Ignore:
Timestamp:
2012-07-16T15:31:56Z (12 years ago)
Author:
Adam Hraska <adam.hraska+hos@…>
Branches:
lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export
Children:
0cf813d
Parents:
0594c7ea
Message:

preemption_disable: Removed failed attempt at rescheduling once preemption is enabled (and needed). Once again, preemption_enable() never reschedules.

File:
1 edited

Legend:

Unmodified
Added
Removed
  • kernel/generic/src/preempt/preemption.c

    r0594c7ea r057e77f  
    3737
    3838#include <preemption.h>
    39 #include <proc/scheduler.h>
    4039
    41 
    42 /** Determines if we are executing an exception/interrupt handler. */
    43 static bool in_exc_handler(void)
    44 {
    45         /* Err on the safe side until all exception processing code is audited. */
    46         return true;
    47 }
    48 
    49 /** Preemption was enabled. Calls scheduler(). */
    50 void preemption_enabled_scheduler(void)
    51 {
    52         ASSERT(PREEMPTION_ENABLED);
    53         ASSERT(PREEMPTION_NEEDED);
    54        
    55         /*
    56          * Avoid a race between a thread about to invoke the scheduler()
    57          * after checking THREAD->need_resched and an interrupt that
    58          * occurs right after the check.
    59          *
    60          * Also ensures that code that relies on disabled interrupts
    61          * to suppress preemption continues to work.
    62          */
    63         if (!interrupts_disabled() && !in_exc_handler()) {
    64                 preemption_clear_needed();
    65                 /* We may be preempted here, so we'll scheduler() again. Too bad. */
    66                 scheduler();
    67         }
    68 }
    69 
    70 /** Sets a flag to reschedule the next time preemption is enabled. */
    71 void preemption_set_needed(void)
    72 {
    73         /* No need to disable interrupts. */
    74         THE->preemption |= PREEMPTION_NEEDED_FLAG;
    75 }
    76 
    77 /** Instructs not to reschedule immediately when preemption is enabled. */
    78 void preemption_clear_needed(void)
    79 {
    80         /* No need to disable interrupts. */
    81         THE->preemption &= ~PREEMPTION_NEEDED_FLAG;
    82 }
    8340
    8441/** @}
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