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<== Date ==> <== Thread ==>

Subject: "spinlock" API
From: Michael Davidsaver <mdavidsaver@bnl.gov>
To: EPICS core-talk <core-talk@aps.anl.gov>
Date: Thu, 07 Jun 2012 10:48:53 -0400
All,

For the implementation of thread pool I would like to allow it to be used from interrupt context on RTEMS/vxworks. So it should need to use epicsInterruptLock(). I want to avoid using a global lock on Linux/Windows/etc.

Now I could implement this internally for the thread pool only, but I thought I would float the possibility of creating a proper spin lock API. Initially RTEMS/vxworks would implement this using epicsInterrupt and the default implement would use epicsMutex.

Are there any supported OSs other than RTEMS/vxworks which allow a non-privileged thread/process to avoid being preempted?


This API might look like this.


struct epicsSL;
typedef struct epicsSL epicsSL;

typedef unsigned long epicsSLFlag;

#define epicsSLLocalFlag(name) epicsSLFlag name = 0

epicsSL* epicsSLCreate()
void epicsSLDestroy(epicsSL*);

void epicsSLLock(epicsSL*, epicsSLFlag*);
int epicsSLTryLock(epicsSL*, epicsSLFlag*);
void epicsSLUnlock(epicsSL*, epicsSLFlag*);


Usage would look like:

struct someStruct {
  epicsSL *SL;
};

myFunc(someStruct* X) {
  epicsSLLocalFlag(iflag);

  epicsSLLock(X->SL, &iflag);
  ... do stuff ...
  epicsSLUnlock(X->SL, &iflag);
}


@Andrew, The epicsSL names are just an example.


Michael


https://code.launchpad.net/~epics-core/epics-base/thread-pool/+merge/108385


Replies:
Re: "spinlock" API Andrew Johnson

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