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[Qemu-devel] Re: [PATCH v3] savevm: Fix no_migrate
From: |
Jan Kiszka |
Subject: |
[Qemu-devel] Re: [PATCH v3] savevm: Fix no_migrate |
Date: |
Fri, 07 Jan 2011 19:47:34 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
Am 07.01.2011 19:39, Alex Williamson wrote:
> The no_migrate save state flag is currently only checked in the
> last phase of migration. This means that we potentially waste
> a lot of time and bandwidth with the live state handlers before
> we ever check the no_migrate flags. The error message printed
> when we catch a non-migratable device doesn't get printed for
> a detached migration. And, no_migrate does nothing to prevent
> an incoming migration to a target that includes a non-migratable
> device. This attempts to fix all of these.
>
> One notable difference in behavior is that an outgoing migration
> now checks for non-migratable devices before ever connecting to
> the target system. This means the target will remain listening
> rather than exit from failure.
>
> Signed-off-by: Alex Williamson <address@hidden>
> ---
>
> Daniel, adding you to see if libvirt cares about the difference in
> whether the target exits on migration failure as noted above.
>
> Also adding Michael as he's complained about the no_migrate check
> happening so late in the process.
>
> migration.c | 4 ++++
> savevm.c | 39 +++++++++++++++++++++++++--------------
> sysemu.h | 1 +
> 3 files changed, 30 insertions(+), 14 deletions(-)
>
> diff --git a/migration.c b/migration.c
> index e5ba51c..d593b1d 100644
> --- a/migration.c
> +++ b/migration.c
> @@ -88,6 +88,10 @@ int do_migrate(Monitor *mon, const QDict *qdict, QObject
> **ret_data)
> return -1;
> }
>
> + if (qemu_savevm_state_blocked(mon)) {
> + return -1;
> + }
> +
> if (strstart(uri, "tcp:", &p)) {
> s = tcp_start_outgoing_migration(mon, p, max_throttle, detach,
> blk, inc);
> diff --git a/savevm.c b/savevm.c
> index 90aa237..6675c33 100644
> --- a/savevm.c
> +++ b/savevm.c
> @@ -1401,19 +1401,13 @@ static int vmstate_load(QEMUFile *f, SaveStateEntry
> *se, int version_id)
> return vmstate_load_state(f, se->vmsd, se->opaque, version_id);
> }
>
> -static int vmstate_save(QEMUFile *f, SaveStateEntry *se)
> +static void vmstate_save(QEMUFile *f, SaveStateEntry *se)
> {
> - if (se->no_migrate) {
> - return -1;
> - }
> -
> if (!se->vmsd) { /* Old style */
> se->save_state(f, se->opaque);
> - return 0;
> + return;
> }
> vmstate_save_state(f,se->vmsd, se->opaque);
> -
> - return 0;
> }
>
> #define QEMU_VM_FILE_MAGIC 0x5145564d
> @@ -1427,6 +1421,20 @@ static int vmstate_save(QEMUFile *f, SaveStateEntry
> *se)
> #define QEMU_VM_SECTION_FULL 0x04
> #define QEMU_VM_SUBSECTION 0x05
>
> +int qemu_savevm_state_blocked(Monitor *mon)
> +{
> + SaveStateEntry *se;
> +
> + QTAILQ_FOREACH(se, &savevm_handlers, entry) {
> + if (se->no_migrate) {
> + monitor_printf(mon, "state blocked by non-migratable device
> '%s'\n",
> + se->idstr);
> + return -EINVAL;
> + }
> + }
> + return 0;
> +}
> +
> int qemu_savevm_state_begin(Monitor *mon, QEMUFile *f, int blk_enable,
> int shared)
> {
> @@ -1508,7 +1516,6 @@ int qemu_savevm_state_iterate(Monitor *mon, QEMUFile *f)
> int qemu_savevm_state_complete(Monitor *mon, QEMUFile *f)
> {
> SaveStateEntry *se;
> - int r;
>
> cpu_synchronize_all_states();
>
> @@ -1541,11 +1548,7 @@ int qemu_savevm_state_complete(Monitor *mon, QEMUFile
> *f)
> qemu_put_be32(f, se->instance_id);
> qemu_put_be32(f, se->version_id);
>
> - r = vmstate_save(f, se);
> - if (r < 0) {
> - monitor_printf(mon, "cannot migrate with device '%s'\n",
> se->idstr);
> - return r;
> - }
> + vmstate_save(f, se);
> }
>
> qemu_put_byte(f, QEMU_VM_EOF);
> @@ -1575,6 +1578,10 @@ static int qemu_savevm_state(Monitor *mon, QEMUFile *f)
> saved_vm_running = vm_running;
> vm_stop(0);
>
> + ret = qemu_savevm_state_blocked(mon);
> + if (ret < 0)
> + goto out;
> +
{ } :)
(Is there really no one bored out there and wants to write a check-patch
script?)
> ret = qemu_savevm_state_begin(mon, f, 0, 0);
> if (ret < 0)
> goto out;
> @@ -1692,6 +1699,10 @@ int qemu_loadvm_state(QEMUFile *f)
> unsigned int v;
> int ret;
>
> + if (qemu_savevm_state_blocked(default_mon)) {
> + return -EINVAL;
> + }
> +
> v = qemu_get_be32(f);
> if (v != QEMU_VM_FILE_MAGIC)
> return -EINVAL;
> diff --git a/sysemu.h b/sysemu.h
> index e728ea1..eefaba5 100644
> --- a/sysemu.h
> +++ b/sysemu.h
> @@ -75,6 +75,7 @@ void qemu_announce_self(void);
>
> void main_loop_wait(int nonblocking);
>
> +int qemu_savevm_state_blocked(Monitor *mon);
> int qemu_savevm_state_begin(Monitor *mon, QEMUFile *f, int blk_enable,
> int shared);
> int qemu_savevm_state_iterate(Monitor *mon, QEMUFile *f);
>
Much nicer!
Jan
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[Qemu-devel] [PATCH v3] savevm: Fix no_migrate, Alex Williamson, 2011/01/07
[Qemu-devel] [PATCH v4] savevm: Fix no_migrate, Alex Williamson, 2011/01/07
[Qemu-devel] Re: [PATCH v4] savevm: Fix no_migrate, Michael S. Tsirkin, 2011/01/09
[Qemu-devel] Re: [PATCH v4] savevm: Fix no_migrate, Michael S. Tsirkin, 2011/01/09
[Qemu-devel] Re: [PATCH v4] savevm: Fix no_migrate, Alex Williamson, 2011/01/10
[Qemu-devel] Re: [PATCH v4] savevm: Fix no_migrate, Michael S. Tsirkin, 2011/01/10
[Qemu-devel] Re: [PATCH v4] savevm: Fix no_migrate, Daniel P. Berrange, 2011/01/10
[Qemu-devel] Re: [PATCH v4] savevm: Fix no_migrate, Alex Williamson, 2011/01/10
[Qemu-devel] [PATCH v5] savevm: Fix no_migrate, Alex Williamson, 2011/01/11