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Migartion pull request for 20240304 

- Bryan's fix on multifd compression level API
 - Fabiano's mapped-ram series (base + multifd only)
 - Steve's amend on cpr document in qapi/
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 kRdiYPU7khMA/0N43rn4LcqKCoq4+T+EAnYizGjIyhH/7BRUyn4DUxgO
 =AeEn
 -----END PGP SIGNATURE-----

Merge tag 'migration-next-pull-request' of https://gitlab.com/peterx/qemu into staging

Migartion pull request for 20240304

- Bryan's fix on multifd compression level API
- Fabiano's mapped-ram series (base + multifd only)
- Steve's amend on cpr document in qapi/

# -----BEGIN PGP SIGNATURE-----
#
# iIgEABYKADAWIQS5GE3CDMRX2s990ak7X8zN86vXBgUCZeUjKhIccGV0ZXJ4QHJl
# ZGhhdC5jb20ACgkQO1/MzfOr1wbv5QD/ZexBUsmZA5qyxgGvZ2yvlUBEGNOvtmKY
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# =AeEn
# -----END PGP SIGNATURE-----
# gpg: Signature made Mon 04 Mar 2024 01:26:02 GMT
# gpg:                using EDDSA key B9184DC20CC457DACF7DD1A93B5FCCCDF3ABD706
# gpg:                issuer "peterx@redhat.com"
# gpg: Good signature from "Peter Xu <xzpeter@gmail.com>" [marginal]
# gpg:                 aka "Peter Xu <peterx@redhat.com>" [marginal]
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: B918 4DC2 0CC4 57DA CF7D  D1A9 3B5F CCCD F3AB D706

* tag 'migration-next-pull-request' of https://gitlab.com/peterx/qemu: (27 commits)
  migration/multifd: Document two places for mapped-ram
  tests/qtest/migration: Add a multifd + mapped-ram migration test
  migration/multifd: Add mapped-ram support to fd: URI
  migration/multifd: Support incoming mapped-ram stream format
  migration/multifd: Support outgoing mapped-ram stream format
  migration/multifd: Prepare multifd sync for mapped-ram migration
  migration/multifd: Add incoming QIOChannelFile support
  migration/multifd: Add outgoing QIOChannelFile support
  migration/multifd: Add a wrapper for channels_created
  migration/multifd: Allow receiving pages without packets
  migration/multifd: Allow multifd without packets
  migration/multifd: Decouple recv method from pages
  migration/multifd: Rename MultiFDSend|RecvParams::data to compress_data
  tests/qtest/migration: Add tests for mapped-ram file-based migration
  migration/ram: Add incoming 'mapped-ram' migration
  migration/ram: Add outgoing 'mapped-ram' migration
  migration: Add mapped-ram URI compatibility check
  migration/ram: Introduce 'mapped-ram' migration capability
  migration/qemu-file: add utility methods for working with seekable channels
  io: fsync before closing a file channel
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

# Conflicts:
#	migration/ram.c
This commit is contained in:
Peter Maydell 2024-03-05 11:19:58 +00:00
parent 4eac9dfbd7 1a6e217c35
commit c90cfb5294
27 changed files with 1666 additions and 160 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
docs/devel/migration/features.rst
View File

@ -10,3 +10,4 @@ Migration has plenty of features to support different use cases.
dirty-limit
vfio
virtio
mapped-ram

138
docs/devel/migration/mapped-ram.rst Normal file
View File

@ -0,0 +1,138 @@
Mapped-ram
==========
Mapped-ram is a new stream format for the RAM section designed to
supplement the existing ``file:`` migration and make it compatible
with ``multifd``. This enables parallel migration of a guest's RAM to
a file.
The core of the feature is to ensure that RAM pages are mapped
directly to offsets in the resulting migration file. This enables the
``multifd`` threads to write exclusively to those offsets even if the
guest is constantly dirtying pages (i.e. live migration). Another
benefit is that the resulting file will have a bounded size, since
pages which are dirtied multiple times will always go to a fixed
location in the file, rather than constantly being added to a
sequential stream. Having the pages at fixed offsets also allows the
usage of O_DIRECT for save/restore of the migration stream as the
pages are ensured to be written respecting O_DIRECT alignment
restrictions (direct-io support not yet implemented).
Usage
-----
On both source and destination, enable the ``multifd`` and
``mapped-ram`` capabilities:
``migrate_set_capability multifd on``
``migrate_set_capability mapped-ram on``
Use a ``file:`` URL for migration:
``migrate file:/path/to/migration/file``
Mapped-ram migration is best done non-live, i.e. by stopping the VM on
the source side before migrating.
Use-cases
---------
The mapped-ram feature was designed for use cases where the migration
stream will be directed to a file in the filesystem and not
immediately restored on the destination VM [#]_. These could be
thought of as snapshots. We can further categorize them into live and
non-live.
- Non-live snapshot
If the use case requires a VM to be stopped before taking a snapshot,
that's the ideal scenario for mapped-ram migration. Not having to
track dirty pages, the migration will write the RAM pages to the disk
as fast as it can.
Note: if a snapshot is taken of a running VM, but the VM will be
stopped after the snapshot by the admin, then consider stopping it
right before the snapshot to take benefit of the performance gains
mentioned above.
- Live snapshot
If the use case requires that the VM keeps running during and after
the snapshot operation, then mapped-ram migration can still be used,
but will be less performant. Other strategies such as
background-snapshot should be evaluated as well. One benefit of
mapped-ram in this scenario is portability since background-snapshot
depends on async dirty tracking (KVM_GET_DIRTY_LOG) which is not
supported outside of Linux.
.. [#] While this same effect could be obtained with the usage of
snapshots or the ``file:`` migration alone, mapped-ram provides
a performance increase for VMs with larger RAM sizes (10s to
100s of GiBs), specially if the VM has been stopped beforehand.
RAM section format
------------------
Instead of having a sequential stream of pages that follow the
RAMBlock headers, the dirty pages for a RAMBlock follow its header
instead. This ensures that each RAM page has a fixed offset in the
resulting migration file.
A bitmap is introduced to track which pages have been written in the
migration file. Pages are written at a fixed location for every
ramblock. Zero pages are ignored as they'd be zero in the destination
migration as well.
::
Without mapped-ram: With mapped-ram:
--------------------- --------------------------------
| ramblock 1 header | | ramblock 1 header |
--------------------- --------------------------------
| ramblock 2 header | | ramblock 1 mapped-ram header |
--------------------- --------------------------------
| ... | | padding to next 1MB boundary |
--------------------- | ... |
| ramblock n header | --------------------------------
--------------------- | ramblock 1 pages |
| RAM_SAVE_FLAG_EOS | | ... |
--------------------- --------------------------------
| stream of pages | | ramblock 2 header |
| (iter 1) | --------------------------------
| ... | | ramblock 2 mapped-ram header |
--------------------- --------------------------------
| RAM_SAVE_FLAG_EOS | | padding to next 1MB boundary |
--------------------- | ... |
| stream of pages | --------------------------------
| (iter 2) | | ramblock 2 pages |
| ... | | ... |
--------------------- --------------------------------
| ... | | ... |
--------------------- --------------------------------
| RAM_SAVE_FLAG_EOS |
--------------------------------
| ... |
--------------------------------
where:
- ramblock header: the generic information for a ramblock, such as
idstr, used_len, etc.
- ramblock mapped-ram header: the information added by this feature:
bitmap of pages written, bitmap size and offset of pages in the
migration file.
Restrictions
------------
Since pages are written to their relative offsets and out of order
(due to the memory dirtying patterns), streaming channels such as
sockets are not supported. A seekable channel such as a file is
required. This can be verified in the QIOChannel by the presence of
the QIO_CHANNEL_FEATURE_SEEKABLE.
The improvements brought by this feature apply only to guest physical
RAM. Other types of memory such as VRAM are migrated as part of device
states.

13
include/exec/ramblock.h
View File

@ -44,6 +44,19 @@ struct RAMBlock {
size_t page_size;
/* dirty bitmap used during migration */
unsigned long *bmap;
/*
* Below fields are only used by mapped-ram migration
*/
/* bitmap of pages present in the migration file */
unsigned long *file_bmap;
/*
* offset in the file pages belonging to this ramblock are saved,
* used only during migration to a file.
*/
off_t bitmap_offset;
uint64_t pages_offset;
/* bitmap of already received pages in postcopy */
unsigned long *receivedmap;

83
include/io/channel.h
View File

@ -44,6 +44,7 @@ enum QIOChannelFeature {
QIO_CHANNEL_FEATURE_LISTEN,
QIO_CHANNEL_FEATURE_WRITE_ZERO_COPY,
QIO_CHANNEL_FEATURE_READ_MSG_PEEK,
QIO_CHANNEL_FEATURE_SEEKABLE,
};
@ -130,6 +131,16 @@ struct QIOChannelClass {
Error **errp);
/* Optional callbacks */
ssize_t (*io_pwritev)(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
off_t offset,
Error **errp);
ssize_t (*io_preadv)(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
off_t offset,
Error **errp);
int (*io_shutdown)(QIOChannel *ioc,
QIOChannelShutdown how,
Error **errp);
@ -528,6 +539,78 @@ void qio_channel_set_follow_coroutine_ctx(QIOChannel *ioc, bool enabled);
int qio_channel_close(QIOChannel *ioc,
Error **errp);
/**
* qio_channel_pwritev
* @ioc: the channel object
* @iov: the array of memory regions to write data from
* @niov: the length of the @iov array
* @offset: offset in the channel where writes should begin
* @errp: pointer to a NULL-initialized error object
*
* Not all implementations will support this facility, so may report
* an error. To avoid errors, the caller may check for the feature
* flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method.
*
* Behaves as qio_channel_writev_full, apart from not supporting
* sending of file handles as well as beginning the write at the
* passed @offset
*
*/
ssize_t qio_channel_pwritev(QIOChannel *ioc, const struct iovec *iov,
size_t niov, off_t offset, Error **errp);
/**
* qio_channel_pwrite
* @ioc: the channel object
* @buf: the memory region to write data into
* @buflen: the number of bytes to @buf
* @offset: offset in the channel where writes should begin
* @errp: pointer to a NULL-initialized error object
*
* Not all implementations will support this facility, so may report
* an error. To avoid errors, the caller may check for the feature
* flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method.
*
*/
ssize_t qio_channel_pwrite(QIOChannel *ioc, char *buf, size_t buflen,
off_t offset, Error **errp);
/**
* qio_channel_preadv
* @ioc: the channel object
* @iov: the array of memory regions to read data into
* @niov: the length of the @iov array
* @offset: offset in the channel where writes should begin
* @errp: pointer to a NULL-initialized error object
*
* Not all implementations will support this facility, so may report
* an error. To avoid errors, the caller may check for the feature
* flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method.
*
* Behaves as qio_channel_readv_full, apart from not supporting
* receiving of file handles as well as beginning the read at the
* passed @offset
*
*/
ssize_t qio_channel_preadv(QIOChannel *ioc, const struct iovec *iov,
size_t niov, off_t offset, Error **errp);
/**
* qio_channel_pread
* @ioc: the channel object
* @buf: the memory region to write data into
* @buflen: the number of bytes to @buf
* @offset: offset in the channel where writes should begin
* @errp: pointer to a NULL-initialized error object
*
* Not all implementations will support this facility, so may report
* an error. To avoid errors, the caller may check for the feature
* flag QIO_CHANNEL_FEATURE_SEEKABLE prior to calling this method.
*
*/
ssize_t qio_channel_pread(QIOChannel *ioc, char *buf, size_t buflen,
off_t offset, Error **errp);
/**
* qio_channel_shutdown:
* @ioc: the channel object

