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05b7ec1890
qemu/migration/multifd.c
Peter Xu 05b7ec1890 migration/multifd: Rename p->num_packets and clean it up 
This field, no matter whether on src or dest, is only used for debugging
purpose.

They can even be removed already, unless it still more or less provide some
accounting on "how many packets are sent/recved for this thread".  The
other more important one is called packet_num, which is embeded in the
multifd packet headers (MultiFDPacket_t).

So let's keep them for now, but make them much easier to understand, by
doing below:

  - Rename both of them to packets_sent / packets_recved, the old
  name (num_packets) are waaay too confusing when we already have
  MultiFDPacket_t.packets_num.

  - Avoid worrying on the "initial packet": we know we will send it, that's
  good enough.  The accounting won't matter a great deal to start with 0 or
  with 1.

  - Move them to where we send/recv the packets.  They're:

    - multifd_send_fill_packet() for senders.
    - multifd_recv_unfill_packet() for receivers.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-10-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
2024-02-05 14:42:10 +08:00

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/*
* Multifd common code
*
* Copyright (c) 2019-2020 Red Hat Inc
*
* Authors:
* Juan Quintela <quintela@redhat.com>
*
* 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/rcu.h"
#include "exec/target_page.h"
#include "sysemu/sysemu.h"
#include "exec/ramblock.h"
#include "qemu/error-report.h"
#include "qapi/error.h"
#include "ram.h"
#include "migration.h"
#include "migration-stats.h"
#include "socket.h"
#include "tls.h"
#include "qemu-file.h"
#include "trace.h"
#include "multifd.h"
#include "threadinfo.h"
#include "options.h"
#include "qemu/yank.h"
#include "io/channel-socket.h"
#include "yank_functions.h"
/* Multiple fd's */
#define MULTIFD_MAGIC 0x11223344U
#define MULTIFD_VERSION 1
typedef struct {
uint32_t magic;
uint32_t version;
unsigned char uuid[16]; /* QemuUUID */
uint8_t id;
uint8_t unused1[7]; /* Reserved for future use */
uint64_t unused2[4]; /* Reserved for future use */
} __attribute__((packed)) MultiFDInit_t;
/* Multifd without compression */
/**
* nocomp_send_setup: setup send side
*
* For no compression this function does nothing.
*
* Returns 0 for success or -1 for error
*
* @p: Params for the channel that we are using
* @errp: pointer to an error
*/
static int nocomp_send_setup(MultiFDSendParams *p, Error **errp)
{
return 0;
}
/**
* nocomp_send_cleanup: cleanup send side
*
* For no compression this function does nothing.
*
* @p: Params for the channel that we are using
* @errp: pointer to an error
*/
static void nocomp_send_cleanup(MultiFDSendParams *p, Error **errp)
{
return;
}
/**
* nocomp_send_prepare: prepare date to be able to send
*
* For no compression we just have to calculate the size of the
* packet.
*
* Returns 0 for success or -1 for error
*
* @p: Params for the channel that we are using
* @errp: pointer to an error
*/
static int nocomp_send_prepare(MultiFDSendParams *p, Error **errp)
{
MultiFDPages_t *pages = p->pages;
for (int i = 0; i < pages->num; i++) {
p->iov[p->iovs_num].iov_base = pages->block->host + pages->offset[i];
p->iov[p->iovs_num].iov_len = p->page_size;
p->iovs_num++;
}
p->next_packet_size = pages->num * p->page_size;
p->flags |= MULTIFD_FLAG_NOCOMP;
return 0;
}
/**
* nocomp_recv_setup: setup receive side
*
* For no compression this function does nothing.
*
* Returns 0 for success or -1 for error
*
* @p: Params for the channel that we are using
* @errp: pointer to an error
*/
static int nocomp_recv_setup(MultiFDRecvParams *p, Error **errp)
{
return 0;
}
/**
* nocomp_recv_cleanup: setup receive side
*
* For no compression this function does nothing.
*
* @p: Params for the channel that we are using
*/
static void nocomp_recv_cleanup(MultiFDRecvParams *p)
{
}
/**
* nocomp_recv_pages: read the data from the channel into actual pages
*
* For no compression we just need to read things into the correct place.
