From: "Maciej S. Szmigiero" <maciej.szmigi...@oracle.com>
A new function multifd_queue_device_state() is provided for device to queue
its state for transmission via a multifd channel.
Signed-off-by: Maciej S. Szmigiero <maciej.szmigi...@oracle.com>
---
include/migration/misc.h | 4 ++
migration/meson.build | 1 +
migration/multifd-device-state.c | 99 ++++++++++++++++++++++++++++++++
migration/multifd-nocomp.c | 6 +-
migration/multifd-qpl.c | 2 +-
migration/multifd-uadk.c | 2 +-
migration/multifd-zlib.c | 2 +-
migration/multifd-zstd.c | 2 +-
migration/multifd.c | 65 +++++++++++++++------
migration/multifd.h | 29 +++++++++-
10 files changed, 184 insertions(+), 28 deletions(-)
create mode 100644 migration/multifd-device-state.c
diff --git a/include/migration/misc.h b/include/migration/misc.h
index bfadc5613bac..7266b1b77d1f 100644
--- a/include/migration/misc.h
+++ b/include/migration/misc.h
@@ -111,4 +111,8 @@ bool migration_in_bg_snapshot(void);
/* migration/block-dirty-bitmap.c */
void dirty_bitmap_mig_init(void);
+/* migration/multifd-device-state.c */
+bool multifd_queue_device_state(char *idstr, uint32_t instance_id,
+ char *data, size_t len);
+
#endif
diff --git a/migration/meson.build b/migration/meson.build
index 77f3abf08eb1..00853595894f 100644
--- a/migration/meson.build
+++ b/migration/meson.build
@@ -21,6 +21,7 @@ system_ss.add(files(
'migration-hmp-cmds.c',
'migration.c',
'multifd.c',
+ 'multifd-device-state.c',
'multifd-nocomp.c',
'multifd-zlib.c',
'multifd-zero-page.c',
diff --git a/migration/multifd-device-state.c b/migration/multifd-device-state.c
new file mode 100644
index 000000000000..c9b44f0b5ab9
--- /dev/null
+++ b/migration/multifd-device-state.c
@@ -0,0 +1,99 @@
+/*
+ * Multifd device state migration
+ *
+ * Copyright (C) 2024 Oracle and/or its affiliates.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/lockable.h"
+#include "migration/misc.h"
+#include "multifd.h"
+
+static QemuMutex queue_job_mutex;
+
+static MultiFDSendData *device_state_send;
+
+size_t multifd_device_state_payload_size(void)
+{
+ return sizeof(MultiFDDeviceState_t);
+}
+
+void multifd_device_state_save_setup(void)
+{
+ qemu_mutex_init(&queue_job_mutex);
+
+ device_state_send = multifd_send_data_alloc();
+}
+
+void multifd_device_state_clear(MultiFDDeviceState_t *device_state)
+{
+ g_clear_pointer(&device_state->idstr, g_free);
+ g_clear_pointer(&device_state->buf, g_free);
+}
+
+void multifd_device_state_save_cleanup(void)
+{
+ g_clear_pointer(&device_state_send, multifd_send_data_free);
+
+ qemu_mutex_destroy(&queue_job_mutex);
+}
+
+static void multifd_device_state_fill_packet(MultiFDSendParams *p)
+{
+ MultiFDDeviceState_t *device_state = &p->data->u.device_state;
+ MultiFDPacketDeviceState_t *packet = p->packet_device_state;
+
+ packet->hdr.flags = cpu_to_be32(p->flags);
+ strncpy(packet->idstr, device_state->idstr, sizeof(packet->idstr));
+ packet->instance_id = cpu_to_be32(device_state->instance_id);
+ packet->next_packet_size = cpu_to_be32(p->next_packet_size);
+}
+
+void multifd_device_state_send_prepare(MultiFDSendParams *p)
+{
+ MultiFDDeviceState_t *device_state = &p->data->u.device_state;
+
+ assert(multifd_payload_device_state(p->data));
+
+ multifd_send_prepare_header_device_state(p);
+
+ assert(!(p->flags & MULTIFD_FLAG_SYNC));
+
+ p->next_packet_size = device_state->buf_len;
+ if (p->next_packet_size > 0) {
+ p->iov[p->iovs_num].iov_base = device_state->buf;
+ p->iov[p->iovs_num].iov_len = p->next_packet_size;
+ p->iovs_num++;
+ }
+
+ p->flags |= MULTIFD_FLAG_NOCOMP | MULTIFD_FLAG_DEVICE_STATE;
+
+ multifd_device_state_fill_packet(p);
+}
+
+bool multifd_queue_device_state(char *idstr, uint32_t instance_id,
+ char *data, size_t len)
+{
+ /* Device state submissions can come from multiple threads */
+ QEMU_LOCK_GUARD(&queue_job_mutex);
+ MultiFDDeviceState_t *device_state;
+
+ assert(multifd_payload_empty(device_state_send));
+
+ multifd_set_payload_type(device_state_send, MULTIFD_PAYLOAD_DEVICE_STATE);
+ device_state = &device_state_send->u.device_state;
+ device_state->idstr = g_strdup(idstr);
+ device_state->instance_id = instance_id;
+ device_state->buf = g_memdup2(data, len);
+ device_state->buf_len = len;
+
+ if (!multifd_send(&device_state_send)) {
+ multifd_send_data_clear(device_state_send);
+ return false;
+ }
+
+ return true;
+}
diff --git a/migration/multifd-nocomp.c b/migration/multifd-nocomp.c
index 39eb77c9b3b7..0b7b543f44db 100644
--- a/migration/multifd-nocomp.c
+++ b/migration/multifd-nocomp.c
@@ -116,13 +116,13 @@ static int multifd_nocomp_send_prepare(MultiFDSendParams
*p, Error **errp)
* Only !zerocopy needs the header in IOV; zerocopy will
* send it separately.
