Commit 3b52726e authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Eric Blake
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migration/block-dirty-bitmap: refactor state global variables 



Move all state variables into one global struct. Reduce global
variable usage, utilizing opaque pointer where possible.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: default avatarAndrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Message-Id: <20200727194236.19551-12-vsementsov@virtuozzo.com>
Signed-off-by: default avatarEric Blake <eblake@redhat.com>
parent d0cccbd1

migration/block-dirty-bitmap.c

+99 −80
Original line number Diff line number Diff line
@@ -128,6 +128,12 @@ typedef struct DBMSaveState { 
    BdrvDirtyBitmap *prev_bitmap;

} DBMSaveState;



typedef struct LoadBitmapState {

    BlockDriverState *bs;

    BdrvDirtyBitmap *bitmap;

    bool migrated;

} LoadBitmapState;



/* State of the dirty bitmap migration (DBM) during load process */

typedef struct DBMLoadState {

    uint32_t flags;
@@ -135,18 +141,17 @@ typedef struct DBMLoadState { 
    char bitmap_name[256];

    BlockDriverState *bs;

    BdrvDirtyBitmap *bitmap;



    GSList *enabled_bitmaps;

    QemuMutex finish_lock;

} DBMLoadState;



static DBMSaveState dirty_bitmap_mig_state;

typedef struct DBMState {

    DBMSaveState save;

    DBMLoadState load;

} DBMState;



/* State of one bitmap during load process */

typedef struct LoadBitmapState {

    BlockDriverState *bs;

    BdrvDirtyBitmap *bitmap;

    bool migrated;

} LoadBitmapState;

static GSList *enabled_bitmaps;

QemuMutex finish_lock;

static DBMState dbm_state;



static uint32_t qemu_get_bitmap_flags(QEMUFile *f)

{
@@ -169,21 +174,21 @@ static void qemu_put_bitmap_flags(QEMUFile *f, uint32_t flags) 
    qemu_put_byte(f, flags);

}



static void send_bitmap_header(QEMUFile *f, SaveBitmapState *dbms,

                               uint32_t additional_flags)

static void send_bitmap_header(QEMUFile *f, DBMSaveState *s,

                               SaveBitmapState *dbms, uint32_t additional_flags)

{

    BlockDriverState *bs = dbms->bs;

    BdrvDirtyBitmap *bitmap = dbms->bitmap;

    uint32_t flags = additional_flags;

    trace_send_bitmap_header_enter();



    if (bs != dirty_bitmap_mig_state.prev_bs) {

        dirty_bitmap_mig_state.prev_bs = bs;

    if (bs != s->prev_bs) {

        s->prev_bs = bs;

        flags |= DIRTY_BITMAP_MIG_FLAG_DEVICE_NAME;

    }



    if (bitmap != dirty_bitmap_mig_state.prev_bitmap) {

        dirty_bitmap_mig_state.prev_bitmap = bitmap;

    if (bitmap != s->prev_bitmap) {

        s->prev_bitmap = bitmap;

        flags |= DIRTY_BITMAP_MIG_FLAG_BITMAP_NAME;

    }
@@ -198,19 +203,22 @@ static void send_bitmap_header(QEMUFile *f, SaveBitmapState *dbms, 
    }

}



static void send_bitmap_start(QEMUFile *f, SaveBitmapState *dbms)

static void send_bitmap_start(QEMUFile *f, DBMSaveState *s,

                              SaveBitmapState *dbms)

{

    send_bitmap_header(f, dbms, DIRTY_BITMAP_MIG_FLAG_START);

    send_bitmap_header(f, s, dbms, DIRTY_BITMAP_MIG_FLAG_START);

    qemu_put_be32(f, bdrv_dirty_bitmap_granularity(dbms->bitmap));

    qemu_put_byte(f, dbms->flags);

}



static void send_bitmap_complete(QEMUFile *f, SaveBitmapState *dbms)

static void send_bitmap_complete(QEMUFile *f, DBMSaveState *s,

                                 SaveBitmapState *dbms)

{

    send_bitmap_header(f, dbms, DIRTY_BITMAP_MIG_FLAG_COMPLETE);

    send_bitmap_header(f, s, dbms, DIRTY_BITMAP_MIG_FLAG_COMPLETE);

}



static void send_bitmap_bits(QEMUFile *f, SaveBitmapState *dbms,

static void send_bitmap_bits(QEMUFile *f, DBMSaveState *s,

                             SaveBitmapState *dbms,

                             uint64_t start_sector, uint32_t nr_sectors)

{

    /* align for buffer_is_zero() */
@@ -235,7 +243,7 @@ static void send_bitmap_bits(QEMUFile *f, SaveBitmapState *dbms, 


    trace_send_bitmap_bits(flags, start_sector, nr_sectors, buf_size);



    send_bitmap_header(f, dbms, flags);

    send_bitmap_header(f, s, dbms, flags);



    qemu_put_be64(f, start_sector);

    qemu_put_be32(f, nr_sectors);
@@ -254,12 +262,12 @@ static void send_bitmap_bits(QEMUFile *f, SaveBitmapState *dbms, 
}



/* Called with iothread lock taken.  */

static void dirty_bitmap_do_save_cleanup(void)

static void dirty_bitmap_do_save_cleanup(DBMSaveState *s)

{

    SaveBitmapState *dbms;



    while ((dbms = QSIMPLEQ_FIRST(&dirty_bitmap_mig_state.dbms_list)) != NULL) {

        QSIMPLEQ_REMOVE_HEAD(&dirty_bitmap_mig_state.dbms_list, entry);

    while ((dbms = QSIMPLEQ_FIRST(&s->dbms_list)) != NULL) {

        QSIMPLEQ_REMOVE_HEAD(&s->dbms_list, entry);

        bdrv_dirty_bitmap_set_busy(dbms->bitmap, false);

        bdrv_unref(dbms->bs);

        g_free(dbms);
@@ -267,7 +275,8 @@ static void dirty_bitmap_do_save_cleanup(void) 
}



/* Called with iothread lock taken. */

static int add_bitmaps_to_list(BlockDriverState *bs, const char *bs_name)

static int add_bitmaps_to_list(DBMSaveState *s, BlockDriverState *bs,

                               const char *bs_name)

{

    BdrvDirtyBitmap *bitmap;

    SaveBitmapState *dbms;
@@ -322,25 +331,24 @@ static int add_bitmaps_to_list(BlockDriverState *bs, const char *bs_name) 
            dbms->flags |= DIRTY_BITMAP_MIG_START_FLAG_PERSISTENT;

        }



        QSIMPLEQ_INSERT_TAIL(&dirty_bitmap_mig_state.dbms_list,

                             dbms, entry);

        QSIMPLEQ_INSERT_TAIL(&s->dbms_list, dbms, entry);

    }



    return 0;

}



/* Called with iothread lock taken. */

static int init_dirty_bitmap_migration(void)

static int init_dirty_bitmap_migration(DBMSaveState *s)

{

    BlockDriverState *bs;

    SaveBitmapState *dbms;

    GHashTable *handled_by_blk = g_hash_table_new(NULL, NULL);

    BlockBackend *blk;



    dirty_bitmap_mig_state.bulk_completed = false;

    dirty_bitmap_mig_state.prev_bs = NULL;

    dirty_bitmap_mig_state.prev_bitmap = NULL;

    dirty_bitmap_mig_state.no_bitmaps = false;

    s->bulk_completed = false;

    s->prev_bs = NULL;

    s->prev_bitmap = NULL;

    s->no_bitmaps = false;



    /*

     * Use blockdevice name for direct (or filtered) children of named block
@@ -369,7 +377,7 @@ static int init_dirty_bitmap_migration(void) 
        }



        if (bs && bs->drv && !bs->drv->is_filter) {

            if (add_bitmaps_to_list(bs, name)) {

            if (add_bitmaps_to_list(s, bs, name)) {

                goto fail;

