@@ -85,17 +85,7 @@ static uint64_t read_cpufreq(unsigned int cpunum);
8585
8686int uv__platform_loop_init (uv_loop_t * loop ) {
8787 int fd ;
88-
89- /* It was reported that EPOLL_CLOEXEC is not defined on Android API < 21,
90- * a.k.a. Lollipop. Since EPOLL_CLOEXEC is an alias for O_CLOEXEC on all
91- * architectures, we just use that instead.
92- */
93- #if defined(__ANDROID_API__ ) && __ANDROID_API__ < 21
94- fd = -1 ;
95- errno = ENOSYS ;
96- #else
9788 fd = epoll_create1 (O_CLOEXEC );
98- #endif
9989
10090 /* epoll_create1() can fail either because it's not implemented (old kernel)
10191 * or because it doesn't understand the O_CLOEXEC flag.
@@ -208,8 +198,10 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
208198 * that being the largest value I have seen in the wild (and only once.)
209199 */
210200 static const int max_safe_timeout = 1789569 ;
211- static int no_epoll_pwait ;
212- static int no_epoll_wait ;
201+ static int no_epoll_pwait_cached ;
202+ static int no_epoll_wait_cached ;
203+ int no_epoll_pwait ;
204+ int no_epoll_wait ;
213205 struct epoll_event events [1024 ];
214206 struct epoll_event * pe ;
215207 struct epoll_event e ;
@@ -281,6 +273,15 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
281273 count = 48 ; /* Benchmarks suggest this gives the best throughput. */
282274 real_timeout = timeout ;
283275
276+ /* You could argue there is a dependency between these two but
277+ * ultimately we don't care about their ordering with respect
278+ * to one another. Worst case, we make a few system calls that
279+ * could have been avoided because another thread already knows
280+ * they fail with ENOSYS. Hardly the end of the world.
281+ */
282+ no_epoll_pwait = uv__load_relaxed (& no_epoll_pwait_cached );
283+ no_epoll_wait = uv__load_relaxed (& no_epoll_wait_cached );
284+
284285 for (;;) {
285286 /* See the comment for max_safe_timeout for an explanation of why
286287 * this is necessary. Executive summary: kernel bug workaround.
@@ -293,25 +294,24 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
293294 abort ();
294295
295296 if (no_epoll_wait != 0 || (sigmask != 0 && no_epoll_pwait == 0 )) {
296- #if defined(__ANDROID_API__ ) && __ANDROID_API__ < 21
297- nfds = -1 ;
298- errno = ENOSYS ;
299- #else
300297 nfds = epoll_pwait (loop -> backend_fd ,
301298 events ,
302299 ARRAY_SIZE (events ),
303300 timeout ,
304301 & sigset );
305- #endif
306- if ( nfds == -1 && errno == ENOSYS )
302+ if ( nfds == -1 && errno == ENOSYS ) {
303+ uv__store_relaxed ( & no_epoll_pwait_cached , 1 );
307304 no_epoll_pwait = 1 ;
305+ }
308306 } else {
309307 nfds = epoll_wait (loop -> backend_fd ,
310308 events ,
311309 ARRAY_SIZE (events ),
312310 timeout );
313- if (nfds == -1 && errno == ENOSYS )
311+ if (nfds == -1 && errno == ENOSYS ) {
312+ uv__store_relaxed (& no_epoll_wait_cached , 1 );
314313 no_epoll_wait = 1 ;
314+ }
315315 }
316316
317317 if (sigmask != 0 && no_epoll_pwait != 0 )
@@ -982,43 +982,51 @@ void uv__set_process_title(const char* title) {
982982}
983983
984984
985- static uint64_t uv__read_proc_meminfo (const char * what ) {
986- uint64_t rc ;
985+ static int uv__slurp (const char * filename , char * buf , size_t len ) {
987986 ssize_t n ;