*/
- multifd_send_prepare_header(p);
+ multifd_send_prepare_header_ram(p);
}
multifd_send_prepare_iovs(p);
p->flags |= MULTIFD_FLAG_NOCOMP;
- multifd_send_fill_packet(p);
+ multifd_send_fill_packet_ram(p);
if (use_zero_copy_send) {
/* Send header first, without zerocopy */
@@ -371,7 +371,7 @@ bool multifd_send_prepare_common(MultiFDSendParams *p)
return false;
}
- multifd_send_prepare_header(p);
+ multifd_send_prepare_header_ram(p);
return true;
}
diff --git a/migration/multifd-qpl.c b/migration/multifd-qpl.c
index 75041a4c4dfe..bd6b5b6a3868 100644
--- a/migration/multifd-qpl.c
+++ b/migration/multifd-qpl.c
@@ -490,7 +490,7 @@ static int multifd_qpl_send_prepare(MultiFDSendParams *p,
Error **errp)
out:
p->flags |= MULTIFD_FLAG_QPL;
- multifd_send_fill_packet(p);
+ multifd_send_fill_packet_ram(p);
return 0;
}
diff --git a/migration/multifd-uadk.c b/migration/multifd-uadk.c
index db2549f59bfe..6e2d26010742 100644
--- a/migration/multifd-uadk.c
+++ b/migration/multifd-uadk.c
@@ -198,7 +198,7 @@ static int multifd_uadk_send_prepare(MultiFDSendParams *p,
Error **errp)
}
out:
p->flags |= MULTIFD_FLAG_UADK;
- multifd_send_fill_packet(p);
+ multifd_send_fill_packet_ram(p);
return 0;
}
diff --git a/migration/multifd-zlib.c b/migration/multifd-zlib.c
index 6787538762d2..62a1fe59ad3e 100644
--- a/migration/multifd-zlib.c
+++ b/migration/multifd-zlib.c
@@ -156,7 +156,7 @@ static int multifd_zlib_send_prepare(MultiFDSendParams *p,
Error **errp)
out:
p->flags |= MULTIFD_FLAG_ZLIB;
- multifd_send_fill_packet(p);
+ multifd_send_fill_packet_ram(p);
return 0;
}
diff --git a/migration/multifd-zstd.c b/migration/multifd-zstd.c
index 1576b1e2adc6..f98b07e7f9f5 100644
--- a/migration/multifd-zstd.c
+++ b/migration/multifd-zstd.c
@@ -143,7 +143,7 @@ static int multifd_zstd_send_prepare(MultiFDSendParams *p,
Error **errp)
out:
p->flags |= MULTIFD_FLAG_ZSTD;
- multifd_send_fill_packet(p);
+ multifd_send_fill_packet_ram(p);
return 0;
}
diff --git a/migration/multifd.c b/migration/multifd.c
index a74e8a5cc891..bebe5b5a9b9c 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -12,6 +12,7 @@
#include "qemu/osdep.h"
#include "qemu/cutils.h"
+#include "qemu/iov.h"
#include "qemu/rcu.h"
#include "exec/target_page.h"
#include "sysemu/sysemu.h"
@@ -19,6 +20,7 @@
#include "qemu/error-report.h"
#include "qapi/error.h"
#include "file.h"
+#include "migration/misc.h"
#include "migration.h"
#include "migration-stats.h"
#include "savevm.h"
@@ -107,7 +109,9 @@ MultiFDSendData *multifd_send_data_alloc(void)
* added to the union in the future are larger than
* (MultiFDPages_t + flex array).
