On Tue, 17 Jun 2014 12:27:44 -0500 Jack Miller <mille...@us.ibm.com> wrote:
> [ RESEND note: Adding relevant CCs, fixed a couple of typos in commit message, > patches unchanged. Original intro follows. ] > > All - > > This is small set of patches our team has had kicking around for a few > versions > internally that fixes tasks getting hung on shm_exit when there are many > threads hammering it at once. > > Anton wrote a simple test to cause the issue: > > http://ozlabs.org/~anton/junkcode/bust_shm_exit.c > > Before applying this patchset, this test code will cause either hanging > tracebacks or pthread out of memory errors. > > After this patchset, it will still produce output like: > > root@somehost:~# ./bust_shm_exit 1024 160 > ... > INFO: rcu_sched detected stalls on CPUs/tasks: {} (detected by 116, t=2111 > jiffies, g=241, c=240, q=7113) > INFO: Stall ended before state dump start > ... > But the task will continue to run along happily, so we consider this an > improvement over hanging, even if it's a bit noisy. > > I didn't author these patches, but I'd be happy to take any feedback and > address any issues. As it stands, these patches will be recorded as authored by yourself. You can override this by putting From: Someone Else <email-address> at the start of the changelog. Please let me know if you'd like me to make such changes. I agree that adding 8/16 bytes to the task_struct (if CONFIG_SYSVIPC) is regrettable. But the poor thing is a dumping ground anyway :( I suppose one could replace this and sysvsem with a struct ipc_stuff *ipc_stuff; /* NULL if I never used IPC */ but there are probably lots of similar changes we could (and one day may) make to the task_struct. I queued the patches, tagged for 3.16-rc1 - hopefully Davidlohr and Manfred will be able to find the time to go over them closely. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
