Re: [Qemu-devel] [RFC PATCH RDMA support v4: 07/10] connection-establishment for RDMA

[Paolo Bonzini <pbonzini@redhat.com>]

Il 18/03/2013 04:19, mrhines@linux.vnet.ibm.com ha scritto:
> From: "Michael R. Hines" <mrhines@us.ibm.com>
> 
> 
> Signed-off-by: Michael R. Hines <mrhines@us.ibm.com>
> ---
>  migration-rdma.c |  205 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 205 insertions(+)
>  create mode 100644 migration-rdma.c
> 
> diff --git a/migration-rdma.c b/migration-rdma.c
> new file mode 100644
> index 0000000..e1ea055
> --- /dev/null
> +++ b/migration-rdma.c
> @@ -0,0 +1,205 @@
> +/*
> + *  Copyright (C) 2013 Michael R. Hines <mrhines@us.ibm.com>
> + *  Copyright (C) 2013 Jiuxing Liu <jl@us.ibm.com>
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; under version 2 of the License.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with this program; if not, see <http://www.gnu.org/licenses/>.
> + */
> +#include "migration/rdma.h"
> +#include "qemu-common.h"
> +#include "migration/migration.h"
> +#include "migration/qemu-file.h"
> +#include <stdio.h>
> +#include <sys/types.h>
> +#include <sys/socket.h>
> +#include <netdb.h>
> +#include <arpa/inet.h>
> +#include <string.h>
> +
> +//#define DEBUG_MIGRATION_RDMA
> +
> +#ifdef DEBUG_MIGRATION_RDMA
> +#define DPRINTF(fmt, ...) \
> +    do { printf("migration-rdma: " fmt, ## __VA_ARGS__); } while (0)
> +#else
> +#define DPRINTF(fmt, ...) \
> +    do { } while (0)
> +#endif
> +
> +static int rdma_accept_incoming_migration(RDMAData *rdma, Error **errp)
> +{
> +    int ret;
> +
> +    ret = qemu_rdma_migrate_listen(rdma, rdma->host, rdma->port);
> +    if (ret) {
> +        qemu_rdma_print("rdma migration: error listening!");
> +        goto err_rdma_server_wait;
> +    }
> +
> +    ret = qemu_rdma_alloc_qp(&rdma->rdma_ctx);
> +    if (ret) {
> +        qemu_rdma_print("rdma migration: error allocating qp!");
> +        goto err_rdma_server_wait;
> +    }
> +
> +    ret = qemu_rdma_migrate_accept(&rdma->rdma_ctx, NULL, NULL, NULL, 0);
> +    if (ret) {
> +        qemu_rdma_print("rdma migration: error accepting connection!");
> +        goto err_rdma_server_wait;
> +    }
> +
> +    ret = qemu_rdma_post_recv_qemu_file(rdma);
> +    if (ret) {
> +        qemu_rdma_print("rdma migration: error posting second qemu file recv!");
> +        goto err_rdma_server_wait;
> +    }
> +
> +    ret = qemu_rdma_post_send_remote_info(rdma);
> +    if (ret) {
> +        qemu_rdma_print("rdma migration: error sending remote info!");
> +        goto err_rdma_server_wait;
> +    }
> +
> +    ret = qemu_rdma_wait_for_wrid(rdma, RDMA_WRID_SEND_REMOTE_INFO);
> +    if (ret < 0) {
> +        qemu_rdma_print("rdma migration: polling remote info error!");
> +        goto err_rdma_server_wait;
> +    }

In a "socket-like" abstraction, all of these steps except the initial
listen are part of "accept".  Please move them to
qemu_rdma_migrate_accept (possibly renaming the existing
qemu_rdma_migrate_accept to a different name).

Similarly, perhaps you can merge qemu_rdma_server_prepare and
qemu_rdma_migrate_listen.

Try to make the public API between modules as small as possible (but not
smaller :)), so that you can easily document it without too many
references to RDMA concepts.

