Am 02.11.2011 07:01, schrieb Zhi Yong Wu:
> Signed-off-by: Zhi Yong Wu <wu...@linux.vnet.ibm.com>
> Signed-off-by: Stefan Hajnoczi <stefa...@linux.vnet.ibm.com>
> ---
> block.c | 233
> +++++++++++++++++++++++++++++++++++++++++++++++--
> block.h | 1 +
> block_int.h | 1 +
> qemu-coroutine-lock.c | 8 ++
> qemu-coroutine.h | 6 ++
> 5 files changed, 242 insertions(+), 7 deletions(-)
>
> diff --git a/block.c b/block.c
> index c70f86d..440e889 100644
> --- a/block.c
> +++ b/block.c
> @@ -74,6 +74,13 @@ static BlockDriverAIOCB
> *bdrv_co_aio_rw_vector(BlockDriverState *bs,
> bool is_write);
> static void coroutine_fn bdrv_co_do_rw(void *opaque);
>
> +static bool bdrv_exceed_bps_limits(BlockDriverState *bs, int nb_sectors,
> + bool is_write, double elapsed_time, uint64_t *wait);
> +static bool bdrv_exceed_iops_limits(BlockDriverState *bs, bool is_write,
> + double elapsed_time, uint64_t *wait);
> +static bool bdrv_exceed_io_limits(BlockDriverState *bs, int nb_sectors,
> + bool is_write, int64_t *wait);
> +
> static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
> QTAILQ_HEAD_INITIALIZER(bdrv_states);
>
> @@ -107,6 +114,28 @@ int is_windows_drive(const char *filename)
> #endif
>
> /* throttling disk I/O limits */
> +void bdrv_io_limits_disable(BlockDriverState *bs)
> +{
> + bs->io_limits_enabled = false;
> +
> + if (!qemu_co_queue_empty(&bs->throttled_reqs)) {
This if is unnecessary, you can just always run the while loop.
> + while (qemu_co_queue_next(&bs->throttled_reqs));
> + }
> +
> + qemu_co_queue_init(&bs->throttled_reqs);
Why?
> +
> + if (bs->block_timer) {
> + qemu_del_timer(bs->block_timer);
> + qemu_free_timer(bs->block_timer);
> + bs->block_timer = NULL;
> + }
> +
> + bs->slice_start = 0;
> + bs->slice_end = 0;
> + bs->slice_time = 0;
> + memset(&bs->io_disps, 0, sizeof(bs->io_disps));
> +}
> +
> static void bdrv_block_timer(void *opaque)
> {
> BlockDriverState *bs = opaque;
> @@ -116,14 +145,13 @@ static void bdrv_block_timer(void *opaque)
>
> void bdrv_io_limits_enable(BlockDriverState *bs)
> {
> - bs->io_limits_enabled = true;
> qemu_co_queue_init(&bs->throttled_reqs);
> -
> - bs->block_timer = qemu_new_timer_ns(vm_clock, bdrv_block_timer, bs);
> - bs->slice_time = 5 * BLOCK_IO_SLICE_TIME;
> - bs->slice_start = qemu_get_clock_ns(vm_clock);
> - bs->slice_end = bs->slice_start + bs->slice_time;
> + bs->block_timer = qemu_new_timer_ns(vm_clock, bdrv_block_timer, bs);
> + bs->slice_time = 5 * BLOCK_IO_SLICE_TIME;
> + bs->slice_start = qemu_get_clock_ns(vm_clock);
> + bs->slice_end = bs->slice_start + bs->slice_time;
You're only changing whitespace here, right? If so, can you please use
the final version in patch 1?
> memset(&bs->io_disps, 0, sizeof(bs->io_disps));
> + bs->io_limits_enabled = true;
> }
>
> bool bdrv_io_limits_enabled(BlockDriverState *bs)
> @@ -137,6 +165,30 @@ bool bdrv_io_limits_enabled(BlockDriverState *bs)
> || io_limits->iops[BLOCK_IO_LIMIT_TOTAL];
> }
>
> +static void bdrv_io_limits_intercept(BlockDriverState *bs,
> + bool is_write, int nb_sectors)
> +{
> + int64_t wait_time = -1;
> +
> + if (!qemu_co_queue_empty(&bs->throttled_reqs)) {
> + qemu_co_queue_wait(&bs->throttled_reqs);
> + goto resume;
> + } else if (bdrv_exceed_io_limits(bs, nb_sectors, is_write, &wait_time)) {
> + qemu_mod_timer(bs->block_timer,
> + wait_time + qemu_get_clock_ns(vm_clock));
> + qemu_co_queue_wait(&bs->throttled_reqs);
> +
> +resume:
This goto construct isn't very nice. You could have avoided it with an
"else return;"
But anyway, why do you even need the else if? Can't you directly use the
while loop? The difference would be that qemu_co_queue_next() is run
even if a request is allowed without going through the queue, but would
that hurt?
> + while (bdrv_exceed_io_limits(bs, nb_sectors, is_write, &wait_time)) {
> + qemu_mod_timer(bs->block_timer,
> + wait_time + qemu_get_clock_ns(vm_clock));
> + qemu_co_queue_wait_insert_head(&bs->throttled_reqs);
Why do you want to insert at the head? Wouldn't a queue be more
appropriate than a stack?
> + }
> +
> + qemu_co_queue_next(&bs->throttled_reqs);
> + }
> +}
> +
> /* check if the path starts with "<protocol>:" */
> static int path_has_protocol(const char *path)
> {
Kevin
