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Re: [PATCH v3] migration/rdma: Fix out of order wrid
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From: |
address@hidden |
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Subject: |
Re: [PATCH v3] migration/rdma: Fix out of order wrid |
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Date: |
Wed, 27 Oct 2021 01:04:17 +0000 |
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Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 |
ping again
On 18/10/2021 18:18, Li, Zhijian/ζ ζΊε wrote:
> ping
>
>
> On 27/09/2021 15:07, Li Zhijian wrote:
>> destination:
>> ../qemu/build/qemu-system-x86_64 -enable-kvm -netdev
>> tap,id=hn0,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown -device
>> e1000,netdev=hn0,mac=50:52:54:00:11:22 -boot c -drive
>> if=none,file=./Fedora-rdma-server-migration.qcow2,id=drive-virtio-disk0
>> -device
>> virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0
>> -m 2048 -smp 2 -device piix3-usb-uhci -device usb-tablet -monitor stdio -vga
>> qxl -spice streaming-video=filter,port=5902,disable-ticketing -incoming
>> rdma:192.168.22.23:8888
>> qemu-system-x86_64: -spice
>> streaming-video=filter,port=5902,disable-ticketing: warning: short-form
>> boolean option 'disable-ticketing' deprecated
>> Please use disable-ticketing=on instead
>> QEMU 6.0.50 monitor - type 'help' for more information
>> (qemu) trace-event qemu_rdma_block_for_wrid_miss on
>> (qemu) dest_init RDMA Device opened: kernel name rxe_eth0 uverbs device name
>> uverbs2, infiniband_verbs class device path
>> /sys/class/infiniband_verbs/uverbs2, infiniband class device path
>> /sys/class/infiniband/rxe_eth0, transport: (2) Ethernet
>> qemu_rdma_block_for_wrid_miss A Wanted wrid CONTROL SEND (2000) but got
>> CONTROL RECV (4000)
>>
>> source:
>> ../qemu/build/qemu-system-x86_64 -enable-kvm -netdev
>> tap,id=hn0,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown -device
>> e1000,netdev=hn0,mac=50:52:54:00:11:22 -boot c -drive
>> if=none,file=./Fedora-rdma-server.qcow2,id=drive-virtio-disk0 -device
>> virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0
>> -m 2048 -smp 2 -device piix3-usb-uhci -device usb-tablet -monitor stdio -vga
>> qxl -spice streaming-video=filter,port=5901,disable-ticketing -S
>> qemu-system-x86_64: -spice
>> streaming-video=filter,port=5901,disable-ticketing: warning: short-form
>> boolean option 'disable-ticketing' deprecated
>> Please use disable-ticketing=on instead
>> QEMU 6.0.50 monitor - type 'help' for more information
>> (qemu)
>> (qemu) trace-event qemu_rdma_block_for_wrid_miss on
>> (qemu) migrate -d rdma:192.168.22.23:8888
>> source_resolve_host RDMA Device opened: kernel name rxe_eth0 uverbs device
>> name uverbs2, infiniband_verbs class device path
>> /sys/class/infiniband_verbs/uverbs2, infiniband class device path
>> /sys/class/infiniband/rxe_eth0, transport: (2) Ethernet
>> (qemu) qemu_rdma_block_for_wrid_miss A Wanted wrid WRITE RDMA (1) but got
>> CONTROL RECV (4000)
>>
>> NOTE: we use soft RoCE as the rdma device.
>> [root@iaas-rpma images]# rdma link show rxe_eth0/1
>> link rxe_eth0/1 state ACTIVE physical_state LINK_UP netdev eth0
>>
>> This migration could not be completed when out of order(OOO) CQ event occurs.
>> The send queue and receive queue shared a same completion queue, and
>> qemu_rdma_block_for_wrid() will drop the CQs it's not interested in. But
>> the dropped CQs by qemu_rdma_block_for_wrid() could be later CQs it wants.
>> So in this case, qemu_rdma_block_for_wrid() will block forever.
>>
>> OOO cases will occur in both source side and destination side. And a
>> forever blocking happens on only SEND and RECV are out of order. OOO between
>> 'WRITE RDMA' and 'RECV' doesn't matter.
>>
>> below the OOO sequence:
>> source destination
>> rdma_write_one() qemu_rdma_registration_handle()
>> 1. S1: post_recv X D1: post_recv Y
>> 2. wait for recv CQ event X
>> 3. D2: post_send X ---------------+
>> 4. wait for send CQ send event X (D2) |
>> 5. recv CQ event X reaches (D2) |
>> 6. +-S2: post_send Y |
>> 7. | wait for send CQ event Y |
>> 8. | recv CQ event Y (S2) (drop it) |
>> 9. +-send CQ event Y reaches (S2) |
>> 10. send CQ event X reaches (D2) -----+
>> 11. wait recv CQ event Y (dropped by
>> (8))
>>
>> Although a hardware IB works fine in my a hundred of runs, the IB
>> specification
>> doesn't guaratee the CQ order in such case.