*
* Returns 0 for success or -1 for error
*
* @p: Params for the channel that we are using
* @errp: pointer to an error
*/
static int nocomp_recv_pages(MultiFDRecvParams *p, Error **errp)
{
uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
if (flags != MULTIFD_FLAG_NOCOMP) {
error_setg(errp, "multifd %u: flags received %x flags expected %x",
p->id, flags, MULTIFD_FLAG_NOCOMP);
return -1;
}
for (int i = 0; i < p->normal_num; i++) {
p->iov[i].iov_base = p->host + p->normal[i];
p->iov[i].iov_len = p->page_size;
}
return qio_channel_readv_all(p->c, p->iov, p->normal_num, errp);
}
static MultiFDMethods multifd_nocomp_ops = {
.send_setup = nocomp_send_setup,
.send_cleanup = nocomp_send_cleanup,
.send_prepare = nocomp_send_prepare,
.recv_setup = nocomp_recv_setup,
.recv_cleanup = nocomp_recv_cleanup,
.recv_pages = nocomp_recv_pages
};
static MultiFDMethods *multifd_ops[MULTIFD_COMPRESSION__MAX] = {
[MULTIFD_COMPRESSION_NONE] = &multifd_nocomp_ops,
};
void multifd_register_ops(int method, MultiFDMethods *ops)
{
assert(0 < method && method < MULTIFD_COMPRESSION__MAX);
multifd_ops[method] = ops;
}
/* Reset a MultiFDPages_t* object for the next use */
static void multifd_pages_reset(MultiFDPages_t *pages)
{
/*
* We don't need to touch offset[] array, because it will be
* overwritten later when reused.
*/
pages->num = 0;
pages->block = NULL;
}
static int multifd_send_initial_packet(MultiFDSendParams *p, Error **errp)
{
MultiFDInit_t msg = {};
size_t size = sizeof(msg);
int ret;
msg.magic = cpu_to_be32(MULTIFD_MAGIC);
msg.version = cpu_to_be32(MULTIFD_VERSION);
msg.id = p->id;
memcpy(msg.uuid, &qemu_uuid.data, sizeof(msg.uuid));
ret = qio_channel_write_all(p->c, (char *)&msg, size, errp);
if (ret != 0) {
return -1;
}
stat64_add(&mig_stats.multifd_bytes, size);
return 0;
}
static int multifd_recv_initial_packet(QIOChannel *c, Error **errp)
{
MultiFDInit_t msg;
int ret;
ret = qio_channel_read_all(c, (char *)&msg, sizeof(msg), errp);
if (ret != 0) {
return -1;
}
msg.magic = be32_to_cpu(msg.magic);
msg.version = be32_to_cpu(msg.version);
if (msg.magic != MULTIFD_MAGIC) {
error_setg(errp, "multifd: received packet magic %x "
"expected %x", msg.magic, MULTIFD_MAGIC);
return -1;
}
if (msg.version != MULTIFD_VERSION) {
error_setg(errp, "multifd: received packet version %u "
"expected %u", msg.version, MULTIFD_VERSION);
return -1;
}
if (memcmp(msg.uuid, &qemu_uuid, sizeof(qemu_uuid))) {
char *uuid = qemu_uuid_unparse_strdup(&qemu_uuid);
char *msg_uuid = qemu_uuid_unparse_strdup((const QemuUUID *)msg.uuid);
error_setg(errp, "multifd: received uuid '%s' and expected "
"uuid '%s' for channel %hhd", msg_uuid, uuid, msg.id);
g_free(uuid);
g_free(msg_uuid);
return -1;
}
if (msg.id > migrate_multifd_channels()) {
error_setg(errp, "multifd: received channel id %u is greater than "
"number of channels %u", msg.id, migrate_multifd_channels());
return -1;
}
return msg.id;
}
static MultiFDPages_t *multifd_pages_init(uint32_t n)
{
MultiFDPages_t *pages = g_new0(MultiFDPages_t, 1);
pages->allocated = n;
pages->offset = g_new0(ram_addr_t, n);
return pages;
}
static void multifd_pages_clear(MultiFDPages_t *pages)
{
multifd_pages_reset(pages);
pages->allocated = 0;
g_free(pages->offset);
pages->offset = NULL;
g_free(pages);
}
static void multifd_send_fill_packet(MultiFDSendParams *p)
{
MultiFDPacket_t *packet = p->packet;
MultiFDPages_t *pages = p->pages;
int i;
packet->flags = cpu_to_be32(p->flags);
packet->pages_alloc = cpu_to_be32(p->pages->allocated);
packet->normal_pages = cpu_to_be32(pages->num);
packet->next_packet_size = cpu_to_be32(p->next_packet_size);
packet->packet_num = cpu_to_be64(p->packet_num);
if (pages->block) {
strncpy(packet->ramblock, pages->block->idstr, 256);
}
for (i = 0; i < pages->num; i++) {
