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Merge remote-tracking branch 'quintela/migration.next' into staging 

# By Michael R. Hines (9) and others
# Via Juan Quintela
* quintela/migration.next:
  rdma: introduce capability x-rdma-pin-all
  rdma: new QEMUFileOps hooks
  rdma: introduce qemu_ram_foreach_block()
  rdma: export qemu_fflush()
  rdma: introduce qemu_file_mode_is_not_valid()
  rdma: export throughput w/ MigrationStats QMP
  rdma: export yield_until_fd_readable()
  rdma: introduce qemu_update_position()
  rdma: add documentation
  migration: do not overwrite zero pages
  Revert "migration: do not sent zero pages in bulk stage"
  arch_init/ram_load: add error message for block length mismatch

Message-id: 1372329455-5995-1-git-send-email-quintela@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Anthony Liguori 2013-06-27 08:48:38 -05:00
parent 3e50873294 60d9222c8f
commit c394ace828
12 changed files with 647 additions and 53 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
arch_init.c
View File

@ -457,15 +457,10 @@ static int ram_save_block(QEMUFile *f, bool last_stage)
bytes_sent = -1; bytes_sent = -1;
if (is_zero_page(p)) { if (is_zero_page(p)) {
acct_info.dup_pages++; acct_info.dup_pages++;
if (!ram_bulk_stage) {
bytes_sent = save_block_hdr(f, block, offset, cont, bytes_sent = save_block_hdr(f, block, offset, cont,
RAM_SAVE_FLAG_COMPRESS); RAM_SAVE_FLAG_COMPRESS);
qemu_put_byte(f, 0); qemu_put_byte(f, 0);
bytes_sent++; bytes_sent++;
} else {
acct_info.skipped_pages++;
bytes_sent = 0;
}
} else if (!ram_bulk_stage && migrate_use_xbzrle()) { } else if (!ram_bulk_stage && migrate_use_xbzrle()) {
current_addr = block->offset + offset; current_addr = block->offset + offset;
bytes_sent = save_xbzrle_page(f, p, current_addr, block, bytes_sent = save_xbzrle_page(f, p, current_addr, block,
@ -498,6 +493,18 @@ static int ram_save_block(QEMUFile *f, bool last_stage)
static uint64_t bytes_transferred; static uint64_t bytes_transferred;
void acct_update_position(QEMUFile *f, size_t size, bool zero)
{
uint64_t pages = size / TARGET_PAGE_SIZE;
if (zero) {
acct_info.dup_pages += pages;
} else {
acct_info.norm_pages += pages;
bytes_transferred += size;
qemu_update_position(f, size);
}
}
static ram_addr_t ram_save_remaining(void) static ram_addr_t ram_save_remaining(void)
{ {
return migration_dirty_pages; return migration_dirty_pages;
@ -808,6 +815,9 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
QTAILQ_FOREACH(block, &ram_list.blocks, next) { QTAILQ_FOREACH(block, &ram_list.blocks, next) {
if (!strncmp(id, block->idstr, sizeof(id))) { if (!strncmp(id, block->idstr, sizeof(id))) {
if (block->length != length) { if (block->length != length) {
fprintf(stderr, "Length mismatch: %s: %ld "
"in != " RAM_ADDR_FMT "\n", id, length,
block->length);
ret = -EINVAL; ret = -EINVAL;
goto done; goto done;
} }
@ -837,6 +847,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
} }
ch = qemu_get_byte(f); ch = qemu_get_byte(f);
if (ch != 0 || !is_zero_page(host)) {
memset(host, ch, TARGET_PAGE_SIZE); memset(host, ch, TARGET_PAGE_SIZE);
#ifndef _WIN32 #ifndef _WIN32
if (ch == 0 && if (ch == 0 &&
@ -845,6 +856,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED); qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED);
} }
#endif #endif
}
} else if (flags & RAM_SAVE_FLAG_PAGE) { } else if (flags & RAM_SAVE_FLAG_PAGE) {
void *host; void *host;

