Created
July 11, 2014 03:35
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void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) { | |
uintx region_size = G1HeapRegionSize; | |
if (FLAG_IS_DEFAULT(G1HeapRegionSize)) { | |
size_t average_heap_size = (initial_heap_size + max_heap_size) / 2; | |
region_size = MAX2(average_heap_size / TARGET_REGION_NUMBER, | |
(uintx) MIN_REGION_SIZE); | |
} | |
int region_size_log = log2_long((jlong) region_size); | |
// Recalculate the region size to make sure it's a power of | |
// 2. This means that region_size is the largest power of 2 that's | |
// <= what we've calculated so far. | |
region_size = ((uintx)1 << region_size_log); | |
// Now make sure that we don't go over or under our limits. | |
if (region_size < MIN_REGION_SIZE) { | |
region_size = MIN_REGION_SIZE; | |
} else if (region_size > MAX_REGION_SIZE) { | |
region_size = MAX_REGION_SIZE; | |
} | |
// And recalculate the log. | |
region_size_log = log2_long((jlong) region_size); | |
// Now, set up the globals. | |
guarantee(LogOfHRGrainBytes == 0, "we should only set it once"); | |
LogOfHRGrainBytes = region_size_log; | |
guarantee(LogOfHRGrainWords == 0, "we should only set it once"); | |
LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize; | |
guarantee(GrainBytes == 0, "we should only set it once"); | |
// The cast to int is safe, given that we've bounded region_size by | |
// MIN_REGION_SIZE and MAX_REGION_SIZE. | |
GrainBytes = (size_t)region_size; | |
guarantee(GrainWords == 0, "we should only set it once"); | |
GrainWords = GrainBytes >> LogHeapWordSize; | |
guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity"); | |
guarantee(CardsPerRegion == 0, "we should only set it once"); | |
CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift; | |
} |
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