/* there are architectures where ram_addr_t is 32 bit */
uint64_t temp = pages->offset[i];
packet->offset[i] = cpu_to_be64(temp);
}
p->packets_sent++;
}
static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
{
MultiFDPacket_t *packet = p->packet;
int i;
packet->magic = be32_to_cpu(packet->magic);
if (packet->magic != MULTIFD_MAGIC) {
error_setg(errp, "multifd: received packet "
"magic %x and expected magic %x",
packet->magic, MULTIFD_MAGIC);
return -1;
}
packet->version = be32_to_cpu(packet->version);
if (packet->version != MULTIFD_VERSION) {
error_setg(errp, "multifd: received packet "
"version %u and expected version %u",
packet->version, MULTIFD_VERSION);
return -1;
}
p->flags = be32_to_cpu(packet->flags);
packet->pages_alloc = be32_to_cpu(packet->pages_alloc);
/*
* If we received a packet that is 100 times bigger than expected
* just stop migration. It is a magic number.
*/
if (packet->pages_alloc > p->page_count) {
error_setg(errp, "multifd: received packet "
"with size %u and expected a size of %u",
packet->pages_alloc, p->page_count) ;
return -1;
}
p->normal_num = be32_to_cpu(packet->normal_pages);
if (p->normal_num > packet->pages_alloc) {
error_setg(errp, "multifd: received packet "
"with %u pages and expected maximum pages are %u",
p->normal_num, packet->pages_alloc) ;
return -1;
}
p->next_packet_size = be32_to_cpu(packet->next_packet_size);
p->packet_num = be64_to_cpu(packet->packet_num);
p->packets_recved++;
if (p->normal_num == 0) {
return 0;
}
/* make sure that ramblock is 0 terminated */
packet->ramblock[255] = 0;
p->block = qemu_ram_block_by_name(packet->ramblock);
if (!p->block) {
error_setg(errp, "multifd: unknown ram block %s",
packet->ramblock);
return -1;
}
p->host = p->block->host;
for (i = 0; i < p->normal_num; i++) {
uint64_t offset = be64_to_cpu(packet->offset[i]);
if (offset > (p->block->used_length - p->page_size)) {
error_setg(errp, "multifd: offset too long %" PRIu64
" (max " RAM_ADDR_FMT ")",
offset, p->block->used_length);
return -1;
}
p->normal[i] = offset;
}
return 0;
}
struct {
MultiFDSendParams *params;
/* array of pages to sent */
MultiFDPages_t *pages;
/* global number of generated multifd packets */
uint64_t packet_num;
/* send channels ready */
QemuSemaphore channels_ready;
/*
* Have we already run terminate threads. There is a race when it
* happens that we got one error while we are exiting.
* We will use atomic operations. Only valid values are 0 and 1.
*/
int exiting;
/* multifd ops */
MultiFDMethods *ops;
} *multifd_send_state;
static bool multifd_send_should_exit(void)
{
return qatomic_read(&multifd_send_state->exiting);
}
/*
* The migration thread can wait on either of the two semaphores. This
* function can be used to kick the main thread out of waiting on either of
* them. Should mostly only be called when something wrong happened with
* the current multifd send thread.
*/
static void multifd_send_kick_main(MultiFDSendParams *p)
{
qemu_sem_post(&p->sem_sync);
qemu_sem_post(&multifd_send_state->channels_ready);
}
/*
* How we use multifd_send_state->pages and channel->pages?
*
* We create a pages for each channel, and a main one. Each time that
* we need to send a batch of pages we interchange the ones between
* multifd_send_state and the channel that is sending it. There are
* two reasons for that:
* - to not have to do so many mallocs during migration
* - to make easier to know what to free at the end of migration
*
* This way we always know who is the owner of each "pages" struct,
* and we don't need any locking. It belongs to the migration thread
* or to the channel thread. Switching is safe because the migration
* thread is using the channel mutex when changing it, and the channel
* have to had finish with its own, otherwise pending_job can't be
* false.
