On 02/03/2014 11:26 AM, Junichi Nomura wrote: > On 01/31/14 23:55, Hannes Reinecke wrote: >> Problem here is that pg_init_done() is per path, so at face value >> SCSI_DH_RETRY is per path, too. >> So from that we should be retrying this path (and this path only). >> Hence it would be correct to call queue_delayed_work directly. >> >> However, typically any pg_init affects _every_ path in the multipath >> device (active paths become passive and vice versa). >> Which seems to be the intended usage, as we're checking for >> pg_init_in_progress prior to invoking queue_delayed_work(). >> >> But _if_ we assume that, then we only need to send a _single_ >> pg_init, as this will switch all paths. So again, a call to >> __pg_init_all_paths will not do the correct thing as it'll >> send activations to _every_ active path. > > Sending activation for every paths was introduced by this: > commit e54f77ddda72781ec1c1696b21aabd6a30cbb7c6 > Author: Chandra Seetharaman <sekharan@xxxxxxxxxx> > Date: Mon Jun 22 10:12:12 2009 +0100 > So if you make change in the logic, you have to check whether the > change does not break what the above solved. > >> (And, in fact, we're trying really hard in scsi_dh_rdac >> and scsi_dh_alua to bunch together all the various pg_init >> requests precisely for the cited reason). >> >> So my inclination here would be to treat SCSI_DH_RETRY >> as _per path_, and retry only this specific path. >> IE removing the check to pg_init_in_progress and call >> queue_delayed_work() directly. >> >> IMHO this would impose the least restriction on >> the internal workings of the various device handlers. >> >> What do you think? > > I don't have strong opinion either way. But if we do that, more code > has to be changed, e.g. the management of retry count. > > Removing the unnecessary workqueue has already a benefit. > It would be nice to focus on that instead of folding in more changes. > Yes, that's what I've figured, too. So I've just included the changes you suggested without modifying the current logic. I've already sent a new patchset, please check if the changes there are correct. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@xxxxxxx +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg) -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
