On Tue, Aug 9, 2011 at 11:19 PM, Stefan Hajnoczi <stefanha@xxxxxxxxx> wrote:
> On Tue, Aug 9, 2011 at 5:17 AM, Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx> wrote:
>> Note:
>> 1.) When bps/iops limits are specified to a small value such as 511 bytes/s, this VM will hang up. We are considering how to handle this senario.
>
> If an I/O request is larger than the limit itself then I think we
> should let it through with a warning that the limit is too low. This
If it will print a waring, it seems to be not a nice way, the
throtting function will take no effect on this scenario.
> reflects the fact that we don't split I/O requests into smaller
> requests and the guest may give us 128 KB (or larger?) requests. In
> practice the lowest feasible limit is probably 256 KB or 512 KB.
>
>> diff --git a/block.c b/block.c
>> index 24a25d5..8fd6643 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -29,6 +29,9 @@
>> #include "module.h"
>> #include "qemu-objects.h"
>>
>> +#include "qemu-timer.h"
>> +#include "block/blk-queue.h"
>> +
>> #ifdef CONFIG_BSD
>> #include <sys/types.h>
>> #include <sys/stat.h>
>> @@ -58,6 +61,13 @@ static int bdrv_read_em(BlockDriverState *bs, int64_t sector_num,
>> static int bdrv_write_em(BlockDriverState *bs, int64_t sector_num,
>> const uint8_t *buf, int nb_sectors);
>>
>> +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, uint64_t *wait);
>> +
>> static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
>> QTAILQ_HEAD_INITIALIZER(bdrv_states);
>>
>> @@ -90,6 +100,68 @@ 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;
>> + bs->req_from_queue = false;
>> +
>> + if (bs->block_queue) {
>> + qemu_block_queue_flush(bs->block_queue);
>> + qemu_del_block_queue(bs->block_queue);
>
> When you fix the acb lifecycle in block-queue.c this will no longer be
> safe. Requests that are dispatched still have acbs that belong to
When the request is dispatched, if it is successfully serviced, our
acb will been removed.
> this queue. It is simplest to keep the queue for the lifetime of the
> BlockDriverState - it's just a list so it doesn't take up much memory.
I more prefer to removing this queue, even though it is simple and
harmless to let it exist.
>
>> + }
>> +
>> + if (bs->block_timer) {
>> + qemu_del_timer(bs->block_timer);
>> + qemu_free_timer(bs->block_timer);
>
> To prevent double frees:
>
> bs->block_timer = NULL;
Can qemu_free_timer() not ensure that it is NULL? This is not necessary.:)
>
>> + }
>> +
>> + bs->slice_start[0] = 0;
>> + bs->slice_start[1] = 0;
>> +
>> + bs->slice_end[0] = 0;
>> + bs->slice_end[1] = 0;
>> +}
>> +
>> +static void bdrv_block_timer(void *opaque)
>> +{
>> + BlockDriverState *bs = opaque;
>> + BlockQueue *queue = bs->block_queue;
>> +
>> + qemu_block_queue_flush(queue);
>> +}
>> +
>> +void bdrv_io_limits_enable(BlockDriverState *bs)
>> +{
>> + bs->req_from_queue = false;
>> +
>> + bs->block_queue = qemu_new_block_queue();
>> + bs->block_timer = qemu_new_timer_ns(vm_clock, bdrv_block_timer, bs);
>> +
>> + bs->slice_start[BLOCK_IO_LIMIT_READ] = qemu_get_clock_ns(vm_clock);
>> + bs->slice_start[BLOCK_IO_LIMIT_WRITE] = qemu_get_clock_ns(vm_clock);
>> +
>> + bs->slice_end[BLOCK_IO_LIMIT_READ] =
>> + qemu_get_clock_ns(vm_clock) + BLOCK_IO_SLICE_TIME;
>> + bs->slice_end[BLOCK_IO_LIMIT_WRITE] =
>> + qemu_get_clock_ns(vm_clock) + BLOCK_IO_SLICE_TIME;
>
> The slice times could just be initialized to 0 here. When
> bdrv_exceed_io_limits() is called it will start a new slice.
