mmap_big.cpp

#include "faasm/faasm.h"

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <string>
#include <sys/mman.h>

int main(int argc, char* argv[])
{
    // Make sure we can allocate more than 1GB of memory (i.e. >16384 pages)
    size_t nPages = 18000;
    size_t chunkSize = 1000;
    size_t nChunks = nPages / chunkSize;
    size_t chunkLen = (chunkSize * 64 * 1024);

    void** regions = new void*[nChunks];
    for (int i = 0; i < nChunks; i++) {
        void* p = mmap(nullptr,
                       chunkLen,
                       PROT_READ | PROT_WRITE,
                       MAP_ANON | MAP_PRIVATE,
                       -1,
                       0);
        if (p == MAP_FAILED) {
            printf("ERROR - mmap failed: %s\n", strerror(errno));
            return 1;
        }

        regions[i] = p;
    }

    for (int i = nChunks - 1; i >= 0; i--) {
        void* p = regions[i];
        int res = munmap(p, chunkLen);
        if (res != 0) {
            printf("ERROR - munmap failed: %s\n", strerror(errno));
            return 1;
        }
    }

    printf("Big mmap succeeded\n");
    return 0;
}