2
include/migration/qemu-file-types.h
View File

@ -50,6 +50,8 @@ unsigned int qemu_get_be16(QEMUFile *f);
unsigned int qemu_get_be32(QEMUFile *f);
uint64_t qemu_get_be64(QEMUFile *f);
bool qemu_file_is_seekable(QEMUFile *f);
static inline void qemu_put_be64s(QEMUFile *f, const uint64_t *pv)
{
qemu_put_be64(f, *pv);

13
include/qemu/bitops.h
View File

@ -67,6 +67,19 @@ static inline void clear_bit(long nr, unsigned long *addr)
*p &= ~mask;
}
/**
* clear_bit_atomic - Clears a bit in memory atomically
* @nr: Bit to clear
* @addr: Address to start counting from
*/
static inline void clear_bit_atomic(long nr, unsigned long *addr)
{
unsigned long mask = BIT_MASK(nr);
unsigned long *p = addr + BIT_WORD(nr);
return qatomic_and(p, ~mask);
}
/**
* change_bit - Toggle a bit in memory
* @nr: Bit to change

69
io/channel-file.c
View File

@ -36,6 +36,10 @@ qio_channel_file_new_fd(int fd)
ioc->fd = fd;
if (lseek(fd, 0, SEEK_CUR) != (off_t)-1) {
qio_channel_set_feature(QIO_CHANNEL(ioc), QIO_CHANNEL_FEATURE_SEEKABLE);
}
trace_qio_channel_file_new_fd(ioc, fd);
return ioc;
@ -60,6 +64,10 @@ qio_channel_file_new_path(const char *path,
return NULL;
}
if (lseek(ioc->fd, 0, SEEK_CUR) != (off_t)-1) {
qio_channel_set_feature(QIO_CHANNEL(ioc), QIO_CHANNEL_FEATURE_SEEKABLE);
}
trace_qio_channel_file_new_path(ioc, path, flags, mode, ioc->fd);
return ioc;
@ -138,6 +146,58 @@ static ssize_t qio_channel_file_writev(QIOChannel *ioc,
return ret;
}
#ifdef CONFIG_PREADV
static ssize_t qio_channel_file_preadv(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
off_t offset,
Error **errp)
{
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
ssize_t ret;
retry:
ret = preadv(fioc->fd, iov, niov, offset);
if (ret < 0) {
if (errno == EAGAIN) {
return QIO_CHANNEL_ERR_BLOCK;
}
if (errno == EINTR) {
goto retry;
}
error_setg_errno(errp, errno, "Unable to read from file");
return -1;
}
return ret;
}
static ssize_t qio_channel_file_pwritev(QIOChannel *ioc,
const struct iovec *iov,
size_t niov,
off_t offset,
Error **errp)
{
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
ssize_t ret;
retry:
ret = pwritev(fioc->fd, iov, niov, offset);
if (ret <= 0) {
if (errno == EAGAIN) {
return QIO_CHANNEL_ERR_BLOCK;
}
if (errno == EINTR) {
goto retry;
}
error_setg_errno(errp, errno, "Unable to write to file");
return -1;
}
return ret;
}
#endif /* CONFIG_PREADV */
static int qio_channel_file_set_blocking(QIOChannel *ioc,
bool enabled,
Error **errp)
@ -182,6 +242,11 @@ static int qio_channel_file_close(QIOChannel *ioc,
{
QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
if (qemu_fdatasync(fioc->fd) < 0) {
error_setg_errno(errp, errno,
"Unable to synchronize file data with storage device");
return -1;
}
if (qemu_close(fioc->fd) < 0) {
error_setg_errno(errp, errno,
"Unable to close file");
@ -223,6 +288,10 @@ static void qio_channel_file_class_init(ObjectClass *klass,
ioc_klass->io_writev = qio_channel_file_writev;
ioc_klass->io_readv = qio_channel_file_readv;
ioc_klass->io_set_blocking = qio_channel_file_set_blocking;
#ifdef CONFIG_PREADV
ioc_klass->io_pwritev = qio_channel_file_pwritev;
ioc_klass->io_preadv = qio_channel_file_preadv;
#endif
ioc_klass->io_seek = qio_channel_file_seek;
ioc_klass->io_close = qio_channel_file_close;
ioc_klass->io_create_watch = qio_channel_file_create_watch;

58
io/channel.c
View File

@ -454,6 +454,64 @@ GSource *qio_channel_add_watch_source(QIOChannel *ioc,
}
ssize_t qio_channel_pwritev(QIOChannel *ioc, const struct iovec *iov,
size_t niov, off_t offset, Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (!klass->io_pwritev) {
error_setg(errp, "Channel does not support pwritev");
return -1;
}
if (!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_SEEKABLE)) {
error_setg_errno(errp, EINVAL, "Requested channel is not seekable");
return -1;
}
return klass->io_pwritev(ioc, iov, niov, offset, errp);
}
ssize_t qio_channel_pwrite(QIOChannel *ioc, char *buf, size_t buflen,
off_t offset, Error **errp)
{
struct iovec iov = {
.iov_base = buf,
.iov_len = buflen
};
return qio_channel_pwritev(ioc, &iov, 1, offset, errp);
}
ssize_t qio_channel_preadv(QIOChannel *ioc, const struct iovec *iov,
size_t niov, off_t offset, Error **errp)
{
QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
if (!klass->io_preadv) {
error_setg(errp, "Channel does not support preadv");
return -1;
}
if (!qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_SEEKABLE)) {
error_setg_errno(errp, EINVAL, "Requested channel is not seekable");
return -1;
}
return klass->io_preadv(ioc, iov, niov, offset, errp);
}
ssize_t qio_channel_pread(QIOChannel *ioc, char *buf, size_t buflen,
off_t offset, Error **errp)
{
struct iovec iov = {
.iov_base = buf,
.iov_len = buflen
};
return qio_channel_preadv(ioc, &iov, 1, offset, errp);
}
int qio_channel_shutdown(QIOChannel *ioc,
QIOChannelShutdown how,
Error **errp)

44
migration/fd.c
View File

@ -15,18 +15,41 @@
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "channel.h"
#include "fd.h"
#include "migration.h"
#include "monitor/monitor.h"
#include "io/channel-file.h"
#include "io/channel-util.h"
#include "options.h"
#include "trace.h"
static struct FdOutgoingArgs {
int fd;
} outgoing_args;
int fd_args_get_fd(void)
{
return outgoing_args.fd;
}
void fd_cleanup_outgoing_migration(void)
{
if (outgoing_args.fd > 0) {
close(outgoing_args.fd);
outgoing_args.fd = -1;
}
}
void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp)
{
QIOChannel *ioc;
int fd = monitor_get_fd(monitor_cur(), fdname, errp);
outgoing_args.fd = -1;
if (fd == -1) {
return;
}
@ -38,6 +61,8 @@ void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **
return;
}
outgoing_args.fd = fd;
qio_channel_set_name(ioc, "migration-fd-outgoing");
migration_channel_connect(s, ioc, NULL, NULL);
object_unref(OBJECT(ioc));
@ -73,4 +98,23 @@ void fd_start_incoming_migration(const char *fdname, Error **errp)
fd_accept_incoming_migration,
NULL, NULL,
g_main_context_get_thread_default());
if (migrate_multifd()) {
int channels = migrate_multifd_channels();
while (channels--) {
ioc = QIO_CHANNEL(qio_channel_file_new_fd(dup(fd)));
if (QIO_CHANNEL_FILE(ioc)->fd == -1) {
error_setg(errp, "Failed to duplicate fd %d", fd);
return;
}
qio_channel_set_name(ioc, "migration-fd-incoming");
qio_channel_add_watch_full(ioc, G_IO_IN,
fd_accept_incoming_migration,
NULL, NULL,
g_main_context_get_thread_default());
}
}
}

2
migration/fd.h
View File

@ -20,4 +20,6 @@ void fd_start_incoming_migration(const char *fdname, Error **errp);
void fd_start_outgoing_migration(MigrationState *s, const char *fdname,
Error **errp);
void fd_cleanup_outgoing_migration(void);
int fd_args_get_fd(void);
#endif

