munch: Add a simple userland program for chewing up lots of memory

Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/23591f2a952

Userland/munch.cpp

@@ -0,0 +1,44 @@
+#include <AK/Types.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+int main(int argc, char** argv)
+{
+    size_t limit = 0;
+    size_t bite_size = 0;
+    int interval = 0;
+    if (argc == 1) {
+        limit = 42 * MB;
+        bite_size = 1 * MB;
+        interval = 200000;
+    } else if (argc == 4) {
+        bite_size = atoi(argv[1]);
+        limit = atoi(argv[2]);
+        interval = atoi(argv[3]);
+    } else {
+        printf("usage: munch [bite_size limit interval]\n");
+        return 1;
+    }
+
+    size_t munched = 0;
+    printf("Munching %zu bytes every %d ms, stopping at %zu\n", bite_size, interval / 1000, limit);
+    for (;;) {
+        auto* ptr = mmap(nullptr, bite_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+        if (ptr == MAP_FAILED) {
+            perror("mmap");
+            return 1;
+        }
+        memset(ptr, 0, bite_size);
+        munched += bite_size;
+        printf("Allocated: %zu\n", munched);
+        if (limit && munched >= limit) {
+            printf("All done!\n");
+            break;
+        }
+        usleep(interval);
+    }
+    return 0;
+}