Here is much easier test. (I'm sorry I'll be absent tomorrow.) the number of cpus is 8. ia64/NUMA. The hang occurs when the number of tasks is not smaller than available cpus. Can be a hint ? == [root@rhel51GA testpro]# cat yield.c #include <sched.h> int main() { while (1) sched_yield(); } [root@rhel51GA testpro]# cat batch-test.sh #!/bin/bash -x mount -t cgroup none /opt/cgroup -o cpu mkdir /opt/cgroup/group_1 mkdir /opt/cgroup/group_2 ./yield & PIDA=$! ./yield & PIDB=$! while true; do echo $PIDA > /opt/cgroup/group_1/tasks echo $PIDB > /opt/cgroup/group_1/tasks echo $PIDA > /opt/cgroup/group_2/tasks; echo $PIDB > /opt/cgroup/group_2/tasks done [root@rhel51GA testpro]#./batech-test.sh no hang. [root@rhel51GA testpro]#taskset 0f ./batech-test.sh no hang [root@rhel51GA testpro]#taskset 03 ./batech-test.sh hang. Pid: 8132, CPU 0, comm: yield psr : 00001210085a2010 ifs : 8000000000000206 ip : [<a000000100067c01>] Not tainted ip is at pick_next_task_fair+0x81/0xe0 unat: 0000000000000000 pfs : 0000000000000b1d rsc : 0000000000000003 rnat: 0000000000000000 bsps: 0000000000000000 pr : 0000000000566959 ldrs: 0000000000000000 ccv : 0000000000000000 fpsr: 0009804c0270033f csd : 0000000000000000 ssd : 0000000000000000 b0 : a0000001006f6ac0 b6 : a000000100076a60 b7 : a000000100067b80 f6 : 000000000000000000000 f7 : 000000000000000000000 f8 : 1003e00000000a0000007 f9 : 1003e0000004633b23e65 f10 : 1003ee04f68ea89dfb4c3 f11 : 1003e000000000000002b r1 : a000000100d87a60 r2 : e0000000011082f0 r3 : 0000000000000060 r8 : 0000000000000000 r9 : e000000001108310 r10 : e000004080032018 r11 : 00000000f86ccc70 r12 : e00000408394fe10 r13 : e000004083940000 r14 : 0000000000000001 r15 : 0000000000000064 r16 : e0000000011089f0 r17 : ffffffffffffffff r18 : e000000001108360 r19 : 0000000000000000 r20 : e00000408003ef10 r21 : 0000000001e9555b r22 : 000000af762794d4 r23 : 00000015e1abc70b r24 : ffffffffffffe463 r25 : e00000408003ef10 r26 : 0000000000000002 r27 : e0000000011082f0 r28 : e000000001108288 r29 : a0000001008a5468 r30 : a000000100076a60 r31 : a000000100b726e0 Call Trace: [<a000000100013bc0>] show_stack+0x40/0xa0 sp=e00000408394f860 bsp=e000004083940f18 [<a000000100014840>] show_regs+0x840/0x880 sp=e00000408394fa30 bsp=e000004083940ec0 [<a000000100036fa0>] die+0x1a0/0x2a0 sp=e00000408394fa30 bsp=e000004083940e78 [<a0000001000370f0>] die_if_kernel+0x50/0x80 sp=e00000408394fa30 bsp=e000004083940e48 [<a000000100038260>] ia64_fault+0x1140/0x1260 sp=e00000408394fa30 bsp=e000004083940de8 [<a00000010000ae20>] ia64_leave_kernel+0x0/0x270 sp=e00000408394fc40 bsp=e000004083940de8 [<a000000100067c00>] pick_next_task_fair+0x80/0xe0 sp=e00000408394fe10 bsp=e000004083940db8 [<a0000001006f6ac0>] schedule+0x940/0x1280 sp=e00000408394fe10 bsp=e000004083940d08 [<a000000100074e20>] sys_sched_yield+0xe0/0x100 sp=e00000408394fe30 bsp=e000004083940ca8 [<a00000010000aca0>] ia64_ret_from_syscall+0x0/0x20 sp=e00000408394fe30 bsp=e000004083940ca8 [<a000000000010720>] __kernel_syscall_via_break+0x0/0x20 sp=e000004083950000 bsp=e000004083940ca8 Thanks, -Kame _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers