android heapStartSize heapMaximumSize heapGrowthLimit heapSize说明

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dalvik/vm/Globals.java代码片段：

struct DvmGlobals {

/*

* Some options from the command line or environment.

*/

char* bootClassPathStr;

char* classPathStr;

size_t heapStartingSize;

size_t heapMaximumSize;

size_t heapGrowthLimit;

size_t stackSize;

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heapStartingSize是进程启动时java heap的初始大小

heapMaximumSize的值必须大于heapGrowthLimit，当heapGrowthLimit值为0时，heapGrowthLimit就被赋值为heapMaximumSize。当Java堆对象总和达到heapGrowthLimit时，dalvik会抛出Error级别的异常，java app的主线程的DefaultUncaughtExceptionHandler会执行，弹出对话框提示app结束。

代码如下：dalvik/vm/alloc/Heap.cpp

/*

* Initialize the GC heap.

*

* Returns true if successful, false otherwise.

*/

bool dvmHeapStartup()

{

GcHeap *gcHeap;

if (gDvm.heapGrowthLimit == 0) {

gDvm.heapGrowthLimit = gDvm.heapMaximumSize;

}

gcHeap = dvmHeapSourceStartup(gDvm.heapStartingSize,

gDvm.heapMaximumSize,

gDvm.heapGrowthLimit);

if (gcHeap == NULL) {

return false;

}

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dalvik.vm.heapsize这个property只对largeHeap的app起作用。当app的AndroidManifest.xml设置了大内存，heapGrowthLimit就不起作用了。