Function storage_init

src/storage.cpp:141–186

initialize the memory subsystem. NOTE: This may be called twice, first with NULL specifying we should use ram later, after the configuration file is loaded with a path to where we should place our temporary file.

//      later, after the configuration file is loaded with a path to where we should
//      place our temporary file.
void storage_init(const char *tmpfilePath, size_t cbFileReserve)
{
    if (tmpfilePath == NULL)
    {
        serverAssert(mkdisk == NULL);
        mkdisk = MEMKIND_DEFAULT;
        pool_initialize(&poolobj, sizeof(robj));
        pool_initialize(&poolembstrobj, EMBSTR_ROBJ_SIZE);
    }
    else
    {
        // First create the file
        serverAssert(mkdisk == MEMKIND_DEFAULT);
        PMEM_DIR = (char*)memkind_malloc(MEMKIND_DEFAULT, strlen(tmpfilePath));
        strcpy((char*)PMEM_DIR, tmpfilePath);
        int errv = memkind_create_pmem(PMEM_DIR, 0, &mkdisk);
        if (errv == MEMKIND_ERROR_INVALID)
        {
            serverLog(LL_WARNING, "Memory pool creation failed: %s", strerror(errno));
            exit(EXIT_FAILURE);
        }
        else if (errv)
        {
            char msgbuf[1024];
            memkind_error_message(errv, msgbuf, 1024);
            serverLog(LL_WARNING, "Memory pool creation failed: %s", msgbuf);
            exit(EXIT_FAILURE);
        }

        // Next test if COW is working
        int fdTest = forkFile();
        if (fdTest < 0)
        {
            serverLog(LL_WARNING, "Scratch file system does not support Copy on Write.  To fix this scratch-file-path must point to a path on a filesystem which supports copy on write, such as btrfs.");
            exit(EXIT_FAILURE);
        }
        close(fdTest);

        // Now lets make the file big
        if (cbFileReserve == 0)
            cbFileReserve = 1*1024*1024*1024;   // 1 GB (enough to be interesting)
        posix_fallocate64(memkind_fd(mkdisk), 0, cbFileReserve);

        pthread_atfork(handle_prefork, handle_postfork_parent, handle_postfork_child);
    }
}