>>
>> Here we introduce a independent send completion queue to distinguish
>> ibv_post_send completion queue from the original mixed completion queue.
>> It helps us to poll the specific CQE we are really interested in.
>>
>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
>> ---
>> V3: rebase code, and combine 2/2 to 1/2
>> V2: Introduce send completion queue
>> ---
>> migration/rdma.c | 132 +++++++++++++++++++++++++++++++++++------------
>> 1 file changed, 98 insertions(+), 34 deletions(-)
>>
>> diff --git a/migration/rdma.c b/migration/rdma.c
>> index 5c2d113aa94..bb19a5afe73 100644
>> --- a/migration/rdma.c
>> +++ b/migration/rdma.c
>> @@ -358,9 +358,11 @@ typedef struct RDMAContext {
>> struct ibv_context *verbs;
>> struct rdma_event_channel *channel;
>> struct ibv_qp *qp; /* queue pair */
>> - struct ibv_comp_channel *comp_channel; /* completion channel */
>> + struct ibv_comp_channel *recv_comp_channel; /* recv completion channel
>> */
>> + struct ibv_comp_channel *send_comp_channel; /* send completion channel
>> */
>> struct ibv_pd *pd; /* protection domain */
>> - struct ibv_cq *cq; /* completion queue */
>> + struct ibv_cq *recv_cq; /* recvieve completion queue */
>> + struct ibv_cq *send_cq; /* send completion queue */
>>
>> /*
>> * If a previous write failed (perhaps because of a failed
>> @@ -1060,19 +1062,32 @@ static int qemu_rdma_alloc_pd_cq(RDMAContext *rdma)
>> }
>>
>> /* create completion channel */
>> - rdma->comp_channel = ibv_create_comp_channel(rdma->verbs);
>> - if (!rdma->comp_channel) {
>> + rdma->recv_comp_channel = ibv_create_comp_channel(rdma->verbs);
>> + if (!rdma->recv_comp_channel) {
>> error_report("failed to allocate completion channel");
>> goto err_alloc_pd_cq;
>> }
>>
>> /*
>> - * Completion queue can be filled by both read and write work requests,
>> - * so must reflect the sum of both possible queue sizes.
>> + * Completion queue can be filled by read work requests.
>> */
>> - rdma->cq = ibv_create_cq(rdma->verbs, (RDMA_SIGNALED_SEND_MAX * 3),
>> - NULL, rdma->comp_channel, 0);
>> - if (!rdma->cq) {
>> + rdma->recv_cq = ibv_create_cq(rdma->verbs, (RDMA_SIGNALED_SEND_MAX * 3),
>> + NULL, rdma->recv_comp_channel, 0);
>> + if (!rdma->recv_cq) {
>> + error_report("failed to allocate completion queue");
>> + goto err_alloc_pd_cq;
>> + }
>> +
>> + /* create send completion channel */
>> + rdma->send_comp_channel = ibv_create_comp_channel(rdma->verbs);
>> + if (!rdma->send_comp_channel) {
>> + error_report("failed to allocate completion channel");
>> + goto err_alloc_pd_cq;
>> + }
>> +
>> + rdma->send_cq = ibv_create_cq(rdma->verbs, (RDMA_SIGNALED_SEND_MAX * 3),
>> + NULL, rdma->send_comp_channel, 0);
>> + if (!rdma->send_cq) {
>> error_report("failed to allocate completion queue");
>> goto err_alloc_pd_cq;
>> }
>> @@ -1083,11 +1098,19 @@ err_alloc_pd_cq:
>> if (rdma->pd) {
>> ibv_dealloc_pd(rdma->pd);
>> }
>> - if (rdma->comp_channel) {
>> - ibv_destroy_comp_channel(rdma->comp_channel);
>> + if (rdma->recv_comp_channel) {
>> + ibv_destroy_comp_channel(rdma->recv_comp_channel);
>> + }
>> + if (rdma->send_comp_channel) {
>> + ibv_destroy_comp_channel(rdma->send_comp_channel);
>> + }
>> + if (rdma->recv_cq) {
>> + ibv_destroy_cq(rdma->recv_cq);
>> + rdma->recv_cq = NULL;
>> }
>> rdma->pd = NULL;
>> - rdma->comp_channel = NULL;
>> + rdma->recv_comp_channel = NULL;
>> + rdma->send_comp_channel = NULL;
>> return -1;
>>
>> }
>> @@ -1104,8 +1127,8 @@ static int qemu_rdma_alloc_qp(RDMAContext *rdma)
>> attr.cap.max_recv_wr = 3;
>> attr.cap.max_send_sge = 1;
>> attr.cap.max_recv_sge = 1;
>> - attr.send_cq = rdma->cq;
>> - attr.recv_cq = rdma->cq;
>> + attr.send_cq = rdma->send_cq;
>> + attr.recv_cq = rdma->recv_cq;
>> attr.qp_type = IBV_QPT_RC;
>>
>> ret = rdma_create_qp(rdma->cm_id, rdma->pd, &attr);
>> @@ -1421,14 +1444,14 @@ static void qemu_rdma_signal_unregister(RDMAContext
>> *rdma, uint64_t index,
>> * (of any kind) has completed.
