From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 6/6] KVM: MMU: Avoid handling same rmap_pde in kvm_handle_hva_range() Date: Sun, 01 Jul 2012 16:31:43 +0300 Message-ID: <4FF0513F.3090909@redhat.com> References: <20120628105733.ccd9abb3.yoshikawa.takuya@oss.ntt.co.jp> <20120628110235.7410445e.yoshikawa.takuya@oss.ntt.co.jp> <4FEC9A2B.6000104@redhat.com> <20120629104629.b369cd40.yoshikawa.takuya@oss.ntt.co.jp> <4FEFFF11.4000309@redhat.com> <20120701221857.f3b9ee04e590ff7f1a0a335a@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Takuya Yoshikawa , mtosatti@redhat.com, agraf@suse.de, paulus@samba.org, aarcange@redhat.com, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linux-kernel@vger.kernel.org To: Takuya Yoshikawa Return-path: In-Reply-To: <20120701221857.f3b9ee04e590ff7f1a0a335a@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 07/01/2012 04:18 PM, Takuya Yoshikawa wrote: > On Sun, 01 Jul 2012 10:41:05 +0300 > Avi Kivity wrote: > >> >> > Note: in the new code we could not use trace_kvm_age_page(), so we just >> >> > dropped the point from kvm_handle_hva_range(). >> >> > >> >> >> >> Can't it be pushed to handler()? >> > >> > Yes, but it will be changed to print rmap, not hva and gfn. >> > I will do in the next version. >> >> We should try to avoid changing the tracepoint ABI. If we pass the >> memslot to handler(), we should be able to reconstruct the gfn and hva. > > That's not enough because we only know rmapp in the handler: we also need > level or something. I agree that passing memslot for keeping the ABI is > good, but how about two more arguments? I don't see a problem with that. But it would be good to move all the address transformations into tp_fast_assign so we only perform them if the tracepoint is active. > BTW, trace_kvm_age_page() is tracing every handler, not just kvm_age_rmapp(). > Is this intentional? No, it's a bug. Pushing the trace into the handler will fix it though. > If we trace in the caller, in kvm_age_hva(), we know hva, but not gfn. gfn is useful to correlate to later events with the same gfn. -- error compiling committee.c: too many arguments to function