Thanks,

Paolo

> +    rdma->total_bytes = 0;
> +    rdma->enabled = 1;
> +    qemu_rdma_dump_gid("server_connect", rdma->rdma_ctx.cm_id);
> +    return 0;
> +
> +err_rdma_server_wait:
> +    qemu_rdma_cleanup(rdma);
> +    return -1;
> +
> +}
> +
> +int rdma_start_incoming_migration(const char * host_port, Error **errp)
> +{
> +    RDMAData *rdma = g_malloc0(sizeof(RDMAData));
> +    QEMUFile *f;
> +    int ret;
> +
> +    if ((ret = qemu_rdma_data_init(rdma, host_port, errp)) < 0)
> +        return ret; 
> +
> +    ret = qemu_rdma_server_init(rdma, NULL);
> +
> +    DPRINTF("Starting RDMA-based incoming migration\n");
> +
> +    if (!ret) {
> +        DPRINTF("qemu_rdma_server_init success\n");
> +        ret = qemu_rdma_server_prepare(rdma, NULL);
> +
> +        if (!ret) {
> +            DPRINTF("qemu_rdma_server_prepare success\n");
> +
> +            ret = rdma_accept_incoming_migration(rdma, NULL);
> +            if(!ret)
> +                DPRINTF("qemu_rdma_accept_incoming_migration success\n");
> +            f = qemu_fopen_rdma(rdma, "rb");
> +            if (f == NULL) {
> +                fprintf(stderr, "could not qemu_fopen RDMA\n");
> +                ret = -EIO;
> +            }
> +
> +            process_incoming_migration(f);
> +        }
> +    }
> +
> +    return ret;
> +}
> +
> +void rdma_start_outgoing_migration(void *opaque, const char *host_port, Error **errp)
> +{
> +    RDMAData *rdma = g_malloc0(sizeof(RDMAData));
> +    MigrationState *s = opaque;
> +    int ret;
> +
> +    if (qemu_rdma_data_init(rdma, host_port, errp) < 0)
> +        return; 
> +
> +    ret = qemu_rdma_client_init(rdma, NULL);
> +    if(!ret) {
> +        DPRINTF("qemu_rdma_client_init success\n");
> +        ret = qemu_rdma_client_connect(rdma, NULL);
> +
> +        if(!ret) {
> +            s->file = qemu_fopen_rdma(rdma, "wb");
> +            DPRINTF("qemu_rdma_client_connect success\n");
> +            migrate_fd_connect(s);
> +            return;
> +        }
> +    }
> +
> +    migrate_fd_error(s);
> +}
> +
> +size_t save_rdma_page(QEMUFile *f, ram_addr_t block_offset, ram_addr_t offset, int cont, size_t size)
> +{
> +    int ret;
> +    size_t bytes_sent = 0;
> +    ram_addr_t current_addr;
> +    RDMAData * rdma = migrate_use_rdma(f);
> +
> +    current_addr = block_offset + offset;
> +
> +    /*
> +     * Add this page to the current 'chunk'. If the chunk
> +     * is full, an actual RDMA write will occur.
> +     */
> +    if ((ret = qemu_rdma_write(rdma, current_addr, size)) < 0) {
> +        fprintf(stderr, "rdma migration: write error! %d\n", ret);
> +        return ret;
> +    }
> +
> +    /*
> +     * Drain the Completion Queue if possible.
> +     * If not, the end of the iteration will do this
> +     * again to make sure we don't overflow the
> +     * request queue. 
> +     */
> +    while (1) {
> +        int ret = qemu_rdma_poll(rdma);
> +        if (ret == RDMA_WRID_NONE) {
> +            break;
> +        }
> +        if (ret < 0) {
> +            fprintf(stderr, "rdma migration: polling error! %d\n", ret);
> +            return ret;
> +        }
> +    }
> +
> +    bytes_sent += size;
> +    return bytes_sent;
> +}
> +
> +size_t qemu_rdma_fill(void * opaque, uint8_t *buf, int size)
> +{
> +    RDMAData * rdma = opaque;
> +    size_t len = 0;
> +
> +    if(rdma->qemu_file_len) {
> +        DPRINTF("RDMA %" PRId64 " of %d bytes already in buffer\n",
> +	    rdma->qemu_file_len, size);
> +
> +        len = MIN(size, rdma->qemu_file_len);
> +        memcpy(buf, rdma->qemu_file_curr, len);
> +        rdma->qemu_file_curr += len;
> +        rdma->qemu_file_len -= len;
> +    }
> +
> +    return len;
> +}
>