OpenE2K/qemu-e2k
13
4
Fork 0
Code Issues 4 Pull Requests Projects 2 Releases Activity

migration: Synchronize multifd threads with main thread

Browse Source 
We synchronize all threads each RAM_SAVE_FLAG_EOS.  Bitmap
synchronizations don't happen inside a  ram section, so we are safe
about two channels trying to overwrite the same memory.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

--
seq needs to be atomic now, will also be accessed from main thread.
Fix the if (true || ...) leftover
We are back to non-atomics
This commit is contained in:
Juan Quintela 2018-02-28 09:10:07 +01:00
parent 0beb5ed327
commit 6df264ac5a
2 changed files with 122 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

147
migration/ram.c
View File

@ -510,6 +510,8 @@ exit:
#define MULTIFD_MAGIC 0x11223344U
#define MULTIFD_VERSION 1
#define MULTIFD_FLAG_SYNC (1 << 0)
typedef struct {
uint32_t magic;
uint32_t version;
@ -577,6 +579,8 @@ typedef struct {
uint64_t num_packets;
/* pages sent through this channel */
uint64_t num_pages;
/* syncs main thread and channels */
QemuSemaphore sem_sync;
} MultiFDSendParams;
typedef struct {
@ -614,6 +618,8 @@ typedef struct {
uint64_t num_packets;
/* pages sent through this channel */
uint64_t num_pages;
/* syncs main thread and channels */
QemuSemaphore sem_sync;
} MultiFDRecvParams;
static int multifd_send_initial_packet(MultiFDSendParams *p, Error **errp)
@ -801,6 +807,10 @@ struct {
int count;
/* array of pages to sent */
MultiFDPages_t *pages;
/* syncs main thread and channels */
QemuSemaphore sem_sync;
/* global number of generated multifd packets */
uint64_t packet_num;
} *multifd_send_state;
static void multifd_send_terminate_threads(Error *err)
@ -848,6 +858,7 @@ int multifd_save_cleanup(Error **errp)
p->c = NULL;
qemu_mutex_destroy(&p->mutex);
qemu_sem_destroy(&p->sem);
qemu_sem_destroy(&p->sem_sync);
g_free(p->name);
p->name = NULL;
multifd_pages_clear(p->pages);
@ -856,6 +867,7 @@ int multifd_save_cleanup(Error **errp)
g_free(p->packet);
p->packet = NULL;
}
qemu_sem_destroy(&multifd_send_state->sem_sync);
g_free(multifd_send_state->params);
multifd_send_state->params = NULL;
multifd_pages_clear(multifd_send_state->pages);
@ -865,6 +877,33 @@ int multifd_save_cleanup(Error **errp)
return ret;
}
static void multifd_send_sync_main(void)
{
int i;
if (!migrate_use_multifd()) {
return;
}
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
trace_multifd_send_sync_main_signal(p->id);
qemu_mutex_lock(&p->mutex);
p->flags |= MULTIFD_FLAG_SYNC;
p->pending_job++;
qemu_mutex_unlock(&p->mutex);
qemu_sem_post(&p->sem);
}
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
trace_multifd_send_sync_main_wait(p->id);
qemu_sem_wait(&multifd_send_state->sem_sync);
}
trace_multifd_send_sync_main(multifd_send_state->packet_num);
}
static void *multifd_send_thread(void *opaque)
{
MultiFDSendParams *p = opaque;
@ -901,15 +940,17 @@ static void *multifd_send_thread(void *opaque)
qemu_mutex_lock(&p->mutex);
p->pending_job--;
qemu_mutex_unlock(&p->mutex);
continue;
if (flags & MULTIFD_FLAG_SYNC) {
qemu_sem_post(&multifd_send_state->sem_sync);
}
} else if (p->quit) {
qemu_mutex_unlock(&p->mutex);
break;
} else {
qemu_mutex_unlock(&p->mutex);
/* sometimes there are spurious wakeups */
}
qemu_mutex_unlock(&p->mutex);
/* this is impossible */
error_setg(&local_err, "multifd_send_thread: Unknown command");
break;
}
out:
@ -961,12 +1002,14 @@ int multifd_save_setup(void)
multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
atomic_set(&multifd_send_state->count, 0);
multifd_send_state->pages = multifd_pages_init(page_count);
qemu_sem_init(&multifd_send_state->sem_sync, 0);
for (i = 0; i < thread_count; i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
qemu_mutex_init(&p->mutex);
qemu_sem_init(&p->sem, 0);
qemu_sem_init(&p->sem_sync, 0);
p->quit = false;
p->pending_job = 0;
p->id = i;
@ -984,6 +1027,10 @@ struct {
MultiFDRecvParams *params;
/* number of created threads */
int count;
/* syncs main thread and channels */
QemuSemaphore sem_sync;
/* global number of generated multifd packets */
uint64_t packet_num;
} *multifd_recv_state;
static void multifd_recv_terminate_threads(Error *err)
@ -1029,6 +1076,7 @@ int multifd_load_cleanup(Error **errp)
p->c = NULL;
qemu_mutex_destroy(&p->mutex);
qemu_sem_destroy(&p->sem);
qemu_sem_destroy(&p->sem_sync);
g_free(p->name);
p->name = NULL;
multifd_pages_clear(p->pages);
@ -1037,6 +1085,7 @@ int multifd_load_cleanup(Error **errp)
g_free(p->packet);
p->packet = NULL;
}
qemu_sem_destroy(&multifd_recv_state->sem_sync);
g_free(multifd_recv_state->params);
multifd_recv_state->params = NULL;
g_free(multifd_recv_state);
@ -1045,6 +1094,42 @@ int multifd_load_cleanup(Error **errp)
return ret;
}
static void multifd_recv_sync_main(void)
{
int i;
if (!migrate_use_multifd()) {
return;
}
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
trace_multifd_recv_sync_main_signal(p->id);
qemu_mutex_lock(&p->mutex);
p->pending_job = true;
qemu_mutex_unlock(&p->mutex);
}
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
trace_multifd_recv_sync_main_wait(p->id);
qemu_sem_wait(&multifd_recv_state->sem_sync);
qemu_mutex_lock(&p->mutex);
if (multifd_recv_state->packet_num < p->packet_num) {
multifd_recv_state->packet_num = p->packet_num;
}
qemu_mutex_unlock(&p->mutex);
}
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
trace_multifd_recv_sync_main_signal(p->id);
qemu_sem_post(&p->sem_sync);
}
trace_multifd_recv_sync_main(multifd_recv_state->packet_num);
}
static void *multifd_recv_thread(void *opaque)
{
MultiFDRecvParams *p = opaque;
@ -1054,37 +1139,30 @@ static void *multifd_recv_thread(void *opaque)
trace_multifd_recv_thread_start(p->id);
while (true) {
qemu_sem_wait(&p->sem);
uint32_t used;
uint32_t flags;
/* ToDo: recv packet here */
qemu_mutex_lock(&p->mutex);
if (p->pending_job) {
uint32_t used;
uint32_t flags;
qemu_mutex_unlock(&p->mutex);
/* ToDo: recv packet here */
qemu_mutex_lock(&p->mutex);
ret = multifd_recv_unfill_packet(p, &local_err);
if (ret) {
qemu_mutex_unlock(&p->mutex);
break;
}
used = p->pages->used;
flags = p->flags;
trace_multifd_recv(p->id, p->packet_num, used, flags);
p->pending_job = false;
p->num_packets++;
p->num_pages += used;
qemu_mutex_unlock(&p->mutex);
} else if (p->quit) {
ret = multifd_recv_unfill_packet(p, &local_err);
if (ret) {
qemu_mutex_unlock(&p->mutex);
break;
}
used = p->pages->used;
flags = p->flags;
trace_multifd_recv(p->id, p->packet_num, used, flags);
p->pending_job = false;
p->num_packets++;
p->num_pages += used;
qemu_mutex_unlock(&p->mutex);
/* this is impossible */
error_setg(&local_err, "multifd_recv_thread: Unknown command");
break;
if (flags & MULTIFD_FLAG_SYNC) {
qemu_sem_post(&multifd_recv_state->sem_sync);
qemu_sem_wait(&p->sem_sync);
}
}
if (local_err) {
@ -1112,12 +1190,14 @@ int multifd_load_setup(void)
multifd_recv_state = g_malloc0(sizeof(*multifd_recv_state));
multifd_recv_state->params = g_new0(MultiFDRecvParams, thread_count);
atomic_set(&multifd_recv_state->count, 0);
qemu_sem_init(&multifd_recv_state->sem_sync, 0);
for (i = 0; i < thread_count; i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
qemu_mutex_init(&p->mutex);
qemu_sem_init(&p->sem, 0);
qemu_sem_init(&p->sem_sync, 0);
p->quit = false;
p->pending_job = false;
p->id = i;
@ -2875,6 +2955,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
ram_control_before_iterate(f, RAM_CONTROL_SETUP);
ram_control_after_iterate(f, RAM_CONTROL_SETUP);
multifd_send_sync_main();
qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
return 0;
@ -2955,6 +3036,7 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)
*/
ram_control_after_iterate(f, RAM_CONTROL_ROUND);
multifd_send_sync_main();
out:
qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
ram_counters.transferred += 8;
@ -3008,6 +3090,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
rcu_read_unlock();
multifd_send_sync_main();
qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
return 0;
@ -3497,6 +3580,7 @@ static int ram_load_postcopy(QEMUFile *f)
break;
case RAM_SAVE_FLAG_EOS:
/* normal exit */
multifd_recv_sync_main();
break;
default:
error_report("Unknown combination of migration flags: %#x"
@ -3685,6 +3769,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
break;
case RAM_SAVE_FLAG_EOS:
/* normal exit */
multifd_recv_sync_main();
break;
default:
if (flags & RAM_SAVE_FLAG_HOOK) {

