From 2b5174253155bdace1262ea2ab53d11347ecdefd Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Tue, 31 Mar 2020 15:43:25 -0300 Subject: nptl: Move cancel state out of cancelhandling Now that thread cancellation state is not accessed concurrently anymore, it is possible to move it out the 'cancelhandling'. The code is also simplified: CANCELLATION_P is replaced with a internal pthread_testcancel call and the CANCELSTATE_BIT{MASK} is removed. With this behavior pthread_setcancelstate does not require to act on cancellation if cancel type is asynchronous (is already handled either by pthread_setcanceltype or by the signal handler). Checked on x86_64-linux-gnu and aarch64-linux-gnu. --- nptl/pthread_setcancelstate.c | 36 +++--------------------------------- 1 file changed, 3 insertions(+), 33 deletions(-) (limited to 'nptl/pthread_setcancelstate.c') diff --git a/nptl/pthread_setcancelstate.c b/nptl/pthread_setcancelstate.c index e3696ca348..7e2b6e4974 100644 --- a/nptl/pthread_setcancelstate.c +++ b/nptl/pthread_setcancelstate.c @@ -31,39 +31,9 @@ __pthread_setcancelstate (int state, int *oldstate) self = THREAD_SELF; - int oldval = THREAD_GETMEM (self, cancelhandling); - while (1) - { - int newval = (state == PTHREAD_CANCEL_DISABLE - ? oldval | CANCELSTATE_BITMASK - : oldval & ~CANCELSTATE_BITMASK); - - /* Store the old value. */ - if (oldstate != NULL) - *oldstate = ((oldval & CANCELSTATE_BITMASK) - ? PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE); - - /* Avoid doing unnecessary work. The atomic operation can - potentially be expensive if the memory has to be locked and - remote cache lines have to be invalidated. */ - if (oldval == newval) - break; - - /* Update the cancel handling word. This has to be done - atomically since other bits could be modified as well. */ - int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval, - oldval); - if (__glibc_likely (curval == oldval)) - { - if (CANCEL_ENABLED_AND_CANCELED_AND_ASYNCHRONOUS (newval)) - __do_cancel (); - - break; - } - - /* Prepare for the next round. */ - oldval = curval; - } + if (oldstate != NULL) + *oldstate = self->cancelstate; + self->cancelstate = state; return 0; } -- cgit v1.2.3