            }

            g_hash_table_add(handled_by_blk, bs);
@@ -381,18 +389,18 @@ static int init_dirty_bitmap_migration(void) 
            continue;

        }



        if (add_bitmaps_to_list(bs, bdrv_get_node_name(bs))) {

        if (add_bitmaps_to_list(s, bs, bdrv_get_node_name(bs))) {

            goto fail;

        }

    }



    /* unset migration flags here, to not roll back it */

    QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) {

    QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) {

        bdrv_dirty_bitmap_skip_store(dbms->bitmap, true);

    }



    if (QSIMPLEQ_EMPTY(&dirty_bitmap_mig_state.dbms_list)) {

        dirty_bitmap_mig_state.no_bitmaps = true;

    if (QSIMPLEQ_EMPTY(&s->dbms_list)) {

        s->no_bitmaps = true;

    }



    g_hash_table_destroy(handled_by_blk);
@@ -401,18 +409,19 @@ static int init_dirty_bitmap_migration(void) 


fail:

    g_hash_table_destroy(handled_by_blk);

    dirty_bitmap_do_save_cleanup();

    dirty_bitmap_do_save_cleanup(s);



    return -1;

}



/* Called with no lock taken.  */

static void bulk_phase_send_chunk(QEMUFile *f, SaveBitmapState *dbms)

static void bulk_phase_send_chunk(QEMUFile *f, DBMSaveState *s,

                                  SaveBitmapState *dbms)

{

    uint32_t nr_sectors = MIN(dbms->total_sectors - dbms->cur_sector,

                             dbms->sectors_per_chunk);



    send_bitmap_bits(f, dbms, dbms->cur_sector, nr_sectors);

    send_bitmap_bits(f, s, dbms, dbms->cur_sector, nr_sectors);



    dbms->cur_sector += nr_sectors;

    if (dbms->cur_sector >= dbms->total_sectors) {
@@ -421,61 +430,66 @@ static void bulk_phase_send_chunk(QEMUFile *f, SaveBitmapState *dbms) 
}



/* Called with no lock taken.  */

static void bulk_phase(QEMUFile *f, bool limit)

static void bulk_phase(QEMUFile *f, DBMSaveState *s, bool limit)

{

    SaveBitmapState *dbms;



    QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) {

    QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) {

        while (!dbms->bulk_completed) {

            bulk_phase_send_chunk(f, dbms);

            bulk_phase_send_chunk(f, s, dbms);

            if (limit && qemu_file_rate_limit(f)) {

                return;

            }

        }

    }



    dirty_bitmap_mig_state.bulk_completed = true;

    s->bulk_completed = true;

}



/* for SaveVMHandlers */

static void dirty_bitmap_save_cleanup(void *opaque)

{

    dirty_bitmap_do_save_cleanup();

    DBMSaveState *s = &((DBMState *)opaque)->save;



    dirty_bitmap_do_save_cleanup(s);

}



static int dirty_bitmap_save_iterate(QEMUFile *f, void *opaque)

{

    DBMSaveState *s = &((DBMState *)opaque)->save;



    trace_dirty_bitmap_save_iterate(migration_in_postcopy());



    if (migration_in_postcopy() && !dirty_bitmap_mig_state.bulk_completed) {

        bulk_phase(f, true);

    if (migration_in_postcopy() && !s->bulk_completed) {

        bulk_phase(f, s, true);

    }



    qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS);



    return dirty_bitmap_mig_state.bulk_completed;

    return s->bulk_completed;

}



/* Called with iothread lock taken.  */



static int dirty_bitmap_save_complete(QEMUFile *f, void *opaque)

{

    DBMSaveState *s = &((DBMState *)opaque)->save;

    SaveBitmapState *dbms;

    trace_dirty_bitmap_save_complete_enter();



    if (!dirty_bitmap_mig_state.bulk_completed) {

        bulk_phase(f, false);

    if (!s->bulk_completed) {

        bulk_phase(f, s, false);

    }



    QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) {

        send_bitmap_complete(f, dbms);

    QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) {

        send_bitmap_complete(f, s, dbms);

