On Sun, Feb 24, 2013 at 04:28:58PM -0500, Peter Hurley wrote: > > On Tue, 2013-01-22 at 13:24 -0800, Dave Hansen wrote: > > This series fixes a hard-to-debug early boot hang on 32-bit > > NUMA systems. It adds coverage to the debugging code, > > adds some helpers, and eventually fixes the original bug I > > was hitting. > > Hi Dave, > > Now that the alloc_remap() has been/is being removed, is most/all of > this being reverted? > > I ask because I was fixing a different bug in KVM's para-virt clock and > saw part of this series (from [PATCH 5/5] fix kvm's use of __pa() on > percpu areas): > > diff -puN arch/x86/kernel/kvmclock.c~fix-kvm-__pa-use-on-percpu-areas arch/x86/kernel/kvmclock.c > --- linux-2.6.git/arch/x86/kernel/kvmclock.c~fix-kvm-__pa-use-on-percpu-areas 2013-01-22 13:17:16.428317508 -0800 > +++ linux-2.6.git-dave/arch/x86/kernel/kvmclock.c 2013-01-22 13:17:16.432317541 -0800 > @@ -162,8 +162,8 @@ int kvm_register_clock(char *txt) > int low, high, ret; > struct pvclock_vcpu_time_info *src = &hv_clock[cpu].pvti; > > - low = (int)__pa(src) | 1; > - high = ((u64)__pa(src) >> 32); > + low = (int)slow_virt_to_phys(src) | 1; > + high = ((u64)slow_virt_to_phys(src) >> 32); > ret = native_write_msr_safe(msr_kvm_system_time, low, high); > printk(KERN_INFO "kvm-clock: cpu %d, msr %x:%x, %s\n", > cpu, high, low, txt); > I think this hunk was converted by mistake since the code does not use per cpu allocations, but since __pa() and slow_virt_to_phys() should return the same thing here it does not matter much. > which confused me because hv_clock is the __va of allocated physical > memory, not a per-cpu variable. > > mem = memblock_alloc(size, PAGE_SIZE); > if (!mem) > return; > hv_clock = __va(mem); > > So in short, my questions are: > 1) is the slow_virt_to_phys() necessary anymore? > 2) if yes, does it apply to the code above? > 3) if yes, would you explain in more detail what the 32-bit NUMA mm is > doing, esp. wrt. when __va(__pa) is not identical across all cpus? > > Regards, > Peter Hurley > -- Gleb. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>