415
docs/rdma.txt Normal file
View File

@ -0,0 +1,415 @@
(RDMA: Remote Direct Memory Access)
RDMA Live Migration Specification, Version # 1
==============================================
Wiki: http://wiki.qemu.org/Features/RDMALiveMigration
Github: git@github.com:hinesmr/qemu.git, 'rdma' branch
Copyright (C) 2013 Michael R. Hines <mrhines@us.ibm.com>
An *exhaustive* paper (2010) shows additional performance details
linked on the QEMU wiki above.
Contents:
=========
* Introduction
* Before running
* Running
* Performance
* RDMA Migration Protocol Description
* Versioning and Capabilities
* QEMUFileRDMA Interface
* Migration of pc.ram
* Error handling
* TODO
Introduction:
=============
RDMA helps make your migration more deterministic under heavy load because
of the significantly lower latency and higher throughput over TCP/IP. This is
because the RDMA I/O architecture reduces the number of interrupts and
data copies by bypassing the host networking stack. In particular, a TCP-based
migration, under certain types of memory-bound workloads, may take a more
unpredicatable amount of time to complete the migration if the amount of
memory tracked during each live migration iteration round cannot keep pace
with the rate of dirty memory produced by the workload.
RDMA currently comes in two flavors: both Ethernet based (RoCE, or RDMA
over Convered Ethernet) as well as Infiniband-based. This implementation of
migration using RDMA is capable of using both technologies because of
the use of the OpenFabrics OFED software stack that abstracts out the
programming model irrespective of the underlying hardware.
Refer to openfabrics.org or your respective RDMA hardware vendor for
an understanding on how to verify that you have the OFED software stack
installed in your environment. You should be able to successfully link
against the "librdmacm" and "libibverbs" libraries and development headers
for a working build of QEMU to run successfully using RDMA Migration.
BEFORE RUNNING:
===============
Use of RDMA during migration requires pinning and registering memory
with the hardware. This means that memory must be physically resident
before the hardware can transmit that memory to another machine.
If this is not acceptable for your application or product, then the use
of RDMA migration may in fact be harmful to co-located VMs or other
software on the machine if there is not sufficient memory available to
relocate the entire footprint of the virtual machine. If so, then the
use of RDMA is discouraged and it is recommended to use standard TCP migration.
Experimental: Next, decide if you want dynamic page registration.
For example, if you have an 8GB RAM virtual machine, but only 1GB
is in active use, then enabling this feature will cause all 8GB to
be pinned and resident in memory. This feature mostly affects the
bulk-phase round of the migration and can be enabled for extremely
high-performance RDMA hardware using the following command:
QEMU Monitor Command:
$ migrate_set_capability x-rdma-pin-all on # disabled by default
Performing this action will cause all 8GB to be pinned, so if that's
not what you want, then please ignore this step altogether.
On the other hand, this will also significantly speed up the bulk round
of the migration, which can greatly reduce the "total" time of your migration.
Example performance of this using an idle VM in the previous example
can be found in the "Performance" section.
Note: for very large virtual machines (hundreds of GBs), pinning all
*all* of the memory of your virtual machine in the kernel is very expensive
may extend the initial bulk iteration time by many seconds,
and thus extending the total migration time. However, this will not
affect the determinism or predictability of your migration you will
still gain from the benefits of advanced pinning with RDMA.
RUNNING:
========
First, set the migration speed to match your hardware's capabilities:
QEMU Monitor Command:
$ migrate_set_speed 40g # or whatever is the MAX of your RDMA device
Next, on the destination machine, add the following to the QEMU command line:
qemu ..... -incoming x-rdma:host:port
Finally, perform the actual migration on the source machine:
QEMU Monitor Command:
$ migrate -d x-rdma:host:port
PERFORMANCE
===========
Here is a brief summary of total migration time and downtime using RDMA:
Using a 40gbps infiniband link performing a worst-case stress test,
using an 8GB RAM virtual machine:
Using the following command:
$ apt-get install stress
$ stress --vm-bytes 7500M --vm 1 --vm-keep
1. Migration throughput: 26 gigabits/second.
2. Downtime (stop time) varies between 15 and 100 milliseconds.
EFFECTS of memory registration on bulk phase round:
For example, in the same 8GB RAM example with all 8GB of memory in
active use and the VM itself is completely idle using the same 40 gbps
infiniband link:
1. x-rdma-pin-all disabled total time: approximately 7.5 seconds @ 9.5 Gbps
2. x-rdma-pin-all enabled total time: approximately 4 seconds @ 26 Gbps
These numbers would of course scale up to whatever size virtual machine
you have to migrate using RDMA.
Enabling this feature does *not* have any measurable affect on
migration *downtime*. This is because, without this feature, all of the
memory will have already been registered already in advance during
the bulk round and does not need to be re-registered during the successive
iteration rounds.
RDMA Protocol Description:
==========================
Migration with RDMA is separated into two parts:
1. The transmission of the pages using RDMA
2. Everything else (a control channel is introduced)
"Everything else" is transmitted using a formal
protocol now, consisting of infiniband SEND messages.
An infiniband SEND message is the standard ibverbs
message used by applications of infiniband hardware.
The only difference between a SEND message and an RDMA
message is that SEND messages cause notifications
to be posted to the completion queue (CQ) on the
infiniband receiver side, whereas RDMA messages (used
for pc.ram) do not (to behave like an actual DMA).
Messages in infiniband require two things:
1. registration of the memory that will be transmitted
2. (SEND only) work requests to be posted on both
sides of the network before the actual transmission
can occur.
RDMA messages are much easier to deal with. Once the memory
on the receiver side is registered and pinned, we're
basically done. All that is required is for the sender
side to start dumping bytes onto the link.
(Memory is not released from pinning until the migration
completes, given that RDMA migrations are very fast.)
SEND messages require more coordination because the
receiver must have reserved space (using a receive
work request) on the receive queue (RQ) before QEMUFileRDMA
can start using them to carry all the bytes as
a control transport for migration of device state.
To begin the migration, the initial connection setup is
as follows (migration-rdma.c):
1. Receiver and Sender are started (command line or libvirt):
2. Both sides post two RQ work requests
3. Receiver does listen()
4. Sender does connect()
5. Receiver accept()
6. Check versioning and capabilities (described later)
At this point, we define a control channel on top of SEND messages
which is described by a formal protocol. Each SEND message has a
header portion and a data portion (but together are transmitted
as a single SEND message).
Header:
* Length (of the data portion, uint32, network byte order)
* Type (what command to perform, uint32, network byte order)
* Repeat (Number of commands in data portion, same type only)
The 'Repeat' field is here to support future multiple page registrations
in a single message without any need to change the protocol itself
so that the protocol is compatible against multiple versions of QEMU.
Version #1 requires that all server implementations of the protocol must
check this field and register all requests found in the array of commands located
in the data portion and return an equal number of results in the response.
The maximum number of repeats is hard-coded to 4096. This is a conservative
limit based on the maximum size of a SEND message along with emperical
observations on the maximum future benefit of simultaneous page registrations.
The 'type' field has 10 different command values:
1. Unused
2. Error (sent to the source during bad things)
3. Ready (control-channel is available)
4. QEMU File (for sending non-live device state)
5. RAM Blocks request (used right after connection setup)
6. RAM Blocks result (used right after connection setup)
7. Compress page (zap zero page and skip registration)
8. Register request (dynamic chunk registration)
9. Register result ('rkey' to be used by sender)
10. Register finished (registration for current iteration finished)
A single control message, as hinted above, can contain within the data
