On Mon, Sep 21, 2015 at 04:01:41PM -0400, Tejun Heo wrote: > (cc'ing scheduler folks) > > On Sun, Sep 20, 2015 at 10:45:25AM -0400, Sasha Levin wrote: > > On 09/13/2015 02:59 PM, Tejun Heo wrote: > > > task_struct->memcg_oom is a sub-struct containing fields which are > > > used for async memcg oom handling. Most task_struct fields aren't > > > packaged this way and it can lead to unnecessary alignment paddings. > > > This patch flattens it. > > > > > > * task.memcg_oom.memcg -> task.memcg_in_oom > > > * task.memcg_oom.gfp_mask -> task.memcg_oom_gfp_mask > > > * task.memcg_oom.order -> task.memcg_oom_order > > > * task.memcg_oom.may_oom -> task.memcg_may_oom > ... > > I've started seeing these warnings: > > > > [1598889.250160] WARNING: CPU: 3 PID: 11648 at include/linux/memcontrol.h:414 handle_mm_fault+0x1020/0x3fa0() > ... > > [1598892.247256] dump_stack (lib/dump_stack.c:52) > > [1598892.249105] warn_slowpath_common (kernel/panic.c:448) > > [1598892.253202] warn_slowpath_null (kernel/panic.c:482) > > [1598892.255148] handle_mm_fault (include/linux/memcontrol.h:414 mm/memory.c:3430) > > [1598892.268151] __do_page_fault (arch/x86/mm/fault.c:1239) > > [1598892.269022] trace_do_page_fault (arch/x86/mm/fault.c:1331 include/linux/jump_label.h:133 include/linux/context_tracking_state.h:30 include/linux/context_tracking.h:46 arch/x86/mm/fault.c:1332) > > [1598892.269894] do_async_page_fault (arch/x86/kernel/kvm.c:280) > > [1598892.270792] async_page_fault (arch/x86/entry/entry_64.S:989) > > > > Not sure if it's because of this patch or not, but I haven't seen them before. > > So, the only way the patch could have caused the above is if someone > who isn't the task itself is writing to the bitfields while the task > is running. Looking through the fields, ->sched_reset_on_fork seems a > bit suspicious. __sched_setscheduler() looks like it can modify the > bit while the target task is running. Peter, am I misreading the > code? Ping? -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>