c0d43507d12702e4b6174d99d299e8cbbb3700df
[mirrors/Programs.git] / c / pthread_extra / pthread_pause.c
1 #define __PTHREAD_EXTRA_INTERNAL
2
3 #include <pthread.h>
4 #include <pthread_extra.h>
5 #include <signal.h>
6 #include <errno.h>
7 #include <unistd.h>
8 #include <sys/resource.h>
9 //#include <stdio.h>
10 #include <stdlib.h>
11 #include <assert.h>
12 //#include <sys/time.h>
13
14 void pthread_pause_handler() {
15 //Do nothing when there are more signals pending (to cleanup the queue)
16 sigset_t pending;
17 sigpending(&pending);
18 if(sigismember(&pending, PTHREAD_XSIG_STOP)) return;
19
20 //Keep waiting for signals until we are supposed to be running
21 sigset_t sigset;
22 sigfillset(&sigset);
23 sigdelset(&sigset, PTHREAD_XSIG_STOP);
24 if(!pthread_user_data_internal(pthread_self())->running) {
25 sigsuspend(&sigset);
26 }
27 }
28
29 void pthread_pause_enable() {
30 //Add thread to internal registry
31 pthread_user_data_internal(pthread_self());
32
33 //Nesting signals too deep is not good for stack
34 //You can get runtime stats using following command:
35 //grep -i sig /proc/$(pgrep binary)/status
36 struct rlimit sigq = {.rlim_cur = 32, .rlim_max=32};
37 setrlimit(RLIMIT_SIGPENDING, &sigq);
38
39 //Setup signal handler
40 signal(PTHREAD_XSIG_STOP, pthread_pause_handler);
41
42 //Unblock signal
43 sigset_t sigset;
44 sigemptyset(&sigset);
45 sigaddset(&sigset, PTHREAD_XSIG_STOP);
46 pthread_sigmask(SIG_UNBLOCK, &sigset, NULL);
47 }
48
49 void pthread_pause_disable() {
50 //Add thread to internal registry
51 pthread_user_data_internal(pthread_self());
52
53 //Block signal
54 sigset_t sigset;
55 sigemptyset(&sigset);
56 sigaddset(&sigset, PTHREAD_XSIG_STOP);
57 pthread_sigmask(SIG_BLOCK, &sigset, NULL);
58 }
59
60 int pthread_pause_reschedule(pthread_t thread) {
61 //Send signal to initiate pause handler
62 while(pthread_kill(thread, PTHREAD_XSIG_STOP) == EAGAIN) usleep(1000);
63 return 0;
64 }
65
66 int pthread_pause(pthread_t thread) {
67 //Set thread as paused and notify it via signal (wait when queue full)
68 pthread_user_data_internal(thread)->running = 0;
69 pthread_pause_reschedule(thread);
70 return 0;
71 }
72
73 int pthread_unpause(pthread_t thread) {
74 //Set thread as running and notify it via signal (wait when queue full)
75 pthread_user_data_internal(thread)->running = 1;
76 pthread_pause_reschedule(thread);
77 return 0;
78 }
79
80
81
82 // Wrappers ///////////////////////////////////////////////////////////
83
84
85 typedef struct pthread_extra_wrapper_t {
86 void *(*start_routine)(void *);
87 void *restrict arg;
88 } pthread_extra_wrapper_t;
89
90 void *pthread_extra_thread_wrapper(void *arg) {
91 pthread_extra_wrapper_t task = *((pthread_extra_wrapper_t*)arg);
92 free(arg);
93
94 //Register new thread to user data structure
95 pthread_user_data_internal(pthread_self());
96
97 //TODO: user_data should do this automaticaly?
98 pthread_cleanup_push(pthread_user_data_cleanup, (void *)pthread_self());
99
100 //Check if we should be running according to pthread_pause sub-scheduler
101 pthread_pause_reschedule(pthread_self());
102
103 return task.start_routine(task.arg);
104
105 pthread_cleanup_pop(1); //Needed by pthread_cleanup_push() macro
106 }
107
108 int pthread_extra_create(pthread_t *restrict thread,
109 const pthread_attr_t *restrict attr,
110 void *(*start_routine)(void *),
111 void *restrict arg) {
112
113 pthread_extra_wrapper_t *task = malloc(sizeof(pthread_extra_wrapper_t));
114 assert(task != NULL);
115 task->start_routine=start_routine;
116 task->arg=arg;
117 return pthread_create(thread, attr, pthread_extra_thread_wrapper, task);
118 }
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