149
migration/file.c
View File

@ -6,17 +6,25 @@
*/
#include "qemu/osdep.h"
#include "exec/ramblock.h"
#include "qemu/cutils.h"
#include "qemu/error-report.h"
#include "qapi/error.h"
#include "channel.h"
#include "fd.h"
#include "file.h"
#include "migration.h"
#include "io/channel-file.h"
#include "io/channel-util.h"
#include "options.h"
#include "trace.h"
#define OFFSET_OPTION ",offset="
static struct FileOutgoingArgs {
char *fname;
} outgoing_args;
/* Remove the offset option from @filespec and return it in @offsetp. */
int file_parse_offset(char *filespec, uint64_t *offsetp, Error **errp)
@ -36,6 +44,41 @@ int file_parse_offset(char *filespec, uint64_t *offsetp, Error **errp)
return 0;
}
void file_cleanup_outgoing_migration(void)
{
g_free(outgoing_args.fname);
outgoing_args.fname = NULL;
}
bool file_send_channel_create(gpointer opaque, Error **errp)
{
QIOChannelFile *ioc;
int flags = O_WRONLY;
bool ret = false;
int fd = fd_args_get_fd();
if (fd && fd != -1) {
ioc = qio_channel_file_new_fd(dup(fd));
} else {
ioc = qio_channel_file_new_path(outgoing_args.fname, flags, 0, errp);
if (!ioc) {
goto out;
}
}
multifd_channel_connect(opaque, QIO_CHANNEL(ioc));
ret = true;
out:
/*
* File channel creation is synchronous. However posting this
* semaphore here is simpler than adding a special case.
*/
multifd_send_channel_created();
return ret;
}
void file_start_outgoing_migration(MigrationState *s,
FileMigrationArgs *file_args, Error **errp)
{
@ -52,6 +95,8 @@ void file_start_outgoing_migration(MigrationState *s,
return;
}
outgoing_args.fname = g_strdup(filename);
ioc = QIO_CHANNEL(fioc);
if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
return;
@ -74,7 +119,8 @@ void file_start_incoming_migration(FileMigrationArgs *file_args, Error **errp)
g_autofree char *filename = g_strdup(file_args->filename);
QIOChannelFile *fioc = NULL;
uint64_t offset = file_args->offset;
QIOChannel *ioc;
int channels = 1;
int i = 0;
trace_migration_file_incoming(filename);
@ -83,13 +129,100 @@ void file_start_incoming_migration(FileMigrationArgs *file_args, Error **errp)
return;
}
ioc = QIO_CHANNEL(fioc);
if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
if (offset &&
qio_channel_io_seek(QIO_CHANNEL(fioc), offset, SEEK_SET, errp) < 0) {
return;
}
qio_channel_set_name(QIO_CHANNEL(ioc), "migration-file-incoming");
qio_channel_add_watch_full(ioc, G_IO_IN,
file_accept_incoming_migration,
NULL, NULL,
g_main_context_get_thread_default());
if (migrate_multifd()) {
channels += migrate_multifd_channels();
}
do {
QIOChannel *ioc = QIO_CHANNEL(fioc);
qio_channel_set_name(ioc, "migration-file-incoming");
qio_channel_add_watch_full(ioc, G_IO_IN,
file_accept_incoming_migration,
NULL, NULL,
g_main_context_get_thread_default());
fioc = qio_channel_file_new_fd(dup(fioc->fd));
if (!fioc || fioc->fd == -1) {
error_setg(errp, "Error creating migration incoming channel");
break;
}
} while (++i < channels);
}
int file_write_ramblock_iov(QIOChannel *ioc, const struct iovec *iov,
int niov, RAMBlock *block, Error **errp)
{
ssize_t ret = -1;
int i, slice_idx, slice_num;
uintptr_t base, next, offset;
size_t len;
slice_idx = 0;
slice_num = 1;
/*
* If the iov array doesn't have contiguous elements, we need to
* split it in slices because we only have one file offset for the
* whole iov. Do this here so callers don't need to break the iov
* array themselves.
*/
for (i = 0; i < niov; i++, slice_num++) {
base = (uintptr_t) iov[i].iov_base;
if (i != niov - 1) {
len = iov[i].iov_len;
next = (uintptr_t) iov[i + 1].iov_base;
if (base + len == next) {
continue;
}
}
/*
* Use the offset of the first element of the segment that
* we're sending.
*/
offset = (uintptr_t) iov[slice_idx].iov_base - (uintptr_t) block->host;
if (offset >= block->used_length) {
error_setg(errp, "offset " RAM_ADDR_FMT
"outside of ramblock %s range", offset, block->idstr);
ret = -1;
break;
}
ret = qio_channel_pwritev(ioc, &iov[slice_idx], slice_num,
block->pages_offset + offset, errp);
if (ret < 0) {
break;
}
slice_idx += slice_num;
slice_num = 0;
}
return (ret < 0) ? ret : 0;
}
int multifd_file_recv_data(MultiFDRecvParams *p, Error **errp)
{
MultiFDRecvData *data = p->data;
size_t ret;
ret = qio_channel_pread(p->c, (char *) data->opaque,
data->size, data->file_offset, errp);
if (ret != data->size) {
error_prepend(errp,
"multifd recv (%u): read 0x%zx, expected 0x%zx",
p->id, ret, data->size);
return -1;
}
return 0;
}

8
migration/file.h
View File

@ -9,10 +9,18 @@
#define QEMU_MIGRATION_FILE_H
#include "qapi/qapi-types-migration.h"
#include "io/task.h"
#include "channel.h"
#include "multifd.h"
void file_start_incoming_migration(FileMigrationArgs *file_args, Error **errp);
void file_start_outgoing_migration(MigrationState *s,
FileMigrationArgs *file_args, Error **errp);
int file_parse_offset(char *filespec, uint64_t *offsetp, Error **errp);
void file_cleanup_outgoing_migration(void);
bool file_send_channel_create(gpointer opaque, Error **errp);
int file_write_ramblock_iov(QIOChannel *ioc, const struct iovec *iov,
int niov, RAMBlock *block, Error **errp);
int multifd_file_recv_data(MultiFDRecvParams *p, Error **errp);
#endif

56
migration/migration.c
View File

@ -140,9 +140,38 @@ static bool transport_supports_multi_channels(MigrationAddress *addr)
if (addr->transport == MIGRATION_ADDRESS_TYPE_SOCKET) {
SocketAddress *saddr = &addr->u.socket;
return saddr->type == SOCKET_ADDRESS_TYPE_INET ||
saddr->type == SOCKET_ADDRESS_TYPE_UNIX ||
saddr->type == SOCKET_ADDRESS_TYPE_VSOCK;
if (saddr->type == SOCKET_ADDRESS_TYPE_FD) {
return migrate_mapped_ram();
}
return (saddr->type == SOCKET_ADDRESS_TYPE_INET ||
saddr->type == SOCKET_ADDRESS_TYPE_UNIX ||
saddr->type == SOCKET_ADDRESS_TYPE_VSOCK);
} else if (addr->transport == MIGRATION_ADDRESS_TYPE_FILE) {
return migrate_mapped_ram();
} else {
return false;
}
}
static bool migration_needs_seekable_channel(void)
{
return migrate_mapped_ram();
}
static bool transport_supports_seeking(MigrationAddress *addr)
{
if (addr->transport == MIGRATION_ADDRESS_TYPE_FILE) {
return true;
}
/*
* At this point, the user might not yet have passed the file
* descriptor to QEMU, so we cannot know for sure whether it
* refers to a plain file or a socket. Let it through anyway.
*/
if (addr->transport == MIGRATION_ADDRESS_TYPE_SOCKET) {
return addr->u.socket.type == SOCKET_ADDRESS_TYPE_FD;
}
return false;
@ -152,6 +181,12 @@ static bool
migration_channels_and_transport_compatible(MigrationAddress *addr,
Error **errp)
{
if (migration_needs_seekable_channel() &&
!transport_supports_seeking(addr)) {
error_setg(errp, "Migration requires seekable transport (e.g. file)");
return false;
}
if (migration_needs_multiple_sockets() &&
!transport_supports_multi_channels(addr)) {
error_setg(errp, "Migration requires multi-channel URIs (e.g. tcp)");
@ -881,7 +916,8 @@ void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
uint32_t channel_magic = 0;
int ret = 0;
if (migrate_multifd() && !migrate_postcopy_ram() &&
if (migrate_multifd() && !migrate_mapped_ram() &&
!migrate_postcopy_ram() &&
qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_READ_MSG_PEEK)) {
/*
* With multiple channels, it is possible that we receive channels
@ -1950,6 +1986,18 @@ static bool migrate_prepare(MigrationState *s, bool blk, bool blk_inc,
return false;
}
if (migrate_mapped_ram()) {
if (migrate_tls()) {
error_setg(errp, "Cannot use TLS with mapped-ram");
return false;
}
if (migrate_multifd_compression()) {
error_setg(errp, "Cannot use compression with mapped-ram");
return false;
}
}
if (migrate_mode_is_cpr(s)) {
const char *conflict = NULL;

26
migration/multifd-zlib.c
View File

@ -69,7 +69,7 @@ static int zlib_send_setup(MultiFDSendParams *p, Error **errp)
err_msg = "out of memory for buf";
goto err_free_zbuff;
}
p->data = z;
p->compress_data = z;
return 0;
err_free_zbuff:
@ -92,15 +92,15 @@ err_free_z:
*/
static void zlib_send_cleanup(MultiFDSendParams *p, Error **errp)
{
struct zlib_data *z = p->data;
struct zlib_data *z = p->compress_data;
deflateEnd(&z->zs);
g_free(z->zbuff);
z->zbuff = NULL;
g_free(z->buf);
z->buf = NULL;
g_free(p->data);
p->data = NULL;
g_free(p->compress_data);
p->compress_data = NULL;
}
/**
@ -117,7 +117,7 @@ static void zlib_send_cleanup(MultiFDSendParams *p, Error **errp)
static int zlib_send_prepare(MultiFDSendParams *p, Error **errp)
{
MultiFDPages_t *pages = p->pages;
struct zlib_data *z = p->data;
struct zlib_data *z = p->compress_data;
z_stream *zs = &z->zs;
uint32_t out_size = 0;
int ret;
@ -194,7 +194,7 @@ static int zlib_recv_setup(MultiFDRecvParams *p, Error **errp)
struct zlib_data *z = g_new0(struct zlib_data, 1);
z_stream *zs = &z->zs;
p->data = z;
p->compress_data = z;
zs->zalloc = Z_NULL;
zs->zfree = Z_NULL;
zs->opaque = Z_NULL;
@ -224,17 +224,17 @@ static int zlib_recv_setup(MultiFDRecvParams *p, Error **errp)
*/
static void zlib_recv_cleanup(MultiFDRecvParams *p)
{
struct zlib_data *z = p->data;
struct zlib_data *z = p->compress_data;
inflateEnd(&z->zs);
g_free(z->zbuff);
z->zbuff = NULL;
g_free(p->data);
p->data = NULL;
g_free(p->compress_data);
p->compress_data = NULL;
}
/**
* zlib_recv_pages: read the data from the channel into actual pages
* zlib_recv: read the data from the channel into actual pages
*
* Read the compressed buffer, and uncompress it into the actual
* pages.
@ -244,9 +244,9 @@ static void zlib_recv_cleanup(MultiFDRecvParams *p)
* @p: Params for the channel that we are using
* @errp: pointer to an error
*/
static int zlib_recv_pages(MultiFDRecvParams *p, Error **errp)
static int zlib_recv(MultiFDRecvParams *p, Error **errp)
{
struct zlib_data *z = p->data;
struct zlib_data *z = p->compress_data;
z_stream *zs = &z->zs;
uint32_t in_size = p->next_packet_size;
/* we measure the change of total_out */
@ -319,7 +319,7 @@ static MultiFDMethods multifd_zlib_ops = {
.send_prepare = zlib_send_prepare,
.recv_setup = zlib_recv_setup,
.recv_cleanup = zlib_recv_cleanup,
.recv_pages = zlib_recv_pages
.recv = zlib_recv
};
static void multifd_zlib_register(void)

