I noticed that memcg OOM event does not trigger as expected when a thread group ID assigned by clone(CLONE_VM without CLONE_THREAD) is specified. A bit of surprise because what the "tasks" file says is not what the limitation is applied to... ---------- #define _GNU_SOURCE #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <sched.h> #include <unistd.h> static int memory_eater(void *unused) { FILE *fp; const unsigned long size = 1048576 * 200; char *buf = malloc(size); mkdir("/sys/fs/cgroup/memory/test1", 0755); fp = fopen("/sys/fs/cgroup/memory/test1/memory.limit_in_bytes", "w"); fprintf(fp, "%lu\n", size / 2); fclose(fp); fp = fopen("/sys/fs/cgroup/memory/test1/tasks", "w"); fprintf(fp, "%u\n", getpid()); fclose(fp); fp = fopen("/dev/zero", "r"); fread(buf, 1, size, fp); fclose(fp); return 0; } int main(int argc, char *argv[]) { if (clone(memory_eater, malloc(8192) + 8192, /*CLONE_SIGHAND | CLONE_THREAD | */CLONE_VM, NULL) == -1) return 1; while (1) pause(); return 0; } ----------