diff options
Diffstat (limited to 'libc')
| -rw-r--r-- | libc/bionic/pthread_mutex.cpp | 27 |
1 files changed, 3 insertions, 24 deletions
diff --git a/libc/bionic/pthread_mutex.cpp b/libc/bionic/pthread_mutex.cpp index a0628b0..83d6b54 100644 --- a/libc/bionic/pthread_mutex.cpp +++ b/libc/bionic/pthread_mutex.cpp @@ -150,30 +150,9 @@ /* Mutex owner field: * * This is only used for recursive and errorcheck mutexes. It holds the - * tid of the owning thread. Note that this works because the Linux - * kernel _only_ uses 16-bit values for tids. - * - * More specifically, it will wrap to 10000 when it reaches over 32768 for - * application processes. You can check this by running the following inside - * an adb shell session: - * - OLDPID=$$; - while true; do - NEWPID=$(sh -c 'echo $$') - if [ "$NEWPID" -gt 32768 ]; then - echo "AARGH: new PID $NEWPID is too high!" - exit 1 - fi - if [ "$NEWPID" -lt "$OLDPID" ]; then - echo "****** Wrapping from PID $OLDPID to $NEWPID. *******" - else - echo -n "$NEWPID!" - fi - OLDPID=$NEWPID - done - - * Note that you can run the same example on a desktop Linux system, - * the wrapping will also happen at 32768, but will go back to 300 instead. + * tid of the owning thread. We use 16 bits to represent tid here, + * so the highest tid is 65535. There is a test to check /proc/sys/kernel/pid_max + * to make sure it will not exceed our limit. */ #define MUTEX_OWNER_SHIFT 16 #define MUTEX_OWNER_LEN 16 |