Hi Al, On Wed, Mar 31, 2021 at 7:29 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > On Wed, Mar 31, 2021 at 07:16:45PM -0700, Manish Varma wrote: > > timerfd doesn't create any wakelocks, but eventpoll can. When it does, > > it names them after the underlying file descriptor, and since all > > timerfd file descriptors are named "[timerfd]" (which saves memory on > > systems like desktops with potentially many timerfd instances), all > > wakesources created as a result of using the eventpoll-on-timerfd idiom > > are called... "[timerfd]". > > > > However, it becomes impossible to tell which "[timerfd]" wakesource is > > affliated with which process and hence troubleshooting is difficult. > > > > This change addresses this problem by changing the way eventpoll > > wakesources are named: > > > > 1) the top-level per-process eventpoll wakesource is now named "epoll:P" > > (instead of just "eventpoll"), where P, is the PID of the creating > > process. > > 2) individual per-underlying-filedescriptor eventpoll wakesources are > > now named "epollitemN:P.F", where N is a unique ID token and P is PID > > of the creating process and F is the name of the underlying file > > descriptor. > > > > All together that should be splitted up into a change to eventpoll and > > timerfd (or other file descriptors). > > FWIW, it smells like a variant of wakeup_source_register() that would > take printf format + arguments would be a good idea. I.e. something > like > > > + snprintf(buf, sizeof(buf), "epoll:%d", task_pid); > > + epi->ep->ws = wakeup_source_register(NULL, buf); > > ... = wakeup_source_register(NULL, "epoll:%d", task_pid); > > etc. Noted. I will fix this in the v3 patch. Thanks, Manish
