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Re: [Qemu-devel] [PATCH] migration: savevm: consult migration blockers
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH] migration: savevm: consult migration blockers |
Date: |
Fri, 16 Nov 2018 17:12:26 +0000 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
* Paolo Bonzini (address@hidden) 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.
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
> 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 ?
Dave
> }
> }
>
> --
> 2.19.1
>
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK