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Diffstat (limited to 'cpukit/ChangeLog')
| -rw-r--r-- | cpukit/ChangeLog | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/cpukit/ChangeLog b/cpukit/ChangeLog index 1e0398fbde..6cc1789bb0 100644 --- a/cpukit/ChangeLog +++ b/cpukit/ChangeLog @@ -1,3 +1,66 @@ +2005-05-14 Sergei Organov <osv@topconrd.ru> + + PR 746/rtems + Optimize realloc(). The problem is that realloc() can neither grow + nor shrink efficiently the current memory region without support + from underlying heap/region modules. The patch introduces one new + routine for each of heap and region modules, _Heap_Resize_block(), + and rtems_region_resize_segment(), respectively, and uses the + latter to optimize realloc(). + + The implementation of _Heap_Resize_block() lead to changing of the + heap allocation strategy: now the heap manager, when splits larger + free block into used and new free parts, makes the first part of + the block used, not the last one as it was before. Due to this new + strategy, _Heap_Resize_block() never needs to change the user + pointer. + + Caveat: unlike previous heap implementation, first few bytes of + the contents of the memory allocated from the heap are now almost + never all zero. This can trigger bugs in client code that have not + been visible before this patch. + + * libcsupport/src/malloc.c (realloc): try to resize segment in + place using new rtems_region_resize_segment() routine before + falling back to the malloc()/free() method. + * score/src/heap.c: + (_Heap_Initialize): change initial heap layout to reflect new + allocation strategy of using of the lower part of a previously + free block when splitting it for the purpose of allocation. + (_Heap_Block_allocate): when split, make the lower part used, and + leave the upper part free. Return type changed from Heap_Block* to + uint32_t. + * score/include/rtems/score/heap.h: + (Heap_Statistics): added 'resizes' field. + (Heap_Resize_status): new enum. + (_Heap_Resize_block): new routine. + (_Heap_Block_allocate): return type changed from Heap_Block* to + uint32_t. + * score/src/heapwalk.c: reflect new heap layout in checks. + * score/src/heapsizeofuserarea.c: more assertions added. + * score/src/heapresizeblock.c: new file. + (_Heap_Resize_block): new routine. + * score/src/heapfree.c: reverse the checks _Heap_Is_block_in() and + _Heap_Is_prev_used() on entry to be in this order. + * score/src/heapallocate.c, score/src/heapallocatealigned.c: + ignore return value of _Heap_Block_allocate(). + * score/Makefile.am (HEAP_C_FILES): added src/heapresizeblock.c. + * rtems/include/rtems/rtems/region.h: + (rtems_region_resize_segment): new interface routine. + (_Region_Process_queue): new internal routine called from + rtems_region_resize_segment() and rtems_region_return_segment(). + * rtems/src/regionreturnsegment.c: move queue management code into + the new internal routine _Region_Process_queue() and call it. + + * rtems/src/regionresizesegment.c: new file. + (rtems_region_resize_segment): new interface routine. + * rtems/src/regionprocessqueue.c: new file. + (_Region_Process_queue): new internal routine containing queue + management code factored out from 'regionreturnsegment.c'. + * rtems/Makefile.am (REGION_C_FILES): Added + src/regionresizesegment.c, and src/regionprocessqueue.c. + * ada/rtems.adb, ada/rtems.ads: Added Region_Resize_Segment. + 2005-05-20 Eric Norum <norume@aps.anl.gov> PR 793/networking |