>> * Return the work request ID that completed.
>> */
>> -static uint64_t qemu_rdma_poll(RDMAContext *rdma, uint64_t *wr_id_out,
>> - uint32_t *byte_len)
>> +static uint64_t qemu_rdma_poll(RDMAContext *rdma, struct ibv_cq *cq,
>> + uint64_t *wr_id_out, uint32_t *byte_len)
>> {
>> int ret;
>> struct ibv_wc wc;
>> uint64_t wr_id;
>>
>> - ret = ibv_poll_cq(rdma->cq, 1, &wc);
>> + ret = ibv_poll_cq(cq, 1, &wc);
>>
>> if (!ret) {
>> *wr_id_out = RDMA_WRID_NONE;
>> @@ -1500,7 +1523,8 @@ static uint64_t qemu_rdma_poll(RDMAContext *rdma,
>> uint64_t *wr_id_out,
>> /* Wait for activity on the completion channel.
>> * Returns 0 on success, none-0 on error.
>> */
>> -static int qemu_rdma_wait_comp_channel(RDMAContext *rdma)
>> +static int qemu_rdma_wait_comp_channel(RDMAContext *rdma,
>> + struct ibv_comp_channel
>> *comp_channel)
>> {
>> struct rdma_cm_event *cm_event;
>> int ret = -1;
>> @@ -1511,7 +1535,7 @@ static int qemu_rdma_wait_comp_channel(RDMAContext
>> *rdma)
>> */
>> if (rdma->migration_started_on_destination &&
>> migration_incoming_get_current()->state ==
>> MIGRATION_STATUS_ACTIVE) {
>> - yield_until_fd_readable(rdma->comp_channel->fd);
>> + yield_until_fd_readable(comp_channel->fd);
>> } else {
>> /* This is the source side, we're in a separate thread
>> * or destination prior to migration_fd_process_incoming()
>> @@ -1522,7 +1546,7 @@ static int qemu_rdma_wait_comp_channel(RDMAContext
>> *rdma)
>> */
>> while (!rdma->error_state && !rdma->received_error) {
>> GPollFD pfds[2];
>> - pfds[0].fd = rdma->comp_channel->fd;
>> + pfds[0].fd = comp_channel->fd;
>> pfds[0].events = G_IO_IN | G_IO_HUP | G_IO_ERR;
>> pfds[0].revents = 0;
>>
>> @@ -1580,6 +1604,17 @@ static int qemu_rdma_wait_comp_channel(RDMAContext
>> *rdma)
>> return rdma->error_state;
>> }
>>
>> +static struct ibv_comp_channel *to_channel(RDMAContext *rdma, int wrid)
>> +{
>> + return wrid < RDMA_WRID_RECV_CONTROL ? rdma->send_comp_channel :
>> + rdma->recv_comp_channel;
>> +}
>> +
>> +static struct ibv_cq *to_cq(RDMAContext *rdma, int wrid)
>> +{
>> + return wrid < RDMA_WRID_RECV_CONTROL ? rdma->send_cq : rdma->recv_cq;
>> +}
>> +
>> /*
>> * Block until the next work request has completed.
