The receiver does migration loop until the migration connection is
lost. Then, it is started as a backup.
The receiver does not load vm state once a migration begins,
instead, it perfetches one whole migration data into a buffer,
then loads vm state from that buffer afterwards.
Signed-off-by: Jules Wang <junqing.w...@cs2c.com.cn>
---
include/migration/qemu-file.h | 1 +
include/sysemu/sysemu.h | 1 +
migration.c | 22 ++++--
savevm.c | 154 ++++++++++++++++++++++++++++++++++++++++--
4 files changed, 168 insertions(+), 10 deletions(-)
diff --git a/include/migration/qemu-file.h b/include/migration/qemu-file.h
index 0f757fb..f01ff10 100644
--- a/include/migration/qemu-file.h
+++ b/include/migration/qemu-file.h
@@ -92,6 +92,7 @@ typedef struct QEMUFileOps {
QEMURamHookFunc *after_ram_iterate;
QEMURamHookFunc *hook_ram_load;
QEMURamSaveFunc *save_page;
+ QEMUFileGetBufferFunc *get_prefetch_buffer;
} QEMUFileOps;
QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index b1aa059..44f23d0 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -81,6 +81,7 @@ void qemu_savevm_state_complete(QEMUFile *f);
void qemu_savevm_state_cancel(void);
uint64_t qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size);
int qemu_loadvm_state(QEMUFile *f);
+int qemu_loadvm_state_ft(QEMUFile *f);
/* SLIRP */
void do_info_slirp(Monitor *mon);
diff --git a/migration.c b/migration.c
index d8a9b2d..9be22a4 100644
--- a/migration.c
+++ b/migration.c
@@ -19,6 +19,7 @@
#include "monitor/monitor.h"
#include "migration/qemu-file.h"
#include "sysemu/sysemu.h"
+#include "sysemu/cpus.h"
#include "block/block.h"
#include "qemu/sockets.h"
#include "migration/block.h"
@@ -112,13 +113,24 @@ static void process_incoming_migration_co(void *opaque)
{
QEMUFile *f = opaque;
int ret;
+ int count = 0;
- ret = qemu_loadvm_state(f);
- qemu_fclose(f);
- if (ret < 0) {
- fprintf(stderr, "load of migration failed\n");
- exit(EXIT_FAILURE);
+ if (ft_enabled()) {
+ while (qemu_loadvm_state_ft(f) >= 0) {
+ count++;
+ DPRINTF("incoming count %d\r", count);
+ }
+ qemu_fclose(f);
+ fprintf(stderr, "ft connection lost, launching self..\n");
+ } else {
+ ret = qemu_loadvm_state(f);
+ qemu_fclose(f);
+ if (ret < 0) {
+ fprintf(stderr, "load of migration failed\n");
+ exit(EXIT_FAILURE);
+ }
}
+ cpu_synchronize_all_post_init();
qemu_announce_self();
DPRINTF("successfully loaded vm state\n");
diff --git a/savevm.c b/savevm.c
index 6daf690..d5bf153 100644
--- a/savevm.c
+++ b/savevm.c
@@ -52,6 +52,8 @@
#define ARP_PTYPE_IP 0x0800
#define ARP_OP_REQUEST_REV 0x3
+#define PFB_SIZE 0x010000
+
static int announce_self_create(uint8_t *buf,
uint8_t *mac_addr)
{
@@ -135,6 +137,10 @@ struct QEMUFile {
unsigned int iovcnt;
int last_error;
+
+ uint8_t *pfb; /* pfb -> PerFetch Buffer */
+ uint64_t pfb_index;
+ uint64_t pfb_size;
};
typedef struct QEMUFileStdio
@@ -193,6 +199,25 @@ static int socket_get_buffer(void *opaque, uint8_t *buf,
int64_t pos, int size)
return len;
}
+static int socket_get_prefetch_buffer(void *opaque, uint8_t *buf,
+ int64_t pos, int size)
+{
+ QEMUFile *f = opaque;
+
+ if (f->pfb_size - pos <= 0) {
+ return 0;
+ }
+
+ if (f->pfb_size - pos < size) {
+ size = f->pfb_size - pos;
+ }
+
+ memcpy(buf, f->pfb+pos, size);
+
+ return size;
+}
+
+
static int socket_close(void *opaque)
{
QEMUFileSocket *s = opaque;
@@ -440,6 +465,7 @@ QEMUFile *qemu_fdopen(int fd, const char *mode)
static const QEMUFileOps socket_read_ops = {
.get_fd = socket_get_fd,
.get_buffer = socket_get_buffer,
+ .get_prefetch_buffer = socket_get_prefetch_buffer,
.close = socket_close
};
@@ -493,7 +519,7 @@ QEMUFile *qemu_fopen(const char *filename, const char *mode)
s->stdio_file = fopen(filename, mode);
