Struct alloc zone

概要

• gcc-4.1.0/gcc/ggc-zone.cにて定義
• ゾーン割り当て構造体

実装

379 /* A zone allocation structure.  There is one of these for every
380    distinct allocation zone.  */
381 struct alloc_zone
382 {
383   /* The most recent free chunk is saved here, instead of in the linked
384      free list, to decrease list manipulation.  It is most likely that we
385      will want this one.  */
386   char *cached_free;
387   size_t cached_free_size;
388 
389   /* Linked lists of free storage.  Slots 1 ... NUM_FREE_BINS have chunks of size
390      FREE_BIN_DELTA.  All other chunks are in slot 0.  */
391   struct alloc_chunk *free_chunks[[[NUM_FREE_BINS]] + 1];
392 
393   /* The highest bin index which might be non-empty.  It may turn out
394      to be empty, in which case we have to search downwards.  */
395   size_t high_free_bin;
396 
397   /* Bytes currently allocated in this zone.  */
398   size_t allocated;
399 
400   /* Linked list of the small pages in this zone.  */
401   struct small_page_entry *pages;
402 
403   /* Doubly linked list of large pages in this zone.  */
404   struct large_page_entry *large_pages;
405 
406   /* If we are currently marking this zone, a pointer to the mark bits.  */
407   mark_type *mark_bits;
408 
409   /* Name of the zone.  */
410   const char *name;
411 

• small pageの数

412   /* The number of small pages currently allocated in this zone.  */
413   size_t n_small_pages;
414 
415   /* Bytes allocated at the end of the last collection.  */
416   size_t allocated_last_gc;
417 

• 現在どの程度マップしているか

418   /* Total amount of memory mapped.  */
419   size_t bytes_mapped;
420 
421   /* A cache of free system pages.  */
422   struct small_page_entry *free_pages;
423 
424   /* Next zone in the linked list of zones.  */
425   struct alloc_zone *next_zone;
426 
427   /* True if this zone was collected during this collection.  */
428   bool was_collected;
429 
430   /* True if this zone should be destroyed after the next collection.  */
431   bool dead;
432 
433 #ifdef GATHER_STATISTICS
434   struct
435   {
436     /* Total memory allocated with ggc_alloc.  */
437     unsigned long long total_allocated;
438     /* Total overhead for memory to be allocated with ggc_alloc.  */
439     unsigned long long total_overhead;
440 
441     /* Total allocations and overhead for sizes less than 32, 64 and 128.
442        These sizes are interesting because they are typical cache line
443        sizes.  */
444    
445     unsigned long long total_allocated_under32;
446     unsigned long long total_overhead_under32;
447   
448     unsigned long long total_allocated_under64;
449     unsigned long long total_overhead_under64;
450   
451     unsigned long long total_allocated_under128;
452     unsigned long long total_overhead_under128;
453   } stats;
454 #endif
455 } main_zone;

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