portion an array of many commands of the same type. If there is more than
one command, then the 'repeat' field will be greater than 1.
After connection setup, message 5 & 6 are used to exchange ram block
information and optionally pin all the memory if requested by the user.
After ram block exchange is completed, we have two protocol-level
functions, responsible for communicating control-channel commands
using the above list of values:
Logically:
qemu_rdma_exchange_recv(header, expected command type)
1. We transmit a READY command to let the sender know that
we are *ready* to receive some data bytes on the control channel.
2. Before attempting to receive the expected command, we post another
RQ work request to replace the one we just used up.
3. Block on a CQ event channel and wait for the SEND to arrive.
4. When the send arrives, librdmacm will unblock us.
5. Verify that the command-type and version received matches the one we expected.
qemu_rdma_exchange_send(header, data, optional response header & data):
1. Block on the CQ event channel waiting for a READY command
from the receiver to tell us that the receiver
is *ready* for us to transmit some new bytes.
2. Optionally: if we are expecting a response from the command
(that we have no yet transmitted), let's post an RQ
work request to receive that data a few moments later.
3. When the READY arrives, librdmacm will
unblock us and we immediately post a RQ work request
to replace the one we just used up.
4. Now, we can actually post the work request to SEND
the requested command type of the header we were asked for.
5. Optionally, if we are expecting a response (as before),
we block again and wait for that response using the additional
work request we previously posted. (This is used to carry
'Register result' commands #6 back to the sender which
hold the rkey need to perform RDMA. Note that the virtual address
corresponding to this rkey was already exchanged at the beginning
of the connection (described below).
All of the remaining command types (not including 'ready')
described above all use the aformentioned two functions to do the hard work:
1. After connection setup, RAMBlock information is exchanged using
this protocol before the actual migration begins. This information includes
a description of each RAMBlock on the server side as well as the virtual addresses
and lengths of each RAMBlock. This is used by the client to determine the
start and stop locations of chunks and how to register them dynamically
before performing the RDMA operations.
2. During runtime, once a 'chunk' becomes full of pages ready to
be sent with RDMA, the registration commands are used to ask the
other side to register the memory for this chunk and respond
with the result (rkey) of the registration.
3. Also, the QEMUFile interfaces also call these functions (described below)
when transmitting non-live state, such as devices or to send
its own protocol information during the migration process.
4. Finally, zero pages are only checked if a page has not yet been registered
using chunk registration (or not checked at all and unconditionally
written if chunk registration is disabled. This is accomplished using
the "Compress" command listed above. If the page *has* been registered
then we check the entire chunk for zero. Only if the entire chunk is
zero, then we send a compress command to zap the page on the other side.
Versioning and Capabilities
===========================
Current version of the protocol is version #1.
The same version applies to both for protocol traffic and capabilities
negotiation. (i.e. There is only one version number that is referred to
by all communication).
librdmacm provides the user with a 'private data' area to be exchanged
at connection-setup time before any infiniband traffic is generated.
Header:
* Version (protocol version validated before send/recv occurs), uint32, network byte order
* Flags (bitwise OR of each capability), uint32, network byte order
There is no data portion of this header right now, so there is
no length field. The maximum size of the 'private data' section
is only 192 bytes per the Infiniband specification, so it's not
very useful for data anyway. This structure needs to remain small.
This private data area is a convenient place to check for protocol
versioning because the user does not need to register memory to
transmit a few bytes of version information.
This is also a convenient place to negotiate capabilities
(like dynamic page registration).
If the version is invalid, we throw an error.
If the version is new, we only negotiate the capabilities that the
requested version is able to perform and ignore the rest.
Currently there is only *one* capability in Version #1: dynamic page registration
Finally: Negotiation happens with the Flags field: If the primary-VM
sets a flag, but the destination does not support this capability, it
will return a zero-bit for that flag and the primary-VM will understand
that as not being an available capability and will thus disable that
capability on the primary-VM side.
QEMUFileRDMA Interface:
=======================
QEMUFileRDMA introduces a couple of new functions:
1. qemu_rdma_get_buffer() (QEMUFileOps rdma_read_ops)
2. qemu_rdma_put_buffer() (QEMUFileOps rdma_write_ops)
These two functions are very short and simply use the protocol
describe above to deliver bytes without changing the upper-level
users of QEMUFile that depend on a bytestream abstraction.
Finally, how do we handoff the actual bytes to get_buffer()?
Again, because we're trying to "fake" a bytestream abstraction
using an analogy not unlike individual UDP frames, we have
to hold on to the bytes received from control-channel's SEND
messages in memory.
Each time we receive a complete "QEMU File" control-channel
message, the bytes from SEND are copied into a small local holding area.
Then, we return the number of bytes requested by get_buffer()
and leave the remaining bytes in the holding area until get_buffer()
comes around for another pass.
If the buffer is empty, then we follow the same steps
listed above and issue another "QEMU File" protocol command,
asking for a new SEND message to re-fill the buffer.
Migration of pc.ram:
====================
At the beginning of the migration, (migration-rdma.c),
the sender and the receiver populate the list of RAMBlocks
to be registered with each other into a structure.
Then, using the aforementioned protocol, they exchange a
description of these blocks with each other, to be used later
during the iteration of main memory. This description includes
a list of all the RAMBlocks, their offsets and lengths, virtual
addresses and possibly includes pre-registered RDMA keys in case dynamic
page registration was disabled on the server-side, otherwise not.
Main memory is not migrated with the aforementioned protocol,
but is instead migrated with normal RDMA Write operations.
Pages are migrated in "chunks" (hard-coded to 1 Megabyte right now).
Chunk size is not dynamic, but it could be in a future implementation.
There's nothing to indicate that this is useful right now.
When a chunk is full (or a flush() occurs), the memory backed by
the chunk is registered with librdmacm is pinned in memory on
both sides using the aforementioned protocol.
After pinning, an RDMA Write is generated and transmitted
for the entire chunk.
Chunks are also transmitted in batches: This means that we
do not request that the hardware signal the completion queue
for the completion of *every* chunk. The current batch size
is about 64 chunks (corresponding to 64 MB of memory).
Only the last chunk in a batch must be signaled.
This helps keep everything as asynchronous as possible
and helps keep the hardware busy performing RDMA operations.
Error-handling:
===============
Infiniband has what is called a "Reliable, Connected"
link (one of 4 choices). This is the mode in which
we use for RDMA migration.
If a *single* message fails,
the decision is to abort the migration entirely and
cleanup all the RDMA descriptors and unregister all
the memory.
After cleanup, the Virtual Machine is returned to normal
operation the same way that would happen if the TCP
socket is broken during a non-RDMA based migration.
TODO:
=====
1. 'migrate x-rdma:host:port' and '-incoming x-rdma' options will be
renamed to 'rdma' after the experimental phase of this work has
completed upstream.
2. Currently, 'ulimit -l' mlock() limits as well as cgroups swap limits
are not compatible with infinband memory pinning and will result in
an aborted migration (but with the source VM left unaffected).
3. Use of the recent /proc/<pid>/pagemap would likely speed up
the use of KSM and ballooning while using RDMA.
4. Also, some form of balloon-device usage tracking would also
help alleviate some issues.

