Jan Kiszka wrote: >>> Anyway, after some thoughts, I think we are going to try and make the >>> current situation work instead of going back to the old way. >>> >>> You can find the patch which attempts to do so here: >>> http://sisyphus.hd.free.fr/~gilles/sched_status.txt >> Ack. At last, this addresses the real issues without asking for >> regression funkiness: fix the lack of barrier before testing XNSCHED in > > Check the kernel, we actually need it on both sides. Wherever the final > barriers will be, we should leave a comment behind why they are there. > Could be picked up from kernel/smp.c.
We have it on both sides: the non-local flags are modified while holding the nklock. Unlocking the nklock implies a barrier. > >> the xnpod_schedule pre-test, and stop sched->status trashing due to >> XNINIRQ/XNHTICK/XNRPICK ops done un-synced on nklock. >> >> In short, this patch looks like moving the local-only flags where they >> belong, i.e. anywhere you want but *outside* of the status with remotely >> accessed bits. XNRPICK seems to be handled differently, but it makes >> sense to group it with other RPI data as you did, so fine with me. > > I just hope we finally converge over a solution. Looks like all > possibilities have been explored now. A few more comments on this one: > > It probably makes sense to group the status bits accordingly (both their > values and definitions) and briefly document on which status field they > are supposed to be applied. Ok, but I wanted them to not use the same values, so that we can use the sched->status | sched->lstatus trick in xnpod_schedule. Something is lacking too: we probably need to use sched->status | sched->lstatus for display in /proc. > > I do not understand the split logic - or some bits are simply not yet > migrated. XNHDEFER, XNSWLOCK, XNKCOUT are all local-only as well, no? > Then better put them in the _local_ status field, that's more consistent > (and would help if we once wanted to optimize their cache line usage). Maybe the naming is not good the. ->status is everything which is modified under nklock, ->lstatus is for XNINIRQ and XNHTICK which are modified without holding the nklock. > > The naming is unfortunate: status vs. lstatus. This is asking for > confusion and typos. They must be better distinguishable, e.g. > local_status. Or we need accessors that have debug checks built in, > catching wrong bits for their target fields. I agree. > > Good catch of the RPI breakage, Gilles! -- Gilles. _______________________________________________ Xenomai-core mailing list Xenomaiemail@example.com https://mail.gna.org/listinfo/xenomai-core