On Fri, Aug 26, 2022 at 1:20 PM Sean Christopherson <seanjc@xxxxxxxxxx> wrote: > > On Tue, Aug 23, 2022, Yosry Ahmed wrote: > > Count the pages used by KVM mmu on x86 in memory stats under secondary > > pagetable stats (e.g. "SecPageTables" in /proc/meminfo) to give better > > visibility into the memory consumption of KVM mmu in a similar way to > > how normal user page tables are accounted. > > > > Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx> > > Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx> > > --- > > arch/x86/kvm/mmu/mmu.c | 16 ++++++++++++++-- > > arch/x86/kvm/mmu/tdp_mmu.c | 12 ++++++++++++ > > 2 files changed, 26 insertions(+), 2 deletions(-) > > > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > index e418ef3ecfcb..4d38e4eba772 100644 > > --- a/arch/x86/kvm/mmu/mmu.c > > +++ b/arch/x86/kvm/mmu/mmu.c > > @@ -1665,6 +1665,18 @@ static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, long nr) > > percpu_counter_add(&kvm_total_used_mmu_pages, nr); > > } > > > > +static void kvm_account_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp) > > +{ > > + kvm_mod_used_mmu_pages(kvm, +1); > > + kvm_account_pgtable_pages((void *)sp->spt, +1); > > +} > > + > > +static void kvm_unaccount_mmu_page(struct kvm *kvm, struct kvm_mmu_page *sp) > > +{ > > + kvm_mod_used_mmu_pages(kvm, -1); > > + kvm_account_pgtable_pages((void *)sp->spt, -1); > > +} > > Hrm, this is causing build on x86 issues for me. AFAICT, modpost doesn't detect > that this creates a new module dependency on __mod_lruvec_page_state() and so doesn't > refresh vmlinux.symvers. > > ERROR: modpost: "__mod_lruvec_page_state" [arch/x86/kvm/kvm.ko] undefined! > make[2]: *** [scripts/Makefile.modpost:128: modules-only.symvers] Error 1 > make[1]: *** [Makefile:1769: modules] Error 2 > make[1]: *** Waiting for unfinished jobs.... > Kernel: arch/x86/boot/bzImage is ready (#128) > make[1]: Leaving directory '/usr/local/google/home/seanjc/build/kernel/vm' > make: *** [Makefile:222: __sub-make] Error 2 > > Both gcc and clang yield the same behavior, so I doubt it's the compiler doing > something odd. Cleaning the build makes the problem go away, but that's a poor > band-aid. > > If I squash this with the prior patch that adds kvm_account_pgtable_pages() to > kvm_host.h, modpost detects the need to refresh and all is well. > > Given that ARM doesn't support building KVM as a module, i.e. can't run afoul > of whatever modpost weirdness I'm hitting, I'm inclined to squash this with the > previous patch and punt on the modpost issue so that we can get this merged. > > Any objections? Or thoughts on what's going wrong? I am not familiar at all with modpost so I have no idea what's going wrong, but I have no problem with squashing the patches if you think this works best.