Difference between revisions of "KScheduler"

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[[Category:Kernel objects]]
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[[Category:Kernel interrupt events]]
  
 
class [[KScheduler]] extends [[KSchedulableInterruptEvent]];
 
class [[KScheduler]] extends [[KSchedulableInterruptEvent]];

Revision as of 02:33, 5 December 2016


class KScheduler extends KSchedulableInterruptEvent;

Size : 0x228 bytes

Offset Type Description
0x0 void ** Pointer to vtable
0x4 KSynchronizationObject * Inherited field. Unused.
0x8 u32 Count for thread switch attempts - this is only added to if a context switch function runs but exits because the scheduler is locked by another thread.
0xC bool Context switch needed
0xD bool Context switch started during interrupt
0xE bool Trigger CPU cross-core interrupt (interrupt 8)
0xF bool Post-interrupt rescheduling needed
0x10 s16 Scheduler core number
0x12 s16 Count of threads currently being managed by this scheduler object
0x14 u32 Bit field for high priority threads in KScheduler(0-31)
0x18 u32 Bit field for low priority threads in KScheduler(32-63)
0x1C KThread* Scheduler's idle thread (runs when no other runnable thread is available)
0x20 u32 Unknown
0x24 u32 Unknown/unused
0x28 ThreadSchedulePrioList[64] List of KThread pair structs by priority


ThreadSchedulePrioList struct:

Offset Type Description
0x0 KThread* First
0x4 KThread* Last


There is 1 KScheduler object per core.

KScheduler instances are mapped to SGI #8. The interrupt handler/callback returns 1, which triggers a post-interrupt rescheduling and context switch (like all the other handlers not returning NULL), but does nothing else in particular. The second virtual method is stubbed.


ThreadSchedulePrioList info:

Each priority of KThread has a pair of KThread object pointers below the KScheduler object. Each pair of pointers makes up 1 entry in that core's Scheduler for their priority. The first KThread in the entry is the first KThread in the linked list and the second is the last KThread in the linked list of KThreads in the scheduler that have the same priority.


Priority bit fields:

Each bit field goes from the most significant bit to the least significant bit, high priority to low priority. This means, for example, that bit 31 in the high priority bit field is for priority 0 and bit 0 is for priority 31. These fields are set when a KThread with the corresponding priority is added for scheduling and are cleared when the last KThread in the linked list for a given priority is removed from the scheduler.