    }



    qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS);



    trace_dirty_bitmap_save_complete_finish();



    dirty_bitmap_do_save_cleanup();

    dirty_bitmap_save_cleanup(opaque);

    return 0;

}
@@ -485,12 +499,13 @@ static void dirty_bitmap_save_pending(QEMUFile *f, void *opaque, 
                                      uint64_t *res_compatible,

                                      uint64_t *res_postcopy_only)

{

    DBMSaveState *s = &((DBMState *)opaque)->save;

    SaveBitmapState *dbms;

    uint64_t pending = 0;



    qemu_mutex_lock_iothread();



    QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) {

    QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) {

        uint64_t gran = bdrv_dirty_bitmap_granularity(dbms->bitmap);

        uint64_t sectors = dbms->bulk_completed ? 0 :

                           dbms->total_sectors - dbms->cur_sector;
@@ -549,7 +564,7 @@ static int dirty_bitmap_load_start(QEMUFile *f, DBMLoadState *s) 
        b->bs = s->bs;

        b->bitmap = s->bitmap;

        b->migrated = false;

        enabled_bitmaps = g_slist_prepend(enabled_bitmaps, b);

        s->enabled_bitmaps = g_slist_prepend(s->enabled_bitmaps, b);

    }



    return 0;
@@ -557,11 +572,12 @@ static int dirty_bitmap_load_start(QEMUFile *f, DBMLoadState *s) 


void dirty_bitmap_mig_before_vm_start(void)

{

    DBMLoadState *s = &dbm_state.load;

    GSList *item;



    qemu_mutex_lock(&finish_lock);

    qemu_mutex_lock(&s->finish_lock);



    for (item = enabled_bitmaps; item; item = g_slist_next(item)) {

    for (item = s->enabled_bitmaps; item; item = g_slist_next(item)) {

        LoadBitmapState *b = item->data;



        if (b->migrated) {
@@ -573,10 +589,10 @@ void dirty_bitmap_mig_before_vm_start(void) 
        g_free(b);

    }



    g_slist_free(enabled_bitmaps);

    enabled_bitmaps = NULL;

    g_slist_free(s->enabled_bitmaps);

    s->enabled_bitmaps = NULL;



    qemu_mutex_unlock(&finish_lock);

    qemu_mutex_unlock(&s->finish_lock);

}



static void dirty_bitmap_load_complete(QEMUFile *f, DBMLoadState *s)
@@ -585,9 +601,9 @@ static void dirty_bitmap_load_complete(QEMUFile *f, DBMLoadState *s) 
    trace_dirty_bitmap_load_complete();

    bdrv_dirty_bitmap_deserialize_finish(s->bitmap);



    qemu_mutex_lock(&finish_lock);

    qemu_mutex_lock(&s->finish_lock);



    for (item = enabled_bitmaps; item; item = g_slist_next(item)) {

    for (item = s->enabled_bitmaps; item; item = g_slist_next(item)) {

        LoadBitmapState *b = item->data;



        if (b->bitmap == s->bitmap) {
@@ -598,7 +614,7 @@ static void dirty_bitmap_load_complete(QEMUFile *f, DBMLoadState *s) 


    if (bdrv_dirty_bitmap_has_successor(s->bitmap)) {

        bdrv_dirty_bitmap_lock(s->bitmap);

        if (enabled_bitmaps == NULL) {

        if (s->enabled_bitmaps == NULL) {

            /* in postcopy */

            bdrv_reclaim_dirty_bitmap_locked(s->bitmap, &error_abort);

            bdrv_enable_dirty_bitmap_locked(s->bitmap);
@@ -617,7 +633,7 @@ static void dirty_bitmap_load_complete(QEMUFile *f, DBMLoadState *s) 
        bdrv_dirty_bitmap_unlock(s->bitmap);

    }



    qemu_mutex_unlock(&finish_lock);

    qemu_mutex_unlock(&s->finish_lock);