26
migration/multifd-zstd.c
View File

@ -52,7 +52,7 @@ static int zstd_send_setup(MultiFDSendParams *p, Error **errp)
struct zstd_data *z = g_new0(struct zstd_data, 1);
int res;
p->data = z;
p->compress_data = z;
z->zcs = ZSTD_createCStream();
if (!z->zcs) {
g_free(z);
@ -90,14 +90,14 @@ static int zstd_send_setup(MultiFDSendParams *p, Error **errp)
*/
static void zstd_send_cleanup(MultiFDSendParams *p, Error **errp)
{
struct zstd_data *z = p->data;
struct zstd_data *z = p->compress_data;
ZSTD_freeCStream(z->zcs);
z->zcs = NULL;
g_free(z->zbuff);
z->zbuff = NULL;
g_free(p->data);
p->data = NULL;
g_free(p->compress_data);
p->compress_data = NULL;
}
/**
@ -114,7 +114,7 @@ static void zstd_send_cleanup(MultiFDSendParams *p, Error **errp)
static int zstd_send_prepare(MultiFDSendParams *p, Error **errp)
{
MultiFDPages_t *pages = p->pages;
struct zstd_data *z = p->data;
struct zstd_data *z = p->compress_data;
int ret;
uint32_t i;
@ -183,7 +183,7 @@ static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp)
struct zstd_data *z = g_new0(struct zstd_data, 1);
int ret;
p->data = z;
p->compress_data = z;
z->zds = ZSTD_createDStream();
if (!z->zds) {
g_free(z);
@ -221,18 +221,18 @@ static int zstd_recv_setup(MultiFDRecvParams *p, Error **errp)
*/
static void zstd_recv_cleanup(MultiFDRecvParams *p)
{
struct zstd_data *z = p->data;
struct zstd_data *z = p->compress_data;
ZSTD_freeDStream(z->zds);
z->zds = NULL;
g_free(z->zbuff);
z->zbuff = NULL;
g_free(p->data);
p->data = NULL;
g_free(p->compress_data);
p->compress_data = NULL;
}
/**
* zstd_recv_pages: read the data from the channel into actual pages
* zstd_recv: read the data from the channel into actual pages
*
* Read the compressed buffer, and uncompress it into the actual
* pages.
@ -242,13 +242,13 @@ static void zstd_recv_cleanup(MultiFDRecvParams *p)
* @p: Params for the channel that we are using
* @errp: pointer to an error
*/
static int zstd_recv_pages(MultiFDRecvParams *p, Error **errp)
static int zstd_recv(MultiFDRecvParams *p, Error **errp)
{
uint32_t in_size = p->next_packet_size;
uint32_t out_size = 0;
uint32_t expected_size = p->normal_num * p->page_size;
uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
struct zstd_data *z = p->data;
struct zstd_data *z = p->compress_data;
int ret;
int i;
@ -310,7 +310,7 @@ static MultiFDMethods multifd_zstd_ops = {
.send_prepare = zstd_send_prepare,
.recv_setup = zstd_recv_setup,
.recv_cleanup = zstd_recv_cleanup,
.recv_pages = zstd_recv_pages
.recv = zstd_recv
};
static void multifd_zstd_register(void)

417
migration/multifd.c
View File

@ -17,7 +17,8 @@
#include "exec/ramblock.h"
#include "qemu/error-report.h"
#include "qapi/error.h"
#include "ram.h"
#include "fd.h"
#include "file.h"
#include "migration.h"
#include "migration-stats.h"
#include "socket.h"
@ -28,6 +29,7 @@
#include "threadinfo.h"
#include "options.h"
#include "qemu/yank.h"
#include "io/channel-file.h"
#include "io/channel-socket.h"
#include "yank_functions.h"
@ -81,9 +83,13 @@ struct {
struct {
MultiFDRecvParams *params;
MultiFDRecvData *data;
/* number of created threads */
int count;
/* syncs main thread and channels */
/*
* This is always posted by the recv threads, the migration thread
* uses it to wait for recv threads to finish assigned tasks.
*/
QemuSemaphore sem_sync;
/* global number of generated multifd packets */
uint64_t packet_num;
@ -92,6 +98,27 @@ struct {
MultiFDMethods *ops;
} *multifd_recv_state;
static bool multifd_use_packets(void)
{
return !migrate_mapped_ram();
}
void multifd_send_channel_created(void)
{
qemu_sem_post(&multifd_send_state->channels_created);
}
static void multifd_set_file_bitmap(MultiFDSendParams *p)
{
MultiFDPages_t *pages = p->pages;
assert(pages->block);
for (int i = 0; i < p->pages->num; i++) {
ramblock_set_file_bmap_atomic(pages->block, pages->offset[i]);
}
}
/* Multifd without compression */
/**
@ -122,6 +149,19 @@ static void nocomp_send_cleanup(MultiFDSendParams *p, Error **errp)
return;
}
static void multifd_send_prepare_iovs(MultiFDSendParams *p)
{
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;
}
/**
* nocomp_send_prepare: prepare date to be able to send
*
@ -136,9 +176,15 @@ static void nocomp_send_cleanup(MultiFDSendParams *p, Error **errp)
static int nocomp_send_prepare(MultiFDSendParams *p, Error **errp)
{
bool use_zero_copy_send = migrate_zero_copy_send();
MultiFDPages_t *pages = p->pages;
int ret;
if (!multifd_use_packets()) {
multifd_send_prepare_iovs(p);
multifd_set_file_bitmap(p);
return 0;
}
if (!use_zero_copy_send) {
/*
* Only !zerocopy needs the header in IOV; zerocopy will
@ -147,13 +193,7 @@ static int nocomp_send_prepare(MultiFDSendParams *p, Error **errp)
multifd_send_prepare_header(p);
}
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;
multifd_send_prepare_iovs(p);
p->flags |= MULTIFD_FLAG_NOCOMP;
multifd_send_fill_packet(p);
@ -197,7 +237,7 @@ static void nocomp_recv_cleanup(MultiFDRecvParams *p)
}
/**
* nocomp_recv_pages: read the data from the channel into actual pages
* nocomp_recv: read the data from the channel
*
* For no compression we just need to read things into the correct place.
*
@ -206,9 +246,15 @@ static void nocomp_recv_cleanup(MultiFDRecvParams *p)
* @p: Params for the channel that we are using
* @errp: pointer to an error
*/
static int nocomp_recv_pages(MultiFDRecvParams *p, Error **errp)
static int nocomp_recv(MultiFDRecvParams *p, Error **errp)
{
uint32_t flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
uint32_t flags;
if (!multifd_use_packets()) {
return multifd_file_recv_data(p, errp);
}
flags = p->flags & MULTIFD_FLAG_COMPRESSION_MASK;
if (flags != MULTIFD_FLAG_NOCOMP) {
error_setg(errp, "multifd %u: flags received %x flags expected %x",
@ -228,7 +274,7 @@ static MultiFDMethods multifd_nocomp_ops = {
.send_prepare = nocomp_send_prepare,
.recv_setup = nocomp_recv_setup,
.recv_cleanup = nocomp_recv_cleanup,
.recv_pages = nocomp_recv_pages
.recv = nocomp_recv
};
static MultiFDMethods *multifd_ops[MULTIFD_COMPRESSION__MAX] = {
@ -663,6 +709,19 @@ static bool multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp)
{
if (p->c) {
migration_ioc_unregister_yank(p->c);
/*
* An explicit close() on the channel here is normally not
* required, but can be helpful for "file:" iochannels, where it
* will include fdatasync() to make sure the data is flushed to the
* disk backend.
*
* The object_unref() cannot guarantee that because: (1) finalize()
* of the iochannel is only triggered on the last reference, and
* it's not guaranteed that we always hold the last refcount when
* reaching here, and, (2) even if finalize() is invoked, it only
* does a close(fd) without data flush.
*/
qio_channel_close(p->c, &error_abort);
object_unref(OBJECT(p->c));
p->c = NULL;
}
@ -684,6 +743,8 @@ static bool multifd_send_cleanup_channel(MultiFDSendParams *p, Error **errp)
static void multifd_send_cleanup_state(void)
{
file_cleanup_outgoing_migration();
fd_cleanup_outgoing_migration();
socket_cleanup_outgoing_migration();
qemu_sem_destroy(&multifd_send_state->channels_created);
qemu_sem_destroy(&multifd_send_state->channels_ready);
@ -795,15 +856,18 @@ static void *multifd_send_thread(void *opaque)
MigrationThread *thread = NULL;
Error *local_err = NULL;
int ret = 0;
bool use_packets = multifd_use_packets();
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;
if (use_packets) {
if (multifd_send_initial_packet(p, &local_err) < 0) {
ret = -1;
goto out;
}
}
while (true) {
@ -829,8 +893,15 @@ static void *multifd_send_thread(void *opaque)
break;
}
ret = qio_channel_writev_full_all(p->c, p->iov, p->iovs_num, NULL,
0, p->write_flags, &local_err);
if (migrate_mapped_ram()) {
ret = file_write_ramblock_iov(p->c, p->iov, p->iovs_num,
p->pages->block, &local_err);
} else {
ret = qio_channel_writev_full_all(p->c, p->iov, p->iovs_num,
NULL, 0, p->write_flags,
&local_err);
}
if (ret != 0) {
break;
}
@ -854,16 +925,20 @@ static void *multifd_send_thread(void *opaque)
* it doesn't require explicit memory barriers.
*/
assert(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) {
break;
if (use_packets) {
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) {
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;
}
/* 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_sem_post(&p->sem_sync);
}
@ -939,7 +1014,7 @@ static bool multifd_tls_channel_connect(MultiFDSendParams *p,
return true;
}
static void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc)
void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc)
{
qio_channel_set_delay(ioc, false);
@ -990,7 +1065,7 @@ out:
* Here we're not interested whether creation succeeded, only that
* it happened at all.
*/
qemu_sem_post(&multifd_send_state->channels_created);
multifd_send_channel_created();
if (ret) {
return;
@ -1007,9 +1082,14 @@ out:
error_free(local_err);
}
static void multifd_new_send_channel_create(gpointer opaque)
static bool multifd_new_send_channel_create(gpointer opaque, Error **errp)
{
if (!multifd_use_packets()) {
return file_send_channel_create(opaque, errp);
}
socket_send_channel_create(multifd_new_send_channel_async, opaque);
return true;
}
bool multifd_send_setup(void)
@ -1018,6 +1098,7 @@ bool multifd_send_setup(void)
Error *local_err = NULL;
int thread_count, ret = 0;
uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
bool use_packets = multifd_use_packets();
uint8_t i;
if (!migrate_multifd()) {
@ -1040,18 +1121,27 @@ bool multifd_send_setup(void)
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);
if (use_packets) {
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);
/* We need one extra place for the packet header */
p->iov = g_new0(struct iovec, page_count + 1);
} else {
p->iov = g_new0(struct iovec, page_count);
}
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;
p->write_flags = 0;
multifd_new_send_channel_create(p);
if (!multifd_new_send_channel_create(p, &local_err)) {
return false;
}
}
/*
@ -1083,6 +1173,57 @@ bool multifd_send_setup(void)
return true;
}
bool multifd_recv(void)
{
int i;
static int next_recv_channel;
MultiFDRecvParams *p = NULL;
MultiFDRecvData *data = multifd_recv_state->data;
/*
* 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_recv_channel %= migrate_multifd_channels();
for (i = next_recv_channel;; i = (i + 1) % migrate_multifd_channels()) {
if (multifd_recv_should_exit()) {
return false;
}
p = &multifd_recv_state->params[i];
if (qatomic_read(&p->pending_job) == false) {
next_recv_channel = (i + 1) % migrate_multifd_channels();
break;
}
}
/*
* Order pending_job read before manipulating p->data below. Pairs
* with qatomic_store_release() at multifd_recv_thread().
*/
smp_mb_acquire();
assert(!p->data->size);
multifd_recv_state->data = p->data;
p->data = data;
/*
* Order p->data update before setting pending_job. Pairs with
* qatomic_load_acquire() at multifd_recv_thread().
*/
qatomic_store_release(&p->pending_job, true);
qemu_sem_post(&p->sem);
return true;
}
MultiFDRecvData *multifd_get_recv_data(void)
{
return multifd_recv_state->data;
}
static void multifd_recv_terminate_threads(Error *err)
{
int i;
@ -1107,10 +1248,27 @@ static void multifd_recv_terminate_threads(Error *err)
MultiFDRecvParams *p = &multifd_recv_state->params[i];
/*
* multifd_recv_thread may hung at MULTIFD_FLAG_SYNC handle code,
* however try to wakeup it without harm in cleanup phase.
* The migration thread and channels interact differently
* depending on the presence of packets.
*/
qemu_sem_post(&p->sem_sync);
if (multifd_use_packets()) {
/*
* The channel receives as long as there are packets. When
* packets end (i.e. MULTIFD_FLAG_SYNC is reached), the
* channel waits for the migration thread to sync. If the
* sync never happens, do it here.
*/
qemu_sem_post(&p->sem_sync);
} else {
/*
* The channel waits for the migration thread to give it
* work. When the migration thread runs out of work, it
* releases the channel and waits for any pending work to
* finish. If we reach here (e.g. due to error) before the
* work runs out, release the channel.
*/
qemu_sem_post(&p->sem);
}
/*
* We could arrive here for two reasons:
@ -1138,6 +1296,7 @@ static void multifd_recv_cleanup_channel(MultiFDRecvParams *p)
p->c = NULL;
qemu_mutex_destroy(&p->mutex);
qemu_sem_destroy(&p->sem_sync);
qemu_sem_destroy(&p->sem);
g_free(p->name);
p->name = NULL;
p->packet_len = 0;
@ -1155,6 +1314,8 @@ static void multifd_recv_cleanup_state(void)
qemu_sem_destroy(&multifd_recv_state->sem_sync);
g_free(multifd_recv_state->params);
multifd_recv_state->params = NULL;
g_free(multifd_recv_state->data);
multifd_recv_state->data = NULL;
g_free(multifd_recv_state);
multifd_recv_state = NULL;
}
@ -1182,18 +1343,53 @@ void multifd_recv_cleanup(void)
void multifd_recv_sync_main(void)
{
int thread_count = migrate_multifd_channels();
bool file_based = !multifd_use_packets();
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);
/*
* File-based channels don't use packets and therefore need to
* wait for more work. Release them to start the sync.
*/
if (file_based) {
for (i = 0; i < thread_count; i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
trace_multifd_recv_sync_main_signal(p->id);
qemu_sem_post(&p->sem);
}
}
/*
* Initiate the synchronization by waiting for all channels.
*
* For socket-based migration this means each channel has received
* the SYNC packet on the stream.
*
* For file-based migration this means each channel is done with
* the work (pending_job=false).
*/
for (i = 0; i < thread_count; i++) {
trace_multifd_recv_sync_main_wait(i);
qemu_sem_wait(&multifd_recv_state->sem_sync);
}
for (i = 0; i < migrate_multifd_channels(); i++) {
if (file_based) {
/*
* For file-based loading is done in one iteration. We're
* done.
*/
return;
}
/*
* Sync done. Release the channels for the next iteration.
*/
for (i = 0; i < thread_count; i++) {
MultiFDRecvParams *p = &multifd_recv_state->params[i];
WITH_QEMU_LOCK_GUARD(&p->mutex) {
@ -1211,46 +1407,87 @@ static void *multifd_recv_thread(void *opaque)
{
MultiFDRecvParams *p = opaque;
Error *local_err = NULL;
bool use_packets = multifd_use_packets();
int ret;
trace_multifd_recv_thread_start(p->id);
rcu_register_thread();
while (true) {
uint32_t flags;
uint32_t flags = 0;
bool has_data = false;
p->normal_num = 0;
if (multifd_recv_should_exit()) {
break;
}
if (use_packets) {
if (multifd_recv_should_exit()) {
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;
}
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_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;
has_data = !!p->normal_num;
qemu_mutex_unlock(&p->mutex);
break;
} else {
/*
* No packets, so we need to wait for the vmstate code to
* give us work.
*/
qemu_sem_wait(&p->sem);
if (multifd_recv_should_exit()) {
break;
}
/* pairs with qatomic_store_release() at multifd_recv() */
if (!qatomic_load_acquire(&p->pending_job)) {
/*
* Migration thread did not send work, this is
* equivalent to pending_sync on the sending
* side. Post sem_sync to notify we reached this
* point.
*/
qemu_sem_post(&multifd_recv_state->sem_sync);
continue;
}
has_data = !!p->data->size;
}
flags = p->flags;
/* recv methods don't know how to handle the SYNC flag */
p->flags &= ~MULTIFD_FLAG_SYNC;
qemu_mutex_unlock(&p->mutex);
if (p->normal_num) {
ret = multifd_recv_state->ops->recv_pages(p, &local_err);
if (has_data) {
ret = multifd_recv_state->ops->recv(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 (use_packets) {
if (flags & MULTIFD_FLAG_SYNC) {
qemu_sem_post(&multifd_recv_state->sem_sync);
qemu_sem_wait(&p->sem_sync);
}
} else {
p->total_normal_pages += p->data->size / qemu_target_page_size();
p->data->size = 0;
/*
* Order data->size update before clearing
* pending_job. Pairs with smp_mb_acquire() at
* multifd_recv().
*/
qatomic_store_release(&p->pending_job, false);
}
}
@ -1269,6 +1506,7 @@ int multifd_recv_setup(Error **errp)
{
int thread_count;
uint32_t page_count = MULTIFD_PACKET_SIZE / qemu_target_page_size();
bool use_packets = multifd_use_packets();
uint8_t i;
/*
@ -1282,6 +1520,10 @@ int multifd_recv_setup(Error **errp)
thread_count = migrate_multifd_channels();
multifd_recv_state = g_malloc0(sizeof(*multifd_recv_state));
multifd_recv_state->params = g_new0(MultiFDRecvParams, thread_count);
multifd_recv_state->data = g_new0(MultiFDRecvData, 1);
multifd_recv_state->data->size = 0;
qatomic_set(&multifd_recv_state->count, 0);
qatomic_set(&multifd_recv_state->exiting, 0);
qemu_sem_init(&multifd_recv_state->sem_sync, 0);
@ -1292,10 +1534,18 @@ int multifd_recv_setup(Error **errp)
qemu_mutex_init(&p->mutex);
qemu_sem_init(&p->sem_sync, 0);
qemu_sem_init(&p->sem, 0);
p->pending_job = false;
p->id = i;
p->packet_len = sizeof(MultiFDPacket_t)
+ sizeof(uint64_t) * page_count;
p->packet = g_malloc0(p->packet_len);
p->data = g_new0(MultiFDRecvData, 1);
p->data->size = 0;
if (use_packets) {
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);
@ -1339,18 +1589,23 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
{
MultiFDRecvParams *p;
Error *local_err = NULL;
bool use_packets = multifd_use_packets();
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;
if (use_packets) {
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);
} else {
id = qatomic_read(&multifd_recv_state->count);
}
trace_multifd_recv_new_channel(id);
p = &multifd_recv_state->params[id];
if (p->c != NULL) {

27
migration/multifd.h
View File

@ -13,8 +13,13 @@
#ifndef QEMU_MIGRATION_MULTIFD_H
#define QEMU_MIGRATION_MULTIFD_H
#include "ram.h"
typedef struct MultiFDRecvData MultiFDRecvData;
bool multifd_send_setup(void);
void multifd_send_shutdown(void);
void multifd_send_channel_created(void);
int multifd_recv_setup(Error **errp);
void multifd_recv_cleanup(void);
void multifd_recv_shutdown(void);
@ -23,6 +28,8 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error **errp);
void multifd_recv_sync_main(void);
int multifd_send_sync_main(void);
bool multifd_queue_page(RAMBlock *block, ram_addr_t offset);
bool multifd_recv(void);
MultiFDRecvData *multifd_get_recv_data(void);
/* Multifd Compression flags */
#define MULTIFD_FLAG_SYNC (1 << 0)
@ -63,6 +70,13 @@ typedef struct {
RAMBlock *block;
} MultiFDPages_t;
struct MultiFDRecvData {
void *opaque;
size_t size;
/* for preadv */
off_t file_offset;
};
typedef struct {
/* Fields are only written at creating/deletion time */
/* No lock required for them, they are read only */
@ -127,7 +141,7 @@ typedef struct {
/* number of iovs used */
uint32_t iovs_num;
/* used for compression methods */
void *data;
void *compress_data;
} MultiFDSendParams;
typedef struct {
@ -152,6 +166,8 @@ typedef struct {
/* syncs main thread and channels */
QemuSemaphore sem_sync;
/* sem where to wait for more work */
QemuSemaphore sem;
/* this mutex protects the following parameters */
QemuMutex mutex;
@ -161,6 +177,8 @@ typedef struct {
uint32_t flags;
/* global number of generated multifd packets */
uint64_t packet_num;
int pending_job;
MultiFDRecvData *data;
/* thread local variables. No locking required */
@ -183,7 +201,7 @@ typedef struct {
/* num of non zero pages */
uint32_t normal_num;
/* used for de-compression methods */
void *data;
void *compress_data;
} MultiFDRecvParams;
typedef struct {
@ -197,8 +215,8 @@ typedef struct {
int (*recv_setup)(MultiFDRecvParams *p, Error **errp);
/* Cleanup for receiving side */
void (*recv_cleanup)(MultiFDRecvParams *p);
/* Read all pages */
int (*recv_pages)(MultiFDRecvParams *p, Error **errp);
/* Read all data */
int (*recv)(MultiFDRecvParams *p, Error **errp);
} MultiFDMethods;
void multifd_register_ops(int method, MultiFDMethods *ops);
@ -211,5 +229,6 @@ static inline void multifd_send_prepare_header(MultiFDSendParams *p)
p->iovs_num++;
}
void multifd_channel_connect(MultiFDSendParams *p, QIOChannel *ioc);
#endif

