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Garbage Collection
[Data]

Files
file	gc.c
	plint garbage collection.
file	gc.h
	plint garbage collection.
Data Structures
struct	_plint_refs
	a list of the references to a node. More...
struct	_plint_cycles
	a list of GC cycles. More...
struct	_plint_gc_link
	the brick of gc mechanism. More...
struct	_plint_gc_cycle
	a cycle. More...
struct	_plint_gc_chunk
Defines
#define	gc_lock()   ++gc_lock_flag, gc_dirty_flag = !0
	locks the triggering of gc. More...
#define	gc_unlock()   --gc_lock_flag
	unlocks the triggering of gc. More...
#define	force_gc_collect()
	forces triggering of the collection algorithm. More...
#define	PLINT_GC_CHUNK_INIT(__p__)
	initializes the gc chunk of a node. More...
Typedefs
typedef _plint_refs *	plint_refs_t
typedef _plint_cycles *	plint_cycles_t
typedef _plint_gc_link *	plint_gc_link_t
typedef _plint_gc_cycle *	plint_gc_cycle_t
Functions
void	gc_collect ()
	the actual garbage collection algorithm. More...
void	plint_gc_init ()
	initialise the Garbage Collection engine.
void	plint_gc_finish ()
	finalize the Garbage Collection engine.
int	plint_gc_empty ()
	test if GCP is empty.
void	plint_cycle_detect (plint_mem_t MEMORY, plint_ref_t REFERENCE)
Variables
unsigned int	gc_lock_flag
	a lock to prevent auto-triggering of gc.
int	gc_dirty_flag
	a variable used in auto-triggered-alarm-time-estimation.

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Define Documentation

#define gc_lock (    )     ++gc_lock_flag, gc_dirty_flag = !0

locks the triggering of gc. Returns: nothing Definition at line 74 of file gc.h. Referenced by plint_data_type_finish, plint_gc_finish, plint_ptr_fre, and plint_var_fre.

#define gc_unlock (    )     --gc_lock_flag

unlocks the triggering of gc. Returns: nothing Definition at line 75 of file gc.h. Referenced by plint_ptr_fre, and plint_var_fre.

#define force_gc_collect (    )

Value: { \ extern void gc_collect(); \ gc_lock(); \ gc_collect(); \ gc_unlock(); \ } forces triggering of the collection algorithm. Precondition: the GC must not be locked Returns: nothing Definition at line 79 of file gc.h. Referenced by plint_type_finish, and plint_type_unregister.

#define PLINT_GC_CHUNK_INIT (  __p__    )

Value: (__p__)->ref = 0; \ (__p__)->cycles_ref = 0; \ (__p__)->refs_ref = 0; \ (__p__)->cycles_head = 0; \ (__p__)->refs_head = 0; \ (__p__)->mark = 0 initializes the gc chunk of a node. Definition at line 56 of file gc.h.

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Function Documentation

void gc_collect (    )

the actual garbage collection algorithm. Returns: nothing Definition at line 636 of file gc.c. References _plint_gc_cycle::cycle, gc_dirty_flag, _plint_gc_cycle::next, and _plint_gc_cycle::skip. { size_t i, m; plint_gc_cycle_t * p; plint_gc_cycle_t q; #ifndef PLINT_DOGC_LAST int r = getpriority(PRIO_PROCESS, 0); sigset_t lock_ss, old_ss; sigfillset(&lock_ss); sigprocmask(SIG_SETMASK, &lock_ss, &old_ss); setpriority(PRIO_PROCESS, 0, -20); #endif for (n = 1; n <= ncycles; ++n) for (p = acycles+n-1; (q = *p); ) { for (i = 0; i < n; ++i) if (0 /* cycle has opened due to a ... */ || plint_ref_var(plint_mrv_ref(q->cycle[i])) != plint_mrv_var(q->cycle[i]) /* ... PLINT_ASG_REF assignment */ || plint_var_mem(plint_mrv_var(q->cycle[i])) != plint_mrv_mem(q->cycle[(i+1)%n])) /* ... PLINT_ASG_VAL assignment */ break; if (i < n) collect(p, q, !0); else p = &q->next; } for (n = 1; n <= ncycles; ++n) for (q = acycles[n-1]; q; q = q->next) if (!q->skip) for (i = 0; i < n; ++i) if (0 /* reference count sum equation */ || plint_mrv_var(q->cycle[i])->_gc.ref > plint_mrv_var(q->cycle[i])->_gc.cycles_ref + plint_mrv_var(q->cycle[i])->_gc.refs_ref || plint_mrv_mem(q->cycle[i])->_gc.ref > plint_mrv_mem(q->cycle[i])->_gc.cycles_ref + plint_mrv_mem(q->cycle[i])->_gc.refs_ref ) { skip(q, n); break; } for (m = 0, n = 1; n <= ncycles; (acycles[n-1] ? 0 : ++m), ++n) for (p = acycles+n-1; (q = *p); ) if (q->skip) { q->skip = 0; p = &q->next; } else collect(p, q, 0); if (m == ncycles) { free(acycles); acycles = 0; ncycles = 0; } #ifndef PLINT_DOGC_LAST gc_dirty_flag = 0; setpriority(PRIO_PROCESS, 0, r); sigprocmask(SIG_SETMASK, &old_ss, 0); #endif }

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