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Groups > linux.kernel > #1485524
| From | Konstantin Khlebnikov <koct9i@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [REGRESSION] RLIMIT_DATA crashes named |
| Date | 2016-09-17 14:10 +0200 |
| Message-ID | <simBr-2mp-3@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <sibcZ-3e3-1@gated-at.bofh.it> <sibmF-3x5-1@gated-at.bofh.it> <sif6W-61z-9@gated-at.bofh.it> <sijkd-ei-1@gated-at.bofh.it> <sijWW-GT-11@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Sat, Sep 17, 2016 at 12:09 PM, Cyrill Gorcunov <gorcunov@gmail.com> wrote:
> On Sat, Sep 17, 2016 at 11:33:56AM +0300, Konstantin Khlebnikov wrote:
>> >
>> > do_just_once just isn't a good name for a global
>> > rate limited mechanism that does something very
>> > different than the name.
>> >
>> > Maybe allow_once_per_ratelimit or the like
>> >
>> > There could be an equivalent do_once
>> >
>> > https://lkml.org/lkml/2009/5/22/3
>> >
>>
>> What about this printk_reriodic() and pr_warn_once_per_minute()?
>>
>> It simply remembers next jiffies to print rather than using that
>> complicated ratelimiting engine.
>
> +#define printk_periodic(period, fmt, ...) \
> +({ \
> + static unsigned long __print_next __read_mostly = INITIAL_JIFFIES; \
> + bool __do_print = time_after_eq(jiffies, __print_next); \
> + \
> + if (__do_print) { \
> + __print_next = jiffies + (period); \
> + printk(fmt, ##__VA_ARGS__); \
> + } \
> + unlikely(__do_print); \
> +})
>
> Seems I don't understand the bottom unlikely...
This is gcc extrension: https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html
Here macro works as a function which returns bool
After second though macro should update __print_next if it's too far
if first warning happens too late here will long period of silence
untill next jiffies overlap.
something like
#define printk_periodic(period, fmt, ...)
({
static unsigned long __print_next = INITIAL_JIFFIES;
unsigned long __print_jiffies = jiffies;
bool __do_print = time_after_eq(__print_jiffies, __print_next);
if (__do_print) {
__print_next = __print_jiffies + (period);
printk(fmt, ##__VA_ARGS__);
} else if (time_after(__print_next, __print_jiffies + (period))
__print_next = __print_jiffies + (period);
unlikely(__do_print);
})
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[REGRESSION] RLIMIT_DATA crashes named Laura Abbott <labbott@redhat.com> - 2016-09-16 17:20 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Linus Torvalds <torvalds@linux-foundation.org> - 2016-09-16 19:50 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Laura Abbott <labbott@redhat.com> - 2016-09-16 22:20 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Linus Torvalds <torvalds@linux-foundation.org> - 2016-09-16 22:40 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Sam Varshavchik <mrsam@courier-mta.com> - 2016-09-17 00:40 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Linus Torvalds <torvalds@linux-foundation.org> - 2016-09-17 02:00 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Linus Torvalds <torvalds@linux-foundation.org> - 2016-09-17 02:10 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Joe Perches <joe@perches.com> - 2016-09-17 06:10 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Konstantin Khlebnikov <koct9i@gmail.com> - 2016-09-17 10:40 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Cyrill Gorcunov <gorcunov@gmail.com> - 2016-09-17 11:20 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Konstantin Khlebnikov <koct9i@gmail.com> - 2016-09-17 14:10 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Cyrill Gorcunov <gorcunov@gmail.com> - 2016-09-17 14:30 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Konstantin Khlebnikov <koct9i@gmail.com> - 2016-09-17 23:50 +0200
Re: [REGRESSION] RLIMIT_DATA crashes named Joe Perches <joe@perches.com> - 2016-09-18 00:00 +0200
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