diff options
Diffstat (limited to 'Zend/zend_gc.c')
| -rw-r--r-- | Zend/zend_gc.c | 57 |
1 files changed, 53 insertions, 4 deletions
diff --git a/Zend/zend_gc.c b/Zend/zend_gc.c index 95be5d80c0..377280e17c 100644 --- a/Zend/zend_gc.c +++ b/Zend/zend_gc.c @@ -19,6 +19,56 @@ /* $Id$ */ + +/** + * zend_gc_collect_cycles + * ====================== + * + * Colors and its meaning + * ---------------------- + * + * BLACK (GC_BLACK) - In use or free. + * GREY (GC_GREY) - Possible member of cycle. + * WHITE (GC_WHITE) - Member of garbage cycle. + * PURPLE (GC_PURPLE) - Possible root of cycle. + * + * Colors described in the paper but not used + * ------------------------------------------ + * + * GREEN - Acyclic + * RED - Candidate cycle underogin + * ORANGE - Candidate cycle awaiting epoch boundary. + * + * + * Flow + * ===== + * + * The garbage collect cycle starts from 'gc_mark_roots', which traverses the + * possible roots, and calls mark_grey for roots are marked purple with + * depth-first traverse. + * + * After all possible roots are traversed and marked, + * gc_scan_roots will be called, and each root will be called with + * gc_scan(root->ref) + * + * gc_scan checkes the colors of possible members. + * + * If the node is marked as grey and the refcount > 0 + * gc_scan_black will be called on that node to scan it's subgraph. + * otherwise (refcount == 0), it marks the node white. + * + * A node MAY be added to possbile roots when ZEND_UNSET_VAR happens or + * zend_assign_to_variable is called only when possible garbage node is + * produced. + * gc_possible_root() will be called to add the nodes to possible roots. + * + * + * For objects, we call their get_gc handler (by default 'zend_std_get_gc') to + * get the object properties to scan. + * + * + * @see http://researcher.watson.ibm.com/researcher/files/us-bacon/Bacon01Concurrent.pdf + */ #include "zend.h" #include "zend_API.h" @@ -243,7 +293,7 @@ ZEND_API void ZEND_FASTCALL gc_possible_root(zend_refcounted *ref) gc_collect_cycles(); GC_REFCOUNT(ref)--; if (UNEXPECTED(GC_REFCOUNT(ref)) == 0) { - zval_dtor_func_for_ptr(ref); + zval_dtor_func(ref); return; } if (UNEXPECTED(GC_INFO(ref))) { @@ -685,7 +735,6 @@ static void gc_add_garbage(zend_refcounted *ref, gc_additional_buffer **addition GC_TYPE(ref) |= GC_FAKE_BUFFER_FLAG; } if (buf) { - GC_REFCOUNT(ref)++; buf->ref = ref; buf->next = GC_G(roots).next; buf->prev = &GC_G(roots); @@ -848,7 +897,6 @@ static int gc_collect_roots(uint32_t *flags, gc_additional_buffer **additional_b current = GC_G(roots).next; while (current != &GC_G(roots)) { - GC_REFCOUNT(current->ref)++; if (GC_REF_GET_COLOR(current->ref) == GC_WHITE) { count += gc_collect_white(current->ref, flags, additional_buffer); } @@ -889,7 +937,6 @@ tail_call: GC_REF_GET_COLOR(ref) == GC_BLACK && GC_ADDRESS(GC_INFO(ref)) != GC_ROOT_BUFFER_MAX_ENTRIES)) { GC_TRACE_REF(ref, "removing from buffer"); - GC_REFCOUNT(ref)--; if (root) { GC_INFO(ref) = 0; GC_REMOVE_FROM_ROOTS(root); @@ -1157,4 +1204,6 @@ ZEND_API int zend_gc_collect_cycles(void) * c-basic-offset: 4 * indent-tabs-mode: t * End: + * + * vim:noexpandtab: */ |