diff options
| -rw-r--r-- | share/man/man9/Makefile | 1 | ||||
| -rw-r--r-- | share/man/man9/timeout.9 | 137 | ||||
| -rw-r--r-- | sys/kern/kern_timeout.c | 95 | ||||
| -rw-r--r-- | sys/sys/callout.h | 3 |
4 files changed, 177 insertions, 59 deletions
diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile index 1d85ef5..6b368bf 100644 --- a/share/man/man9/Makefile +++ b/share/man/man9/Makefile @@ -1401,6 +1401,7 @@ MLINKS+=timeout.9 callout.9 \ timeout.9 callout_schedule_sbt_curcpu.9 \ timeout.9 callout_schedule_sbt_on.9 \ timeout.9 callout_stop.9 \ + timeout.9 callout_when.9 \ timeout.9 untimeout.9 MLINKS+=ucred.9 crcopy.9 \ ucred.9 crdup.9 \ diff --git a/share/man/man9/timeout.9 b/share/man/man9/timeout.9 index 7202815..6009fa6 100644 --- a/share/man/man9/timeout.9 +++ b/share/man/man9/timeout.9 @@ -29,7 +29,7 @@ .\" .\" $FreeBSD$ .\" -.Dd October 8, 2014 +.Dd July 27, 2016 .Dt TIMEOUT 9 .Os .Sh NAME @@ -55,6 +55,7 @@ .Nm callout_schedule_sbt_curcpu , .Nm callout_schedule_sbt_on , .Nm callout_stop , +.Nm callout_when , .Nm timeout , .Nm untimeout .Nd execute a function after a specified length of time @@ -88,20 +89,48 @@ struct callout_handle handle = CALLOUT_HANDLE_INITIALIZER(&handle); .Ft int .Fn callout_reset "struct callout *c" "int ticks" "timeout_t *func" "void *arg" .Ft int -.Fn callout_reset_curcpu "struct callout *c" "int ticks" "timeout_t *func" \ -"void *arg" +.Fo callout_reset_curcpu +.Fa "struct callout *c" +.Fa "int ticks" +.Fa "timeout_t *func" +.Fa "void *arg" +.Fc .Ft int -.Fn callout_reset_on "struct callout *c" "int ticks" "timeout_t *func" \ -"void *arg" "int cpu" +.Fo callout_reset_on +.Fa "struct callout *c" +.Fa "int ticks" +.Fa "timeout_t *func" +.Fa "void *arg" +.Fa "int cpu" +.Fc .Ft int -.Fn callout_reset_sbt "struct callout *c" "sbintime_t sbt" \ -"sbintime_t pr" "timeout_t *func" "void *arg" "int flags" +.Fo callout_reset_sbt +.Fa "struct callout *c" +.Fa "sbintime_t sbt" +.Fa "sbintime_t pr" +.Fa "timeout_t *func" +.Fa "void *arg" +.Fa "int flags" +.Fc .Ft int -.Fn callout_reset_sbt_curcpu "struct callout *c" "sbintime_t sbt" \ -"sbintime_t pr" "timeout_t *func" "void *arg" "int flags" +.Fo callout_reset_sbt_curcpu +.Fa "struct callout *c" +.Fa "sbintime_t sbt" +.Fa "sbintime_t pr" +.Fa "timeout_t *func" +.Fa "void *arg" +.Fa "int flags" +.Fc .Ft int -.Fn callout_reset_sbt_on "struct callout *c" "sbintime_t sbt" \ -"sbintime_t pr" "timeout_t *func" "void *arg" "int cpu" "int flags" +.Fo callout_reset_sbt_on +.Fa "struct callout *c" +.Fa "sbintime_t sbt" +.Fa "sbintime_t pr" +.Fa "timeout_t *func" +.Fa "void *arg" +.Fa "int cpu" +.Fa "int flags" +.Fc .Ft int .Fn callout_schedule "struct callout *c" "int ticks" .Ft int @@ -109,16 +138,37 @@ struct callout_handle handle = CALLOUT_HANDLE_INITIALIZER(&handle); .Ft int .Fn callout_schedule_on "struct callout *c" "int ticks" "int cpu" .Ft int -.Fn callout_schedule_sbt "struct callout *c" "sbintime_t sbt" \ -"sbintime_t pr" "int flags" +.Fo callout_schedule_sbt +.Fa "struct callout *c" +.Fa "sbintime_t sbt" +.Fa "sbintime_t pr" +.Fa "int flags" +.Fc .Ft int -.Fn callout_schedule_sbt_curcpu "struct callout *c" "sbintime_t sbt" \ -"sbintime_t pr" "int flags" +.Fo callout_schedule_sbt_curcpu +.Fa "struct