The result should be same as current method even though they are set to ZERO.
>
>> +}
>> +
>> +bool bdrv_io_limits_enabled(BlockDriverState *bs)
>> +{
>> + BlockIOLimit *io_limits = &bs->io_limits;
>> + if ((io_limits->bps[BLOCK_IO_LIMIT_READ] == 0)
>> + && (io_limits->bps[BLOCK_IO_LIMIT_WRITE] == 0)
>> + && (io_limits->bps[BLOCK_IO_LIMIT_TOTAL] == 0)
>> + && (io_limits->iops[BLOCK_IO_LIMIT_READ] == 0)
>> + && (io_limits->iops[BLOCK_IO_LIMIT_WRITE] == 0)
>> + && (io_limits->iops[BLOCK_IO_LIMIT_TOTAL] == 0)) {
>> + return false;
>> + }
>> +
>> + return true;
>> +}
>> +
>> /* check if the path starts with "<protocol>:" */
>> static int path_has_protocol(const char *path)
>> {
>> @@ -642,6 +714,11 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
>> bs->change_cb(bs->change_opaque, CHANGE_MEDIA);
>> }
>>
>> + /* throttling disk I/O limits */
>> + if (bs->io_limits_enabled) {
>> + bdrv_io_limits_enable(bs);
>> + }
>> +
>> return 0;
>>
>> unlink_and_fail:
>> @@ -680,6 +757,16 @@ void bdrv_close(BlockDriverState *bs)
>> if (bs->change_cb)
>> bs->change_cb(bs->change_opaque, CHANGE_MEDIA);
>> }
>> +
>> + /* throttling disk I/O limits */
>> + if (bs->block_queue) {
>> + qemu_del_block_queue(bs->block_queue);
>> + }
>> +
>> + if (bs->block_timer) {
>> + qemu_del_timer(bs->block_timer);
>> + qemu_free_timer(bs->block_timer);
>> + }
>> }
>>
>> void bdrv_close_all(void)
>> @@ -1312,6 +1399,15 @@ void bdrv_get_geometry_hint(BlockDriverState *bs,
>> *psecs = bs->secs;
>> }
>>
>> +/* throttling disk io limits */
>> +void bdrv_set_io_limits(BlockDriverState *bs,
>> + BlockIOLimit *io_limits)
>> +{
>> + memset(&bs->io_limits, 0, sizeof(BlockIOLimit));
>
> The assignment from *io_limits overwrites all of bs->io_limits, the
> memset() can be removed.
OK.
>
>> + bs->io_limits = *io_limits;
>> + bs->io_limits_enabled = bdrv_io_limits_enabled(bs);
>> +}
>> +
>> /* Recognize floppy formats */
>> typedef struct FDFormat {
>> FDriveType drive;
>> @@ -1707,6 +1803,16 @@ static void bdrv_print_dict(QObject *obj, void *opaque)
>> qdict_get_bool(qdict, "ro"),
>> qdict_get_str(qdict, "drv"),
>> qdict_get_bool(qdict, "encrypted"));
>> +
>> + monitor_printf(mon, " bps=%" PRId64 " bps_rd=%" PRId64
>> + " bps_wr=%" PRId64 " iops=%" PRId64
>> + " iops_rd=%" PRId64 " iops_wr=%" PRId64,
>> + qdict_get_int(qdict, "bps"),
>> + qdict_get_int(qdict, "bps_rd"),
>> + qdict_get_int(qdict, "bps_wr"),
>> + qdict_get_int(qdict, "iops"),
>> + qdict_get_int(qdict, "iops_rd"),
>> + qdict_get_int(qdict, "iops_wr"));
>> } else {
>> monitor_printf(mon, " [not inserted]");
>> }
>> @@ -1739,10 +1845,22 @@ void bdrv_info(Monitor *mon, QObject **ret_data)
>> QDict *bs_dict = qobject_to_qdict(bs_obj);
>>
>> obj = qobject_from_jsonf("{ 'file': %s, 'ro': %i, 'drv': %s, "
>> - "'encrypted': %i }",
>> + "'encrypted': %i, "
>> + "'bps': %" PRId64 ","
>> + "'bps_rd': %" PRId64 ","
