[CRIU] [PATCH] zdtm: check one-shot posix timers
Pavel Emelyanov
xemul at parallels.com
Tue May 14 13:05:27 EDT 2013
On 05/14/2013 08:59 PM, Vladimir Davydov wrote:
> On 5/14/13 8:49 PM, Pavel Emelyanov wrote:
>> On 05/14/2013 06:25 PM, Vladimir Davydov wrote:
>>> On 5/14/13 6:19 PM, Andrew Vagin wrote:
>>>> On Tue, May 14, 2013 at 05:41:22PM +0400, Vladimir Davydov wrote:
>>>>>
>>>>> With the patch zdtm will check not only periodic timers, but also
>>>>> one-shot ones.
>>>>
>>>> How?
>>>
>>> Set one-shot timer to expire in a very long interval (INT_MAX in the
>>> test), and check its remaining value after checkpoint/restore. The
>>> following relationship must hold:
>>>
>>> initial_value - remaining_value = time_passed
>>
>> It will not be true, as dump/restore will spoil timings.
>
> Hmm... For calculating time passed we use corresponding clock -
> monotonic or realtime - depending on the timer. If realtime clock is
> synced between source and destination and CT's monotonic clock freezes
> when CT is checkpointed, the relationship must hold provided the timer
> is checkpointed/restored correctly.
>
> The test passes on OpenVZ.
>
> BTW, for periodic timers we use approx the same relationship and it
> works fine:
>
> time_passed = timer_period * (expiration_count + overrun_count)
I'd understand if it worked in "a - delta < b < a + delta" form, but
exact match looks really wrong.
>>
>>>>
>>>>>
>>>>> Signed-off-by: Vladimir Davydov <vdavydov at parallels.com>
>>>>> ---
>>>>> test/zdtm/live/static/posix_timers.c | 108 ++++++++++++++++++++++++++++------
>>>>> 1 files changed, 90 insertions(+), 18 deletions(-)
>>>>>
>>>>
>>>>> diff --git a/test/zdtm/live/static/posix_timers.c b/test/zdtm/live/static/posix_timers.c
>>>>> index 587a6be..ae9a882 100644
>>>>> --- a/test/zdtm/live/static/posix_timers.c
>>>>> +++ b/test/zdtm/live/static/posix_timers.c
>>>>> @@ -3,6 +3,8 @@
>>>>> #include <signal.h>
>>>>> #include <time.h>
>>>>> #include <sys/time.h>
>>>>> +#include <limits.h>
>>>>> +#include <string.h>
>>>>>
>>>>> #include "zdtmtst.h"
>>>>>
>>>>> @@ -17,14 +19,24 @@ sigset_t mask;
>>>>>
>>>>> #define MAX_TIMER_DISPLACEMENT 10
>>>>>
>>>>> -static void realtime_handler(int sig, siginfo_t *si, void *uc);
>>>>> -static void monotonic_handler(int sig, siginfo_t *si, void *uc);
>>>>> +static void realtime_periodic_handler(int sig, siginfo_t *si, void *uc);
>>>>> +static void monotonic_periodic_handler(int sig, siginfo_t *si, void *uc);
>>>>> +static void realtime_oneshot_handler(int sig, siginfo_t *si, void *uc);
>>>>> +static void monotonic_oneshot_handler(int sig, siginfo_t *si, void *uc);
>>>>> +
>>>>> +enum {
>>>>> + REALTIME_PERIODIC_INFO,
>>>>> + MONOTONIC_PERIODIC_INFO,
>>>>> + REALTIME_ONESHOT_INFO,
>>>>> + MONOTONIC_ONESHOT_INFO,
>>>>> +};
>>>>>
>>>>> static struct posix_timers_info {
>>>>> char clock;
>>>>> char *name;
>>>>> void (*handler)(int sig, siginfo_t *si, void *uc);
>>>>> int sig;
>>>>> + int oneshot;
>>>>> int ms_int;
>>>>> struct sigaction sa;
>>>>> int handler_status;
>>>>> @@ -33,17 +45,24 @@ static struct posix_timers_info {
