2018-03-30 19:00 GMT+08:00 Geert Uytterhoeven <ge...@linux-m68k.org>:
> On Fri, Mar 30, 2018 at 12:25 PM, Rafael J. Wysocki <r...@rjwysocki.net>
> wrote:
>> On Monday, March 5, 2018 9:47:46 AM CEST Ganesh Mahendran wrote:
>>> single_open() interface requires that the whole output must
>>> fit into a single buffer. This will lead to timeout when
>>> system memory is not in a good situation.
>>>
>>> This patch use seq_open() to show wakeup stats. This method
>>> need only one page, so timeout will not be observed.
>>>
>>> Signed-off-by: Ganesh Mahendran <opensource.gan...@gmail.com>
>>> ----
>>> v2: use srcu_read_lock instead of rcu_read_lock
>>> ---
>>> drivers/base/power/wakeup.c | 77
>>> +++++++++++++++++++++++++++++++++++----------
>>> 1 file changed, 61 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
>>> index ea01621..3bcab7d 100644
>>> --- a/drivers/base/power/wakeup.c
>>> +++ b/drivers/base/power/wakeup.c
>>> @@ -1029,32 +1029,77 @@ static int print_wakeup_source_stats(struct
>>> seq_file *m,
>>> return 0;
>>> }
>>>
>>> -/**
>>> - * wakeup_sources_stats_show - Print wakeup sources statistics information.
>>> - * @m: seq_file to print the statistics into.
>>> - */
>>> -static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
>>> +static void *wakeup_sources_stats_seq_start(struct seq_file *m,
>>> + loff_t *pos)
>>> {
>>> struct wakeup_source *ws;
>>> - int srcuidx;
>>> + loff_t n = *pos;
>>> + int *srcuidx = m->private;
>>>
>>> - seq_puts(m, "name\t\tactive_count\tevent_count\twakeup_count\t"
>>> - "expire_count\tactive_since\ttotal_time\tmax_time\t"
>>> - "last_change\tprevent_suspend_time\n");
>>> + if (n == 0) {
>>> + seq_puts(m,
>>> "name\t\tactive_count\tevent_count\twakeup_count\t"
>>> + "expire_count\tactive_since\ttotal_time\tmax_time\t"
>>> + "last_change\tprevent_suspend_time\n");
>>> + }
>>>
>>> - srcuidx = srcu_read_lock(&wakeup_srcu);
>>> - list_for_each_entry_rcu(ws, &wakeup_sources, entry)
>>> - print_wakeup_source_stats(m, ws);
>>> - srcu_read_unlock(&wakeup_srcu, srcuidx);
>>> + *srcuidx = srcu_read_lock(&wakeup_srcu);
>>> + list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
>>> + if (n-- > 0)
>>> + continue;
>>> + goto out;
>>> + }
>>> + ws = NULL;
>>> +out:
>>> + return ws;
>>> +}
>>
>> Please clean up the above at least.
>>
>> If I'm not mistaken, you don't need the label and the goto here.
>
> The continue is also not needed, if the test condition is inverted.
Hi, Geert
We need to locate to the last read item. What is your suggestion here?
Thanks.
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> ge...@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like
> that.
> -- Linus Torvalds
