From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32769) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gOo9z-0001Sa-Cz for qemu-devel@nongnu.org; Mon, 19 Nov 2018 13:20:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gOo9y-0007H4-Cn for qemu-devel@nongnu.org; Mon, 19 Nov 2018 13:20:35 -0500 Received: from mail-wm1-x344.google.com ([2a00:1450:4864:20::344]:52510) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gOo9y-0007FH-36 for qemu-devel@nongnu.org; Mon, 19 Nov 2018 13:20:34 -0500 Received: by mail-wm1-x344.google.com with SMTP id r11-v6so6313154wmb.2 for ; Mon, 19 Nov 2018 10:20:33 -0800 (PST) Sender: Paolo Bonzini References: <20181116164806.26929-1-pbonzini@redhat.com> <20181116164806.26929-2-pbonzini@redhat.com> <20181116171226.GC2457@work-vm> From: Paolo Bonzini Message-ID: Date: Mon, 19 Nov 2018 19:20:30 +0100 MIME-Version: 1.0 In-Reply-To: <20181116171226.GC2457@work-vm> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] migration: savevm: consult migration blockers List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: qemu-devel@nongnu.org On 16/11/18 18:12, Dr. David Alan Gilbert wrote: > * Paolo Bonzini (pbonzini@redhat.com) wrote: >> There is really no difference between live migration and savevm, except >> that savevm does not require bdrv_invalidate_cache to be implemented >> by all disks. However, it is unlikely that savevm is used with anything >> except qcow2 disks, so the penalty is small and worth the improvement >> in catching bad usage of savevm. >> >> Only one place was taking care of savevm when adding a migration blocker, >> and it can be removed. > > OK, I'm not sure if it was actually a split between savevm and migration > or just that the migration blockers were added later. Just the latter, I think. >> Signed-off-by: Paolo Bonzini >> --- >> migration/savevm.c | 4 ++++ >> target/i386/kvm.c | 3 --- >> 2 files changed, 4 insertions(+), 3 deletions(-) >> >> diff --git a/migration/savevm.c b/migration/savevm.c >> index ef707b8c43..1c49776a91 100644 >> --- a/migration/savevm.c >> +++ b/migration/savevm.c >> @@ -2455,6 +2455,10 @@ int save_snapshot(const char *name, Error **errp) >> struct tm tm; >> AioContext *aio_context; >> >> + if (migration_is_blocked(errp)) { >> + return false; >> + } >> + >> if (!replay_can_snapshot()) { >> error_setg(errp, "Record/replay does not allow making snapshot " >> "right now. Try once more later."); >> diff --git a/target/i386/kvm.c b/target/i386/kvm.c >> index 3b6fbd3f20..d222b68fe4 100644 >> --- a/target/i386/kvm.c >> +++ b/target/i386/kvm.c >> @@ -1284,7 +1284,6 @@ int kvm_arch_init_vcpu(CPUState *cs) >> if (!env->user_tsc_khz) { >> if ((env->features[FEAT_8000_0007_EDX] & CPUID_APM_INVTSC) && >> invtsc_mig_blocker == NULL) { >> - /* for migration */ >> error_setg(&invtsc_mig_blocker, >> "State blocked by non-migratable CPU device" >> " (invtsc flag)"); >> @@ -1294,8 +1293,6 @@ int kvm_arch_init_vcpu(CPUState *cs) >> error_free(invtsc_mig_blocker); >> return r; >> } >> - /* for savevm */ >> - vmstate_x86_cpu.unmigratable = 1; > > So that means vmstate_x86_cpu can be static now - but why does it live > in machine.c rather than cpu.c ? Generally all vmstate lives in machine.c. Just historical reasons, it was moved out of vl.c (!) many moons ago. Paolo