Eliot Miranda uploaded a new version of Kernel to project The Trunk: http://source.squeak.org/trunk/Kernel-eem.1184.mcz
==================== Summary ====================
Name: Kernel-eem.1184 Author: eem Time: 26 July 2018, 9:02:17.653687 pm UUID: 37221c94-8415-41a5-8535-b047f59150b9 Ancestors: Kernel-eem.1183
Now that Kernel-eem.1183 has fixed the process termination in critical: in the face of higher priority processes issue, we can go back to a simpler implementation of Semaphore>>critical:, albeit one marked with ther <criticalSection> pragma for visibility in Process>>#terminate.
=============== Diff against Kernel-eem.1183 ===============
Item was changed: ----- Method: Semaphore>>critical: (in category 'mutual exclusion') ----- critical: mutuallyExcludedBlock "Evaluate mutuallyExcludedBlock only if the receiver is not currently in the process of running the critical: message. If the receiver is, evaluate mutuallyExcludedBlock after the other critical: message is finished." <criticalSection> + self wait. + ^mutuallyExcludedBlock ensure: [self signal] - | caught | - "We need to catch eventual interruptions very carefully. - The naive approach of just doing, e.g.,: - self wait. - aBlock ensure:[self signal]. - will fail if the active process gets terminated while in the wait. - However, the equally naive: - [self wait. - aBlock value] ensure:[self signal]. - will fail too, since the active process may get interrupted while - entering the ensured block and leave the semaphore signaled twice. - To avoid both problems we make use of the fact that interrupts only - occur on sends (or backward jumps) and use an assignment (bytecode) - right before we go into the wait primitive (which cannot be preempted)." - - caught := false. - ^[ - caught := true. - self wait. - mutuallyExcludedBlock value - ] ensure: [ caught ifTrue: [self signal] ] !