xemu/migration/multifd.h
Juan Quintela 4a8f19c95c multifd: Document the locking of MultiFD{Send/Recv}Params
Reorder the structures so we can know if the fields are:
- Read only
- Their own locking (i.e. sems)
- Protected by 'mutex'
- Only for the multifd channel

Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20220531104318.7494-2-quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
  dgilbert: Typo fixes from Chen Zhang
2022-07-20 12:15:09 +01:00

202 lines
5.8 KiB
C

/*
* Multifd common functions
*
* Copyright (c) 2019-2020 Red Hat Inc
*
* Authors:
* Juan Quintela <quintela@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef QEMU_MIGRATION_MULTIFD_H
#define QEMU_MIGRATION_MULTIFD_H
int multifd_save_setup(Error **errp);
void multifd_save_cleanup(void);
int multifd_load_setup(Error **errp);
int multifd_load_cleanup(Error **errp);
bool multifd_recv_all_channels_created(void);
bool multifd_recv_new_channel(QIOChannel *ioc, Error **errp);
void multifd_recv_sync_main(void);
int multifd_send_sync_main(QEMUFile *f);
int multifd_queue_page(QEMUFile *f, RAMBlock *block, ram_addr_t offset);
/* Multifd Compression flags */
#define MULTIFD_FLAG_SYNC (1 << 0)
/* We reserve 3 bits for compression methods */
#define MULTIFD_FLAG_COMPRESSION_MASK (7 << 1)
/* we need to be compatible. Before compression value was 0 */
#define MULTIFD_FLAG_NOCOMP (0 << 1)
#define MULTIFD_FLAG_ZLIB (1 << 1)
#define MULTIFD_FLAG_ZSTD (2 << 1)
/* This value needs to be a multiple of qemu_target_page_size() */
#define MULTIFD_PACKET_SIZE (512 * 1024)
typedef struct {
uint32_t magic;
uint32_t version;
uint32_t flags;
/* maximum number of allocated pages */
uint32_t pages_alloc;
/* non zero pages */
uint32_t normal_pages;
/* size of the next packet that contains pages */
uint32_t next_packet_size;
uint64_t packet_num;
uint64_t unused[4]; /* Reserved for future use */
char ramblock[256];
uint64_t offset[];
} __attribute__((packed)) MultiFDPacket_t;
typedef struct {
/* number of used pages */
uint32_t num;
/* number of allocated pages */
uint32_t allocated;
/* global number of generated multifd packets */
uint64_t packet_num;
/* offset of each page */
ram_addr_t *offset;
RAMBlock *block;
} MultiFDPages_t;
typedef struct {
/* Fields are only written at creating/deletion time */
/* No lock required for them, they are read only */
/* channel number */
uint8_t id;
/* channel thread name */
char *name;
/* channel thread id */
QemuThread thread;
/* communication channel */
QIOChannel *c;
/* is the yank function registered */
bool registered_yank;
/* packet allocated len */
uint32_t packet_len;
/* multifd flags for sending ram */
int write_flags;
/* sem where to wait for more work */
QemuSemaphore sem;
/* syncs main thread and channels */
QemuSemaphore sem_sync;
/* this mutex protects the following parameters */
QemuMutex mutex;
/* is this channel thread running */
bool running;
/* should this thread finish */
bool quit;
/* multifd flags for each packet */
uint32_t flags;
/* global number of generated multifd packets */
uint64_t packet_num;
/* thread has work to do */
int pending_job;
/* array of pages to sent.
* The owner of 'pages' depends of 'pending_job' value:
* pending_job == 0 -> migration_thread can use it.
* pending_job != 0 -> multifd_channel can use it.
*/
MultiFDPages_t *pages;
/* thread local variables. No locking required */
/* pointer to the packet */
MultiFDPacket_t *packet;
/* size of the next packet that contains pages */
uint32_t next_packet_size;
/* packets sent through this channel */
uint64_t num_packets;
/* non zero pages sent through this channel */
uint64_t total_normal_pages;
/* buffers to send */
struct iovec *iov;
/* number of iovs used */
uint32_t iovs_num;
/* Pages that are not zero */
ram_addr_t *normal;
/* num of non zero pages */
uint32_t normal_num;
/* used for compression methods */
void *data;
} MultiFDSendParams;
typedef struct {
/* Fields are only written at creating/deletion time */
/* No lock required for them, they are read only */
/* channel number */
uint8_t id;
/* channel thread name */
char *name;
/* channel thread id */
QemuThread thread;
/* communication channel */
QIOChannel *c;
/* packet allocated len */
uint32_t packet_len;
/* syncs main thread and channels */
QemuSemaphore sem_sync;
/* this mutex protects the following parameters */
QemuMutex mutex;
/* is this channel thread running */
bool running;
/* should this thread finish */
bool quit;
/* multifd flags for each packet */
uint32_t flags;
/* global number of generated multifd packets */
uint64_t packet_num;
/* thread local variables. No locking required */
/* pointer to the packet */
MultiFDPacket_t *packet;
/* size of the next packet that contains pages */
uint32_t next_packet_size;
/* packets sent through this channel */
uint64_t num_packets;
/* ramblock host address */
uint8_t *host;
/* non zero pages recv through this channel */
uint64_t total_normal_pages;
/* buffers to recv */
struct iovec *iov;
/* Pages that are not zero */
ram_addr_t *normal;
/* num of non zero pages */
uint32_t normal_num;
/* used for de-compression methods */
void *data;
} MultiFDRecvParams;
typedef struct {
/* Setup for sending side */
int (*send_setup)(MultiFDSendParams *p, Error **errp);
/* Cleanup for sending side */
void (*send_cleanup)(MultiFDSendParams *p, Error **errp);
/* Prepare the send packet */
int (*send_prepare)(MultiFDSendParams *p, Error **errp);
/* Setup for receiving side */
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);
} MultiFDMethods;
void multifd_register_ops(int method, MultiFDMethods *ops);
#endif