*/
- max_payload_size = MAX(multifd_ram_payload_size(), sizeof(MultiFDPayload));
+ max_payload_size = MAX(multifd_ram_payload_size(),
+ multifd_device_state_payload_size());
+ max_payload_size = MAX(max_payload_size, sizeof(MultiFDPayload));
/*
* Account for any holes the compiler might insert. We can't pack
@@ -126,6 +130,9 @@ void multifd_send_data_clear(MultiFDSendData *data)
}
switch (data->type) {
+ case MULTIFD_PAYLOAD_DEVICE_STATE:
+ multifd_device_state_clear(&data->u.device_state);
+ break;
default:
/* Nothing to do */
break;
@@ -228,7 +235,7 @@ static int multifd_recv_initial_packet(QIOChannel *c, Error
**errp)
return msg.id;
}
-void multifd_send_fill_packet(MultiFDSendParams *p)
+void multifd_send_fill_packet_ram(MultiFDSendParams *p)
{
MultiFDPacket_t *packet = p->packet;
uint64_t packet_num;
@@ -397,20 +404,16 @@ bool multifd_send(MultiFDSendData **send_data)
p = &multifd_send_state->params[i];
/*
- * Lockless read to p->pending_job is safe, because only multifd
- * sender thread can clear it.
+ * Lockless RMW on p->pending_job_preparing is safe, because only
multifd
+ * sender thread can clear it after it had seen p->pending_job being
set.
+ *
+ * Pairs with qatomic_store_release() in multifd_send_thread().
*/
- if (qatomic_read(&p->pending_job) == false) {
+ if (qatomic_cmpxchg(&p->pending_job_preparing, false, true) == false) {
break;
}
}
- /*
- * Make sure we read p->pending_job before all the rest. Pairs with
- * qatomic_store_release() in multifd_send_thread().
- */
- smp_mb_acquire();
-
assert(multifd_payload_empty(p->data));
/*
@@ -534,6 +537,7 @@ static bool multifd_send_cleanup_channel(MultiFDSendParams
*p, Error **errp)
p->name = NULL;
g_clear_pointer(&p->data, multifd_send_data_free);
p->packet_len = 0;
+ g_clear_pointer(&p->packet_device_state, g_free);
g_free(p->packet);
p->packet = NULL;
multifd_send_state->ops->send_cleanup(p, errp);
@@ -545,6 +549,7 @@ static void multifd_send_cleanup_state(void)
{
file_cleanup_outgoing_migration();
socket_cleanup_outgoing_migration();
+ multifd_device_state_save_cleanup();
qemu_sem_destroy(&multifd_send_state->channels_created);
qemu_sem_destroy(&multifd_send_state->channels_ready);
g_free(multifd_send_state->params);
@@ -670,19 +675,29 @@ static void *multifd_send_thread(void *opaque)
* qatomic_store_release() in multifd_send().
*/
if (qatomic_load_acquire(&p->pending_job)) {
+ bool is_device_state = multifd_payload_device_state(p->data);
+ size_t total_size;
+
p->flags = 0;
p->iovs_num = 0;
assert(!multifd_payload_empty(p->data));
- ret = multifd_send_state->ops->send_prepare(p, &local_err);
- if (ret != 0) {
- break;
+ if (is_device_state) {
+ multifd_device_state_send_prepare(p);
+ } else {
+ ret = multifd_send_state->ops->send_prepare(p, &local_err);
+ if (ret != 0) {
+ break;
+ }
}
if (migrate_mapped_ram()) {
+ assert(!is_device_state);
+
ret = file_write_ramblock_iov(p->c, p->iov, p->iovs_num,
&p->data->u.ram, &local_err);
} else {
+ total_size = iov_size(p->iov, p->iovs_num);
ret = qio_channel_writev_full_all(p->c, p->iov, p->iovs_num,
NULL, 0, p->write_flags,
&local_err);
@@ -692,18 +707,27 @@ static void *multifd_send_thread(void *opaque)
break;
}
- stat64_add(&mig_stats.multifd_bytes,
- p->next_packet_size + p->packet_len);
+ if (is_device_state) {
+ stat64_add(&mig_stats.multifd_bytes, total_size);
+ } else {
+ /*
+ * Can't just always add total_size since IOVs do not include
+ * packet header in the zerocopy RAM case.
+ */
+ stat64_add(&mig_stats.multifd_bytes,
+ p->next_packet_size + p->packet_len);
+ }
p->next_packet_size = 0;
multifd_send_data_clear(p->data);
/*
* Making sure p->data is published before saying "we're
- * free". Pairs with the smp_mb_acquire() in
+ * free". Pairs with the qatomic_cmpxchg() in
* multifd_send().
