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Date: Mon, 2 Dec 2019 19:15:23 +0800 From: Dust Li <dust.li@...ux.alibaba.com> To: Cong Wang <xiyou.wangcong@...il.com> Cc: Jamal Hadi Salim <jhs@...atatu.com>, Jiri Pirko <jiri@...nulli.us>, John Fastabend <john.fastabend@...il.com>, Tony Lu <tonylu@...ux.alibaba.com>, Linux Kernel Network Developers <netdev@...r.kernel.org> Subject: Re: [PATCH] net: sched: keep __gnet_stats_copy_xxx() same semantics for percpu stats On 11/30/19 1:44 PM, Cong Wang wrote: > On Wed, Nov 27, 2019 at 10:31 PM Dust Li <dust.li@...ux.alibaba.com> wrote: >> __gnet_stats_copy_basic/queue() support both percpu stat and >> non-percpu stat, but they are handle in a different manner: >> 1. For percpu stat, percpu stats are added to the return value; >> 2. For non-percpu stat, non-percpu stats will overwrite the >> return value; >> We should keep the same semantics for both type. >> >> This patch makes percpu stats follow non-percpu's manner by >> reset the return bstats before add the percpu bstats to it. >> Also changes the caller in sch_mq.c/sch_mqprio.c to make sure >> they dump the right statistics for percpu qdisc. >> >> One more thing, the sch->q.qlen is not set with nonlock child >> qdisc in mq_dump()/mqprio_dump(), add that. >> >> Fixes: 22e0f8b9322c ("net: sched: make bstats per cpu and estimator RCU safe") >> Signed-off-by: Dust Li <dust.li@...ux.alibaba.com> >> Signed-off-by: Tony Lu <tonylu@...ux.alibaba.com> >> --- >> net/core/gen_stats.c | 2 ++ >> net/sched/sch_mq.c | 34 ++++++++++++++++------------------ >> net/sched/sch_mqprio.c | 35 +++++++++++++++++------------------ >> 3 files changed, 35 insertions(+), 36 deletions(-) >> >> diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c >> index 1d653fbfcf52..d71af69196c9 100644 >> --- a/net/core/gen_stats.c >> +++ b/net/core/gen_stats.c >> @@ -120,6 +120,7 @@ __gnet_stats_copy_basic_cpu(struct gnet_stats_basic_packed *bstats, >> { >> int i; >> >> + memset(bstats, 0, sizeof(*bstats)); >> for_each_possible_cpu(i) { >> struct gnet_stats_basic_cpu *bcpu = per_cpu_ptr(cpu, i); >> unsigned int start; >> @@ -288,6 +289,7 @@ __gnet_stats_copy_queue_cpu(struct gnet_stats_queue *qstats, >> { >> int i; >> >> + memset(qstats, 0, sizeof(*qstats)); > > I think its caller is responsible to clear the stats, so you don't need to > clear them here? It looks like you do memset() twice. Yes, I should do this in its caller. I will change it, thanks. The memset() is in two different functions, one for xxx_basic_cpu(), and the other for xxx_queue_cpu(). > Does this patch fix any bug? It looks more like a clean up to me, if so > please mark it for net-next. It only fixes the 'sch->q.qlen' not set for NOLOCK child qdisc. But as Dave said, I should split that into an individual patch. So I will change this and mark it for net-next. Thanks Dust Li
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