[PATCH v18 8/8] eal: implement functions for mutex management

[Dmitry Kozlyuk]

Hi Stephen,

2022-02-24 09:44 (UTC-0800), Stephen Hemminger:
> There seems to be some confusion here:
>    pthread_mutex put thread to sleep if contended and on linux are built on the futex system call.
>    pthread_rwlock are the reader/writer versions of these.
> 
> The DPDK has primitives for multiple types of locks: spinlock, rwlock, ticketlock, pflock, etc
>    these are build using atomic primitives (no syscall).
>    these are platform independent
>    these spin if contended
> 
> Not sure about Windows, but it looks like slim rwlocks came from Windows NT and are an implementation
> of the same kind of spinning lock DPDK already has.

Both CRITICAL_SECTION and SRW lock spin shortly before going into kernel,
but both do this eventually---SRW lock is not a purely user space primitive.