47
migration/options.c
View File

@ -204,6 +204,7 @@ Property migration_properties[] = {
DEFINE_PROP_MIG_CAP("x-switchover-ack",
MIGRATION_CAPABILITY_SWITCHOVER_ACK),
DEFINE_PROP_MIG_CAP("x-dirty-limit", MIGRATION_CAPABILITY_DIRTY_LIMIT),
DEFINE_PROP_MIG_CAP("mapped-ram", MIGRATION_CAPABILITY_MAPPED_RAM),
DEFINE_PROP_END_OF_LIST(),
};
@ -263,6 +264,13 @@ bool migrate_events(void)
return s->capabilities[MIGRATION_CAPABILITY_EVENTS];
}
bool migrate_mapped_ram(void)
{
MigrationState *s = migrate_get_current();
return s->capabilities[MIGRATION_CAPABILITY_MAPPED_RAM];
}
bool migrate_ignore_shared(void)
{
MigrationState *s = migrate_get_current();
@ -645,6 +653,26 @@ bool migrate_caps_check(bool *old_caps, bool *new_caps, Error **errp)
}
}
if (new_caps[MIGRATION_CAPABILITY_MAPPED_RAM]) {
if (new_caps[MIGRATION_CAPABILITY_XBZRLE]) {
error_setg(errp,
"Mapped-ram migration is incompatible with xbzrle");
return false;
}
if (new_caps[MIGRATION_CAPABILITY_COMPRESS]) {
error_setg(errp,
"Mapped-ram migration is incompatible with compression");
return false;
}
if (new_caps[MIGRATION_CAPABILITY_POSTCOPY_RAM]) {
error_setg(errp,
"Mapped-ram migration is incompatible with postcopy");
return false;
}
}
return true;
}
@ -1218,6 +1246,13 @@ bool migrate_params_check(MigrationParameters *params, Error **errp)
}
#endif
if (migrate_mapped_ram() &&
(migrate_multifd_compression() || migrate_tls())) {
error_setg(errp,
"Mapped-ram only available for non-compressed non-TLS multifd migration");
return false;
}
if (params->has_x_vcpu_dirty_limit_period &&
(params->x_vcpu_dirty_limit_period < 1 ||
params->x_vcpu_dirty_limit_period > 1000)) {
@ -1312,6 +1347,12 @@ static void migrate_params_test_apply(MigrateSetParameters *params,
if (params->has_multifd_compression) {
dest->multifd_compression = params->multifd_compression;
}
if (params->has_multifd_zlib_level) {
dest->multifd_zlib_level = params->multifd_zlib_level;
}
if (params->has_multifd_zstd_level) {
dest->multifd_zstd_level = params->multifd_zstd_level;
}
if (params->has_xbzrle_cache_size) {
dest->xbzrle_cache_size = params->xbzrle_cache_size;
}
@ -1447,6 +1488,12 @@ static void migrate_params_apply(MigrateSetParameters *params, Error **errp)
if (params->has_multifd_compression) {
s->parameters.multifd_compression = params->multifd_compression;
}
if (params->has_multifd_zlib_level) {
s->parameters.multifd_zlib_level = params->multifd_zlib_level;
}
if (params->has_multifd_zstd_level) {
s->parameters.multifd_zstd_level = params->multifd_zstd_level;
}
if (params->has_xbzrle_cache_size) {
s->parameters.xbzrle_cache_size = params->xbzrle_cache_size;
xbzrle_cache_resize(params->xbzrle_cache_size, errp);

1
migration/options.h
View File

@ -31,6 +31,7 @@ bool migrate_compress(void);
bool migrate_dirty_bitmaps(void);
bool migrate_dirty_limit(void);
bool migrate_events(void);
bool migrate_mapped_ram(void);
bool migrate_ignore_shared(void);
bool migrate_late_block_activate(void);
bool migrate_multifd(void);

106
migration/qemu-file.c
View File

@ -33,6 +33,7 @@
#include "options.h"
#include "qapi/error.h"
#include "rdma.h"
#include "io/channel-file.h"
#define IO_BUF_SIZE 32768
#define MAX_IOV_SIZE MIN_CONST(IOV_MAX, 64)
@ -255,6 +256,10 @@ static void qemu_iovec_release_ram(QEMUFile *f)
memset(f->may_free, 0, sizeof(f->may_free));
}
bool qemu_file_is_seekable(QEMUFile *f)
{
return qio_channel_has_feature(f->ioc, QIO_CHANNEL_FEATURE_SEEKABLE);
}
/**
* Flushes QEMUFile buffer
@ -447,6 +452,107 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, size_t size)
}
}
void qemu_put_buffer_at(QEMUFile *f, const uint8_t *buf, size_t buflen,
off_t pos)
{
Error *err = NULL;
size_t ret;
if (f->last_error) {
return;
}
qemu_fflush(f);
ret = qio_channel_pwrite(f->ioc, (char *)buf, buflen, pos, &err);
if (err) {
qemu_file_set_error_obj(f, -EIO, err);
return;
}
if ((ssize_t)ret == QIO_CHANNEL_ERR_BLOCK) {
qemu_file_set_error_obj(f, -EAGAIN, NULL);
return;
}
if (ret != buflen) {
error_setg(&err, "Partial write of size %zu, expected %zu", ret,
buflen);
qemu_file_set_error_obj(f, -EIO, err);
return;
}
stat64_add(&mig_stats.qemu_file_transferred, buflen);
return;
}
size_t qemu_get_buffer_at(QEMUFile *f, const uint8_t *buf, size_t buflen,
off_t pos)
{
Error *err = NULL;
size_t ret;
if (f->last_error) {
return 0;
}
ret = qio_channel_pread(f->ioc, (char *)buf, buflen, pos, &err);
if ((ssize_t)ret == -1 || err) {
qemu_file_set_error_obj(f, -EIO, err);
return 0;
}
if ((ssize_t)ret == QIO_CHANNEL_ERR_BLOCK) {
qemu_file_set_error_obj(f, -EAGAIN, NULL);
return 0;
}
if (ret != buflen) {
error_setg(&err, "Partial read of size %zu, expected %zu", ret, buflen);
qemu_file_set_error_obj(f, -EIO, err);
return 0;
}
return ret;
}
void qemu_set_offset(QEMUFile *f, off_t off, int whence)
{
Error *err = NULL;
off_t ret;
if (qemu_file_is_writable(f)) {
qemu_fflush(f);
} else {
/* Drop all cached buffers if existed; will trigger a re-fill later */
f->buf_index = 0;
f->buf_size = 0;
}
ret = qio_channel_io_seek(f->ioc, off, whence, &err);
if (ret == (off_t)-1) {
qemu_file_set_error_obj(f, -EIO, err);
}
}
off_t qemu_get_offset(QEMUFile *f)
{
Error *err = NULL;
off_t ret;
qemu_fflush(f);
ret = qio_channel_io_seek(f->ioc, 0, SEEK_CUR, &err);
if (ret == (off_t)-1) {
qemu_file_set_error_obj(f, -EIO, err);
}
return ret;
}
void qemu_put_byte(QEMUFile *f, int v)
{
if (f->last_error) {

6
migration/qemu-file.h
View File

@ -75,6 +75,12 @@ QEMUFile *qemu_file_get_return_path(QEMUFile *f);
int qemu_fflush(QEMUFile *f);
void qemu_file_set_blocking(QEMUFile *f, bool block);
int qemu_file_get_to_fd(QEMUFile *f, int fd, size_t size);
void qemu_set_offset(QEMUFile *f, off_t off, int whence);
off_t qemu_get_offset(QEMUFile *f);
void qemu_put_buffer_at(QEMUFile *f, const uint8_t *buf, size_t buflen,
off_t pos);
size_t qemu_get_buffer_at(QEMUFile *f, const uint8_t *buf, size_t buflen,
off_t pos);
QIOChannel *qemu_file_get_ioc(QEMUFile *file);

