2015-05-09 0:25 GMT+09:00 Tejun Heo <tj@xxxxxxxxxx>: > Hello, Kyungmin. > > On Fri, May 08, 2015 at 09:04:26AM +0900, Kyungmin Park wrote: >> > I need to think more about it but as an *optimization* we can add >> > freezing() test before actually waking tasks up during resume, but can >> > you please clarify what you're seeing? >> >> The mobile application has life cycle and one of them is 'suspend' >> state. it's different from 'pause' or 'background'. >> if there are some application and enter go 'suspend' state. all >> behaviors are stopped and can't do anything. right it's suspended. but >> after system suspend & resume, these application is thawed and >> running. even though system know it's suspended. >> >> We made some test application, print out some message within infinite >> loop. when it goes 'suspend' state. nothing is print out. but after >> system suspend & resume, it prints out again. that's not desired >> behavior. and want to address it. >> >> frozen user processes should be remained as frozen while system >> suspend & resume. > > Yes, they should and I'm not sure why what you're saying is happening > because freezing() test done from the frozen tasks themselves should > keep them in the freezer. Which kernel version did you test? Can you > please verify it against a recent kernel? Hi, I tested it on v4.1-rc3 and next-20150508. Task was moved to frozen cgroup: ----- root@localhost:/sys/fs/cgroup/freezer/frozen# grep . * cgroup.clone_children:0 cgroup.procs:2750 freezer.parent_freezing:0 freezer.self_freezing:1 freezer.state:FROZEN notify_on_release:0 tasks:2750 tasks:2773 ----- Unfortunately during system resume the process was woken up. The "if (frozen(p))" check was true. Is it expected behaviour? Best regards, Krzysztof -- 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>