9
exec.c
View File

@ -2630,3 +2630,12 @@ bool cpu_physical_memory_is_io(hwaddr phys_addr)
memory_region_is_romd(mr)); memory_region_is_romd(mr));
} }
#endif #endif
void qemu_ram_foreach_block(RAMBlockIterFunc func, void *opaque)
{
RAMBlock *block;
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
func(block->host, block->offset, block->length, opaque);
}
}

2
hmp.c
View File

@ -169,6 +169,8 @@ void hmp_info_migrate(Monitor *mon, const QDict *qdict)
if (info->has_ram) { if (info->has_ram) {
monitor_printf(mon, "transferred ram: %" PRIu64 " kbytes\n", monitor_printf(mon, "transferred ram: %" PRIu64 " kbytes\n",
info->ram->transferred >> 10); info->ram->transferred >> 10);
monitor_printf(mon, "throughput: %0.2f mbps\n",
info->ram->mbps);
monitor_printf(mon, "remaining ram: %" PRIu64 " kbytes\n", monitor_printf(mon, "remaining ram: %" PRIu64 " kbytes\n",
info->ram->remaining >> 10); info->ram->remaining >> 10);
monitor_printf(mon, "total ram: %" PRIu64 " kbytes\n", monitor_printf(mon, "total ram: %" PRIu64 " kbytes\n",

