[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Re: performance regression from c/s 21647:cfba1560054a
Jan, On Thu, Nov 10, 2011 at 7:11 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote: >>>> On 10.11.11 at 15:59, Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> > wrote: >> On Thu, 10 Nov 2011, Jan Beulich wrote: >>> It's SLE11 SP1 guests that suffered a regression after a maintenance >>> update (originally shipped with 4.0.0, while that patch got backported >>> later into 4.0.x). >> >> Is SLES11 SP1 using HVMOP_pagetable_dying (see >> arch/x86/xen/mmu.c:xen_hvm_init_mmu_ops)? > > No, it's not. Can you please try the inline patch? Unfortunately I have no unstable test machine or infrastructure at the moment, so I can;t really test it. I finally recalled a bit of details about this patch, so this check is clearly a bug as-it-is: it was written with the assumption that all the HVM guests would have been Windows guests with particular PV-drivers, so I wasn't particularly nice with the checks. Thank you, Gianluca diff -r 068d3d55ce6e xen/arch/x86/mm/shadow/multi.c --- a/xen/arch/x86/mm/shadow/multi.c Tue Nov 01 19:03:38 2011 +0000 +++ b/xen/arch/x86/mm/shadow/multi.c Thu Nov 10 16:46:50 2011 -0800 @@ -2723,8 +2723,9 @@ || ( !v->domain->arch.paging.shadow.pagetable_dying_op && v->arch.paging.shadow.last_emulated_mfn_for_unshadow == mfn_x(gmfn) ) ) && sh_mfn_is_a_page_table(gmfn) - && !(mfn_to_page(gmfn)->shadow_flags - & (SHF_L2_32|SHF_L2_PAE|SHF_L2H_PAE|SHF_L4_64)) ) + && (!v->domain->arch.paging.shadow.pagetable_dying_op || + !(mfn_to_page(gmfn)->shadow_flags + & (SHF_L2_32|SHF_L2_PAE|SHF_L2H_PAE|SHF_L4_64))) ) { perfc_incr(shadow_early_unshadow); sh_remove_shadows(v, gmfn, 1, 0 /* Fast, can fail to unshadow */ ); -- It was a type of people I did not know, I found them very strange and they did not inspire confidence at all. Later I learned that I had been introduced to electronic engineers. E. W. Dijkstra _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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