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Wed, 20 Jul 2022 11:20:05 +0000 (UTC) Received: from dgilbert-t580.localhost (unknown [10.33.36.158]) by smtp.corp.redhat.com (Postfix) with ESMTP id 070D92166B26; Wed, 20 Jul 2022 11:20:04 +0000 (UTC) From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, leobras@redhat.com, quintela@redhat.com, berrange@redhat.com, peterx@redhat.com, iii@linux.ibm.com, huangy81@chinatelecom.cn Subject: [PULL 28/30] multifd: Document the locking of MultiFD{Send/Recv}Params Date: Wed, 20 Jul 2022 12:19:24 +0100 Message-Id: <20220720111926.107055-29-dgilbert@redhat.com> In-Reply-To: <20220720111926.107055-1-dgilbert@redhat.com> References: <20220720111926.107055-1-dgilbert@redhat.com> MIME-Version: 1.0 Content-type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 Received-SPF: pass client-ip=170.10.133.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Juan Quintela 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 Message-Id: <20220531104318.7494-2-quintela@redhat.com> Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Dr. David Alan Gilbert dgilbert: Typo fixes from Chen Zhang --- migration/multifd.h | 66 ++++++++++++++++++++++++++++----------------- 1 file changed, 41 insertions(+), 25 deletions(-) diff --git a/migration/multifd.h b/migration/multifd.h index 4d8d89e5e5..519f498643 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 */ -- 2.36.1