>> + "'bps_wr': %" PRId64 ","
>> + "'iops': %" PRId64 ","
>> + "'iops_rd': %" PRId64 ","
>> + "'iops_wr': %" PRId64 "}",
>> bs->filename, bs->read_only,
>> bs->drv->format_name,
>> - bdrv_is_encrypted(bs));
>> + bdrv_is_encrypted(bs),
>> + bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL],
>> + bs->io_limits.bps[BLOCK_IO_LIMIT_READ],
>> + bs->io_limits.bps[BLOCK_IO_LIMIT_WRITE],
>> + bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL],
>> + bs->io_limits.iops[BLOCK_IO_LIMIT_READ],
>> + bs->io_limits.iops[BLOCK_IO_LIMIT_WRITE]);
>> if (bs->backing_file[0] != '\0') {
>> QDict *qdict = qobject_to_qdict(obj);
>> qdict_put(qdict, "backing_file",
>> @@ -2111,6 +2229,165 @@ char *bdrv_snapshot_dump(char *buf, int buf_size, QEMUSnapshotInfo *sn)
>> return buf;
>> }
>>
>> +static bool bdrv_exceed_bps_limits(BlockDriverState *bs, int nb_sectors,
>> + bool is_write, double elapsed_time, uint64_t *wait) {
>> + uint64_t bps_limit = 0;
>> + double bytes_limit, bytes_disp, bytes_res;
>> + double slice_time, wait_time;
>> +
>> + if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL]) {
>> + bps_limit = bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL];
>> + } else if (bs->io_limits.bps[is_write]) {
>> + bps_limit = bs->io_limits.bps[is_write];
>> + } else {
>> + if (wait) {
>> + *wait = 0;
>> + }
>> +
>> + return false;
>> + }
>> +
>> + slice_time = bs->slice_end[is_write] - bs->slice_start[is_write];
>> + slice_time /= (BLOCK_IO_SLICE_TIME * 10.0);
>> + bytes_limit = bps_limit * slice_time;
>> + bytes_disp = bs->io_disps.bytes[is_write];
>> + if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL]) {
>> + bytes_disp += bs->io_disps.bytes[!is_write];
>> + }
>> +
>> + bytes_res = (unsigned) nb_sectors * BDRV_SECTOR_SIZE;
>> +
>> + if (bytes_disp + bytes_res <= bytes_limit) {
>> + if (wait) {
>> + *wait = 0;
>> + }
>> +
>> + return false;
>> + }
>> +
>> + /* Calc approx time to dispatch */
>> + wait_time = (bytes_disp + bytes_res) / bps_limit - elapsed_time;
>> +
>> + if (wait) {
>> + *wait = wait_time * BLOCK_IO_SLICE_TIME * 10;
>> + }
>> +
>> + return true;
>> +}
>> +
>> +static bool bdrv_exceed_iops_limits(BlockDriverState *bs, bool is_write,
>> + double elapsed_time, uint64_t *wait) {
>> + uint64_t iops_limit = 0;
>> + double ios_limit, ios_disp;
>> + double slice_time, wait_time;
>> +
>> + if (bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) {
>> + iops_limit = bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL];
>> + } else if (bs->io_limits.iops[is_write]) {
>> + iops_limit = bs->io_limits.iops[is_write];
>> + } else {
>> + if (wait) {
>> + *wait = 0;
>> + }
>> +
>> + return false;
>> + }
>> +
>> + slice_time = bs->slice_end[is_write] - bs->slice_start[is_write];
>> + slice_time /= (BLOCK_IO_SLICE_TIME * 10.0);
>> + ios_limit = iops_limit * slice_time;
>> + ios_disp = bs->io_disps.ios[is_write];
