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strace: further optimize unblocking of the delay signal handler

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Do not unblock the delay signal handler unless the delay timer is armed.

* defs.h (is_delay_timer_created): Remove.
(is_delay_timer_armed, delay_timer_expired): New prototypes.
* delay.c (delay_timer_is_armed): New static variable.
(is_delay_timer_created): Add static qualifier.
(is_delay_timer_armed, delay_timer_expired): New functions.
(arm_delay_timer): Set delay_timer_is_armed.
* strace.c (next_event): Use is_delay_timer_armed instead of
is_delay_timer_created to check whether the delay signal handler
has to be unblocked.
(timer_sighandler): Invoke delay_timer_expired.
This commit is contained in:
Дмитрий Левин 2018-03-23 00:20:33 +00:00
parent f56a3feb32
commit 5c0896d9d8
3 changed files with 21 additions and 3 deletions
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3
defs.h
View File

@ -1026,7 +1026,8 @@ extern struct inject_opts *inject_vec[SUPPORTED_PERSONALITIES];
uint16_t alloc_delay_data(void);
void fill_delay_data(uint16_t delay_idx, int intval, bool isenter);
bool is_delay_timer_created(void);
bool is_delay_timer_armed(void);
void delay_timer_expired(void);
void arm_delay_timer(const struct tcb *);
void delay_tcb(struct tcb *, uint16_t delay_idx, bool isenter);

17
delay.c
View File

@ -37,6 +37,7 @@ static size_t delay_data_vec_capacity; /* size of the arena */
static size_t delay_data_vec_size; /* size of the used arena */
static timer_t delay_timer = (timer_t) -1;
static bool delay_timer_is_armed;
static void
expand_delay_data_vec(void)
@ -80,12 +81,24 @@ fill_delay_data(uint16_t delay_idx, int intval, bool isenter)
ts->tv_nsec = intval % 1000000 * 1000;
}
bool
static bool
is_delay_timer_created(void)
{
return delay_timer != (timer_t) -1;
}
bool
is_delay_timer_armed(void)
{
return delay_timer_is_armed;
}
void
delay_timer_expired(void)
{
delay_timer_is_armed = false;
}
void
arm_delay_timer(const struct tcb *const tcp)
{
@ -96,6 +109,8 @@ arm_delay_timer(const struct tcb *const tcp)
if (timer_settime(delay_timer, TIMER_ABSTIME, &its, NULL))
perror_msg_and_die("timer_settime");
delay_timer_is_armed = true;
debug_func_msg("timer set to %lld.%09ld for pid %d",
(long long) tcp->delay_expiration_time.tv_sec,
(long) tcp->delay_expiration_time.tv_nsec,

4
strace.c
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@ -2236,7 +2236,7 @@ next_event(int *pstatus, siginfo_t *si)
return TE_BREAK;
}
const bool unblock_delay_timer = is_delay_timer_created();
const bool unblock_delay_timer = is_delay_timer_armed();
/*
* The window of opportunity to handle expirations
@ -2607,6 +2607,8 @@ restart_delayed_tcbs(void)
static void
timer_sighandler(int sig)
{
delay_timer_expired();
if (restart_failed)
return;