[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v6 16/18] vmx: Add some scheduler hooks for VT-d posted interrupts
> -----Original Message----- > From: Jan Beulich [mailto:JBeulich@xxxxxxxx] > Sent: Thursday, September 10, 2015 5:26 PM > To: Wu, Feng > Cc: Andrew Cooper; Dario Faggioli; George Dunlap; Tian, Kevin; > xen-devel@xxxxxxxxxxxxx; Keir Fraser > Subject: RE: [PATCH v6 16/18] vmx: Add some scheduler hooks for VT-d posted > interrupts > > >> > Anyway, I go through the main path of the code as below, I really don't > >> > find > >> > anything unsafe here. > >> > > >> > context_switch() --> > >> > pi_ctxt_switch_from() --> > >> > vmx_pre_ctx_switch_pi() --> > >> > vcpu_unblock() --> > >> > vcpu_wake() --> > >> > SCHED_OP(VCPU2OP(v), wake, v) --> > >> > csched_vcpu_wake() --> > >> > __runq_insert() > >> > __runq_tickle() > >> > > >> > If you continue to think it is unsafe, pointing out the place will be > >> > welcome! > >> > >> Once again - I didn't say it's unsafe (and hence can't point at a > >> particular place). What bothers me is that vcpu_unblock() affects > >> scheduler state, and altering scheduler state from inside the > >> context switch path looks problematic at the first glance. I'd be > >> happy if I was told there is no such problem, but be aware that > >> this would have to include latent ones: Even if right now things > >> are safe, having such feedback have the potential of becoming > >> an actual problem with a later scheduler change is already an > >> issue, as finding the problem is then likely going to be rather hard > >> (and I suspect it's not going to be you to debug this). > > > > What I can say is that after investigation, I don't find anything bad > > for this vcpu_unblock(), I tested it in my experiment. So that is why > > I'd like to ask some ideas from scheduler expects. > > Agreed - I'm also awaiting their input. Hi Dario, & George, could you please gave your thoughts about this? Your input is very important for us! Thanks, Feng _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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