On Mon, Jan 20, 2020 at 03:20:14PM -0500, John Stoffel wrote: > >>>>> "Benjamin" == Benjamin Marzinski <[email protected]> writes: > > Benjamin> On Sat, Jan 18, 2020 at 12:43:49PM -0500, John Stoffel wrote: > >> >>>>> "Benjamin" == Benjamin Marzinski <[email protected]> writes: > >> > Benjamin> The way that the checkers async mode worked in multipathd didn't > make > Benjamin> much sense. When multipathd starts up, all checker classes are in > the > Benjamin> sync mode, and any pathinfo() calls on devices would run the > checker in > Benjamin> sync mode. However, the First time a checker class was used in > Benjamin> checkerloop, it would set that checker class to async (assuming > Benjamin> force_sync wasn't set). After that, no matter when a checker from > that > Benjamin> class was called, it would always run in async mode. Multipathd > doesn't > Benjamin> need to run checkers in sync mode at all, so don't. > >> > >> Sorry, I had a hard time parsing this description, especially the last > >> sentence. Do you mean that checkers should default to async then, > >> instead of sync mode? And from looking at the code, don't you mean > >> that you force sync mode? I guess the question is whether checker > >> classes should default sync, or async. And if they move to async, > >> should they stay there? > >> > > Benjamin> Sorry. I mean that right now multipathd runs the checkers from > pathinfo(), > Benjamin> wait_for_pending_paths() and check_path(). When multipathd starts, > all > Benjamin> checkers are in sync mode. The first time a checker is run from > Benjamin> check_path(), it is switched to async mode, and stays there for the > rest > Benjamin> of the time multipathd is runing. > > Benjamin> There is no need for multipathd to run checkers in sync mode at > all, so > Benjamin> we shouldn't be doing so for these first checks. > > Thanks, that makes the entire issue much more clear. This raises the > question of why there is a sync mode at all then? In any case, the > above makes the issue more understandable.
The multipath command, which uses the same checkers, runs in sync mode. -Ben > > John -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
