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author | Juan Quintela <quintela@redhat.com> | 2022-05-31 12:43:06 +0200 |
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committer | Dr. David Alan Gilbert <dgilbert@redhat.com> | 2022-07-20 12:15:09 +0100 |
commit | 4a8f19c95cf55aec5f63c64bd0a67f65a27c43de (patch) | |
tree | 40bff3b3e74a2f305b89b752c62d958129f5ddbc /migration/multifd.h | |
parent | d59c40cc483729f2e67c80e58df769ad19976fe9 (diff) | |
download | qemu-4a8f19c95cf55aec5f63c64bd0a67f65a27c43de.zip qemu-4a8f19c95cf55aec5f63c64bd0a67f65a27c43de.tar.gz qemu-4a8f19c95cf55aec5f63c64bd0a67f65a27c43de.tar.bz2 |
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
Diffstat (limited to 'migration/multifd.h')
-rw-r--r-- | migration/multifd.h | 66 |
1 files changed, 41 insertions, 25 deletions
diff --git a/migration/multifd.h b/migration/multifd.h index 4d8d89e..519f498 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -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; + /* 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 */ + /* 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; - /* packet allocated len */ - uint32_t packet_len; + + /* thread local variables. No locking required */ + /* 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 */ /* 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 */ |