On Thu, Aug 04, 2016 at 12:52:54AM +0200, Jann Horn wrote: ... > > > > Thanks for this! I tweaked your text somewhat, and added some > > details about kernel configuration options, so that now the text > > reads: > > > > /proc/[pid]/task/[tid]/children (since Linux 3.5) > > A space-separated list of child tasks of this task. > > Each child task is represented by its TID. > > > > This option is intended for use by the checkpoint- > > restore (CRIU) system, and reliably provides a list of > > children only if all of the child processes are > > stopped or frozen. It does not work properly if chil‐ > > dren of the target task exit while the file is being > > read! Exiting children may cause non-exiting children > > to be omitted from the list. This makes this inter‐ > > face even more unreliable than classic PID-based > > approaches if the inspected task and its children > > aren't frozen, and most code should probably not use > > this interface. Hi! First of all, sorry for delay. Guys, this is not really true. The same applies to plain "ls /proc". You can fetch pid from the procfs and then process get dead just right after you've finished reading. So this interface works "properly" all the time, but if one needs precise results it should stop/freeze processes first. In contrary I think it worth switching into children interface in user-space programs because it incredibly fast. > > > > Until Linux 4.2, the presence of this file was gov‐ > > erned by the CONFIG_CHECKPOINT_RESTORE kernel configu‐ > > ration option. Since Linux 4.2, it it is governed by > > the CONFIG_PROC_CHILDREN option. > > > > Look okay? > > Looks good to me. Cyrill -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