*/
static int multifd_send_pages(void)
{
int i;
static int next_channel;
MultiFDSendParams *p = NULL; /* make happy gcc */
MultiFDPages_t *pages = multifd_send_state->pages;
if (multifd_send_should_exit()) {
return -1;
}
/* We wait here, until at least one channel is ready */
qemu_sem_wait(&multifd_send_state->channels_ready);
/*
* next_channel can remain from a previous migration that was
* using more channels, so ensure it doesn't overflow if the
* limit is lower now.
*/
next_channel %= migrate_multifd_channels();
for (i = next_channel;; i = (i + 1) % migrate_multifd_channels()) {
if (multifd_send_should_exit()) {
return -1;
}
p = &multifd_send_state->params[i];
/*
* Lockless read to p->pending_job is safe, because only multifd
* sender thread can clear it.
*/
if (qatomic_read(&p->pending_job) == false) {
next_channel = (i + 1) % migrate_multifd_channels();
break;
}
}
qemu_mutex_lock(&p->mutex);
assert(!p->pages->num);
assert(!p->pages->block);
/*
* Double check on pending_job==false with the lock. In the future if
* we can have >1 requester thread, we can replace this with a "goto
* retry", but that is for later.
*/
assert(qatomic_read(&p->pending_job) == false);
qatomic_set(&p->pending_job, true);
p->packet_num = multifd_send_state->packet_num++;
multifd_send_state->pages = p->pages;
p->pages = pages;
qemu_mutex_unlock(&p->mutex);
qemu_sem_post(&p->sem);
return 1;
}
int multifd_queue_page(RAMBlock *block, ram_addr_t offset)
{
MultiFDPages_t *pages = multifd_send_state->pages;
bool changed = false;
if (!pages->block) {
pages->block = block;
}
if (pages->block == block) {
pages->offset[pages->num] = offset;
pages->num++;
if (pages->num < pages->allocated) {
return 1;
}
} else {
changed = true;
}
if (multifd_send_pages() < 0) {
return -1;
}
if (changed) {
return multifd_queue_page(block, offset);
}
return 1;
}
static void multifd_send_terminate_threads(Error *err)
{
int i;
/*
* We don't want to exit each threads twice. Depending on where
* we get the error, or if there are two independent errors in two
* threads at the same time, we can end calling this function
* twice.
*/
if (qatomic_xchg(&multifd_send_state->exiting, 1)) {
return;
}
trace_multifd_send_terminate_threads(err != NULL);
if (err) {
MigrationState *s = migrate_get_current();
migrate_set_error(s, err);
if (s->state == MIGRATION_STATUS_SETUP ||
s->state == MIGRATION_STATUS_PRE_SWITCHOVER ||
s->state == MIGRATION_STATUS_DEVICE ||
s->state == MIGRATION_STATUS_ACTIVE) {
migrate_set_state(&s->state, s->state,
MIGRATION_STATUS_FAILED);
}
}
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
qemu_sem_post(&p->sem);
if (p->c) {
qio_channel_shutdown(p->c, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
}
}
}
static int multifd_send_channel_destroy(QIOChannel *send)
{
return socket_send_channel_destroy(send);
}
void multifd_save_cleanup(void)
{
int i;
if (!migrate_multifd()) {
return;
}
multifd_send_terminate_threads(NULL);
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
if (p->running) {
qemu_thread_join(&p->thread);
}
}
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
Error *local_err = NULL;
if (p->registered_yank) {
migration_ioc_unregister_yank(p->c);
}
multifd_send_channel_destroy(p->c);
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);
p->pages = NULL;
p->packet_len = 0;
g_free(p->packet);
p->packet = NULL;
g_free(p->iov);
p->iov = NULL;
multifd_send_state->ops->send_cleanup(p, &local_err);
if (local_err) {
migrate_set_error(migrate_get_current(), local_err);
error_free(local_err);
}
}
qemu_sem_destroy(&multifd_send_state->channels_ready);
g_free(multifd_send_state->params);
multifd_send_state->params = NULL;
multifd_pages_clear(multifd_send_state->pages);
multifd_send_state->pages = NULL;
g_free(multifd_send_state);
multifd_send_state = NULL;
}
static int multifd_zero_copy_flush(QIOChannel *c)
{
int ret;
Error *err = NULL;
ret = qio_channel_flush(c, &err);
if (ret < 0) {
error_report_err(err);
return -1;
}
if (ret == 1) {
stat64_add(&mig_stats.dirty_sync_missed_zero_copy, 1);
}
return ret;
}
int multifd_send_sync_main(void)
{
int i;
bool flush_zero_copy;
if (!migrate_multifd()) {
return 0;
}
if (multifd_send_state->pages->num) {
if (multifd_send_pages() < 0) {
error_report("%s: multifd_send_pages fail", __func__);
return -1;
}
}
flush_zero_copy = migrate_zero_copy_send();
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
if (multifd_send_should_exit()) {
return -1;
}
trace_multifd_send_sync_main_signal(p->id);
qemu_mutex_lock(&p->mutex);
p->packet_num = multifd_send_state->packet_num++;
/*
* We should be the only user so far, so not possible to be set by
* others concurrently.
