lua中通过C推送的torch张量是否进行垃圾回收?

根据这个回答(https://groups.google.com/forum/#!msg/torch7/rmIcBYCiFG8/IC68Xzd3DgAJ),似乎torch会自动释放不再使用的张量。我已经遇到过这个问题,lua自动释放了张量指针,在c程序中导致了段错误。然而,从我的实验来看,不手动调用C代码中的free函数会导致内存泄漏,程序内存不断增加。

以下是我的测试代码:

#include <iostream>
#include <chrono>
#include <thread>

#include <lua.hpp>
extern "C" {
#include <TH.h>
#include <luaT.h>
}

using namespace std;

int main(int argc, char** argv)
{
    lua_State* L = luaL_newstate();

    luaL_openlibs(L);

    lua_getglobal(L, "require");
    lua_pushstring(L, "torch");
    lua_pcall(L,1,0,0); // require "torch"

    int h=224, w=224, nb_channel=3;

    int len = h * w * nb_channel;
    long stride_1 = h * w;
    long stride_2 = w;
    long stride_3 = 1;

    for (size_t i = 0 ; i < 1000000 ; ++i)
    {
        float *tensorData = (float*)malloc(sizeof(float)*len); // Should be when the storage is freed
        THFloatStorage *storage = THFloatStorage_newWithData(tensorData, len); // Memory released when tensor input is freed by lua garbadge collector
        THFloatTensor* input = THFloatTensor_newWithStorage3d(storage,
                                                              0, // Offset
                                                              nb_channel, stride_1, // Channels
                                                              h,          stride_2, // Height
                                                              w,          stride_3); // Width
        // Do some initialisation of the tensor...

        luaT_pushudata(L, (void*) input, "torch.FloatTensor"); // Send the tensor to lua
        // Do some stuff with the input... (call lua torch scripts...)
        lua_pop(L, 1);

        // If those two lines is not set, we get a memory leak
        THFloatTensor_free(input); // Will  sometimes create a segfault as the tensor seems to be deleted by the lua garbadge collector
        THFloatStorage_free(storage);

        if (i%10000 == 0)
            std::cout << i << std::endl;
        std::this_thread::sleep_for(std::chrono::microseconds(1));
    }

    return 0;
}

如何正确管理C和lua中的内存,以避免段错误而又不会有内存泄漏?

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用户7016409
用户7016409

我认为你之所以出现内存泄漏的原因是没有释放 "tensordata" 在这一行中分配的内存:

float *tensordata = (float*)malloc(sizeof(float)*len);

希望能有所帮助。

2016-10-13 23:10:42