6
include/block/coroutine.h
View File

@ -209,4 +209,10 @@ void qemu_co_rwlock_unlock(CoRwlock *lock);
*/ */
void coroutine_fn co_sleep_ns(QEMUClock *clock, int64_t ns); void coroutine_fn co_sleep_ns(QEMUClock *clock, int64_t ns);
/**
* Yield until a file descriptor becomes readable
*
* Note that this function clobbers the handlers for the file descriptor.
*/
void coroutine_fn yield_until_fd_readable(int fd);
#endif /* QEMU_COROUTINE_H */ #endif /* QEMU_COROUTINE_H */

5
include/exec/cpu-common.h
View File

@ -113,6 +113,11 @@ void cpu_physical_memory_write_rom(hwaddr addr,
extern struct MemoryRegion io_mem_rom; extern struct MemoryRegion io_mem_rom;
extern struct MemoryRegion io_mem_notdirty; extern struct MemoryRegion io_mem_notdirty;
typedef void (RAMBlockIterFunc)(void *host_addr,
ram_addr_t offset, ram_addr_t length, void *opaque);
void qemu_ram_foreach_block(RAMBlockIterFunc func, void *opaque);
#endif #endif
#endif /* !CPU_COMMON_H */ #endif /* !CPU_COMMON_H */

25
include/migration/migration.h
View File

@ -21,6 +21,7 @@
#include "qapi/error.h" #include "qapi/error.h"
#include "migration/vmstate.h" #include "migration/vmstate.h"
#include "qapi-types.h" #include "qapi-types.h"
#include "exec/cpu-common.h"
struct MigrationParams { struct MigrationParams {
bool blk; bool blk;
@ -40,6 +41,7 @@ struct MigrationState
int state; int state;
MigrationParams params; MigrationParams params;
double mbps;
int64_t total_time; int64_t total_time;
int64_t downtime; int64_t downtime;
int64_t expected_downtime; int64_t expected_downtime;
@ -92,6 +94,8 @@ uint64_t ram_bytes_remaining(void);
uint64_t ram_bytes_transferred(void); uint64_t ram_bytes_transferred(void);
uint64_t ram_bytes_total(void); uint64_t ram_bytes_total(void);
void acct_update_position(QEMUFile *f, size_t size, bool zero);
extern SaveVMHandlers savevm_ram_handlers; extern SaveVMHandlers savevm_ram_handlers;
uint64_t dup_mig_bytes_transferred(void); uint64_t dup_mig_bytes_transferred(void);
@ -119,6 +123,8 @@ void migrate_add_blocker(Error *reason);
*/ */
void migrate_del_blocker(Error *reason); void migrate_del_blocker(Error *reason);
bool migrate_rdma_pin_all(void);
int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen, int xbzrle_encode_buffer(uint8_t *old_buf, uint8_t *new_buf, int slen,
uint8_t *dst, int dlen); uint8_t *dst, int dlen);
int xbzrle_decode_buffer(uint8_t *src, int slen, uint8_t *dst, int dlen); int xbzrle_decode_buffer(uint8_t *src, int slen, uint8_t *dst, int dlen);
@ -127,4 +133,23 @@ int migrate_use_xbzrle(void);
int64_t migrate_xbzrle_cache_size(void); int64_t migrate_xbzrle_cache_size(void);
int64_t xbzrle_cache_resize(int64_t new_size); int64_t xbzrle_cache_resize(int64_t new_size);
void ram_control_before_iterate(QEMUFile *f, uint64_t flags);
void ram_control_after_iterate(QEMUFile *f, uint64_t flags);
void ram_control_load_hook(QEMUFile *f, uint64_t flags);
/* Whenever this is found in the data stream, the flags
* will be passed to ram_control_load_hook in the incoming-migration
* side. This lets before_ram_iterate/after_ram_iterate add
* transport-specific sections to the RAM migration data.
*/
#define RAM_SAVE_FLAG_HOOK 0x80
#define RAM_SAVE_CONTROL_NOT_SUPP -1000
#define RAM_SAVE_CONTROL_DELAYED -2000
size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
ram_addr_t offset, size_t size,
int *bytes_sent);
#endif #endif

