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6819085: G1: use larger and/or user settable region size

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Instead of the region size being hard-coded, allow the user to set it.

Reviewed-by: jmasa, johnc, apetrusenko
This commit is contained in:
Antonios Printezis 2009-07-30 16:22:58 -04:00
parent c6763b5bad
commit 243367ec16
11 changed files with 125 additions and 41 deletions
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73
hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp
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@ -25,6 +25,12 @@
#include "incls/_precompiled.incl"
#include "incls/_heapRegion.cpp.incl"
int HeapRegion::LogOfHRGrainBytes = 0;
int HeapRegion::LogOfHRGrainWords = 0;
int HeapRegion::GrainBytes = 0;
int HeapRegion::GrainWords = 0;
int HeapRegion::CardsPerRegion = 0;
HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
HeapRegion* hr, OopClosure* cl,
CardTableModRefBS::PrecisionStyle precision,
@ -231,6 +237,73 @@ void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,
}
}
// Minimum region size; we won't go lower than that.
// We might want to decrease this in the future, to deal with small
// heaps a bit more efficiently.
#define MIN_REGION_SIZE ( 1024 * 1024 )
// Maximum region size; we don't go higher than that. There's a good
// reason for having an upper bound. We don't want regions to get too
// large, otherwise cleanup's effectiveness would decrease as there
// will be fewer opportunities to find totally empty regions after
// marking.
#define MAX_REGION_SIZE ( 32 * 1024 * 1024 )
// The automatic region size calculation will try to have around this
// many regions in the heap (based on the min heap size).
#define TARGET_REGION_NUMBER 2048
void HeapRegion::setup_heap_region_size(uintx min_heap_size) {
// region_size in bytes
uintx region_size = G1HeapRegionSize;
if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
// We base the automatic calculation on the min heap size. This
// can be problematic if the spread between min and max is quite
// wide, imagine -Xms128m -Xmx32g. But, if we decided it based on
// the max size, the region size might be way too large for the
// min size. Either way, some users might have to set the region
// size manually for some -Xms / -Xmx combos.
region_size = MAX2(min_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 = 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 = (int) region_size;
guarantee(GrainWords == 0, "we should only set it once");
GrainWords = GrainBytes >> LogHeapWordSize;
guarantee(1 << LogOfHRGrainWords == GrainWords, "sanity");
guarantee(CardsPerRegion == 0, "we should only set it once");
CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
}
void HeapRegion::reset_after_compaction() {
G1OffsetTableContigSpace::reset_after_compaction();
// After a compaction the mark bitmap is invalid, so we must