>> + if (bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) {
>> + ios_disp += bs->io_disps.ios[!is_write];
>> + }
>> +
>> + if (ios_disp + 1 <= ios_limit) {
>> + if (wait) {
>> + *wait = 0;
>> + }
>> +
>> + return false;
>> + }
>> +
>> + /* Calc approx time to dispatch */
>> + wait_time = (ios_disp + 1) / iops_limit;
>> + if (wait_time > elapsed_time) {
>> + wait_time = wait_time - elapsed_time;
>> + } else {
>> + wait_time = 0;
>> + }
>> +
>> + if (wait) {
>> + *wait = wait_time * BLOCK_IO_SLICE_TIME * 10;
>> + }
>> +
>> + return true;
>> +}
>> +
>> +static bool bdrv_exceed_io_limits(BlockDriverState *bs, int nb_sectors,
>> + bool is_write, uint64_t *wait) {
>> + int64_t real_time, real_slice;
>> + uint64_t bps_wait = 0, iops_wait = 0, max_wait;
>> + double elapsed_time;
>> + int bps_ret, iops_ret;
>> +
>> + real_time = qemu_get_clock_ns(vm_clock);
>
> Please call it 'now' instead of 'real_time'. There is a "real-time
> clock" called rt_clock and this variable name could be confusing.
OK.
>
>> + real_slice = bs->slice_end[is_write] - bs->slice_start[is_write];
>> + if ((bs->slice_start[is_write] < real_time)
>> + && (bs->slice_end[is_write] > real_time)) {
>> + bs->slice_end[is_write] = real_time + BLOCK_IO_SLICE_TIME;
>> + } else {
>> + bs->slice_start[is_write] = real_time;
>> + bs->slice_end[is_write] = real_time + BLOCK_IO_SLICE_TIME;
>> +
>> + bs->io_disps.bytes[is_write] = 0;
>> + bs->io_disps.bytes[!is_write] = 0;
>> +
>> + bs->io_disps.ios[is_write] = 0;
>> + bs->io_disps.ios[!is_write] = 0;
>> + }
>> +
>> + /* If a limit was exceeded, immediately queue this request */
>> + if (!bs->req_from_queue
>> + && !QTAILQ_EMPTY(&bs->block_queue->requests)) {
>
> bs->req_from_queue seems to be a way to prevent requests
> unconditionally being queued during flush. Please define a BlockQueue
> interface instead, something like this:
>
> /* If a limit was exceeded, immediately queue this request */
> if (qemu_block_queue_has_pending(bs->block_queue)) {
>
> Then req_from_queue can be hidden inside BlockQueue. I'd rename it to
> bool flushing. qemu_block_queue_flush() will set it to true at the
> start of the function and false at the end of the function.
Good advice.
>
>> + if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL]
>> + || bs->io_limits.bps[is_write] || bs->io_limits.iops[is_write]
>> + || bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) {
>> + if (wait) {
>> + *wait = 0;
>
> No estimated wait time? That's okay only if we stop setting the timer
> whenever a request is queued - more comments about this below.
Yeah.
>
>> + }
>> +
>> + return true;
>> + }
>> + }
>> +
>> + elapsed_time = real_time - bs->slice_start[is_write];
>> + elapsed_time /= (BLOCK_IO_SLICE_TIME * 10.0);
>
> Why * 10.0?
elapsed_time currently is in ns, and it need to be translated into a
floating value in minutes.