}



static int dirty_bitmap_load_bits(QEMUFile *f, DBMLoadState *s)
@@ -714,7 +730,7 @@ static int dirty_bitmap_load_header(QEMUFile *f, DBMLoadState *s) 


static int dirty_bitmap_load(QEMUFile *f, void *opaque, int version_id)

{

    static DBMLoadState s;

    DBMLoadState *s = &((DBMState *)opaque)->load;

    int ret = 0;



    trace_dirty_bitmap_load_enter();
@@ -724,17 +740,17 @@ static int dirty_bitmap_load(QEMUFile *f, void *opaque, int version_id) 
    }



    do {

        ret = dirty_bitmap_load_header(f, &s);

        ret = dirty_bitmap_load_header(f, s);

        if (ret < 0) {

            return ret;

        }



        if (s.flags & DIRTY_BITMAP_MIG_FLAG_START) {

            ret = dirty_bitmap_load_start(f, &s);

        } else if (s.flags & DIRTY_BITMAP_MIG_FLAG_COMPLETE) {

            dirty_bitmap_load_complete(f, &s);

        } else if (s.flags & DIRTY_BITMAP_MIG_FLAG_BITS) {

            ret = dirty_bitmap_load_bits(f, &s);

        if (s->flags & DIRTY_BITMAP_MIG_FLAG_START) {

            ret = dirty_bitmap_load_start(f, s);

        } else if (s->flags & DIRTY_BITMAP_MIG_FLAG_COMPLETE) {

            dirty_bitmap_load_complete(f, s);

        } else if (s->flags & DIRTY_BITMAP_MIG_FLAG_BITS) {

            ret = dirty_bitmap_load_bits(f, s);

        }



        if (!ret) {
@@ -744,7 +760,7 @@ static int dirty_bitmap_load(QEMUFile *f, void *opaque, int version_id) 
        if (ret) {

            return ret;

        }

    } while (!(s.flags & DIRTY_BITMAP_MIG_FLAG_EOS));

    } while (!(s->flags & DIRTY_BITMAP_MIG_FLAG_EOS));



    trace_dirty_bitmap_load_success();

    return 0;
@@ -752,13 +768,14 @@ static int dirty_bitmap_load(QEMUFile *f, void *opaque, int version_id) 


static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque)

{

    DBMSaveState *s = &((DBMState *)opaque)->save;

    SaveBitmapState *dbms = NULL;

    if (init_dirty_bitmap_migration() < 0) {

    if (init_dirty_bitmap_migration(s) < 0) {

        return -1;

    }



    QSIMPLEQ_FOREACH(dbms, &dirty_bitmap_mig_state.dbms_list, entry) {

        send_bitmap_start(f, dbms);

    QSIMPLEQ_FOREACH(dbms, &s->dbms_list, entry) {

        send_bitmap_start(f, s, dbms);

    }

    qemu_put_bitmap_flags(f, DIRTY_BITMAP_MIG_FLAG_EOS);
@@ -767,7 +784,9 @@ static int dirty_bitmap_save_setup(QEMUFile *f, void *opaque) 


static bool dirty_bitmap_is_active(void *opaque)

{

    return migrate_dirty_bitmaps() && !dirty_bitmap_mig_state.no_bitmaps;

    DBMSaveState *s = &((DBMState *)opaque)->save;



    return migrate_dirty_bitmaps() && !s->no_bitmaps;

}



static bool dirty_bitmap_is_active_iterate(void *opaque)
@@ -795,10 +814,10 @@ static SaveVMHandlers savevm_dirty_bitmap_handlers = { 


void dirty_bitmap_mig_init(void)

{

    QSIMPLEQ_INIT(&dirty_bitmap_mig_state.dbms_list);

    qemu_mutex_init(&finish_lock);

    QSIMPLEQ_INIT(&dbm_state.save.dbms_list);

    qemu_mutex_init(&dbm_state.load.finish_lock);



    register_savevm_live("dirty-bitmap", 0, 1,

                         &savevm_dirty_bitmap_handlers,

                         &dirty_bitmap_mig_state);

                         &dbm_state);

}