>>>>> int overrun;
>>>>> struct timespec start, end;
>>>>> } posix_timers[] = {
>>>>> - [CLOCK_REALTIME] = {CLOCK_REALTIME, "REALTIME", realtime_handler, SIGALRM, 1},
>>>>> - [CLOCK_MONOTONIC] = {CLOCK_MONOTONIC, "MONOTONIC", monotonic_handler, SIGINT, 3},
>>>>> + [REALTIME_PERIODIC_INFO] = {CLOCK_REALTIME, "REALTIME (periodic)",
>>>>> + realtime_periodic_handler, SIGALRM, 0, 1},
>>>>> + [MONOTONIC_PERIODIC_INFO] = {CLOCK_MONOTONIC, "MONOTONIC (periodic)",
>>>>> + monotonic_periodic_handler, SIGINT, 0, 3},
>>>>> + [REALTIME_ONESHOT_INFO] = {CLOCK_REALTIME, "REALTIME (oneshot)",
>>>>> + realtime_oneshot_handler, SIGUSR1, 1, INT_MAX},
>>>>> + [MONOTONIC_ONESHOT_INFO] = {CLOCK_MONOTONIC, "MONOTONIC (oneshot)",
>>>>> + monotonic_oneshot_handler, SIGUSR2, 1, INT_MAX},
>>>>> { }
>>>>> };
>>>>>
>>>>> -static int check_handler_status(struct posix_timers_info *info, int ms_passed)
>>>>> +static int check_handler_status(struct posix_timers_info *info,
>>>>> + struct itimerspec *its, int ms_passed)
>>>>> {
>>>>> int displacement;
>>>>> int timer_ms;
>>>>>
>>>>> - if (!info->handler_cnt) {
>>>>> + if (!info->handler_cnt && !info->oneshot) {
>>>>> fail("%s: Signal handler wasn't called\n", info->name);
>>>>> return -EINVAL;
>>>>> }
>>>>> @@ -58,7 +77,41 @@ static int check_handler_status(struct posix_timers_info *info, int ms_passed)
>>>>> return -1;
>>>>> }
>>>>>
>>>>> - timer_ms = (info->overrun + info->handler_cnt) * info->ms_int;
>>>>> + if (!info->oneshot && !its->it_value.tv_sec && !its->it_value.tv_nsec) {
>>>>> + fail("%s: timer became unset\n", info->name);
>>>>> + return -EFAULT;
>>>>> + }
>>>>> +
>>>>> + if (info->oneshot && (its->it_interval.tv_sec || its->it_interval.tv_nsec)) {
>>>>> + fail("%s: timer became periodic\n", info->name);
>>>>> + return -EFAULT;
>>>>> + }
>>>>> +
>>>>> + if (!info->oneshot && !its->it_interval.tv_sec && !its->it_interval.tv_nsec) {
>>>>> + fail("%s: timer became oneshot\n", info->name);
>>>>> + return -EFAULT;
>>>>> + }
>>>>> +
>>>>> + if (info->oneshot) {
>>>>> + int val = its->it_value.tv_sec * 1000 + its->it_value.tv_nsec / 1000 / 1000;
>>>>> + if (info->handler_cnt) {
>>>>> + if (val != 0) {
>>>>> + fail("%s: timer continues ticking after expiration\n", info->name);
>>>>> + return -EFAULT;
>>>>> + }
>>>>> + if (info->handler_cnt > 1) {
>>>>> + fail("%s: timer expired %d times\n", info->name, info->handler_cnt);
>>>>> + return -EFAULT;
>>>>> + }
>>>>> + if (info->ms_int > ms_passed) {
>>>>> + fail("%s: timer expired too early\n", info->name);
>>>>> + return -EFAULT;
>>>>> + }
>>>>> + return 0;
>>>>> + }
>>>>> + timer_ms = info->ms_int - val;
>>>>> + } else
>>>>> + timer_ms = (info->overrun + info->handler_cnt) * info->ms_int;
>>>>> displacement = abs(ms_passed - timer_ms) * 100 / ms_passed;
>>>>>
>>>>> if (displacement > MAX_TIMER_DISPLACEMENT) {
>>>>> @@ -76,6 +129,7 @@ static int check_timers(void)
>>>>> struct posix_timers_info *info = posix_timers;
>>>>> int ms_passed;
>>>>> int status = 0;
>>>>> + struct itimerspec val, oldval;
>>>>>
>>>>> if (sigprocmask(SIG_UNBLOCK, &mask, NULL) == -1) {
