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Sat, 6 Mar 2021 16:45:26 +0800 From: Zheng Chuan Subject: Re: [PATCH v4 17/18] migration/rdma: send data for both rdma-pin-all and NOT rdma-pin-all mode To: "Dr. David Alan Gilbert" References: <1612339311-114805-1-git-send-email-zhengchuan@huawei.com> <1612339311-114805-18-git-send-email-zhengchuan@huawei.com> <20210204101836.GE3039@work-vm> Message-ID: <1f1e75f3-c619-19e1-a6fe-bfc6f01992e6@huawei.com> Date: Sat, 6 Mar 2021 16:45:26 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20210204101836.GE3039@work-vm> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.186.51] X-CFilter-Loop: Reflected Received-SPF: pass client-ip=45.249.212.191; envelope-from=zhengchuan@huawei.com; helo=szxga05-in.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: yubihong@huawei.com, berrange@redhat.com, zhang.zhanghailiang@huawei.com, quintela@redhat.com, qemu-devel@nongnu.org, xiexiangyou@huawei.com, alex.chen@huawei.com, wanghao232@huawei.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2021/2/4 18:18, Dr. David Alan Gilbert wrote: > * Chuan Zheng (zhengchuan@huawei.com) wrote: >> Signed-off-by: Zhimin Feng >> Signed-off-by: Chuan Zheng >> --- >> migration/rdma.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++---- >> 1 file changed, 61 insertions(+), 4 deletions(-) >> >> diff --git a/migration/rdma.c b/migration/rdma.c >> index 2097839..c19a91f 100644 >> --- a/migration/rdma.c >> +++ b/migration/rdma.c >> @@ -2002,6 +2002,20 @@ static int qemu_rdma_write_one(QEMUFile *f, RDMAContext *rdma, >> .repeat = 1, >> }; >> >> + /* use multifd to send data */ >> + if (migrate_use_multifd()) { >> + int channel = get_multifd_RDMA_channel(); >> + int ret = 0; >> + MultiFDSendParams *multifd_send_param = NULL; >> + ret = get_multifd_send_param(channel, &multifd_send_param); >> + if (ret) { >> + error_report("rdma: error getting multifd_send_param(%d)", channel); >> + return -EINVAL; >> + } >> + rdma = (RDMAContext *)multifd_send_param->rdma; >> + block = &(rdma->local_ram_blocks.block[current_index]); >> + } >> + >> retry: >> sge.addr = (uintptr_t)(block->local_host_addr + >> (current_addr - block->offset)); >> @@ -2197,6 +2211,27 @@ retry: >> return 0; >> } >> >> +static int multifd_rdma_write_flush(void) >> +{ >> + /* The multifd RDMA threads send data */ >> + MultiFDSendParams *multifd_send_param = NULL; >> + RDMAContext *rdma = NULL; >> + MigrationState *s = migrate_get_current(); >> + int ret = 0; >> + >> + ret = get_multifd_send_param(s->rdma_channel, >> + &multifd_send_param); >> + if (ret) { >> + error_report("rdma: error getting multifd_send_param(%d)", >> + s->rdma_channel); > > Do we need these error_report's for get_multifd_send_param calls - how > can they fail in practice? > Maybe we do not need it. The s->rdma_channel should not exceed the migrate_multifd_channels and should not negative. >> + return ret; >> + } >> + rdma = (RDMAContext *)(multifd_send_param->rdma); >> + rdma->nb_sent++; >> + >> + return ret; > > But this doesn't actually 'flush' anything? > Yes, it just use to increase the nb_sent. we need to choose a more suitable function name. >> +} >> + >> /* >> * Push out any unwritten RDMA operations. >> * >> @@ -2219,8 +2254,15 @@ static int qemu_rdma_write_flush(QEMUFile *f, RDMAContext *rdma) >> } >> >> if (ret == 0) { >> - rdma->nb_sent++; >> - trace_qemu_rdma_write_flush(rdma->nb_sent); >> + if (migrate_use_multifd()) { >> + ret = multifd_rdma_write_flush(); >> + if (ret) { >> + return ret; >> + } >> + } else { >> + rdma->nb_sent++; >> + trace_qemu_rdma_write_flush(rdma->nb_sent); >> + } >> } >> >> rdma->current_length = 0; >> @@ -4062,6 +4104,7 @@ wait_reg_complete: >> } >> >> qemu_sem_post(&multifd_send_param->sem_sync); >> + qemu_sem_wait(&multifd_send_param->sem); > > why? > The multifd send thread would post sem signal after finishing sending data. The main thread need wait for multifd RDMA send threads to poll the CQE. >> } >> } >> >> @@ -4443,6 +4486,7 @@ static void *multifd_rdma_send_thread(void *opaque) >> Error *local_err = NULL; >> int ret = 0; >> RDMAControlHeader head = { .len = 0, .repeat = 1 }; >> + RDMAContext *rdma = p->rdma; >> >> trace_multifd_send_thread_start(p->id); >> if (multifd_send_initial_packet(p, &local_err) < 0) { >> @@ -4451,7 +4495,7 @@ static void *multifd_rdma_send_thread(void *opaque) >> >> /* wait for semaphore notification to register memory */ >> qemu_sem_wait(&p->sem_sync); >> - if (qemu_rdma_registration(p->rdma) < 0) { >> + if (qemu_rdma_registration(rdma) < 0) { >> goto out; >> } >> /* >> @@ -4466,12 +4510,25 @@ static void *multifd_rdma_send_thread(void *opaque) >> break; >> } >> } >> + /* To complete polling(CQE) */ >> + while (rdma->nb_sent) { > > Where is nb_sent decremented? > the nb_sent is decreased in qemu_rdma_poll which is called by qemu_rdma_block_for_wrid. >> + ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_RDMA_WRITE, NULL); >> + if (ret < 0) { >> + error_report("multifd RDMA migration: " >> + "complete polling error!"); >> + return NULL; >> + } >> + } >> /* Send FINISHED to the destination */ >> head.type = RDMA_CONTROL_REGISTER_FINISHED; >> - ret = qemu_rdma_exchange_send(p->rdma, &head, NULL, NULL, NULL, NULL); >> + ret = qemu_rdma_exchange_send(rdma, &head, NULL, NULL, NULL, NULL); >> if (ret < 0) { >> + error_report("multifd RDMA migration: " >> + "sending remote error!"); >> return NULL; >> } >> + /* sync main thread */ >> + qemu_sem_post(&p->sem); >> } >> >> out: >> -- >> 1.8.3.1 >> -- Regards. Chuan