On Tue, Mar 06, 2007 at 03:16:55PM +0100, Michael Ellerman wrote: > On Tue, 2007-03-06 at 19:27 +0530, Mohan Kumar M wrote: > > Hi, > > > > Here comes the revised version of patch to fix the interrupt missing > > problem when a kdump kernel is booted with "maxcpus=1" kernel parameter. > > > > In the xics initialization code a check is made to detemine whether > > maxcpus kernel parameter is present and if its present then > > default_distrib_server variable is initialized to the current boot cpu > > id (by default_server variable). So that when ever a kernel is booted > > with maxcpus kernel parameter all interrupts are routed to the boot cpu > > only. > > > > Tested on POWER5 and JS20 systems. > > First, I don't know why we keep telling people to use maxcpus=1 for > kexec/kdump - it's causing bugs, and I don't know of any that it fixes?
Some distros want to use maxcpus=1 for kdump. > > Second, the way you've written this is not so good. The xics code should > not be checking that "maxcpus" exists on the command line, it should be > checking that the distrib server points to a cpu that is online - using > cpu_online() etc. > In get_irq_server function in xics.c, "noirqdistrib" command line parameter is indirectly checked for routing the interrupts either to a specific cpu or to all cpus. So I think checking for maxcpus= command line parameter in xics.c is not a problem. Also during the xics_init_IRQ function other cpus (secondary cpus) will not be online, they are made online at a later stage. So using cpu_online() function at xics_init_IRQ will return true only for boot cpu id. > cheers > > -- > Michael Ellerman > OzLabs, IBM Australia Development Lab > > wwweb: http://michael.ellerman.id.au > phone: +61 2 6212 1183 (tie line 70 21183) > > We do not inherit the earth from our ancestors, > we borrow it from our children. - S.M.A.R.T Person _______________________________________________ fastboot mailing list [email protected] https://lists.osdl.org/mailman/listinfo/fastboot