>> *
>> @@ -1600,13 +1635,15 @@ static int qemu_rdma_block_for_wrid(RDMAContext
>> *rdma, int wrid_requested,
>> struct ibv_cq *cq;
>> void *cq_ctx;
>> uint64_t wr_id = RDMA_WRID_NONE, wr_id_in;
>> + struct ibv_comp_channel *ch = to_channel(rdma, wrid_requested);
>> + struct ibv_cq *poll_cq = to_cq(rdma, wrid_requested);
>>
>> - if (ibv_req_notify_cq(rdma->cq, 0)) {
>> + if (ibv_req_notify_cq(poll_cq, 0)) {
>> return -1;
>> }
>> /* poll cq first */
>> while (wr_id != wrid_requested) {
>> - ret = qemu_rdma_poll(rdma, &wr_id_in, byte_len);
>> + ret = qemu_rdma_poll(rdma, poll_cq, &wr_id_in, byte_len);
>> if (ret < 0) {
>> return ret;
>> }
>> @@ -1627,12 +1664,12 @@ static int qemu_rdma_block_for_wrid(RDMAContext
>> *rdma, int wrid_requested,
>> }
>>
>> while (1) {
>> - ret = qemu_rdma_wait_comp_channel(rdma);
>> + ret = qemu_rdma_wait_comp_channel(rdma, ch);
>> if (ret) {
>> goto err_block_for_wrid;
>> }
>>
>> - ret = ibv_get_cq_event(rdma->comp_channel, &cq, &cq_ctx);
>> + ret = ibv_get_cq_event(ch, &cq, &cq_ctx);
>> if (ret) {
>> perror("ibv_get_cq_event");
>> goto err_block_for_wrid;
>> @@ -1646,7 +1683,7 @@ static int qemu_rdma_block_for_wrid(RDMAContext *rdma,
>> int wrid_requested,
>> }
>>
>> while (wr_id != wrid_requested) {
>> - ret = qemu_rdma_poll(rdma, &wr_id_in, byte_len);
>> + ret = qemu_rdma_poll(rdma, poll_cq, &wr_id_in, byte_len);
>> if (ret < 0) {
>> goto err_block_for_wrid;
>> }
>> @@ -2362,13 +2399,21 @@ static void qemu_rdma_cleanup(RDMAContext *rdma)
>> rdma_destroy_qp(rdma->cm_id);
>> rdma->qp = NULL;
>> }
>> - if (rdma->cq) {
>> - ibv_destroy_cq(rdma->cq);
>> - rdma->cq = NULL;
>> + if (rdma->recv_cq) {
>> + ibv_destroy_cq(rdma->recv_cq);
>> + rdma->recv_cq = NULL;
>> + }
>> + if (rdma->send_cq) {
>> + ibv_destroy_cq(rdma->send_cq);
>> + rdma->send_cq = NULL;
>> }
>> - if (rdma->comp_channel) {
>> - ibv_destroy_comp_channel(rdma->comp_channel);
>> - rdma->comp_channel = NULL;
>> + if (rdma->recv_comp_channel) {
>> + ibv_destroy_comp_channel(rdma->recv_comp_channel);
>> + rdma->recv_comp_channel = NULL;
>> + }
>> + if (rdma->send_comp_channel) {
>> + ibv_destroy_comp_channel(rdma->send_comp_channel);
>> + rdma->send_comp_channel = NULL;
>> }
>> if (rdma->pd) {
>> ibv_dealloc_pd(rdma->pd);
>> @@ -3040,10 +3085,14 @@ static void
>> qio_channel_rdma_set_aio_fd_handler(QIOChannel *ioc,
>> {
>> QIOChannelRDMA *rioc = QIO_CHANNEL_RDMA(ioc);
>> if (io_read) {
>> - aio_set_fd_handler(ctx, rioc->rdmain->comp_channel->fd,
>> + aio_set_fd_handler(ctx, rioc->rdmain->recv_comp_channel->fd,
>> + false, io_read, io_write, NULL, opaque);
>> + aio_set_fd_handler(ctx, rioc->rdmain->send_comp_channel->fd,
>> false, io_read, io_write, NULL, opaque);
>> } else {
>> - aio_set_fd_handler(ctx, rioc->rdmaout->comp_channel->fd,
>> + aio_set_fd_handler(ctx, rioc->rdmaout->recv_comp_channel->fd,
>> + false, io_read, io_write, NULL, opaque);
>> + aio_set_fd_handler(ctx, rioc->rdmaout->send_comp_channel->fd,
>> false, io_read, io_write, NULL, opaque);
>> }
>> }
>> @@ -3257,7 +3306,22 @@ static size_t qemu_rdma_save_page(QEMUFile *f, void
>> *opaque,
>> */
>> while (1) {
>> uint64_t wr_id, wr_id_in;
>> - int ret = qemu_rdma_poll(rdma, &wr_id_in, NULL);
>> + int ret = qemu_rdma_poll(rdma, rdma->recv_cq, &wr_id_in, NULL);
>> + if (ret < 0) {
>> + error_report("rdma migration: polling error! %d", ret);
>> + goto err;
>> + }
>> +
>> + wr_id = wr_id_in & RDMA_WRID_TYPE_MASK;
>> +
>> + if (wr_id == RDMA_WRID_NONE) {
>> + break;
>> + }
>> + }
>> +
>> + while (1) {
>> + uint64_t wr_id, wr_id_in;
>> + int ret = qemu_rdma_poll(rdma, rdma->send_cq, &wr_id_in, NULL);
>> if (ret < 0) {
>> error_report("rdma migration: polling error! %d", ret);
>> goto err;