>>>>> fail("Failed to unlock signal\n");
>>>>> @@ -83,8 +137,9 @@ static int check_timers(void)
>>>>> }
>>>>>
>>>>> while (info->handler) {
>>>>> - if (timer_delete(info->timerid) == -1) {
>>>>> - fail("%s: Failed to delete timer\n", info->name);
>>>>> + memset(&val, 0, sizeof(val));
>>>>> + if (timer_settime(info->timerid, 0, &val, &oldval) == -1) {
>>>>> + fail("%s: failed to reset timer\n", info->name);
>>>>> return -errno;
>>>>> }
>>>>>
>>>>> @@ -96,7 +151,7 @@ static int check_timers(void)
>>>>> ms_passed = (info->end.tv_sec - info->start.tv_sec) * 1000 +
>>>>> (info->end.tv_nsec - info->start.tv_nsec) / (1000 * 1000);
>>>>>
>>>>> - if (check_handler_status(info, ms_passed))
>>>>> + if (check_handler_status(info, &oldval, ms_passed))
>>>>> status--;
>>>>> info++;
>>>>> }
>>>>> @@ -124,14 +179,28 @@ static void generic_handler(struct posix_timers_info *info,
>>>>> info->handler_cnt++;
>>>>> }
>>>>>
>>>>> -static void monotonic_handler(int sig, siginfo_t *si, void *uc)
>>>>> +static void monotonic_periodic_handler(int sig, siginfo_t *si, void *uc)
>>>>> +{
>>>>> + generic_handler(si->si_value.sival_ptr,
>>>>> + &posix_timers[MONOTONIC_PERIODIC_INFO], sig);
>>>>> +}
>>>>> +
>>>>> +static void monotonic_oneshot_handler(int sig, siginfo_t *si, void *uc)
>>>>> +{
>>>>> + generic_handler(si->si_value.sival_ptr,
>>>>> + &posix_timers[MONOTONIC_ONESHOT_INFO], sig);
>>>>> +}
>>>>> +
>>>>> +static void realtime_periodic_handler(int sig, siginfo_t *si, void *uc)
>>>>> {
>>>>> - generic_handler(si->si_value.sival_ptr, &posix_timers[CLOCK_MONOTONIC], sig);
>>>>> + generic_handler(si->si_value.sival_ptr,
>>>>> + &posix_timers[REALTIME_PERIODIC_INFO], sig);
>>>>> }
>>>>>
>>>>> -static void realtime_handler(int sig, siginfo_t *si, void *uc)
>>>>> +static void realtime_oneshot_handler(int sig, siginfo_t *si, void *uc)
>>>>> {
>>>>> - generic_handler(si->si_value.sival_ptr, &posix_timers[CLOCK_REALTIME], sig);
>>>>> + generic_handler(si->si_value.sival_ptr,
>>>>> + &posix_timers[REALTIME_ONESHOT_INFO], sig);
>>>>> }
>>>>>
>>>>> static int setup_timers(void)
>>>>> @@ -171,10 +240,13 @@ static int setup_timers(void)
>>>>> return -errno;
>>>>> }
>>>>>
>>>>> - its.it_value.tv_sec = 0;
>>>>> - its.it_value.tv_nsec = info->ms_int * 1000 * 1000;
>>>>> - its.it_interval.tv_sec = its.it_value.tv_sec;
>>>>> - its.it_interval.tv_nsec = its.it_value.tv_nsec;
>>>>> + its.it_value.tv_sec = info->ms_int / 1000;
>>>>> + its.it_value.tv_nsec = info->ms_int % 1000 * 1000 * 1000;
>>>>> + if (!info->oneshot) {
>>>>> + its.it_interval.tv_sec = its.it_value.tv_sec;
>>>>> + its.it_interval.tv_nsec = its.it_value.tv_nsec;
>>>>> + } else
>>>>> + its.it_interval.tv_sec = its.it_interval.tv_nsec = 0;
>>>>>
>>>>> if (clock_gettime(info->clock, &info->start) == -1) {
>>>>> err("Can't get %s start time\n", info->name);
>>>>
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>>>>> CRIU at openvz.org
>>>>> https://lists.openvz.org/mailman/listinfo/criu
>>>>
>>>
>>> .
>>>
>>
>>
>
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