Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 2 Apr 2018 08:46:58 +0200 | Subject | Re: [PATCH v2] PM / wakeup: use seq_open() to show wakeup stats |
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Hi Ganesh,
On Mon, Apr 2, 2018 at 3:33 AM, Ganesh Mahendran <opensource.ganesh@gmail.com> wrote: > 2018-03-30 19:00 GMT+08:00 Geert Uytterhoeven <geert@linux-m68k.org>: >> On Fri, Mar 30, 2018 at 12:25 PM, Rafael J. Wysocki <rjw@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.
>>>> --- 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) >>>> {
>>>> + 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?
I didn't mean to get rid of that logic, but to reorganize the code to make it simpler:
list_for_each_entry_rcu(ws, &wakeup_sources, entry) { if (n-- <= 0) return ws; }
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@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
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