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[Qemu-devel] [PATCH v10 16/24] migration: Synchronize recv threads
From: |
Juan Quintela |
Subject: |
[Qemu-devel] [PATCH v10 16/24] migration: Synchronize recv threads |
Date: |
Wed, 7 Mar 2018 12:00:02 +0100 |
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 <address@hidden>
---
migration/ram.c | 37 ++++++++++++++++++++++++++++++++++++-
migration/trace-events | 1 +
2 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/migration/ram.c b/migration/ram.c
index 153c7560cb..0266bd200c 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -551,6 +551,7 @@ struct MultiFDRecvParams {
QemuMutex mutex;
bool running;
bool quit;
+ bool sync;
};
typedef struct MultiFDRecvParams MultiFDRecvParams;
@@ -558,6 +559,8 @@ struct {
MultiFDRecvParams *params;
/* number of created threads */
int count;
+ /* syncs main thread and channels */
+ QemuSemaphore sem_main;
} *multifd_recv_state;
static void terminate_multifd_recv_threads(Error *errp)
@@ -605,6 +608,7 @@ int multifd_load_cleanup(Error **errp)
g_free(p->name);
p->name = NULL;
}
+ qemu_sem_destroy(&multifd_recv_state->sem_main);
g_free(multifd_recv_state->params);
multifd_recv_state->params = NULL;
g_free(multifd_recv_state);
@@ -613,18 +617,45 @@ 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];
+
+ qemu_mutex_lock(&p->mutex);
+ p->sync = true;
+ qemu_mutex_unlock(&p->mutex);
+ qemu_sem_post(&p->sem);
+ }
+ for (i = 0; i < migrate_multifd_channels(); i++) {
+ qemu_sem_wait(&multifd_recv_state->sem_main);
+ }
+ trace_multifd_recv_sync_main();
+}
+
static void *multifd_recv_thread(void *opaque)
{
MultiFDRecvParams *p = opaque;
while (true) {
+ qemu_sem_wait(&p->sem);
qemu_mutex_lock(&p->mutex);
+ if (p->sync) {
+ p->sync = false;
+ qemu_mutex_unlock(&p->mutex);
+ qemu_sem_post(&multifd_recv_state->sem_main);
+ continue;
+ }
if (p->quit) {
qemu_mutex_unlock(&p->mutex);
break;
}
qemu_mutex_unlock(&p->mutex);
- qemu_sem_wait(&p->sem);
}
return NULL;
@@ -642,6 +673,7 @@ 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_main, 0);
for (i = 0; i < thread_count; i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
@@ -655,6 +687,7 @@ int multifd_load_setup(void)
QEMU_THREAD_JOINABLE);
atomic_inc(&multifd_recv_state->count);
}
+
return 0;
}
@@ -2868,6 +2901,7 @@ 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"
@@ -3053,6 +3087,7 @@ 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) {
diff --git a/migration/trace-events b/migration/trace-events
index 97b5ac564f..76075c26bc 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -78,6 +78,7 @@ ram_postcopy_send_discard_bitmap(void) ""
ram_save_page(const char *rbname, uint64_t offset, void *host) "%s: offset:
0x%" PRIx64 " host: %p"
ram_save_queue_pages(const char *rbname, size_t start, size_t len) "%s: start:
0x%zx len: 0x%zx"
multifd_send_sync_main(void) ""
+multifd_recv_sync_main(void) ""
# migration/migration.c
await_return_path_close_on_source_close(void) ""
--
2.14.3
- [Qemu-devel] [PATCH v10 01/24] tests: Add migration precopy test, (continued)
- [Qemu-devel] [PATCH v10 01/24] tests: Add migration precopy test, Juan Quintela, 2018/03/07
- [Qemu-devel] [PATCH v10 10/24] migration: In case of error just end the migration, Juan Quintela, 2018/03/07
- [Qemu-devel] [PATCH v10 02/24] tests: Add migration xbzrle test, Juan Quintela, 2018/03/07
- [Qemu-devel] [PATCH v10 13/24] migration: Introduce multifd_recv_new_channel(), Juan Quintela, 2018/03/07
- [Qemu-devel] [PATCH v10 18/24] migration: Add multifd traces for start/end thread, Juan Quintela, 2018/03/07
- [Qemu-devel] [PATCH v10 16/24] migration: Synchronize recv threads,
Juan Quintela <=
- [Qemu-devel] [PATCH v10 15/24] migration: Synchronize send threads, Juan Quintela, 2018/03/07
- [Qemu-devel] [PATCH v10 19/24] migration: Create multifd channels, Juan Quintela, 2018/03/07
[Qemu-devel] [PATCH v10 23/24] migration: Create pages structure for reception, Juan Quintela, 2018/03/07
[Qemu-devel] [PATCH v10 21/24] migration: Transmit initial package through the multifd channels, Juan Quintela, 2018/03/07
[Qemu-devel] [PATCH v10 20/24] migration: Delay start of migration main routines, Juan Quintela, 2018/03/07