351
migration/ram.c
View File

@ -94,6 +94,24 @@
#define RAM_SAVE_FLAG_MULTIFD_FLUSH 0x200
/* We can't use any flag that is bigger than 0x200 */
/*
* mapped-ram migration supports O_DIRECT, so we need to make sure the
* userspace buffer, the IO operation size and the file offset are
* aligned according to the underlying device's block size. The first
* two are already aligned to page size, but we need to add padding to
* the file to align the offset. We cannot read the block size
* dynamically because the migration file can be moved between
* different systems, so use 1M to cover most block sizes and to keep
* the file offset aligned at page size as well.
*/
#define MAPPED_RAM_FILE_OFFSET_ALIGNMENT 0x100000
/*
* When doing mapped-ram migration, this is the amount we read from
* the pages region in the migration file at a time.
*/
#define MAPPED_RAM_LOAD_BUF_SIZE 0x100000
XBZRLECacheStats xbzrle_counters;
/* used by the search for pages to send */
@ -1126,12 +1144,18 @@ static int save_zero_page(RAMState *rs, PageSearchStatus *pss,
return 0;
}
stat64_add(&mig_stats.zero_pages, 1);
if (migrate_mapped_ram()) {
/* zero pages are not transferred with mapped-ram */
clear_bit_atomic(offset >> TARGET_PAGE_BITS, pss->block->file_bmap);
return 1;
}
len += save_page_header(pss, file, pss->block, offset | RAM_SAVE_FLAG_ZERO);
qemu_put_byte(file, 0);
len += 1;
ram_release_page(pss->block->idstr, offset);
stat64_add(&mig_stats.zero_pages, 1);
ram_transferred_add(len);
/*
@ -1189,14 +1213,20 @@ static int save_normal_page(PageSearchStatus *pss, RAMBlock *block,
{
QEMUFile *file = pss->pss_channel;
ram_transferred_add(save_page_header(pss, pss->pss_channel, block,
offset | RAM_SAVE_FLAG_PAGE));
if (async) {
qemu_put_buffer_async(file, buf, TARGET_PAGE_SIZE,
migrate_release_ram() &&
migration_in_postcopy());
if (migrate_mapped_ram()) {
qemu_put_buffer_at(file, buf, TARGET_PAGE_SIZE,
block->pages_offset + offset);
set_bit(offset >> TARGET_PAGE_BITS, block->file_bmap);
} else {
qemu_put_buffer(file, buf, TARGET_PAGE_SIZE);
ram_transferred_add(save_page_header(pss, pss->pss_channel, block,
offset | RAM_SAVE_FLAG_PAGE));
if (async) {
qemu_put_buffer_async(file, buf, TARGET_PAGE_SIZE,
migrate_release_ram() &&
migration_in_postcopy());
} else {
qemu_put_buffer(file, buf, TARGET_PAGE_SIZE);
}
}
ram_transferred_add(TARGET_PAGE_SIZE);
stat64_add(&mig_stats.normal_pages, 1);
@ -1332,14 +1362,18 @@ static int find_dirty_block(RAMState *rs, PageSearchStatus *pss)
pss->block = QLIST_NEXT_RCU(pss->block, next);
if (!pss->block) {
if (migrate_multifd() &&
!migrate_multifd_flush_after_each_section()) {
(!migrate_multifd_flush_after_each_section() ||
migrate_mapped_ram())) {
QEMUFile *f = rs->pss[RAM_CHANNEL_PRECOPY].pss_channel;
int ret = multifd_send_sync_main();
if (ret < 0) {
return ret;
}
qemu_put_be64(f, RAM_SAVE_FLAG_MULTIFD_FLUSH);
qemu_fflush(f);
if (!migrate_mapped_ram()) {
qemu_put_be64(f, RAM_SAVE_FLAG_MULTIFD_FLUSH);
qemu_fflush(f);
}
}
/*
* If memory migration starts over, we will meet a dirtied page
@ -2778,6 +2812,9 @@ static void ram_list_init_bitmaps(void)
*/
block->bmap = bitmap_new(pages);
bitmap_set(block->bmap, 0, pages);
if (migrate_mapped_ram()) {
block->file_bmap = bitmap_new(pages);
}
block->clear_bmap_shift = shift;
block->clear_bmap = bitmap_new(clear_bmap_size(pages, shift));
}
@ -2915,6 +2952,89 @@ void qemu_guest_free_page_hint(void *addr, size_t len)
}
}
#define MAPPED_RAM_HDR_VERSION 1
struct MappedRamHeader {
uint32_t version;
/*
* The target's page size, so we know how many pages are in the
* bitmap.
*/
uint64_t page_size;
/*
* The offset in the migration file where the pages bitmap is
* stored.
*/
uint64_t bitmap_offset;
/*
* The offset in the migration file where the actual pages (data)
* are stored.
*/
uint64_t pages_offset;
} QEMU_PACKED;
typedef struct MappedRamHeader MappedRamHeader;
static void mapped_ram_setup_ramblock(QEMUFile *file, RAMBlock *block)
{
g_autofree MappedRamHeader *header = NULL;
size_t header_size, bitmap_size;
long num_pages;
header = g_new0(MappedRamHeader, 1);
header_size = sizeof(MappedRamHeader);
num_pages = block->used_length >> TARGET_PAGE_BITS;
bitmap_size = BITS_TO_LONGS(num_pages) * sizeof(unsigned long);
/*
* Save the file offsets of where the bitmap and the pages should
* go as they are written at the end of migration and during the
* iterative phase, respectively.
*/
block->bitmap_offset = qemu_get_offset(file) + header_size;
block->pages_offset = ROUND_UP(block->bitmap_offset +
bitmap_size,
MAPPED_RAM_FILE_OFFSET_ALIGNMENT);
header->version = cpu_to_be32(MAPPED_RAM_HDR_VERSION);
header->page_size = cpu_to_be64(TARGET_PAGE_SIZE);
header->bitmap_offset = cpu_to_be64(block->bitmap_offset);
header->pages_offset = cpu_to_be64(block->pages_offset);
qemu_put_buffer(file, (uint8_t *) header, header_size);
/* prepare offset for next ramblock */
qemu_set_offset(file, block->pages_offset + block->used_length, SEEK_SET);
}
static bool mapped_ram_read_header(QEMUFile *file, MappedRamHeader *header,
Error **errp)
{
size_t ret, header_size = sizeof(MappedRamHeader);
ret = qemu_get_buffer(file, (uint8_t *)header, header_size);
if (ret != header_size) {
error_setg(errp, "Could not read whole mapped-ram migration header "
"(expected %zd, got %zd bytes)", header_size, ret);
return false;
}
/* migration stream is big-endian */
header->version = be32_to_cpu(header->version);
if (header->version > MAPPED_RAM_HDR_VERSION) {
error_setg(errp, "Migration mapped-ram capability version not "
"supported (expected <= %d, got %d)", MAPPED_RAM_HDR_VERSION,
header->version);
return false;
}
header->page_size = be64_to_cpu(header->page_size);
header->bitmap_offset = be64_to_cpu(header->bitmap_offset);
header->pages_offset = be64_to_cpu(header->pages_offset);
return true;
}
/*
* Each of ram_save_setup, ram_save_iterate and ram_save_complete has
* long-running RCU critical section. When rcu-reclaims in the code
@ -2970,6 +3090,10 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
if (migrate_ignore_shared()) {
qemu_put_be64(f, block->mr->addr);
}
if (migrate_mapped_ram()) {
mapped_ram_setup_ramblock(f, block);
}
}
}
@ -2995,7 +3119,8 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
return ret;
}
if (migrate_multifd() && !migrate_multifd_flush_after_each_section()) {
if (migrate_multifd() && !migrate_multifd_flush_after_each_section()
&& !migrate_mapped_ram()) {
qemu_put_be64(f, RAM_SAVE_FLAG_MULTIFD_FLUSH);
}
@ -3003,6 +3128,33 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
return qemu_fflush(f);
}
static void ram_save_file_bmap(QEMUFile *f)
{
RAMBlock *block;
RAMBLOCK_FOREACH_MIGRATABLE(block) {
long num_pages = block->used_length >> TARGET_PAGE_BITS;
long bitmap_size = BITS_TO_LONGS(num_pages) * sizeof(unsigned long);
qemu_put_buffer_at(f, (uint8_t *)block->file_bmap, bitmap_size,
block->bitmap_offset);
ram_transferred_add(bitmap_size);
/*
* Free the bitmap here to catch any synchronization issues
* with multifd channels. No channels should be sending pages
* after we've written the bitmap to file.
*/
g_free(block->file_bmap);
block->file_bmap = NULL;
}
}
void ramblock_set_file_bmap_atomic(RAMBlock *block, ram_addr_t offset)
{
set_bit_atomic(offset >> TARGET_PAGE_BITS, block->file_bmap);
}
/**
* ram_save_iterate: iterative stage for migration
*
@ -3112,7 +3264,8 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)
out:
if (ret >= 0
&& migration_is_setup_or_active(migrate_get_current()->state)) {
if (migrate_multifd() && migrate_multifd_flush_after_each_section()) {
if (migrate_multifd() && migrate_multifd_flush_after_each_section() &&
!migrate_mapped_ram()) {
ret = multifd_send_sync_main();
if (ret < 0) {
return ret;
@ -3192,7 +3345,20 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
return ret;
}
if (migrate_multifd() && !migrate_multifd_flush_after_each_section()) {
if (migrate_mapped_ram()) {
ram_save_file_bmap(f);
if (qemu_file_get_error(f)) {
Error *local_err = NULL;
int err = qemu_file_get_error_obj(f, &local_err);
error_reportf_err(local_err, "Failed to write bitmap to file: ");
return -err;
}
}
if (migrate_multifd() && !migrate_multifd_flush_after_each_section() &&
!migrate_mapped_ram()) {
qemu_put_be64(f, RAM_SAVE_FLAG_MULTIFD_FLUSH);
}
qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
@ -3792,23 +3958,149 @@ void colo_flush_ram_cache(void)
trace_colo_flush_ram_cache_end();
}
static size_t ram_load_multifd_pages(void *host_addr, size_t size,
uint64_t offset)
{
MultiFDRecvData *data = multifd_get_recv_data();
data->opaque = host_addr;
data->file_offset = offset;
data->size = size;
if (!multifd_recv()) {
return 0;
}
return size;
}
static bool read_ramblock_mapped_ram(QEMUFile *f, RAMBlock *block,
long num_pages, unsigned long *bitmap,
Error **errp)
{
ERRP_GUARD();
unsigned long set_bit_idx, clear_bit_idx;
ram_addr_t offset;
void *host;
size_t read, unread, size;
for (set_bit_idx = find_first_bit(bitmap, num_pages);
set_bit_idx < num_pages;
set_bit_idx = find_next_bit(bitmap, num_pages, clear_bit_idx + 1)) {
clear_bit_idx = find_next_zero_bit(bitmap, num_pages, set_bit_idx + 1);
unread = TARGET_PAGE_SIZE * (clear_bit_idx - set_bit_idx);
offset = set_bit_idx << TARGET_PAGE_BITS;
while (unread > 0) {
host = host_from_ram_block_offset(block, offset);
if (!host) {
error_setg(errp, "page outside of ramblock %s range",
block->idstr);
return false;
}
size = MIN(unread, MAPPED_RAM_LOAD_BUF_SIZE);
if (migrate_multifd()) {
read = ram_load_multifd_pages(host, size,
block->pages_offset + offset);
} else {
read = qemu_get_buffer_at(f, host, size,
block->pages_offset + offset);
}
if (!read) {
goto err;
}
offset += read;
unread -= read;
}
}
return true;
err:
qemu_file_get_error_obj(f, errp);
error_prepend(errp, "(%s) failed to read page " RAM_ADDR_FMT
"from file offset %" PRIx64 ": ", block->idstr, offset,
block->pages_offset + offset);
return false;
}
static void parse_ramblock_mapped_ram(QEMUFile *f, RAMBlock *block,
ram_addr_t length, Error **errp)
{
g_autofree unsigned long *bitmap = NULL;
MappedRamHeader header;
size_t bitmap_size;
long num_pages;
if (!mapped_ram_read_header(f, &header, errp)) {
return;
}
block->pages_offset = header.pages_offset;
/*
* Check the alignment of the file region that contains pages. We
* don't enforce MAPPED_RAM_FILE_OFFSET_ALIGNMENT to allow that
* value to change in the future. Do only a sanity check with page
* size alignment.
*/
if (!QEMU_IS_ALIGNED(block->pages_offset, TARGET_PAGE_SIZE)) {
error_setg(errp,
"Error reading ramblock %s pages, region has bad alignment",
block->idstr);
return;
}
num_pages = length / header.page_size;
bitmap_size = BITS_TO_LONGS(num_pages) * sizeof(unsigned long);
bitmap = g_malloc0(bitmap_size);
if (qemu_get_buffer_at(f, (uint8_t *)bitmap, bitmap_size,
header.bitmap_offset) != bitmap_size) {
error_setg(errp, "Error reading dirty bitmap");
return;
}
if (!read_ramblock_mapped_ram(f, block, num_pages, bitmap, errp)) {
return;
}
/* Skip pages array */
qemu_set_offset(f, block->pages_offset + length, SEEK_SET);
return;
}
static int parse_ramblock(QEMUFile *f, RAMBlock *block, ram_addr_t length)
{
int ret = 0;
/* ADVISE is earlier, it shows the source has the postcopy capability on */
bool postcopy_advised = migration_incoming_postcopy_advised();
int max_hg_page_size;
Error *local_err = NULL;
assert(block);
if (migrate_mapped_ram()) {
parse_ramblock_mapped_ram(f, block, length, &local_err);
if (local_err) {
error_report_err(local_err);
return -EINVAL;
}
return 0;
}
if (!qemu_ram_is_migratable(block)) {
error_report("block %s should not be migrated !", block->idstr);
return -EINVAL;
}
if (length != block->used_length) {
Error *local_err = NULL;
ret = qemu_ram_resize(block, length, &local_err);
if (local_err) {
error_report_err(local_err);
@ -3899,6 +4191,12 @@ static int ram_load_precopy(QEMUFile *f)
invalid_flags |= RAM_SAVE_FLAG_COMPRESS_PAGE;
}
if (migrate_mapped_ram()) {
invalid_flags |= (RAM_SAVE_FLAG_HOOK | RAM_SAVE_FLAG_MULTIFD_FLUSH |
RAM_SAVE_FLAG_PAGE | RAM_SAVE_FLAG_XBZRLE |
RAM_SAVE_FLAG_ZERO);
}
while (!ret && !(flags & RAM_SAVE_FLAG_EOS)) {
ram_addr_t addr;
void *host = NULL, *host_bak = NULL;
@ -3920,6 +4218,8 @@ static int ram_load_precopy(QEMUFile *f)
addr &= TARGET_PAGE_MASK;
if (flags & invalid_flags) {
error_report("Unexpected RAM flags: %d", flags & invalid_flags);
if (flags & invalid_flags & RAM_SAVE_FLAG_COMPRESS_PAGE) {
error_report("Received an unexpected compressed page");
}
@ -3972,6 +4272,16 @@ static int ram_load_precopy(QEMUFile *f)
switch (flags & ~RAM_SAVE_FLAG_CONTINUE) {
case RAM_SAVE_FLAG_MEM_SIZE:
ret = parse_ramblocks(f, addr);
/*
* For mapped-ram migration (to a file) using multifd, we sync
* once and for all here to make sure all tasks we queued to
* multifd threads are completed, so that all the ramblocks
* (including all the guest memory pages within) are fully
* loaded after this sync returns.
*/
if (migrate_mapped_ram()) {
multifd_recv_sync_main();
}
break;
case RAM_SAVE_FLAG_ZERO:
@ -4012,7 +4322,12 @@ static int ram_load_precopy(QEMUFile *f)
case RAM_SAVE_FLAG_EOS:
/* normal exit */
if (migrate_multifd() &&
migrate_multifd_flush_after_each_section()) {
migrate_multifd_flush_after_each_section() &&
/*
* Mapped-ram migration flushes once and for all after
* parsing ramblocks. Always ignore EOS for it.
*/
!migrate_mapped_ram()) {
multifd_recv_sync_main();
}
break;

