[RFC PATCH 2/2] separate thread for VM migration

Umesh Deshapnde
2011-07-22T19:58:16Z

This patch creates a separate thread for the guest migration on the source side.
The migration routine is called from the migration clock.

Signed-off-by: Umesh Deshpande <udeshpan@redhat.com>
---
arch_init.c | 14 ++++++++++--
buffered_file.c | 12 ++++++----
exec.c | 4 +++
migration-tcp.c | 18 ++++++++--------
migration-unix.c | 7 ++---
migration.c | 59 ++++++++++++++++++++++++++++++-----------------------
migration.h | 4 +-
7 files changed, 69 insertions(+), 49 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index 484b39d..cd545bc 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -110,7 +110,7 @@ static int is_dup_page(uint8_t *page, uint8_t ch)
static RAMBlock *last_block;
static ram_addr_t last_offset;

-static int ram_save_block(QEMUFile *f)
+static int ram_save_block(QEMUFile *f, int stage)
{
RAMBlock *block = last_block;
ram_addr_t offset = last_offset;
@@ -131,6 +131,10 @@ static int ram_save_block(QEMUFile *f)
current_addr + TARGET_PAGE_SIZE,
MIGRATION_DIRTY_FLAG);

+ if (stage != 3) {
+ qemu_mutex_unlock_iothread();
+ }
+
p = block->host + offset;

if (is_dup_page(p, *p)) {
@@ -153,6 +157,10 @@ static int ram_save_block(QEMUFile *f)
bytes_sent = TARGET_PAGE_SIZE;
}

+ if (stage != 3) {
+ qemu_mutex_lock_iothread();
+ }
+
break;
}

@@ -301,7 +309,7 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
while (!qemu_file_rate_limit(f)) {
int bytes_sent;

- bytes_sent = ram_save_block(f);
+ bytes_sent = ram_save_block(f, stage);
bytes_transferred += bytes_sent;
if (bytes_sent == 0) { /* no more blocks */
break;
@@ -322,7 +330,7 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque)
int bytes_sent;

/* flush all remaining blocks regardless of rate limiting */
- while ((bytes_sent = ram_save_block(f)) != 0) {
+ while ((bytes_sent = ram_save_block(f, stage)) != 0) {
bytes_transferred += bytes_sent;
}
cpu_physical_memory_set_dirty_tracking(0);
diff --git a/buffered_file.c b/buffered_file.c
index 41b42c3..73e9666 100644
--- a/buffered_file.c
+++ b/buffered_file.c
@@ -237,7 +237,7 @@ static void buffered_rate_tick(void *opaque)
return;
}

- qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100);
+ qemu_mod_timer(s->timer, qemu_get_clock_ms(migration_clock) + 100);

if (s->freeze_output)
return;
@@ -246,8 +246,10 @@ static void buffered_rate_tick(void *opaque)

buffered_flush(s);

- /* Add some checks around this */
s->put_ready(s->opaque);
+ qemu_mutex_unlock_iothread();
+ usleep(qemu_timer_difference(s->timer, migration_clock) * 1000);
+ qemu_mutex_lock_iothread();
}

QEMUFile *qemu_fopen_ops_buffered(void *opaque,
@@ -271,11 +273,11 @@ QEMUFile *qemu_fopen_ops_buffered(void *opaque,
s->file = qemu_fopen_ops(s, buffered_put_buffer, NULL,
buffered_close, buffered_rate_limit,
buffered_set_rate_limit,
- buffered_get_rate_limit);
+ buffered_get_rate_limit);

- s->timer = qemu_new_timer_ms(rt_clock, buffered_rate_tick, s);
+ s->timer = qemu_new_timer_ms(migration_clock, buffered_rate_tick, s);

- qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 100);
+ qemu_mod_timer(s->timer, qemu_get_clock_ms(migration_clock) + 100);

return s->file;
}
diff --git a/exec.c b/exec.c
index 0e2ce57..97f60c6 100644
--- a/exec.c
+++ b/exec.c
@@ -2106,6 +2106,10 @@ void cpu_physical_memory_reset_dirty(ram_addr_t start, ram_addr_t end,
abort();
}

+ if (kvm_enabled()) {
+ return;
+ }
+
for(env = first_cpu; env != NULL; env = env->next_cpu) {
int mmu_idx;
for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
diff --git a/migration-tcp.c b/migration-tcp.c
index d3d80c9..5840668 100644
--- a/migration-tcp.c
+++ b/migration-tcp.c
@@ -65,11 +65,9 @@ static void tcp_wait_for_connect(void *opaque)
return;
}

- qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
-
- if (val == 0)
+ if (val == 0) {
migrate_fd_connect(s);
- else {
+ } else {
DPRINTF("error connecting %d\n", val);
migrate_fd_error(s);
}
@@ -79,8 +77,8 @@ MigrationState *tcp_start_outgoing_migration(Monitor *mon,
const char *host_port,
int64_t bandwidth_limit,
int detach,
- int blk,
- int inc)
+ int blk,
+ int inc)
{
struct sockaddr_in addr;
FdMigrationState *s;
@@ -121,15 +119,17 @@ MigrationState *tcp_start_outgoing_migration(Monitor *mon,
if (ret == -1)
ret = -(s->get_error(s));

- if (ret == -EINPROGRESS || ret == -EWOULDBLOCK)
- qemu_set_fd_handler2(s->fd, NULL, NULL, tcp_wait_for_connect, s);
} while (ret == -EINTR);

if (ret < 0 && ret != -EINPROGRESS && ret != -EWOULDBLOCK) {
DPRINTF("connect failed\n");
migrate_fd_error(s);
- } else if (ret >= 0)
+ } else if (ret >= 0) {
migrate_fd_connect(s);
+ } else {
+ migrate_fd_wait_for_unfreeze(s);
+ tcp_wait_for_connect(s);
+ }

return &s->mig_state;
}
diff --git a/migration-unix.c b/migration-unix.c
index c8625c7..e0a8f6f 100644
--- a/migration-unix.c
+++ b/migration-unix.c
@@ -64,8 +64,6 @@ static void unix_wait_for_connect(void *opaque)
return;
}

- qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
-
if (val == 0)
migrate_fd_connect(s);
else {
@@ -116,13 +114,14 @@ MigrationState *unix_start_outgoing_migration(Monitor *mon,
if (ret == -1)
ret = -(s->get_error(s));

- if (ret == -EINPROGRESS || ret == -EWOULDBLOCK)
- qemu_set_fd_handler2(s->fd, NULL, NULL, unix_wait_for_connect, s);
} while (ret == -EINTR);

if (ret < 0 && ret != -EINPROGRESS && ret != -EWOULDBLOCK) {
DPRINTF("connect failed\n");
goto err_after_open;
+ } else if (ret == -EINPROGRESS || ret == -EWOULDBLOCK) {
+ migrate_fd_wait_for_unfreeze(s);
+ unix_wait_for_connect(s);
}

if (!detach) {
diff --git a/migration.c b/migration.c
index af3a1f2..4649691 100644
--- a/migration.c
+++ b/migration.c
@@ -12,6 +12,8 @@
*/

#include "qemu-common.h"
+#include "qemu-thread.h"
+#include "qemu-timer.h"
#include "migration.h"
#include "monitor.h"
#include "buffered_file.h"
@@ -35,6 +37,7 @@
static int64_t max_throttle = (32 << 20);

static MigrationState *current_migration;
+char host_port[50];

static NotifierList migration_state_notifiers =
NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
@@ -284,8 +287,6 @@ int migrate_fd_cleanup(FdMigrationState *s)
{
int ret = 0;

- qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
-
if (s->file) {
DPRINTF("closing file\n");
if (qemu_fclose(s->file) != 0) {
@@ -307,14 +308,6 @@ int migrate_fd_cleanup(FdMigrationState *s)
return ret;
}

-void migrate_fd_put_notify(void *opaque)
-{
- FdMigrationState *s = opaque;
-
- qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
- qemu_file_put_notify(s->file);
-}
-
ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
{
FdMigrationState *s = opaque;
@@ -327,9 +320,7 @@ ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
if (ret == -1)
ret = -(s->get_error(s));

- if (ret == -EAGAIN) {
- qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
- } else if (ret < 0) {
+ if (ret < 0 && ret != -EAGAIN) {
if (s->mon) {
monitor_resume(s->mon);
}
@@ -340,10 +331,34 @@ ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
return ret;
}

-void migrate_fd_connect(FdMigrationState *s)
+void *migrate_run_timers(void *arg)
{
+ FdMigrationState *s = arg;
int ret;

+ qemu_mutex_lock_iothread();
+ ret = qemu_savevm_state_begin(s->mon, s->file, s->mig_state.blk,
+ s->mig_state.shared);
+ if (ret < 0) {
+ DPRINTF("failed, %d\n", ret);
+ migrate_fd_error(s);
+ return NULL;
+ }
+
+ migrate_fd_put_ready(s);
+
+ while (s->state == MIG_STATE_ACTIVE) {
+ qemu_run_timers(migration_clock);
+ }
+
+ qemu_mutex_unlock_iothread();
+
+ return NULL;
+}
+
+void migrate_fd_connect(FdMigrationState *s)
+{
+ struct QemuThread migrate_thread;
s->file = qemu_fopen_ops_buffered(s,
s->bandwidth_limit,
migrate_fd_put_buffer,
@@ -352,15 +367,7 @@ void migrate_fd_connect(FdMigrationState *s)
migrate_fd_close);

DPRINTF("beginning savevm\n");
- ret = qemu_savevm_state_begin(s->mon, s->file, s->mig_state.blk,
- s->mig_state.shared);
- if (ret < 0) {
- DPRINTF("failed, %d\n", ret);
- migrate_fd_error(s);
- return;
- }
-
- migrate_fd_put_ready(s);
+ qemu_thread_create(&migrate_thread, migrate_run_timers, s);
}

void migrate_fd_put_ready(void *opaque)
@@ -376,8 +383,6 @@ void migrate_fd_put_ready(void *opaque)
if (qemu_savevm_state_iterate(s->mon, s->file) == 1) {
int state;
int old_vm_running = vm_running;
-
- DPRINTF("done iterating\n");
vm_stop(VMSTOP_MIGRATE);

if ((qemu_savevm_state_complete(s->mon, s->file)) < 0) {
@@ -396,6 +401,9 @@ void migrate_fd_put_ready(void *opaque)
}
s->state = state;
notifier_list_notify(&migration_state_notifiers);
+ } else {
+ migrate_fd_wait_for_unfreeze(s);
+ qemu_file_put_notify(s->file);
}
}

@@ -458,7 +466,6 @@ int migrate_fd_close(void *opaque)
{
FdMigrationState *s = opaque;

- qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
return s->close(s);
}

diff --git a/migration.h b/migration.h
index 050c56c..8d8b7c9 100644
--- a/migration.h
+++ b/migration.h
@@ -72,6 +72,8 @@ void do_info_migrate(Monitor *mon, QObject **ret_data);

int exec_start_incoming_migration(const char *host_port);

+void *migrate_run_timers(void *);
+
MigrationState *exec_start_outgoing_migration(Monitor *mon,
const char *host_port,
int64_t bandwidth_limit,
@@ -112,8 +114,6 @@ void migrate_fd_error(FdMigrationState *s);

int migrate_fd_cleanup(FdMigrationState *s);

-void migrate_fd_put_notify(void *opaque);
-
ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size);

void migrate_fd_connect(FdMigrationState *s);
--
1.7.4.1