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
This commit is contained in:
Juan Quintela 2022-05-31 12:43:06 +02:00 committed by Dr. David Alan Gilbert
parent d59c40cc48
commit 4a8f19c95c

View File

@ -65,7 +65,9 @@ typedef struct {
} MultiFDPages_t;
typedef struct {
/* this fields are not changed once the thread is created */
/* 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 */
@ -74,39 +76,47 @@ typedef struct {
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;
/* is the yank function registered */
bool registered_yank;
/* thread has work to do */
int pending_job;
/* array of pages to sent */
MultiFDPages_t *pages;
/* packet allocated len */
uint32_t packet_len;
/* pointer to the packet */
MultiFDPacket_t *packet;
/* multifd flags for sending ram */
int write_flags;
/* multifd flags for each packet */
uint32_t flags;
/* size of the next packet that contains pages */
uint32_t next_packet_size;
/* global number of generated multifd packets */
uint64_t packet_num;
/* thread local variables */
/* 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;
/* syncs main thread and channels */
QemuSemaphore sem_sync;
/* buffers to send */
struct iovec *iov;
/* number of iovs used */
@ -120,7 +130,9 @@ typedef struct {
} MultiFDSendParams;
typedef struct {
/* this fields are not changed once the thread is created */
/* 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 */
@ -129,31 +141,35 @@ typedef struct {
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;
/* ramblock host address */
uint8_t *host;
/* packet allocated len */
uint32_t packet_len;
/* pointer to the packet */
MultiFDPacket_t *packet;
/* multifd flags for each packet */
uint32_t flags;
/* global number of generated multifd packets */
uint64_t packet_num;
/* thread local variables */
/* 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;
/* syncs main thread and channels */
QemuSemaphore sem_sync;
/* buffers to recv */
struct iovec *iov;
/* Pages that are not zero */