*/
qatomic_store_release(&p->pending_job, false);
+ qatomic_store_release(&p->pending_job_preparing, false);
} else {
/*
* If not a normal job, must be a sync request. Note that
@@ -714,7 +738,7 @@ static void *multifd_send_thread(void *opaque)
if (use_packets) {
p->flags = MULTIFD_FLAG_SYNC;
- multifd_send_fill_packet(p);
+ multifd_send_fill_packet_ram(p);
ret = qio_channel_write_all(p->c, (void *)p->packet,
p->packet_len, &local_err);
if (ret != 0) {
@@ -910,6 +934,9 @@ bool multifd_send_setup(void)
p->packet_len = sizeof(MultiFDPacket_t)
+ sizeof(uint64_t) * page_count;
p->packet = g_malloc0(p->packet_len);
+ p->packet_device_state =
g_malloc0(sizeof(*p->packet_device_state));
+ p->packet_device_state->hdr.magic = cpu_to_be32(MULTIFD_MAGIC);
+ p->packet_device_state->hdr.version = cpu_to_be32(MULTIFD_VERSION);
}
p->name = g_strdup_printf("mig/src/send_%d", i);
p->write_flags = 0;
@@ -944,6 +971,8 @@ bool multifd_send_setup(void)
}
}
+ multifd_device_state_save_setup();
+
return true;
err:
diff --git a/migration/multifd.h b/migration/multifd.h
index a0853622153e..c15c83104c8b 100644
--- a/migration/multifd.h
+++ b/migration/multifd.h
@@ -120,10 +120,12 @@ typedef struct {
typedef enum {
MULTIFD_PAYLOAD_NONE,
MULTIFD_PAYLOAD_RAM,
+ MULTIFD_PAYLOAD_DEVICE_STATE,
} MultiFDPayloadType;
typedef union MultiFDPayload {
MultiFDPages_t ram;
+ MultiFDDeviceState_t device_state;
} MultiFDPayload;
struct MultiFDSendData {
@@ -136,6 +138,11 @@ static inline bool multifd_payload_empty(MultiFDSendData
*data)
return data->type == MULTIFD_PAYLOAD_NONE;
}
+static inline bool multifd_payload_device_state(MultiFDSendData *data)
+{
+ return data->type == MULTIFD_PAYLOAD_DEVICE_STATE;
+}
+
static inline void multifd_set_payload_type(MultiFDSendData *data,
MultiFDPayloadType type)
{
@@ -182,13 +189,15 @@ typedef struct {
* cleared by the multifd sender threads.
*/
bool pending_job;
+ bool pending_job_preparing;
bool pending_sync;
MultiFDSendData *data;
/* thread local variables. No locking required */
- /* pointer to the packet */
+ /* pointers to the possible packet types */
MultiFDPacket_t *packet;
+ MultiFDPacketDeviceState_t *packet_device_state;
/* size of the next packet that contains pages */
uint32_t next_packet_size;
/* packets sent through this channel */
@@ -276,18 +285,25 @@ typedef struct {
} MultiFDMethods;
void multifd_register_ops(int method, MultiFDMethods *ops);
-void multifd_send_fill_packet(MultiFDSendParams *p);
+void multifd_send_fill_packet_ram(MultiFDSendParams *p);
bool multifd_send_prepare_common(MultiFDSendParams *p);
void multifd_send_zero_page_detect(MultiFDSendParams *p);
void multifd_recv_zero_page_process(MultiFDRecvParams *p);
-static inline void multifd_send_prepare_header(MultiFDSendParams *p)
+static inline void multifd_send_prepare_header_ram(MultiFDSendParams *p)
{
p->iov[0].iov_len = p->packet_len;
p->iov[0].iov_base = p->packet;
p->iovs_num++;
}
+static inline void multifd_send_prepare_header_device_state(MultiFDSendParams
*p)
+{
+ p->iov[0].iov_len = sizeof(*p->packet_device_state);
+ p->iov[0].iov_base = p->packet_device_state;
+ p->iovs_num++;
+}
+
void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc);
bool multifd_send(MultiFDSendData **send_data);
MultiFDSendData *multifd_send_data_alloc(void);
@@ -310,4 +326,11 @@ int multifd_ram_flush_and_sync(void);
size_t multifd_ram_payload_size(void);
void multifd_ram_fill_packet(MultiFDSendParams *p);
int multifd_ram_unfill_packet(MultiFDRecvParams *p, Error **errp);
+
+size_t multifd_device_state_payload_size(void);
+void multifd_device_state_save_setup(void);
+void multifd_device_state_clear(MultiFDDeviceState_t *device_state);
+void multifd_device_state_save_cleanup(void);
+void multifd_device_state_send_prepare(MultiFDSendParams *p);
+
#endif