32
include/migration/qemu-file.h
View File

@ -23,6 +23,7 @@
*/ */
#ifndef QEMU_FILE_H #ifndef QEMU_FILE_H
#define QEMU_FILE_H 1 #define QEMU_FILE_H 1
#include "exec/cpu-common.h"
/* This function writes a chunk of data to a file at the given position. /* This function writes a chunk of data to a file at the given position.
* The pos argument can be ignored if the file is only being used for * The pos argument can be ignored if the file is only being used for
@ -57,12 +58,40 @@ typedef int (QEMUFileGetFD)(void *opaque);
typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov, typedef ssize_t (QEMUFileWritevBufferFunc)(void *opaque, struct iovec *iov,
int iovcnt, int64_t pos); int iovcnt, int64_t pos);
/*
* This function provides hooks around different
* stages of RAM migration.
*/
typedef int (QEMURamHookFunc)(QEMUFile *f, void *opaque, uint64_t flags);
/*
* Constants used by ram_control_* hooks
*/
#define RAM_CONTROL_SETUP 0
#define RAM_CONTROL_ROUND 1
#define RAM_CONTROL_HOOK 2
#define RAM_CONTROL_FINISH 3
/*
* This function allows override of where the RAM page
* is saved (such as RDMA, for example.)
*/
typedef size_t (QEMURamSaveFunc)(QEMUFile *f, void *opaque,
ram_addr_t block_offset,
ram_addr_t offset,
size_t size,
int *bytes_sent);
typedef struct QEMUFileOps { typedef struct QEMUFileOps {
QEMUFilePutBufferFunc *put_buffer; QEMUFilePutBufferFunc *put_buffer;
QEMUFileGetBufferFunc *get_buffer; QEMUFileGetBufferFunc *get_buffer;
QEMUFileCloseFunc *close; QEMUFileCloseFunc *close;
QEMUFileGetFD *get_fd; QEMUFileGetFD *get_fd;
QEMUFileWritevBufferFunc *writev_buffer; QEMUFileWritevBufferFunc *writev_buffer;
QEMURamHookFunc *before_ram_iterate;
QEMURamHookFunc *after_ram_iterate;
QEMURamHookFunc *hook_ram_load;
QEMURamSaveFunc *save_page;
} QEMUFileOps; } QEMUFileOps;
QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops); QEMUFile *qemu_fopen_ops(void *opaque, const QEMUFileOps *ops);
@ -80,6 +109,7 @@ void qemu_put_byte(QEMUFile *f, int v);
* The buffer should be available till it is sent asynchronously. * The buffer should be available till it is sent asynchronously.
*/ */
void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size); void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size);
bool qemu_file_mode_is_not_valid(const char *mode);
static inline void qemu_put_ubyte(QEMUFile *f, unsigned int v) static inline void qemu_put_ubyte(QEMUFile *f, unsigned int v)
{ {
@ -93,6 +123,7 @@ void qemu_put_be32(QEMUFile *f, unsigned int v);
void qemu_put_be64(QEMUFile *f, uint64_t v); void qemu_put_be64(QEMUFile *f, uint64_t v);
int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size); int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size);
int qemu_get_byte(QEMUFile *f); int qemu_get_byte(QEMUFile *f);
void qemu_update_position(QEMUFile *f, size_t size);
static inline unsigned int qemu_get_ubyte(QEMUFile *f) static inline unsigned int qemu_get_ubyte(QEMUFile *f)
{ {
@ -110,6 +141,7 @@ void qemu_file_reset_rate_limit(QEMUFile *f);
void qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate); void qemu_file_set_rate_limit(QEMUFile *f, int64_t new_rate);
int64_t qemu_file_get_rate_limit(QEMUFile *f); int64_t qemu_file_get_rate_limit(QEMUFile *f);
int qemu_file_get_error(QEMUFile *f); int qemu_file_get_error(QEMUFile *f);
void qemu_fflush(QEMUFile *f);
static inline void qemu_put_be64s(QEMUFile *f, const uint64_t *pv) static inline void qemu_put_be64s(QEMUFile *f, const uint64_t *pv)
{ {

