diff options
Diffstat (limited to 'migration.c')
| -rw-r--r-- | migration.c | 233 |
1 files changed, 232 insertions, 1 deletions
diff --git a/migration.c b/migration.c index b6374ae072..2937c87f9a 100644 --- a/migration.c +++ b/migration.c @@ -16,7 +16,7 @@ #include "qemu-common.h" #include "migration/migration.h" #include "monitor/monitor.h" -#include "buffered_file.h" +#include "migration/qemu-file.h" #include "sysemu/sysemu.h" #include "block/block.h" #include "qemu/sockets.h" @@ -587,3 +587,234 @@ int64_t migrate_xbzrle_cache_size(void) return s->xbzrle_cache_size; } + +/* migration thread support */ + +typedef struct QEMUFileBuffered { + MigrationState *migration_state; + QEMUFile *file; + size_t bytes_xfer; + size_t xfer_limit; + uint8_t *buffer; + size_t buffer_size; + size_t buffer_capacity; + QemuThread thread; +} QEMUFileBuffered; + +static ssize_t buffered_flush(QEMUFileBuffered *s) +{ + size_t offset = 0; + ssize_t ret = 0; + + DPRINTF("flushing %zu byte(s) of data\n", s->buffer_size); + + while (s->bytes_xfer < s->xfer_limit && offset < s->buffer_size) { + size_t to_send = MIN(s->buffer_size - offset, s->xfer_limit - s->bytes_xfer); + ret = migrate_fd_put_buffer(s->migration_state, s->buffer + offset, + to_send); + if (ret <= 0) { + DPRINTF("error flushing data, %zd\n", ret); + break; + } else { + DPRINTF("flushed %zd byte(s)\n", ret); + offset += ret; + s->bytes_xfer += ret; + } + } + + DPRINTF("flushed %zu of %zu byte(s)\n", offset, s->buffer_size); + memmove(s->buffer, s->buffer + offset, s->buffer_size - offset); + s->buffer_size -= offset; + + if (ret < 0) { + return ret; + } + return offset; +} + +static int buffered_put_buffer(void *opaque, const uint8_t *buf, + int64_t pos, int size) +{ + QEMUFileBuffered *s = opaque; + ssize_t error; + + DPRINTF("putting %d bytes at %" PRId64 "\n", size, pos); + + error = qemu_file_get_error(s->file); + if (error) { + DPRINTF("flush when error, bailing: %s\n", strerror(-error)); + return error; + } + + if (size <= 0) { + return size; + } + + if (size > (s->buffer_capacity - s->buffer_size)) { + DPRINTF("increasing buffer capacity from %zu by %zu\n", + s->buffer_capacity, size + 1024); + + s->buffer_capacity += size + 1024; + + s->buffer = g_realloc(s->buffer, s->buffer_capacity); + } + + memcpy(s->buffer + s->buffer_size, buf, size); + s->buffer_size += size; + + return size; +} + +static int buffered_close(void *opaque) +{ + QEMUFileBuffered *s = opaque; + ssize_t ret = 0; + int ret2; + + DPRINTF("closing\n"); + + s->xfer_limit = INT_MAX; + while (!qemu_file_get_error(s->file) && s->buffer_size) { + ret = buffered_flush(s); + if (ret < 0) { + break; + } + } + + ret2 = migrate_fd_close(s->migration_state); + if (ret >= 0) { + ret = ret2; + } + ret = migrate_fd_close(s->migration_state); + s->migration_state->complete = true; + return ret; +} + +static int buffered_get_fd(void *opaque) +{ + QEMUFileBuffered *s = opaque; + + return qemu_get_fd(s->file); +} + +/* + * The meaning of the return values is: + * 0: We can continue sending + * 1: Time to stop + * negative: There has been an error + */ +static int buffered_rate_limit(void *opaque) +{ + QEMUFileBuffered *s = opaque; + int ret; + + ret = qemu_file_get_error(s->file); + if (ret) { + return ret; + } + + if (s->bytes_xfer > s->xfer_limit) { + return 1; + } + + return 0; +} + +static int64_t buffered_set_rate_limit(void *opaque, int64_t new_rate) +{ + QEMUFileBuffered *s = opaque; + if (qemu_file_get_error(s->file)) { + goto out; + } + if (new_rate > SIZE_MAX) { + new_rate = SIZE_MAX; + } + + s->xfer_limit = new_rate / 10; + +out: + return s->xfer_limit; +} + +static int64_t buffered_get_rate_limit(void *opaque) +{ + QEMUFileBuffered *s = opaque; + + return s->xfer_limit; +} + +/* 100ms xfer_limit is the limit that we should write each 100ms */ +#define BUFFER_DELAY 100 + +static void *buffered_file_thread(void *opaque) +{ + QEMUFileBuffered *s = opaque; + int64_t initial_time = qemu_get_clock_ms(rt_clock); + int64_t max_size = 0; + bool last_round = false; + + while (true) { + int64_t current_time = qemu_get_clock_ms(rt_clock); + + if (s->migration_state->complete) { + break; + } + if (current_time >= initial_time + BUFFER_DELAY) { + uint64_t transferred_bytes = s->bytes_xfer; + uint64_t time_spent = current_time - initial_time; + double bandwidth = transferred_bytes / time_spent; + max_size = bandwidth * migrate_max_downtime() / 1000000; + + DPRINTF("transferred %" PRIu64 " time_spent %" PRIu64 + " bandwidth %g max_size %" PRId64 "\n", + transferred_bytes, time_spent, bandwidth, max_size); + + s->bytes_xfer = 0; + initial_time = current_time; + } + if (!last_round && (s->bytes_xfer >= s->xfer_limit)) { + /* usleep expects microseconds */ + g_usleep((initial_time + BUFFER_DELAY - current_time)*1000); + } + if (buffered_flush(s) < 0) { + break; + } + + DPRINTF("file is ready\n"); + if (s->bytes_xfer < s->xfer_limit) { + DPRINTF("notifying client\n"); + last_round = migrate_fd_put_ready(s->migration_state, max_size); + } + } + + g_free(s->buffer); + g_free(s); + return NULL; +} + +static const QEMUFileOps buffered_file_ops = { + .get_fd = buffered_get_fd, + .put_buffer = buffered_put_buffer, + .close = buffered_close, + .rate_limit = buffered_rate_limit, + .get_rate_limit = buffered_get_rate_limit, + .set_rate_limit = buffered_set_rate_limit, +}; + +void qemu_fopen_ops_buffered(MigrationState *migration_state) +{ + QEMUFileBuffered *s; + + s = g_malloc0(sizeof(*s)); + + s->migration_state = migration_state; + s->xfer_limit = migration_state->bandwidth_limit / 10; + s->migration_state->complete = false; + + s->file = qemu_fopen_ops(s, &buffered_file_ops); + + migration_state->file = s->file; + + qemu_thread_create(&s->thread, buffered_file_thread, s, + QEMU_THREAD_DETACHED); +} |