*/
assert(qatomic_read(&p->pending_sync) == false);
qatomic_set(&p->pending_sync, true);
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];
if (multifd_send_should_exit()) {
return -1;
}
qemu_sem_wait(&multifd_send_state->channels_ready);
trace_multifd_send_sync_main_wait(p->id);
qemu_sem_wait(&p->sem_sync);
if (flush_zero_copy && p->c && (multifd_zero_copy_flush(p->c) < 0)) {
return -1;
}
}
trace_multifd_send_sync_main(multifd_send_state->packet_num);
return 0;
}
static void *multifd_send_thread(void *opaque)
{
MultiFDSendParams *p = opaque;
MigrationThread *thread = NULL;
Error *local_err = NULL;
int ret = 0;
bool use_zero_copy_send = migrate_zero_copy_send();
thread = migration_threads_add(p->name, qemu_get_thread_id());
trace_multifd_send_thread_start(p->id);
rcu_register_thread();
if (multifd_send_initial_packet(p, &local_err) < 0) {
ret = -1;
goto out;
}
while (true) {
qemu_sem_post(&multifd_send_state->channels_ready);
qemu_sem_wait(&p->sem);
if (multifd_send_should_exit()) {
break;
}
qemu_mutex_lock(&p->mutex);
if (qatomic_read(&p->pending_job)) {
uint64_t packet_num = p->packet_num;
MultiFDPages_t *pages = p->pages;
if (use_zero_copy_send) {
p->iovs_num = 0;
} else {
p->iovs_num = 1;
}
assert(pages->num);
ret = multifd_send_state->ops->send_prepare(p, &local_err);
if (ret != 0) {
qemu_mutex_unlock(&p->mutex);
break;
}
multifd_send_fill_packet(p);
p->total_normal_pages += pages->num;
trace_multifd_send(p->id, packet_num, pages->num, p->flags,
p->next_packet_size);
if (use_zero_copy_send) {
/* Send header first, without zerocopy */
ret = qio_channel_write_all(p->c, (void *)p->packet,
p->packet_len, &local_err);
if (ret != 0) {
break;
}
} else {
/* Send header using the same writev call */
p->iov[0].iov_len = p->packet_len;
p->iov[0].iov_base = p->packet;
}
ret = qio_channel_writev_full_all(p->c, p->iov, p->iovs_num, NULL,
0, p->write_flags, &local_err);
if (ret != 0) {
qemu_mutex_unlock(&p->mutex);
break;
}
stat64_add(&mig_stats.multifd_bytes,
p->next_packet_size + p->packet_len);
multifd_pages_reset(p->pages);
p->next_packet_size = 0;
qatomic_set(&p->pending_job, false);
qemu_mutex_unlock(&p->mutex);
} else if (qatomic_read(&p->pending_sync)) {
p->flags = MULTIFD_FLAG_SYNC;
multifd_send_fill_packet(p);
ret = qio_channel_write_all(p->c, (void *)p->packet,
p->packet_len, &local_err);
if (ret != 0) {
qemu_mutex_unlock(&p->mutex);
break;
}
/* p->next_packet_size will always be zero for a SYNC packet */
stat64_add(&mig_stats.multifd_bytes, p->packet_len);
p->flags = 0;
qatomic_set(&p->pending_sync, false);
qemu_mutex_unlock(&p->mutex);
qemu_sem_post(&p->sem_sync);
} else {
qemu_mutex_unlock(&p->mutex);
/* sometimes there are spurious wakeups */
}
}
out:
if (ret) {
assert(local_err);
trace_multifd_send_error(p->id);
multifd_send_terminate_threads(local_err);
multifd_send_kick_main(p);
error_free(local_err);
}
qemu_mutex_lock(&p->mutex);
p->running = false;
qemu_mutex_unlock(&p->mutex);
rcu_unregister_thread();
migration_threads_remove(thread);
trace_multifd_send_thread_end(p->id, p->packets_sent, p->total_normal_pages);
return NULL;
}
static bool multifd_channel_connect(MultiFDSendParams *p,
QIOChannel *ioc,
Error **errp);
static void multifd_tls_outgoing_handshake(QIOTask *task,
gpointer opaque)
{
MultiFDSendParams *p = opaque;
QIOChannel *ioc = QIO_CHANNEL(qio_task_get_source(task));
