Messages in this thread | | | From | Eric Dumazet <> | Date | Tue, 14 Mar 2023 07:59:27 -0700 | Subject | Re: [PATCH v2 net-next 1/2] net-sysfs: display two backlog queue len separately |
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On Mon, Mar 13, 2023 at 8:06 PM Jason Xing <kerneljasonxing@gmail.com> wrote: > > From: Jason Xing <kernelxing@tencent.com> > > Sometimes we need to know which one of backlog queue can be exactly > long enough to cause some latency when debugging this part is needed. > Thus, we can then separate the display of both. > > Signed-off-by: Jason Xing <kernelxing@tencent.com> > --- > v2: keep the total len of backlog queues untouched as Eric said > Link: https://lore.kernel.org/lkml/20230311151756.83302-1-kerneljasonxing@gmail.com/ > --- > net/core/net-procfs.c | 20 ++++++++++++++++---- > 1 file changed, 16 insertions(+), 4 deletions(-) > > diff --git a/net/core/net-procfs.c b/net/core/net-procfs.c > index 1ec23bf8b05c..2809b663e78d 100644 > --- a/net/core/net-procfs.c > +++ b/net/core/net-procfs.c > @@ -115,10 +115,19 @@ static int dev_seq_show(struct seq_file *seq, void *v) > return 0; > } > > +static u32 softnet_input_pkt_queue_len(struct softnet_data *sd) > +{ > + return skb_queue_len_lockless(&sd->input_pkt_queue); > +} > + > +static u32 softnet_process_queue_len(struct softnet_data *sd) > +{ > + return skb_queue_len_lockless(&sd->process_queue); > +} > + > static u32 softnet_backlog_len(struct softnet_data *sd) > { > - return skb_queue_len_lockless(&sd->input_pkt_queue) + > - skb_queue_len_lockless(&sd->process_queue); > + return softnet_input_pkt_queue_len(sd) + softnet_process_queue_len(sd);
Reading these variables twice might lead to inconsistency that can easily be avoided.
I would suggest you cache the values,
u32 len1 = softnet_input_pkt_queue_len(sd); u32 len2 = softnet_process_queue_len(sd);
> } > > static struct softnet_data *softnet_get_online(loff_t *pos) > @@ -169,12 +178,15 @@ static int softnet_seq_show(struct seq_file *seq, void *v) > * mapping the data a specific CPU > */ > seq_printf(seq, > - "%08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x\n", > + "%08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x " > + "%08x %08x\n", > sd->processed, sd->dropped, sd->time_squeeze, 0, > 0, 0, 0, 0, /* was fastroute */ > 0, /* was cpu_collision */ > sd->received_rps, flow_limit_count, > - softnet_backlog_len(sd), (int)seq->index); > + softnet_backlog_len(sd), /* keep it untouched */ len1 + len2.
> + (int)seq->index, > + softnet_input_pkt_queue_len(sd), softnet_process_queue_len(sd)); len1, len2);
> return 0; > } > > -- > 2.37.3 >
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