6
migration/trace-events
View File

@ -77,9 +77,15 @@ migration_bitmap_sync_start(void) ""
migration_bitmap_sync_end(uint64_t dirty_pages) "dirty_pages %" PRIu64
migration_throttle(void) ""
multifd_recv(uint8_t id, uint64_t packet_num, uint32_t used, uint32_t flags) "channel %d packet number %" PRIu64 " pages %d flags 0x%x"
multifd_recv_sync_main(long packet_num) "packet num %ld"
multifd_recv_sync_main_signal(uint8_t id) "channel %d"
multifd_recv_sync_main_wait(uint8_t id) "channel %d"
multifd_recv_thread_end(uint8_t id, uint64_t packets, uint64_t pages) "channel %d packets %" PRIu64 " pages %" PRIu64
multifd_recv_thread_start(uint8_t id) "%d"
multifd_send(uint8_t id, uint64_t packet_num, uint32_t used, uint32_t flags) "channel %d packet_num %" PRIu64 " pages %d flags 0x%x"
multifd_send_sync_main(long packet_num) "packet num %ld"
multifd_send_sync_main_signal(uint8_t id) "channel %d"
multifd_send_sync_main_wait(uint8_t id) "channel %d"
multifd_send_thread_end(uint8_t id, uint64_t packets, uint64_t pages) "channel %d packets %" PRIu64 " pages %" PRIu64
multifd_send_thread_start(uint8_t id) "%d"
ram_discard_range(const char *rbname, uint64_t start, size_t len) "%s: start: %" PRIx64 " %zx"