if (!s->stdio_file)
goto fail;
-
+
if(mode[0] == 'w') {
s->file = qemu_fopen_ops(s, &stdio_file_write_ops);
} else {
@@ -739,6 +765,11 @@ int qemu_fclose(QEMUFile *f)
if (f->last_error) {
ret = f->last_error;
}
+
+ if (f->pfb) {
+ g_free(f->pfb);
+ }
+
g_free(f);
return ret;
}
@@ -822,6 +853,14 @@ void qemu_put_byte(QEMUFile *f, int v)
static void qemu_file_skip(QEMUFile *f, int size)
{
+ if (f->pfb_index + size <= f->pfb_size) {
+ f->pfb_index += size;
+ return;
+ } else {
+ size -= f->pfb_size - f->pfb_index;
+ f->pfb_index = f->pfb_size;
+ }
+
if (f->buf_index + size <= f->buf_size) {
f->buf_index += size;
}
@@ -831,6 +870,21 @@ static int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int
size, size_t offset)
{
int pending;
int index;
+ int done;
+
+ if (f->ops->get_prefetch_buffer) {
+ if (f->pfb_index + offset < f->pfb_size) {
+ done = f->ops->get_prefetch_buffer(f, buf, f->pfb_index + offset,
+ size);
+ if (done == size) {
+ return size;
+ }
+ size -= done;
+ buf += done;
+ } else {
+ offset -= f->pfb_size - f->pfb_index;
+ }
+ }
assert(!qemu_file_is_writable(f));
@@ -875,7 +929,15 @@ int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size)
static int qemu_peek_byte(QEMUFile *f, int offset)
{
- int index = f->buf_index + offset;
+ int index;
+
+ if (f->pfb_index + offset < f->pfb_size) {
+ return f->pfb[f->pfb_index + offset];
+ } else {
+ offset -= f->pfb_size - f->pfb_index;
+ }
+
+ index = f->buf_index + offset;
assert(!qemu_file_is_writable(f));
@@ -1851,7 +1913,7 @@ void qemu_savevm_state_begin(QEMUFile *f,
}
se->ops->set_params(params, se->opaque);
}
-
+
qemu_put_be32(f, QEMU_VM_FILE_MAGIC);
qemu_put_be32(f, QEMU_VM_FILE_VERSION);
@@ -2294,8 +2356,6 @@ int qemu_loadvm_state(QEMUFile *f)
}
}
- cpu_synchronize_all_post_init();
-
ret = 0;
out:
@@ -2311,6 +2371,89 @@ out:
return ret;
}
+int qemu_loadvm_state_ft(QEMUFile *f)
+{
+ int ret = 0;
+ int i = 0;
+ int j = 0;
+ int done = 0;
+ uint64_t size = 0;
+ uint64_t count = 0;
+ uint8_t *pfb = NULL;
+ uint8_t *buf = NULL;
+
+ uint64_t max_mem = last_ram_offset() * 1.5;
+
+ if (!f->ops->get_prefetch_buffer) {
+ fprintf(stderr, "Fault tolerant is not supported by this protocol.\n");
+ return EINVAL;
+ }
+
+ size = PFB_SIZE;
+ pfb = g_malloc(size);
+
+ while (true) {
+ if (count + TARGET_PAGE_SIZE >= size) {
+ if (size*2 > max_mem) {
+ fprintf(stderr, "qemu_loadvm_state_ft: warning:" \
+ "Prefetch buffer becomes too large.\n" \
+ "Fault tolerant is unstable when you see this,\n" \
+ "please increase the bandwidth or increase " \
+ "the max down time.\n");
+ break;
+ }
+ size = size * 2;
+ buf = g_try_realloc(pfb, size);
+ if (!buf) {
+ error_report("qemu_loadvm_state_ft: out of memory.\n");
+ g_free(pfb);
+ return ENOMEM;
+ }
+
+ pfb = buf;
+ }
+
+ done = qemu_get_buffer(f, pfb + count, TARGET_PAGE_SIZE);
+
+ ret = qemu_file_get_error(f);
+ if (ret != 0) {
+ g_free(pfb);
+ return ret;
+ }
+
+ buf = pfb + count;
+ count += done;
+ for (i = 0; i < done; i++) {
+ if (buf[i] != 0xfe) {
+ continue;
+ }
+ if (buf[i-1] != 0xCa) {
+ continue;
+ }
+ if (buf[i-2] != 0xed) {
+ continue;
+ }
+ if (buf[i-3] == 0xFe) {
+ goto out;
+ }
+ }
+ }
+ out:
+ if (f->pfb) {
+ free(f->pfb);
+ }
+ f->pfb_size = count;
+ f->pfb_index = 0;
+ f->pfb = pfb;
+
+ ret = qemu_loadvm_state(f);
+
+ /* Skip magic number */
+ qemu_get_be32(f);
+
+ return ret;
+}
+
static BlockDriverState *find_vmstate_bs(void)
{
BlockDriverState *bs = NULL;
@@ -2419,6 +2562,7 @@ void do_savevm(Monitor *mon, const QDict *qdict)
goto the_end;
}
ret = qemu_savevm_state(f);
+ cpu_synchronize_all_post_init();
vm_state_size = qemu_ftell(f);
qemu_fclose(f);
if (ret < 0) {
--
1.8.0.1