callout *c" +.Fa "sbintime_t sbt" +.Fa "sbintime_t pr" +.Fa "int flags" +.Fc .Ft int -.Fn callout_schedule_sbt_on "struct callout *c" "sbintime_t sbt" \ -"sbintime_t pr" "int cpu" "int flags" +.Fo callout_schedule_sbt_on +.Fa "struct callout *c" +.Fa "sbintime_t sbt" +.Fa "sbintime_t pr" +.Fa "int cpu" +.Fa "int flags" +.Fc .Ft int .Fn callout_stop "struct callout *c" +.Ft sbintime_t +.Fo callout_when +.Fa "sbintime_t sbt" +.Fa "sbintime_t precision" +.Fa "int flags" +.Fa "sbintime_t *sbt_res" +.Fa "sbintime_t *precision_res" +.Fc .Ft struct callout_handle .Fn timeout "timeout_t *func" "void *arg" "int ticks" .Ft void @@ -354,6 +404,26 @@ or this value is used as the length of the time window. Smaller values .Pq which result in larger time intervals allow the callout subsystem to aggregate more events in one timer interrupt. +.It Dv C_PRECALC +The +.Fa sbt +argument specifies the absolute time at which the callout should be run, +and the +.Fa pr +argument specifies the requested precision, which will not be +adjusted during the scheduling process. +The +.Fa sbt +and +.Fa pr +values should be calculated by an earlier call to +.Fn callout_when +which uses the user-supplied +.Fa sbt , +.Fa pr , +and +.Fa flags +values. .It Dv C_HARDCLOCK Align the timeouts to .Fn hardclock @@ -470,6 +540,39 @@ but it .Em does not clear it when a callout expires normally via the execution of the callout function. +.Pp +The +.Fn callout_when +function may be used to pre-calculate the absolute time at which the +timeout should be run and the precision of the scheduled run time +according to the required time +.Fa sbt , +precision +.Fa precision , +and additional adjustments requested by the +.Fa flags +argument. +Flags accepted by the +.Fn callout_when +function are the same as flags for the +.Fn callout_reset +function. +The resulting time is assigned to the variable pointed to by the +.Fa sbt_res +argument, and the resulting precision is assigned to +.Fa *precision_res . +When passing the results to +.Fa callout_reset , +add the +.Va C_PRECALC +flag to +.Fa flags , +to avoid incorrect re-adjustment. +The function is intended for situations where precise time of the callout +run should be known in advance, since +trying to read this time from the callout structure itself after a +.Fn callout_reset +call is racy. .Ss "Avoiding Race Conditions" The callout subsystem invokes callout functions from its own thread context. diff --git a/sys/kern/kern_timeout.c b/sys/kern/kern_timeout.c index ec9c3c4..7e5aab7 100644 --- a/sys/kern/kern_timeout.c +++ b/sys/kern/kern_timeout.c @@ -896,6 +896,56 @@ callout_handle_init(struct callout_handle *handle) handle->callout = NULL; } +void +callout_when(sbintime_t sbt, sbintime_t precision, int flags, + sbintime_t *res, sbintime_t *prec_res) +{ + sbintime_t to_sbt, to_pr; + + if ((flags & (C_ABSOLUTE | C_PRECALC)) != 0) { + *res = sbt; + *prec_res = precision; + return; + } + if ((flags & C_HARDCLOCK) != 0 && sbt < tick_sbt) + sbt = tick_sbt; + if ((flags & C_HARDCLOCK) != 0 || +#ifdef NO_EVENTTIMERS + sbt >= sbt_timethreshold) { + to_sbt = getsbinuptime(); + + /* Add safety belt for the case of hz > 1000. */ + to_sbt += tc_tick_sbt - tick_sbt; +#else + sbt >= sbt_tickthreshold) { + /* + * Obtain the time of the last hardclock() call on + * this CPU directly from the kern_clocksource.c. + * This value is per-CPU, but it is equal for all + * active ones. + */ +#ifdef __LP64__ + to_sbt = DPCPU_GET(hardclocktime); +#else + spinlock_enter(); + to_sbt = DPCPU_GET(hardclocktime); + spinlock_exit(); +#endif +#endif + if ((flags & C_HARDCLOCK) == 0) + to_sbt += tick_sbt; + } else + to_sbt = sbinuptime(); + if (SBT_MAX - to_sbt < sbt) + to_sbt = SBT_MAX; + else + to_sbt += sbt; + *res = to_sbt; + to_pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : + sbt >> C_PRELGET(flags)); + *prec_res = to_pr > precision ? to_pr : precision; +} + /* * New interface; clients allocate their own callout structures. * @@ -913,10 +963,10 @@ callout_handle_init(struct callout_handle *handle) * callout_deactivate() - marks the callout as having been serviced */ int -callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision, +callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t prec, void (*ftn)(void *), void *arg, int cpu, int flags) { - sbintime_t to_sbt, pr; + sbintime_t to_sbt, precision; struct callout_cpu *cc; int cancelled, direct; int ignore_cpu=0; @@ -929,47 +979,8 @@ callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision, /* Invalid CPU spec */ panic("Invalid CPU in callout %d", cpu); } - if (flags & C_ABSOLUTE) { - to_sbt = sbt; - } else { - if ((flags & C_HARDCLOCK) && (sbt < tick_sbt)) - sbt = tick_sbt; - if ((flags & C_HARDCLOCK) || -#ifdef NO_EVENTTIMERS - sbt >= sbt_timethreshold) { - to_sbt = getsbinuptime(); + callout_when(sbt, prec, flags, &to_sbt, &precision); - /* Add safety belt for the case of hz > 1000. */ - to_sbt += tc_tick_sbt - tick_sbt; -#else - sbt >= sbt_tickthreshold) { - /* - * Obtain the time of the last hardclock() call on - * this CPU directly from the kern_clocksource.c. - * This value is per-CPU, but it is equal for all - * active ones. - */ -#ifdef __LP64__ - to_sbt = DPCPU_GET(hardclocktime); -#else - spinlock_enter(); - to_sbt = DPCPU_GET(hardclocktime); - spinlock_exit(); -#endif -#endif - if ((flags & C_HARDCLOCK) == 0) - to_sbt += tick_sbt; - } else - to_sbt = sbinuptime(); - if (SBT_MAX - to_sbt < sbt) - to_sbt = SBT_MAX; - else - to_sbt += sbt; - pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp : - sbt >> C_PRELGET(flags)); - if (pr > precision) - precision = pr; - } /* * This flag used to be added by callout_cc_add, but the * first time you call this we could end up with the diff --git a/sys/sys/callout.h b/sys/sys/callout.h index d3f2bca..4e86b16 100644 --- a/sys/sys/callout.h +++ b/sys/sys/callout.h @@ -57,6 +57,7 @@ #define C_PRELGET(x) (int)((((x) >> 1) & C_PRELRANGE) - 1) #define C_HARDCLOCK 0x0100 /* align to hardclock() calls */ #define C_ABSOLUTE 0x0200 /* event time is absolute. */ +#define C_PRECALC 0x0400 /* event time is pre-calculated. */ struct callout_handle { struct callout *callout; @@ -129,6 +130,8 @@ int callout_schedule_on(struct callout *, int, int); int _callout_stop_safe(struct callout *, int); void callout_process(sbintime_t now); +void callout_when(sbintime_t sbt, sbintime_t precision, int flags, + sbintime_t *sbt_res, sbintime_t *prec_res); #endif #endif /* _SYS_CALLOUT_H_ */ |