Error *err = NULL;
if (!qio_task_propagate_error(task, &err)) {
trace_multifd_tls_outgoing_handshake_complete(ioc);
if (multifd_channel_connect(p, ioc, &err)) {
return;
}
}
trace_multifd_tls_outgoing_handshake_error(ioc, error_get_pretty(err));
multifd_send_terminate_threads(err);
multifd_send_kick_main(p);
error_free(err);
}
static void *multifd_tls_handshake_thread(void *opaque)
{
MultiFDSendParams *p = opaque;
QIOChannelTLS *tioc = QIO_CHANNEL_TLS(p->c);
qio_channel_tls_handshake(tioc,
multifd_tls_outgoing_handshake,
p,
NULL,
NULL);
return NULL;
}
static bool multifd_tls_channel_connect(MultiFDSendParams *p,
QIOChannel *ioc,
Error **errp)
{
MigrationState *s = migrate_get_current();
const char *hostname = s->hostname;
QIOChannelTLS *tioc;
tioc = migration_tls_client_create(ioc, hostname, errp);
if (!tioc) {
return false;
}
object_unref(OBJECT(ioc));
trace_multifd_tls_outgoing_handshake_start(ioc, tioc, hostname);
qio_channel_set_name(QIO_CHANNEL(tioc), "multifd-tls-outgoing");
p->c = QIO_CHANNEL(tioc);
qemu_thread_create(&p->thread, "multifd-tls-handshake-worker",
multifd_tls_handshake_thread, p,
QEMU_THREAD_JOINABLE);
return true;
}
static bool multifd_channel_connect(MultiFDSendParams *p,
QIOChannel *ioc,
Error **errp)
{
trace_multifd_set_outgoing_channel(
ioc, object_get_typename(OBJECT(ioc)),
migrate_get_current()->hostname);
if (migrate_channel_requires_tls_upgrade(ioc)) {
/*
* tls_channel_connect will call back to this
* function after the TLS handshake,
* so we mustn't call multifd_send_thread until then
*/
return multifd_tls_channel_connect(p, ioc, errp);
}
migration_ioc_register_yank(ioc);
p->registered_yank = true;
p->c = ioc;
qemu_thread_create(&p->thread, p->name, multifd_send_thread, p,
QEMU_THREAD_JOINABLE);
return true;
}
static void multifd_new_send_channel_async(QIOTask *task, gpointer opaque)
{
MultiFDSendParams *p = opaque;
QIOChannel *ioc = QIO_CHANNEL(qio_task_get_source(task));
Error *local_err = NULL;
trace_multifd_new_send_channel_async(p->id);
if (!qio_task_propagate_error(task, &local_err)) {
qio_channel_set_delay(ioc, false);
p->running = true;
if (multifd_channel_connect(p, ioc, &local_err)) {
return;
}
}
trace_multifd_new_send_channel_async_error(p->id, local_err);
multifd_send_terminate_threads(local_err);
multifd_send_kick_main(p);
object_unref(OBJECT(ioc));
error_free(local_err);
}
static void multifd_new_send_channel_create(gpointer opaque)
{
socket_send_channel_create(multifd_new_send_channel_async, opaque);
}
int multifd_save_setup(Error **errp)
{
int thread_count;
uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
uint8_t i;
if (!migrate_multifd()) {
return 0;
}
thread_count = migrate_multifd_channels();
multifd_send_state = g_malloc0(sizeof(*multifd_send_state));
multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
multifd_send_state->pages = multifd_pages_init(page_count);
qemu_sem_init(&multifd_send_state->channels_ready, 0);
qatomic_set(&multifd_send_state->exiting, 0);
multifd_send_state->ops = multifd_ops[migrate_multifd_compression()];
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->id = i;
p->pages = multifd_pages_init(page_count);
p->packet_len = sizeof(MultiFDPacket_t)
+ sizeof(uint64_t) * page_count;
p->packet = g_malloc0(p->packet_len);
p->packet->magic = cpu_to_be32(MULTIFD_MAGIC);
