 +447,9 @@ static int cbs_init(struct Qdisc *sch, struct nlattr *opt,
q->enqueue = cbs_enqueue_soft;
q->dequeue = cbs_dequeue_soft;
- qdisc_watchdog_init(&q->watchdog, sch);
+ hrtimer_init(&q->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
+ q->timer.function = cbs_timer;
+ q->sch = sch;
return cbs_change(sch, opt, extack);
}
@@ -438,7 +463,7 @@ static void cbs_destroy(struct Qdisc *sch)
if (!q->qdisc)
return;
- qdisc_watchdog_cancel(&q->watchdog);
+ hrtimer_cancel(&q->timer);
cbs_disable_offload(dev, q);
spin_lock(&cbs_list_lock);
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] net/sched: cbs: fix calculation error of idleslope credits
2020-09-18 8:42 [PATCH] net/sched: cbs: fix calculation error of idleslope credits Xiaoyong Yan
@ 2020-09-19 0:50 ` David Miller
2020-09-19 11:35 ` kernel test robot
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2020-09-19 0:50 UTC (permalink / raw)
To: yanxiaoyong5; +Cc: jhs, xiyou.wangcong, jiri, netdev, linux-kernel
From: Xiaoyong Yan <yanxiaoyong5@gmail.com>
Date: Fri, 18 Sep 2020 01:42:52 -0700
> + delay = delay_from_credits(q->credits, q->idleslope);
> + cbs_timer_schedule(q, now+ delay);
> + q->last = now;
This indentation cannot be correct.
Please fix this.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] net/sched: cbs: fix calculation error of idleslope credits
2020-09-18 8:42 [PATCH] net/sched: cbs: fix calculation error of idleslope credits Xiaoyong Yan
2020-09-19 0:50 ` David Miller
@ 2020-09-19 11:35 ` kernel test robot
1 sibling, 0 replies; 3+ messages in thread
From: kernel test robot @ 2020-09-19 11:35 UTC (permalink / raw)
To: Xiaoyong Yan, jhs, xiyou.wangcong, jiri
Cc: kbuild-all, davem, netdev, linux-kernel, Xiaoyong Yan
[-- Attachment #1: Type: text/plain, Size: 2796 bytes --]
Hi Xiaoyong,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v5.9-rc5 next-20200918]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Xiaoyong-Yan/net-sched-cbs-fix-calculation-error-of-idleslope-credits/20200918-164430
base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 10b82d5176488acee2820e5a2cf0f2ec5c3488b6
config: h8300-randconfig-m031-20200917 (attached as .config)
compiler: h8300-linux-gcc (GCC) 9.3.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
smatch warnings:
net/sched/sch_cbs.c:224 cbs_dequeue_soft() warn: inconsistent indenting
# https://github.com/0day-ci/linux/commit/6e3656a6f5879070aaee0343f90e633de7d2d85a
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Xiaoyong-Yan/net-sched-cbs-fix-calculation-error-of-idleslope-credits/20200918-164430
git checkout 6e3656a6f5879070aaee0343f90e633de7d2d85a
vim +224 net/sched/sch_cbs.c
205
206 static struct sk_buff *cbs_dequeue_soft(struct Qdisc *sch)
207 {
208 struct cbs_sched_data *q = qdisc_priv(sch);
209 struct Qdisc *qdisc = q->qdisc;
210 s64 now = ktime_get_ns();
211 struct sk_buff *skb;
212 s64 credits;
213 int len;
214
215 /* The previous packet is still being sent */
216 if (now < q->last) {
217 cbs_timer_schedule(q, q->last);
218 return NULL;
219 }
220 if (q->credits < 0) {
221 s64 delay;
222
223 delay = delay_from_credits(q->credits, q->idleslope);
> 224 cbs_timer_schedule(q, now+ delay);
225 q->last = now;
226
227 return NULL;
228 }
229 skb = cbs_child_dequeue(sch, qdisc);
230 if (!skb)
231 return NULL;
232
233 len = qdisc_pkt_len(skb);
234
235 /* As sendslope is a negative number, this will decrease the
236 * amount of q->credits.
237 */
238 credits = credits_from_len(len, q->sendslope,
239 atomic64_read(&q->port_rate));
240 credits += q->credits;
241
242 q->credits = max_t(s64, credits, q->locredit);
243 /* Estimate of the transmission of the last byte of the packet in ns */
244 if (unlikely(atomic64_read(&q->port_rate) == 0))
245 q->last = now;
246 else
247 q->last = now + div64_s64(len * NSEC_PER_SEC,
248 atomic64_read(&q->port_rate));
249
250 return skb;
251 }
252
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 23901 bytes --]
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-09-19 11:38 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-09-18 8:42 [PATCH] net/sched: cbs: fix calculation error of idleslope credits Xiaoyong Yan
2020-09-19 0:50 ` David Miller
2020-09-19 11:35 ` kernel test robot
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).