Re: [PATCH v4 00/15] Add futex2 syscalls

* Adhemerval Zanella:

Also currently we don't have a specific usage.  The proposed patch to
add the 'pthread_mutex_lock_any' and 'pthreada_timedlock_any' [3] 
also did not gave much detail in realword usages or how it can be
leveraged.

The current rwlock implementation in glibc uses a torn 32-bit futex read
which is part of an atomically updated 64-bit word.  That's just really,
really ugly, and I suspect we could make that go away with futex2.

Thanks,
Florian

On 08/06/2021 15:19, Florian Weimer wrote:

* Adhemerval Zanella:

quoted

Also currently we don't have a specific usage.  The proposed patch to
add the 'pthread_mutex_lock_any' and 'pthreada_timedlock_any' [3] 
also did not gave much detail in realword usages or how it can be
leveraged.

The current rwlock implementation in glibc uses a torn 32-bit futex read
which is part of an atomically updated 64-bit word.  That's just really,
really ugly, and I suspect we could make that go away with futex2.

You are right, I had in the mind the multiple wait proposed by this
patch and by the glib RFC one.  Not only rwlock, but the posix
semaphore might also be simplified on 32 bits I think.