p->packet->version = cpu_to_be32(MULTIFD_VERSION);
p->name = g_strdup_printf("multifdsend_%d", i);
/* We need one extra place for the packet header */
p->iov = g_new0(struct iovec, page_count + 1);
p->page_size = qemu_target_page_size();
p->page_count = page_count;
if (migrate_zero_copy_send()) {
p->write_flags = QIO_CHANNEL_WRITE_FLAG_ZERO_COPY;
} else {
p->write_flags = 0;
}
multifd_new_send_channel_create(p);
}
for (i = 0; i < thread_count; i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
int ret;
ret = multifd_send_state->ops->send_setup(p, errp);
if (ret) {
return ret;
}
}
return 0;
}
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 ops */
MultiFDMethods *ops;
} *multifd_recv_state;
static void multifd_recv_terminate_threads(Error *err)
{
int i;
trace_multifd_recv_terminate_threads(err != NULL);
if (err) {
MigrationState *s = migrate_get_current();
migrate_set_error(s, err);
if (s->state == MIGRATION_STATUS_SETUP ||
s->state == MIGRATION_STATUS_ACTIVE) {
migrate_set_state(&s->state, s->state,
MIGRATION_STATUS_FAILED);
}
}
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
qemu_mutex_lock(&p->mutex);
p->quit = true;
/*
* We could arrive here for two reasons:
* - normal quit, i.e. everything went fine, just finished
* - error quit: We close the channels so the channel threads
* finish the qio_channel_read_all_eof()
*/
if (p->c) {
qio_channel_shutdown(p->c, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
}
qemu_mutex_unlock(&p->mutex);
}
}
void multifd_load_shutdown(void)
{
if (migrate_multifd()) {
multifd_recv_terminate_threads(NULL);
}
}
void multifd_load_cleanup(void)
{
int i;
if (!migrate_multifd()) {
return;
}
multifd_recv_terminate_threads(NULL);
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
if (p->running) {
/*
* multifd_recv_thread may hung at MULTIFD_FLAG_SYNC handle code,
* however try to wakeup it without harm in cleanup phase.
*/
qemu_sem_post(&p->sem_sync);
}
qemu_thread_join(&p->thread);
}
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
migration_ioc_unregister_yank(p->c);
object_unref(OBJECT(p->c));
p->c = NULL;
qemu_mutex_destroy(&p->mutex);
qemu_sem_destroy(&p->sem_sync);
g_free(p->name);
p->name = NULL;
p->packet_len = 0;
g_free(p->packet);
p->packet = NULL;
g_free(p->iov);
p->iov = NULL;
g_free(p->normal);
p->normal = NULL;
multifd_recv_state->ops->recv_cleanup(p);
}
qemu_sem_destroy(&multifd_recv_state->sem_sync);
g_free(multifd_recv_state->params);
multifd_recv_state->params = NULL;
g_free(multifd_recv_state);
multifd_recv_state = NULL;
}
void multifd_recv_sync_main(void)
{
int i;
if (!migrate_multifd()) {
return;
}
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);
}
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
WITH_QEMU_LOCK_GUARD(&p->mutex) {
if (multifd_recv_state->packet_num < p->packet_num) {
multifd_recv_state->packet_num = p->packet_num;
}
}
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;
Error *local_err = NULL;
int ret;
trace_multifd_recv_thread_start(p->id);
rcu_register_thread();
while (true) {
uint32_t flags;
if (p->quit) {
break;
}
ret = qio_channel_read_all_eof(p->c, (void *)p->packet,
p->packet_len, &local_err);
if (ret == 0 || ret == -1) { /* 0: EOF -1: Error */
break;
}
qemu_mutex_lock(&p->mutex);
ret = multifd_recv_unfill_packet(p, &local_err);
if (ret) {
qemu_mutex_unlock(&p->mutex);
break;
}
flags = p->flags;
