Commit 5f1f1902 authored by David Hildenbrand's avatar David Hildenbrand Committed by Michael S. Tsirkin
Browse files

migration/rdma: Use ram_block_discard_disable() 



RDMA will pin all guest memory (as documented in docs/rdma.txt). We want
to disable RAM block discards - however, to keep it simple use
ram_block_discard_is_required() instead of inhibiting.

Note: It is not sufficient to limit disabling to pin_all. Even when only
conditionally pinning 1 MB chunks, as soon as one page within such a
chunk was discarded and one page not, the discarded pages will be pinned
as well.

Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Juan Quintela <quintela@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Message-Id: <20200626072248.78761-9-david@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent fee3f3ba

migration/rdma.c

+16 −2
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include "qemu/sockets.h"

#include "qemu/bitmap.h"

#include "qemu/coroutine.h"

#include "exec/memory.h"

#include <sys/socket.h>

#include <netdb.h>

#include <arpa/inet.h>
@@ -4017,8 +4018,14 @@ void rdma_start_incoming_migration(const char *host_port, Error **errp) 
    Error *local_err = NULL;



    trace_rdma_start_incoming_migration();

    rdma = qemu_rdma_data_init(host_port, &local_err);



    /* Avoid ram_block_discard_disable(), cannot change during migration. */

    if (ram_block_discard_is_required()) {

        error_setg(errp, "RDMA: cannot disable RAM discard");

        return;

    }



    rdma = qemu_rdma_data_init(host_port, &local_err);

    if (rdma == NULL) {

        goto err;

    }
@@ -4067,10 +4074,17 @@ void rdma_start_outgoing_migration(void *opaque, 
                            const char *host_port, Error **errp)

{

    MigrationState *s = opaque;

    RDMAContext *rdma = qemu_rdma_data_init(host_port, errp);

    RDMAContext *rdma_return_path = NULL;

    RDMAContext *rdma;

    int ret = 0;



    /* Avoid ram_block_discard_disable(), cannot change during migration. */

    if (ram_block_discard_is_required()) {

        error_setg(errp, "RDMA: cannot disable RAM discard");

        return;

    }



    rdma = qemu_rdma_data_init(host_port, errp);

    if (rdma == NULL) {

        goto err;

    }