Commit 06df2e69 authored by David Hildenbrand's avatar David Hildenbrand Committed by Michael S. Tsirkin
Browse files

virtio-balloon: Rip out qemu_balloon_inhibit() 



The only remaining special case is postcopy. It cannot handle
concurrent discards yet, which would result in requesting already sent
pages from the source. Special-case it in virtio-balloon instead.

Introduce migration_in_incoming_postcopy(), to find out if incoming
postcopy is active.

Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@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: <20200626072248.78761-7-david@redhat.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent b030958c

balloon.c

+0 −18
Original line number Diff line number Diff line
@@ -36,24 +36,6 @@ 
static QEMUBalloonEvent *balloon_event_fn;

static QEMUBalloonStatus *balloon_stat_fn;

static void *balloon_opaque;

static int balloon_inhibit_count;



bool qemu_balloon_is_inhibited(void)

{

    return atomic_read(&balloon_inhibit_count) > 0 ||

           ram_block_discard_is_disabled();

}



void qemu_balloon_inhibit(bool state)

{

    if (state) {

        atomic_inc(&balloon_inhibit_count);

    } else {

        atomic_dec(&balloon_inhibit_count);

    }



    assert(atomic_read(&balloon_inhibit_count) >= 0);

}



static bool have_balloon(Error **errp)

{

hw/virtio/virtio-balloon.c

+8 −2
Original line number Diff line number Diff line
@@ -63,6 +63,12 @@ static bool virtio_balloon_pbp_matches(PartiallyBalloonedPage *pbp, 
    return pbp->base_gpa == base_gpa;

}



static bool virtio_balloon_inhibited(void)

{

    /* Postcopy cannot deal with concurrent discards, so it's special. */

    return ram_block_discard_is_disabled() || migration_in_incoming_postcopy();

}



static void balloon_inflate_page(VirtIOBalloon *balloon,

                                 MemoryRegion *mr, hwaddr mr_offset,

                                 PartiallyBalloonedPage *pbp)
@@ -336,7 +342,7 @@ static void virtio_balloon_handle_report(VirtIODevice *vdev, VirtQueue *vq) 
         * accessible by another device or process, or if the guest is

         * expecting it to retain a non-zero value.

         */

        if (qemu_balloon_is_inhibited() || dev->poison_val) {

        if (virtio_balloon_inhibited() || dev->poison_val) {

            goto skip_element;

        }
@@ -421,7 +427,7 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq) 


            trace_virtio_balloon_handle_output(memory_region_name(section.mr),

                                               pa);

            if (!qemu_balloon_is_inhibited()) {

            if (!virtio_balloon_inhibited()) {

                if (vq == s->ivq) {

                    balloon_inflate_page(s, section.mr,

                                         section.offset_within_region, &pbp);

include/migration/misc.h

+2 −0
Original line number Diff line number Diff line
@@ -69,6 +69,8 @@ bool migration_has_failed(MigrationState *); 
/* ...and after the device transmission */

bool migration_in_postcopy_after_devices(MigrationState *);

void migration_global_dump(Monitor *mon);

/* True if incomming migration entered POSTCOPY_INCOMING_DISCARD */

bool migration_in_incoming_postcopy(void);



/* migration/block-dirty-bitmap.c */

void dirty_bitmap_mig_init(void);

include/sysemu/balloon.h

+0 −2
Original line number Diff line number Diff line
@@ -23,7 +23,5 @@ typedef void (QEMUBalloonStatus)(void *opaque, BalloonInfo *info); 
int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,

                             QEMUBalloonStatus *stat_func, void *opaque);

void qemu_remove_balloon_handler(void *opaque);

bool qemu_balloon_is_inhibited(void);

void qemu_balloon_inhibit(bool state);



#endif

migration/migration.c

+7 −0
Original line number Diff line number Diff line
@@ -1772,6 +1772,13 @@ bool migration_in_postcopy_after_devices(MigrationState *s) 
    return migration_in_postcopy() && s->postcopy_after_devices;

}



bool migration_in_incoming_postcopy(void)

{

    PostcopyState ps = postcopy_state_get();



    return ps >= POSTCOPY_INCOMING_DISCARD && ps < POSTCOPY_INCOMING_END;

}



bool migration_is_idle(void)

{

    MigrationState *s = current_migration;