/* recv methods don't know how to handle the SYNC flag */
p->flags &= ~MULTIFD_FLAG_SYNC;
trace_multifd_recv(p->id, p->packet_num, p->normal_num, flags,
p->next_packet_size);
p->total_normal_pages += p->normal_num;
qemu_mutex_unlock(&p->mutex);
if (p->normal_num) {
ret = multifd_recv_state->ops->recv_pages(p, &local_err);
if (ret != 0) {
break;
}
}
if (flags & MULTIFD_FLAG_SYNC) {
qemu_sem_post(&multifd_recv_state->sem_sync);
qemu_sem_wait(&p->sem_sync);
}
}
if (local_err) {
multifd_recv_terminate_threads(local_err);
error_free(local_err);
}
qemu_mutex_lock(&p->mutex);
p->running = false;
qemu_mutex_unlock(&p->mutex);
rcu_unregister_thread();
trace_multifd_recv_thread_end(p->id, p->packets_recved, p->total_normal_pages);
return NULL;
}
int multifd_load_setup(Error **errp)
{
int thread_count;
uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
uint8_t i;
/*
* Return successfully if multiFD recv state is already initialised
* or multiFD is not enabled.
*/
if (multifd_recv_state || !migrate_multifd()) {
return 0;
}
thread_count = migrate_multifd_channels();
multifd_recv_state = g_malloc0(sizeof(*multifd_recv_state));
multifd_recv_state->params = g_new0(MultiFDRecvParams, thread_count);
qatomic_set(&multifd_recv_state->count, 0);
qemu_sem_init(&multifd_recv_state->sem_sync, 0);
multifd_recv_state->ops = multifd_ops[migrate_multifd_compression()];
for (i = 0; i < thread_count; i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
qemu_mutex_init(&p->mutex);
qemu_sem_init(&p->sem_sync, 0);
p->quit = false;
p->id = i;
p->packet_len = sizeof(MultiFDPacket_t)
+ sizeof(uint64_t) * page_count;
p->packet = g_malloc0(p->packet_len);
p->name = g_strdup_printf("multifdrecv_%d", i);
p->iov = g_new0(struct iovec, page_count);
p->normal = g_new0(ram_addr_t, page_count);
p->page_count = page_count;
p->page_size = qemu_target_page_size();
}
for (i = 0; i < thread_count; i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
int ret;
ret = multifd_recv_state->ops->recv_setup(p, errp);
if (ret) {
return ret;
}
}
return 0;
}
bool multifd_recv_all_channels_created(void)
{
int thread_count = migrate_multifd_channels();
if (!migrate_multifd()) {
return true;
}
if (!multifd_recv_state) {
/* Called before any connections created */
return false;
}
return thread_count == qatomic_read(&multifd_recv_state->count);
}
/*
* Try to receive all multifd channels to get ready for the migration.
* Sets @errp when failing to receive the current channel.
*/
void multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
{
MultiFDRecvParams *p;
Error *local_err = NULL;
int id;
id = multifd_recv_initial_packet(ioc, &local_err);
if (id < 0) {
multifd_recv_terminate_threads(local_err);
error_propagate_prepend(errp, local_err,
"failed to receive packet"
" via multifd channel %d: ",
qatomic_read(&multifd_recv_state->count));
return;
}
trace_multifd_recv_new_channel(id);
p = &multifd_recv_state->params[id];
if (p->c != NULL) {
error_setg(&local_err, "multifd: received id '%d' already setup'",
id);
multifd_recv_terminate_threads(local_err);
error_propagate(errp, local_err);
return;
}
p->c = ioc;
object_ref(OBJECT(ioc));
p->running = true;
qemu_thread_create(&p->thread, p->name, multifd_recv_thread, p,
QEMU_THREAD_JOINABLE);
qatomic_inc(&multifd_recv_state->count);
}
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