988- char * p ;
989987 int fd ;
990- char buf [4096 ]; /* Large enough to hold all of /proc/meminfo. */
991988
992- rc = 0 ;
993- fd = uv__open_cloexec ("/proc/meminfo" , O_RDONLY );
989+ assert (len > 0 );
994990
991+ fd = uv__open_cloexec (filename , O_RDONLY );
995992 if (fd < 0 )
996- return 0 ;
993+ return fd ;
994+
995+ do
996+ n = read (fd , buf , len - 1 );
997+ while (n == -1 && errno == EINTR );
997998
998- n = read (fd , buf , sizeof (buf ) - 1 );
999+ if (uv__close_nocheckstdio (fd ))
1000+ abort ();
9991001
1000- if (n <= 0 )
1001- goto out ;
1002+ if (n < 0 )
1003+ return UV__ERR ( errno ) ;
10021004
10031005 buf [n ] = '\0' ;
1004- p = strstr (buf , what );
10051006
1006- if ( p == NULL )
1007- goto out ;
1007+ return 0 ;
1008+ }
10081009
1009- p += strlen (what );
10101010
1011- if (1 != sscanf (p , "%" PRIu64 " kB" , & rc ))
1012- goto out ;
1011+ static uint64_t uv__read_proc_meminfo (const char * what ) {
1012+ uint64_t rc ;
1013+ char * p ;
1014+ char buf [4096 ]; /* Large enough to hold all of /proc/meminfo. */
10131015
1014- rc *= 1024 ;
1016+ if (uv__slurp ("/proc/meminfo" , buf , sizeof (buf )))
1017+ return 0 ;
10151018
1016- out :
1019+ p = strstr ( buf , what );
10171020
1018- if (uv__close_nocheckstdio ( fd ) )
1019- abort () ;
1021+ if (p == NULL )
1022+ return 0 ;
10201023
1021- return rc ;
1024+ p += strlen (what );
1025+
1026+ rc = 0 ;
1027+ sscanf (p , "%" PRIu64 " kB" , & rc );
1028+
1029+ return rc * 1024 ;
10221030}
10231031
10241032
@@ -1056,28 +1064,13 @@ uint64_t uv_get_total_memory(void) {
10561064
10571065static uint64_t uv__read_cgroups_uint64 (const char * cgroup , const char * param ) {
10581066 char filename [256 ];
1059- uint64_t rc ;
1060- int fd ;
1061- ssize_t n ;
10621067 char buf [32 ]; /* Large enough to hold an encoded uint64_t. */
1063-
1064- snprintf (filename , 256 , "/sys/fs/cgroup/%s/%s" , cgroup , param );
1068+ uint64_t rc ;
10651069
10661070 rc = 0 ;
1067- fd = uv__open_cloexec (filename , O_RDONLY );
1068-
1069- if (fd < 0 )
1070- return 0 ;
1071-
1072- n = read (fd , buf , sizeof (buf ) - 1 );
1073-
1074- if (n > 0 ) {
1075- buf [n ] = '\0' ;
1071+ snprintf (filename , sizeof (filename ), "/sys/fs/cgroup/%s/%s" , cgroup , param );
1072+ if (0 == uv__slurp (filename , buf , sizeof (buf )))
10761073 sscanf (buf , "%" PRIu64 , & rc );
1077- }
1078-
1079- if (uv__close_nocheckstdio (fd ))
1080- abort ();
10811074
10821075 return rc ;
10831076}
@@ -1091,3 +1084,20 @@ uint64_t uv_get_constrained_memory(void) {
10911084 */
10921085 return uv__read_cgroups_uint64 ("memory" , "memory.limit_in_bytes" );
10931086}
1087+
1088+
1089+ void uv_loadavg (double avg [3 ]) {
1090+ struct sysinfo info ;
1091+ char buf [128 ]; /* Large enough to hold all of /proc/loadavg. */
1092+
1093+ if (0 == uv__slurp ("/proc/loadavg" , buf , sizeof (buf )))
1094+ if (3 == sscanf (buf , "%lf %lf %lf" , & avg [0 ], & avg [1 ], & avg [2 ]))
1095+ return ;
1096+
1097+ if (sysinfo (& info ) < 0 )
1098+ return ;
1099+
1100+ avg [0 ] = (double ) info .loads [0 ] / 65536.0 ;
1101+ avg [1 ] = (double ) info .loads [1 ] / 65536.0 ;
1102+ avg [2 ] = (double ) info .loads [2 ] / 65536.0 ;
1103+ }
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