Commit 42ac2144 authored by Vladimir Sementsov-Ogievskiy's avatar Vladimir Sementsov-Ogievskiy Committed by Max Reitz
Browse files

block/block-copy: refactor task creation 



Instead of just relying on the comment "Called only on full-dirty
region" in block_copy_task_create() let's move initial dirty area
search directly to block_copy_task_create(). Let's also use effective
bdrv_dirty_bitmap_next_dirty_area instead of looping through all
non-dirty clusters.

Signed-off-by: default avatarVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Message-Id: <20200429130847.28124-5-vsementsov@virtuozzo.com>
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent 1348a657

block/block-copy.c

+46 −34
Original line number Diff line number Diff line
@@ -32,6 +32,11 @@ typedef struct BlockCopyTask { 
    CoQueue wait_queue; /* coroutines blocked on this task */

} BlockCopyTask;



static int64_t task_end(BlockCopyTask *task)

{

    return task->offset + task->bytes;

}



typedef struct BlockCopyState {

    /*

     * BdrvChild objects are not owned or managed by block-copy. They are
@@ -106,17 +111,29 @@ static bool coroutine_fn block_copy_wait_one(BlockCopyState *s, int64_t offset, 
    return true;

}



/* Called only on full-dirty region */

/*

 * Search for the first dirty area in offset/bytes range and create task at

 * the beginning of it.

 */

static BlockCopyTask *block_copy_task_create(BlockCopyState *s,

                                             int64_t offset, int64_t bytes)

{

    BlockCopyTask *task = g_new(BlockCopyTask, 1);

    BlockCopyTask *task;



    if (!bdrv_dirty_bitmap_next_dirty_area(s->copy_bitmap,

                                           offset, offset + bytes,

                                           s->copy_size, &offset, &bytes))

    {

        return NULL;

    }



    /* region is dirty, so no existent tasks possible in it */

    assert(!find_conflicting_task(s, offset, bytes));



    bdrv_reset_dirty_bitmap(s->copy_bitmap, offset, bytes);

    s->in_flight_bytes += bytes;



    task = g_new(BlockCopyTask, 1);

    *task = (BlockCopyTask) {

        .s = s,

        .offset = offset,
@@ -466,6 +483,7 @@ static int coroutine_fn block_copy_dirty_clusters(BlockCopyState *s, 
{

    int ret = 0;

    bool found_dirty = false;

    int64_t end = offset + bytes;



    /*

     * block_copy() user is responsible for keeping source and target in same
@@ -479,58 +497,52 @@ static int coroutine_fn block_copy_dirty_clusters(BlockCopyState *s, 


    while (bytes) {

        g_autofree BlockCopyTask *task = NULL;

        int64_t next_zero, cur_bytes, status_bytes;

        int64_t status_bytes;



        if (!bdrv_dirty_bitmap_get(s->copy_bitmap, offset)) {

            trace_block_copy_skip(s, offset);

            offset += s->cluster_size;

            bytes -= s->cluster_size;

            continue; /* already copied */

        task = block_copy_task_create(s, offset, bytes);

        if (!task) {

            /* No more dirty bits in the bitmap */

            trace_block_copy_skip_range(s, offset, bytes);

            break;

        }

        if (task->offset > offset) {

            trace_block_copy_skip_range(s, offset, task->offset - offset);

        }



        found_dirty = true;



        cur_bytes = MIN(bytes, s->copy_size);



        next_zero = bdrv_dirty_bitmap_next_zero(s->copy_bitmap, offset,

                                                cur_bytes);

        if (next_zero >= 0) {

            assert(next_zero > offset); /* offset is dirty */

            assert(next_zero < offset + cur_bytes); /* no need to do MIN() */

            cur_bytes = next_zero - offset;

        }

        task = block_copy_task_create(s, offset, cur_bytes);



        ret = block_copy_block_status(s, offset, cur_bytes, &status_bytes);

        ret = block_copy_block_status(s, task->offset, task->bytes,

                                      &status_bytes);

        assert(ret >= 0); /* never fail */

        cur_bytes = MIN(cur_bytes, status_bytes);

        block_copy_task_shrink(task, cur_bytes);

        if (status_bytes < task->bytes) {

            block_copy_task_shrink(task, status_bytes);

        }

        if (s->skip_unallocated && !(ret & BDRV_BLOCK_ALLOCATED)) {

            block_copy_task_end(task, 0);

            progress_set_remaining(s->progress,

                                   bdrv_get_dirty_count(s->copy_bitmap) +

                                   s->in_flight_bytes);

            trace_block_copy_skip_range(s, offset, status_bytes);

            offset += status_bytes;

            bytes -= status_bytes;

            trace_block_copy_skip_range(s, task->offset, task->bytes);

            offset = task_end(task);

            bytes = end - offset;

            continue;

        }



        trace_block_copy_process(s, offset);

        trace_block_copy_process(s, task->offset);



        co_get_from_shres(s->mem, cur_bytes);

        ret = block_copy_do_copy(s, offset, cur_bytes, ret & BDRV_BLOCK_ZERO,

                                 error_is_read);

        co_put_to_shres(s->mem, cur_bytes);

        co_get_from_shres(s->mem, task->bytes);

        ret = block_copy_do_copy(s, task->offset, task->bytes,

                                 ret & BDRV_BLOCK_ZERO, error_is_read);

        co_put_to_shres(s->mem, task->bytes);

        block_copy_task_end(task, ret);

        if (ret < 0) {

            return ret;

        }



        progress_work_done(s->progress, cur_bytes);

        s->progress_bytes_callback(cur_bytes, s->progress_opaque);

        offset += cur_bytes;

        bytes -= cur_bytes;

        progress_work_done(s->progress, task->bytes);

        s->progress_bytes_callback(task->bytes, s->progress_opaque);

        offset = task_end(task);

        bytes = end - offset;

    }



    return found_dirty;