Re: ZEND_MM_SMALL_FREE_BUCKET and ZEND_MM_REST_BUCKET

From:	Stas Malyshev	Date:	Fri, 02 Mar 2012 18:44:44 +0000
Subject:	Re: ZEND_MM_SMALL_FREE_BUCKET and ZEND_MM_REST_BUCKET
References:	1	Groups:	php.internals
Request:	Send a blank email to [email protected] to get a copy of this message

Hi!


#define ZEND_MM_SMALL_FREE_BUCKET(heap, index) \
(zend_mm_free_block*) ((char*)&heap->free_buckets[index * 2] + \
sizeof(zend_mm_free_block*) * 2 - \
sizeof(zend_mm_small_free_block))
#define
ZEND_MM_REST_BUCKET(heap) \
(zend_mm_free_block*)((char*)&heap->rest_buckets[0] + \
sizeof(zend_mm_free_block*) * 2 - \
sizeof(zend_mm_small_free_block))

IIRC the purpose of these defines is that the MM caches small free blocks so that it could find them faster, so that for example allocating zvals (frequent case) goes faster. So it has a small cache for such blocks, by size, so the allocator can for example quickly find a free block of size of zval or of size of Hashtable. These macros try to find such free block for given small size (first one) or for the rest of blocks (i.e. bigger blocks which share one free list).
-- 
Stanislav Malyshev, Software Architect
SugarCRM: http://www.sugarcrm.com/
(408)454-6900 ext. 227


   

Thread (12 messages)

• Adi MutuFri, 02 Mar 2012 12:51:43 +0000
  • jpauliFri, 02 Mar 2012 13:43:47 +0000Re: ZEND_MM_SMALL_FREE_BUCKET and ZEND_MM_REST_BUCKET
    • Adi MutuFri, 02 Mar 2012 13:57:50 +0000
      • Ferenc KovacsFri, 02 Mar 2012 14:00:38 +0000
        • Adi MutuFri, 02 Mar 2012 14:12:31 +0000
          • LaruenceFri, 02 Mar 2012 14:52:08 +0000
            • Adi MutuFri, 02 Mar 2012 15:01:23 +0000
      • jpauliFri, 02 Mar 2012 14:21:18 +0000
  • LaruenceFri, 02 Mar 2012 14:41:23 +0000Re: ZEND_MM_SMALL_FREE_BUCKET and ZEND_MM_REST_BUCKET
  • Stas MalyshevFri, 02 Mar 2012 18:44:44 +0000
    • Adi MutuFri, 02 Mar 2012 19:10:07 +0000
• adit aditMon, 05 Mar 2012 06:41:09 +0000Re: ZEND_MM_SMALL_FREE_BUCKET and ZEND_MM_REST_BUCKET