15
migration.c
View File

@ -66,6 +66,7 @@ MigrationState *migrate_get_current(void)
.state = MIG_STATE_SETUP, .state = MIG_STATE_SETUP,
.bandwidth_limit = MAX_THROTTLE, .bandwidth_limit = MAX_THROTTLE,
.xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE, .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
.mbps = -1,
}; };
return &current_migration; return &current_migration;
@ -201,6 +202,7 @@ MigrationInfo *qmp_query_migrate(Error **errp)
info->ram->normal = norm_mig_pages_transferred(); info->ram->normal = norm_mig_pages_transferred();
info->ram->normal_bytes = norm_mig_bytes_transferred(); info->ram->normal_bytes = norm_mig_bytes_transferred();
info->ram->dirty_pages_rate = s->dirty_pages_rate; info->ram->dirty_pages_rate = s->dirty_pages_rate;
info->ram->mbps = s->mbps;
if (blk_mig_active()) { if (blk_mig_active()) {
info->has_disk = true; info->has_disk = true;
@ -230,6 +232,7 @@ MigrationInfo *qmp_query_migrate(Error **errp)
info->ram->skipped = skipped_mig_pages_transferred(); info->ram->skipped = skipped_mig_pages_transferred();
info->ram->normal = norm_mig_pages_transferred(); info->ram->normal = norm_mig_pages_transferred();
info->ram->normal_bytes = norm_mig_bytes_transferred(); info->ram->normal_bytes = norm_mig_bytes_transferred();
info->ram->mbps = s->mbps;
break; break;
case MIG_STATE_ERROR: case MIG_STATE_ERROR:
info->has_status = true; info->has_status = true;
@ -473,6 +476,15 @@ void qmp_migrate_set_downtime(double value, Error **errp)
max_downtime = (uint64_t)value; max_downtime = (uint64_t)value;
} }
bool migrate_rdma_pin_all(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_X_RDMA_PIN_ALL];
}
int migrate_use_xbzrle(void) int migrate_use_xbzrle(void)
{ {
MigrationState *s; MigrationState *s;
@ -543,6 +555,9 @@ static void *migration_thread(void *opaque)
double bandwidth = transferred_bytes / time_spent; double bandwidth = transferred_bytes / time_spent;
max_size = bandwidth * migrate_max_downtime() / 1000000; max_size = bandwidth * migrate_max_downtime() / 1000000;
s->mbps = time_spent ? (((double) transferred_bytes * 8.0) /
((double) time_spent / 1000.0)) / 1000.0 / 1000.0 : -1;
DPRINTF("transferred %" PRIu64 " time_spent %" PRIu64 DPRINTF("transferred %" PRIu64 " time_spent %" PRIu64
" bandwidth %g max_size %" PRId64 "\n", " bandwidth %g max_size %" PRId64 "\n",
transferred_bytes, time_spent, bandwidth, max_size); transferred_bytes, time_spent, bandwidth, max_size);

12
qapi-schema.json
View File

@ -513,12 +513,15 @@
# @dirty-pages-rate: number of pages dirtied by second by the # @dirty-pages-rate: number of pages dirtied by second by the
# guest (since 1.3) # guest (since 1.3)
# #
# @mbps: throughput in megabits/sec. (since 1.6)
#
# Since: 0.14.0 # Since: 0.14.0
## ##
{ 'type': 'MigrationStats', { 'type': 'MigrationStats',
'data': {'transferred': 'int', 'remaining': 'int', 'total': 'int' , 'data': {'transferred': 'int', 'remaining': 'int', 'total': 'int' ,
'duplicate': 'int', 'skipped': 'int', 'normal': 'int', 'duplicate': 'int', 'skipped': 'int', 'normal': 'int',
'normal-bytes': 'int', 'dirty-pages-rate' : 'int' } } 'normal-bytes': 'int', 'dirty-pages-rate' : 'int',
'mbps' : 'number' } }
## ##
# @XBZRLECacheStats # @XBZRLECacheStats
@ -605,10 +608,15 @@
# This feature allows us to minimize migration traffic for certain work # This feature allows us to minimize migration traffic for certain work
# loads, by sending compressed difference of the pages # loads, by sending compressed difference of the pages
# #
# @x-rdma-pin-all: Controls whether or not the entire VM memory footprint is
# mlock()'d on demand or all at once. Refer to docs/rdma.txt for usage.
# Disabled by default. Experimental: may (or may not) be renamed after
# further testing is complete. (since 1.6)
#
# Since: 1.2 # Since: 1.2
## ##
{ 'enum': 'MigrationCapability', { 'enum': 'MigrationCapability',
'data': ['xbzrle'] } 'data': ['xbzrle', 'x-rdma-pin-all'] }
## ##
# @MigrationCapabilityStatus # @MigrationCapabilityStatus

23
qemu-coroutine-io.c
View File

@ -63,3 +63,26 @@ qemu_co_send_recv(int sockfd, void *buf, size_t bytes, bool do_send)
struct iovec iov = { .iov_base = buf, .iov_len = bytes }; struct iovec iov = { .iov_base = buf, .iov_len = bytes };
return qemu_co_sendv_recvv(sockfd, &iov, 1, 0, bytes, do_send); return qemu_co_sendv_recvv(sockfd, &iov, 1, 0, bytes, do_send);
} }
typedef struct {
Coroutine *co;
int fd;
} FDYieldUntilData;
static void fd_coroutine_enter(void *opaque)
{
FDYieldUntilData *data = opaque;
qemu_set_fd_handler(data->fd, NULL, NULL, NULL);
qemu_coroutine_enter(data->co, NULL);
}
void coroutine_fn yield_until_fd_readable(int fd)
{
FDYieldUntilData data;
assert(qemu_in_coroutine());
data.co = qemu_coroutine_self();
data.fd = fd;
qemu_set_fd_handler(fd, fd_coroutine_enter, NULL, &data);
qemu_coroutine_yield();
}