1
migration/ram.h
View File

@ -75,6 +75,7 @@ bool ram_dirty_bitmap_reload(MigrationState *s, RAMBlock *rb, Error **errp);
bool ramblock_page_is_discarded(RAMBlock *rb, ram_addr_t start);
void postcopy_preempt_shutdown_file(MigrationState *s);
void *postcopy_preempt_thread(void *opaque);
void ramblock_set_file_bmap_atomic(RAMBlock *block, ram_addr_t offset);
/* ram cache */
int colo_init_ram_cache(void);

1
migration/savevm.c
View File

@ -245,6 +245,7 @@ static bool should_validate_capability(int capability)
/* Validate only new capabilities to keep compatibility. */
switch (capability) {
case MIGRATION_CAPABILITY_X_IGNORE_SHARED:
case MIGRATION_CAPABILITY_MAPPED_RAM:
return true;
default:
return false;

2
migration/trace-events
View File

@ -132,7 +132,7 @@ multifd_recv(uint8_t id, uint64_t packet_num, uint32_t used, uint32_t flags, uin
multifd_recv_new_channel(uint8_t id) "channel %u"
multifd_recv_sync_main(long packet_num) "packet num %ld"
multifd_recv_sync_main_signal(uint8_t id) "channel %u"
multifd_recv_sync_main_wait(uint8_t id) "channel %u"
multifd_recv_sync_main_wait(uint8_t id) "iter %u"
multifd_recv_terminate_threads(bool error) "error %d"
multifd_recv_thread_end(uint8_t id, uint64_t packets, uint64_t pages) "channel %u packets %" PRIu64 " pages %" PRIu64
multifd_recv_thread_start(uint8_t id) "%u"

42
qapi/migration.json
View File

@ -531,6 +531,10 @@
# and can result in more stable read performance. Requires KVM
# with accelerator property "dirty-ring-size" set. (Since 8.1)
#
# @mapped-ram: Migrate using fixed offsets in the migration file for
# each RAM page. Requires a migration URI that supports seeking,
# such as a file. (since 9.0)
#
# Features:
#
# @deprecated: Member @block is deprecated. Use blockdev-mirror with
@ -555,7 +559,7 @@
{ 'name': 'x-ignore-shared', 'features': [ 'unstable' ] },
'validate-uuid', 'background-snapshot',
'zero-copy-send', 'postcopy-preempt', 'switchover-ack',
'dirty-limit'] }
'dirty-limit', 'mapped-ram'] }
##
# @MigrationCapabilityStatus:
@ -636,28 +640,30 @@
#
# @normal: the original form of migration. (since 8.2)
#
# @cpr-reboot: The migrate command stops the VM and saves state to the URI.
# After quitting qemu, the user resumes by running qemu -incoming.
# @cpr-reboot: The migrate command stops the VM and saves state to
# the URI. After quitting QEMU, the user resumes by running
# QEMU -incoming.
#
# This mode allows the user to quit qemu, and restart an updated version
# of qemu. The user may even update and reboot the OS before restarting,
# as long as the URI persists across a reboot.
# This mode allows the user to quit QEMU, optionally update and
# reboot the OS, and restart QEMU. If the user reboots, the URI
# must persist across the reboot, such as by using a file.
#
# Unlike normal mode, the use of certain local storage options does not
# block the migration, but the user must not modify guest block devices
# between the quit and restart.
# Unlike normal mode, the use of certain local storage options
# does not block the migration, but the user must not modify the
# contents of guest block devices between the quit and restart.
#
# This mode supports vfio devices provided the user first puts the guest
# in the suspended runstate, such as by issuing guest-suspend-ram to the
# qemu guest agent.
# This mode supports VFIO devices provided the user first puts
# the guest in the suspended runstate, such as by issuing
# guest-suspend-ram to the QEMU guest agent.
#
# Best performance is achieved when the memory backend is shared and the
# @x-ignore-shared migration capability is set, but this is not required.
# Further, if the user reboots before restarting such a configuration, the
# shared backend must be be non-volatile across reboot, such as by backing
# it with a dax device.
# Best performance is achieved when the memory backend is shared
# and the @x-ignore-shared migration capability is set, but this
# is not required. Further, if the user reboots before restarting
# such a configuration, the shared memory must persist across the
# reboot, such as by backing it with a dax device.
#
# cpr-reboot may not be used with postcopy, colo, or background-snapshot.
# @cpr-reboot may not be used with postcopy, background-snapshot,
# or COLO.
#
# (since 8.2)
##

137
tests/qtest/migration-test.c
View File

@ -2200,6 +2200,14 @@ static void *test_mode_reboot_start(QTestState *from, QTestState *to)
return NULL;
}
static void *migrate_mapped_ram_start(QTestState *from, QTestState *to)
{
migrate_set_capability(from, "mapped-ram", true);
migrate_set_capability(to, "mapped-ram", true);
return NULL;
}
static void test_mode_reboot(void)
{
g_autofree char *uri = g_strdup_printf("file:%s/%s", tmpfs,
@ -2214,6 +2222,72 @@ static void test_mode_reboot(void)
test_file_common(&args, true);
}
static void test_precopy_file_mapped_ram_live(void)
{
g_autofree char *uri = g_strdup_printf("file:%s/%s", tmpfs,
FILE_TEST_FILENAME);
MigrateCommon args = {
.connect_uri = uri,
.listen_uri = "defer",
.start_hook = migrate_mapped_ram_start,
};
test_file_common(&args, false);
}
static void test_precopy_file_mapped_ram(void)
{
g_autofree char *uri = g_strdup_printf("file:%s/%s", tmpfs,
FILE_TEST_FILENAME);
MigrateCommon args = {
.connect_uri = uri,
.listen_uri = "defer",
.start_hook = migrate_mapped_ram_start,
};
test_file_common(&args, true);
}
static void *migrate_multifd_mapped_ram_start(QTestState *from, QTestState *to)
{
migrate_mapped_ram_start(from, to);
migrate_set_parameter_int(from, "multifd-channels", 4);
migrate_set_parameter_int(to, "multifd-channels", 4);
migrate_set_capability(from, "multifd", true);
migrate_set_capability(to, "multifd", true);
return NULL;
}
static void test_multifd_file_mapped_ram_live(void)
{
g_autofree char *uri = g_strdup_printf("file:%s/%s", tmpfs,
FILE_TEST_FILENAME);
MigrateCommon args = {
.connect_uri = uri,
.listen_uri = "defer",
.start_hook = migrate_multifd_mapped_ram_start,
};
test_file_common(&args, false);
}
static void test_multifd_file_mapped_ram(void)
{
g_autofree char *uri = g_strdup_printf("file:%s/%s", tmpfs,
FILE_TEST_FILENAME);
MigrateCommon args = {
.connect_uri = uri,
.listen_uri = "defer",
.start_hook = migrate_multifd_mapped_ram_start,
};
test_file_common(&args, true);
}
static void test_precopy_tcp_plain(void)
{
MigrateCommon args = {
@ -2462,6 +2536,13 @@ static void *migrate_precopy_fd_file_start(QTestState *from, QTestState *to)
return NULL;
}
static void *migrate_fd_file_mapped_ram_start(QTestState *from, QTestState *to)
{
migrate_mapped_ram_start(from, to);
return migrate_precopy_fd_file_start(from, to);
}
static void test_migrate_precopy_fd_file(void)
{
MigrateCommon args = {
@ -2472,6 +2553,36 @@ static void test_migrate_precopy_fd_file(void)
};
test_file_common(&args, true);
}
static void test_migrate_precopy_fd_file_mapped_ram(void)
{
MigrateCommon args = {
.listen_uri = "defer",
.connect_uri = "fd:fd-mig",
.start_hook = migrate_fd_file_mapped_ram_start,
.finish_hook = test_migrate_fd_finish_hook
};
test_file_common(&args, true);
}
static void *migrate_multifd_fd_mapped_ram_start(QTestState *from,
QTestState *to)
{
migrate_multifd_mapped_ram_start(from, to);
return migrate_precopy_fd_file_start(from, to);
}
static void test_multifd_fd_mapped_ram(void)
{
MigrateCommon args = {
.connect_uri = "fd:fd-mig",
.listen_uri = "defer",
.start_hook = migrate_multifd_fd_mapped_ram_start,
.finish_hook = test_migrate_fd_finish_hook
};
test_file_common(&args, true);
}
#endif /* _WIN32 */
static void do_test_validate_uuid(MigrateStart *args, bool should_fail)
@ -2664,6 +2775,13 @@ static void *
test_migrate_precopy_tcp_multifd_zlib_start(QTestState *from,
QTestState *to)
{
/*
* Overloading this test to also check that set_parameter does not error.
* This is also done in the tests for the other compression methods.
*/
migrate_set_parameter_int(from, "multifd-zlib-level", 2);
migrate_set_parameter_int(to, "multifd-zlib-level", 2);
return test_migrate_precopy_tcp_multifd_start_common(from, to, "zlib");
}
@ -2672,6 +2790,9 @@ static void *
test_migrate_precopy_tcp_multifd_zstd_start(QTestState *from,
QTestState *to)
{
migrate_set_parameter_int(from, "multifd-zstd-level", 2);
migrate_set_parameter_int(to, "multifd-zstd-level", 2);
return test_migrate_precopy_tcp_multifd_start_common(from, to, "zstd");
}
#endif /* CONFIG_ZSTD */
@ -3509,6 +3630,20 @@ int main(int argc, char **argv)
migration_test_add("/migration/mode/reboot", test_mode_reboot);
}
migration_test_add("/migration/precopy/file/mapped-ram",
test_precopy_file_mapped_ram);
migration_test_add("/migration/precopy/file/mapped-ram/live",
test_precopy_file_mapped_ram_live);
migration_test_add("/migration/multifd/file/mapped-ram",
test_multifd_file_mapped_ram);
migration_test_add("/migration/multifd/file/mapped-ram/live",
test_multifd_file_mapped_ram_live);
#ifndef _WIN32
migration_test_add("/migration/multifd/fd/mapped-ram",
test_multifd_fd_mapped_ram);
#endif
#ifdef CONFIG_GNUTLS
migration_test_add("/migration/precopy/unix/tls/psk",
test_precopy_unix_tls_psk);
@ -3570,6 +3705,8 @@ int main(int argc, char **argv)
test_migrate_precopy_fd_socket);
migration_test_add("/migration/precopy/fd/file",
test_migrate_precopy_fd_file);
migration_test_add("/migration/precopy/fd/file/mapped-ram",
test_migrate_precopy_fd_file_mapped_ram);
#endif
migration_test_add("/migration/validate_uuid", test_validate_uuid);
migration_test_add("/migration/validate_uuid_error",