114
savevm.c
View File

@ -149,34 +149,6 @@ typedef struct QEMUFileSocket
QEMUFile *file; QEMUFile *file;
} QEMUFileSocket; } QEMUFileSocket;
typedef struct {
Coroutine *co;
int fd;
} FDYieldUntilData;
static void fd_coroutine_enter(void *opaque)
{
FDYieldUntilData *data = opaque;
qemu_set_fd_handler(data->fd, NULL, NULL, NULL);
qemu_coroutine_enter(data->co, NULL);
}
/**
* Yield until a file descriptor becomes readable
*
* Note that this function clobbers the handlers for the file descriptor.
*/
static void coroutine_fn yield_until_fd_readable(int fd)
{
FDYieldUntilData data;
assert(qemu_in_coroutine());
data.co = qemu_coroutine_self();
data.fd = fd;
qemu_set_fd_handler(fd, fd_coroutine_enter, NULL, &data);
qemu_coroutine_yield();
}
static ssize_t socket_writev_buffer(void *opaque, struct iovec *iov, int iovcnt, static ssize_t socket_writev_buffer(void *opaque, struct iovec *iov, int iovcnt,
int64_t pos) int64_t pos)
{ {
@ -477,14 +449,23 @@ static const QEMUFileOps socket_write_ops = {
.close = socket_close .close = socket_close
}; };
QEMUFile *qemu_fopen_socket(int fd, const char *mode) bool qemu_file_mode_is_not_valid(const char *mode)
{ {
QEMUFileSocket *s;
if (mode == NULL || if (mode == NULL ||
(mode[0] != 'r' && mode[0] != 'w') || (mode[0] != 'r' && mode[0] != 'w') ||
mode[1] != 'b' || mode[2] != 0) { mode[1] != 'b' || mode[2] != 0) {
fprintf(stderr, "qemu_fopen: Argument validity check failed\n"); fprintf(stderr, "qemu_fopen: Argument validity check failed\n");
return true;
}
return false;
}
QEMUFile *qemu_fopen_socket(int fd, const char *mode)
{
QEMUFileSocket *s;
if (qemu_file_mode_is_not_valid(mode)) {
return NULL; return NULL;
} }
@ -503,10 +484,7 @@ QEMUFile *qemu_fopen(const char *filename, const char *mode)
{ {
QEMUFileStdio *s; QEMUFileStdio *s;
if (mode == NULL || if (qemu_file_mode_is_not_valid(mode)) {
(mode[0] != 'r' && mode[0] != 'w') ||
mode[1] != 'b' || mode[2] != 0) {
fprintf(stderr, "qemu_fopen: Argument validity check failed\n");
return NULL; return NULL;
} }
@ -611,7 +589,7 @@ static inline bool qemu_file_is_writable(QEMUFile *f)
* If there is writev_buffer QEMUFileOps it uses it otherwise uses * If there is writev_buffer QEMUFileOps it uses it otherwise uses
* put_buffer ops. * put_buffer ops.
*/ */
static void qemu_fflush(QEMUFile *f) void qemu_fflush(QEMUFile *f)
{ {
ssize_t ret = 0; ssize_t ret = 0;
@ -638,6 +616,65 @@ static void qemu_fflush(QEMUFile *f)
} }
} }
void ram_control_before_iterate(QEMUFile *f, uint64_t flags)
{
int ret = 0;
if (f->ops->before_ram_iterate) {
ret = f->ops->before_ram_iterate(f, f->opaque, flags);
if (ret < 0) {
qemu_file_set_error(f, ret);
}
}
}
void ram_control_after_iterate(QEMUFile *f, uint64_t flags)
{
int ret = 0;
if (f->ops->after_ram_iterate) {
ret = f->ops->after_ram_iterate(f, f->opaque, flags);
if (ret < 0) {
qemu_file_set_error(f, ret);
}
}
}
void ram_control_load_hook(QEMUFile *f, uint64_t flags)
{
int ret = 0;
if (f->ops->hook_ram_load) {
ret = f->ops->hook_ram_load(f, f->opaque, flags);
if (ret < 0) {
qemu_file_set_error(f, ret);
}
} else {
qemu_file_set_error(f, ret);
}
}
size_t ram_control_save_page(QEMUFile *f, ram_addr_t block_offset,
ram_addr_t offset, size_t size, int *bytes_sent)
{
if (f->ops->save_page) {
int ret = f->ops->save_page(f, f->opaque, block_offset,
offset, size, bytes_sent);
if (ret != RAM_SAVE_CONTROL_DELAYED) {
if (*bytes_sent > 0) {
qemu_update_position(f, *bytes_sent);
} else if (ret < 0) {
qemu_file_set_error(f, ret);
}
}
return ret;
}
return RAM_SAVE_CONTROL_NOT_SUPP;
}
static void qemu_fill_buffer(QEMUFile *f) static void qemu_fill_buffer(QEMUFile *f)
{ {
int len; int len;
@ -671,6 +708,11 @@ int qemu_get_fd(QEMUFile *f)
return -1; return -1;
} }
void qemu_update_position(QEMUFile *f, size_t size)
{
f->pos += size;
}
/** Closes the file /** Closes the file
* *
* Returns negative error value if any error happened on previous operations or * Returns negative error value if any error happened on previous operations or