>
>> +
>> + bps_ret = bdrv_exceed_bps_limits(bs, nb_sectors,
>> + is_write, elapsed_time, &bps_wait);
>> + iops_ret = bdrv_exceed_iops_limits(bs, is_write,
>> + elapsed_time, &iops_wait);
>> + if (bps_ret || iops_ret) {
>> + max_wait = bps_wait > iops_wait ? bps_wait : iops_wait;
>> + if (wait) {
>> + *wait = max_wait;
>> + }
>> +
>> + real_time = qemu_get_clock_ns(vm_clock);
>> + if (bs->slice_end[is_write] < real_time + max_wait) {
>> + bs->slice_end[is_write] = real_time + max_wait;
>> + }
>
> Why is this necessary? We have already extended the slice at the top
> of the function.
Here it will adjust this end of slice time based on
bdrv_exceed_bps_limits(bdrv_exceed_iops_limits).
This will be more accurate.
>
>> +
>> + return true;
>> + }
>> +
>> + if (wait) {
>> + *wait = 0;
>> + }
>> +
>> + return false;
>> +}
>>
>> /**************************************************************/
>> /* async I/Os */
>> @@ -2121,13 +2398,28 @@ BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num,
>> {
>> BlockDriver *drv = bs->drv;
>> BlockDriverAIOCB *ret;
>> + uint64_t wait_time = 0;
>>
>> trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque);
>>
>> - if (!drv)
>> - return NULL;
>> - if (bdrv_check_request(bs, sector_num, nb_sectors))
>> + if (!drv || bdrv_check_request(bs, sector_num, nb_sectors)) {
>> + if (bs->io_limits_enabled) {
>> + bs->req_from_queue = false;
>> + }
>> return NULL;
>> + }
>> +
>> + /* throttling disk read I/O */
>> + if (bs->io_limits_enabled) {
>> + if (bdrv_exceed_io_limits(bs, nb_sectors, false, &wait_time)) {
>> + ret = qemu_block_queue_enqueue(bs->block_queue, bs, bdrv_aio_readv,
>> + sector_num, qiov, nb_sectors, cb, opaque);
>> + qemu_mod_timer(bs->block_timer,
>> + wait_time + qemu_get_clock_ns(vm_clock));
>
> If a guest keeps sending I/O requests, say every millisecond, then we
> will delay dispatch forever. In practice we hope the storage
> interface (virtio-blk, LSI SCSI, etc) has a resource limit that
> prevents this. But the point remains that this delays requests that
> should be dispatched for too long. Once the timer has been set we
> should not set it again.
Can you elaborate this?
>
>> + bs->req_from_queue = false;
>> + return ret;
>> + }
>> + }
>>
>> ret = drv->bdrv_aio_readv(bs, sector_num, qiov, nb_sectors,
>> cb, opaque);
>> @@ -2136,6 +2428,16 @@ BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num,
>> /* Update stats even though technically transfer has not happened. */
>> bs->rd_bytes += (unsigned) nb_sectors * BDRV_SECTOR_SIZE;
>> bs->rd_ops ++;
>> +
>> + if (bs->io_limits_enabled) {
>> + bs->io_disps.bytes[BLOCK_IO_LIMIT_READ] +=
>> + (unsigned) nb_sectors * BDRV_SECTOR_SIZE;
>> + bs->io_disps.ios[BLOCK_IO_LIMIT_READ]++;
>> + }
>> + }
>> +
>> + if (bs->io_limits_enabled) {
>> + bs->req_from_queue = false;
>> }
>>
>> return ret;
>> @@ -2184,15 +2486,18 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num,
>> BlockDriver *drv = bs->drv;
>> BlockDriverAIOCB *ret;
>> BlockCompleteData *blk_cb_data;
>> + uint64_t wait_time = 0;
>>
>> trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque);
>>
>> - if (!drv)
>> - return NULL;
>> - if (bs->read_only)
>> - return NULL;
>> - if (bdrv_check_request(bs, sector_num, nb_sectors))
>> + if (!drv || bs->read_only
>> + || bdrv_check_request(bs, sector_num, nb_sectors)) {
>> + if (bs->io_limits_enabled) {
>> + bs->req_from_queue = false;
>> + }
>> +
>> return NULL;
>> + }
>>
>> if (bs->dirty_bitmap) {
>> blk_cb_data = blk_dirty_cb_alloc(bs, sector_num, nb_sectors, cb,
>> @@ -2201,6 +2506,18 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num,
>> opaque = blk_cb_data;
>> }
>>
>> + /* throttling disk write I/O */
>> + if (bs->io_limits_enabled) {
>> + if (bdrv_exceed_io_limits(bs, nb_sectors, true, &wait_time)) {
>> + ret = qemu_block_queue_enqueue(bs->block_queue, bs, bdrv_aio_writev,
>> + sector_num, qiov, nb_sectors, cb, opaque);
>> + qemu_mod_timer(bs->block_timer,
>> + wait_time + qemu_get_clock_ns(vm_clock));
>> + bs->req_from_queue = false;
>> + return ret;
>> + }
>> + }
>> +
>> ret = drv->bdrv_aio_writev(bs, sector_num, qiov, nb_sectors,
>> cb, opaque);
>>
>> @@ -2211,6 +2528,16 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num,
>> if (bs->wr_highest_sector < sector_num + nb_sectors - 1) {
>> bs->wr_highest_sector = sector_num + nb_sectors - 1;
>> }
>> +
>> + if (bs->io_limits_enabled) {
>> + bs->io_disps.bytes[BLOCK_IO_LIMIT_WRITE] +=
>> + (unsigned) nb_sectors * BDRV_SECTOR_SIZE;
>> + bs->io_disps.ios[BLOCK_IO_LIMIT_WRITE]++;
>> + }
>> + }
>> +
>> + if (bs->io_limits_enabled) {
>> + bs->req_from_queue = false;
>> }
>>
>> return ret;
>> diff --git a/block.h b/block.h
>> index 859d1d9..3d02902 100644
>> --- a/block.h
>> +++ b/block.h
>> @@ -57,6 +57,11 @@ void bdrv_info(Monitor *mon, QObject **ret_data);
>> void bdrv_stats_print(Monitor *mon, const QObject *data);
>> void bdrv_info_stats(Monitor *mon, QObject **ret_data);
>>
>> +/* disk I/O throttling */
>> +void bdrv_io_limits_enable(BlockDriverState *bs);
>> +void bdrv_io_limits_disable(BlockDriverState *bs);
>> +bool bdrv_io_limits_enabled(BlockDriverState *bs);
>> +
>> void bdrv_init(void);
>> void bdrv_init_with_whitelist(void);
>> BlockDriver *bdrv_find_protocol(const char *filename);
>> @@ -97,7 +102,6 @@ int bdrv_change_backing_file(BlockDriverState *bs,
>> const char *backing_file, const char *backing_fmt);
>> void bdrv_register(BlockDriver *bdrv);
>>
>> -
>> typedef struct BdrvCheckResult {
>> int corruptions;
>> int leaks;
>> diff --git a/block_int.h b/block_int.h
>> index 1e265d2..a4cd458 100644
>> --- a/block_int.h
>> +++ b/block_int.h
>> @@ -27,10 +27,17 @@
>> #include "block.h"
>> #include "qemu-option.h"
>> #include "qemu-queue.h"
>> +#include "block/blk-queue.h"
>>
>> #define BLOCK_FLAG_ENCRYPT 1
>> #define BLOCK_FLAG_COMPAT6 4
>>
>> +#define BLOCK_IO_LIMIT_READ 0
>> +#define BLOCK_IO_LIMIT_WRITE 1
>> +#define BLOCK_IO_LIMIT_TOTAL 2
>> +
>> +#define BLOCK_IO_SLICE_TIME 100000000
>
> Please add a comment indicating the units: /* nanoseconds */
>
>> +
>> #define BLOCK_OPT_SIZE "size"
>> #define BLOCK_OPT_ENCRYPT "encryption"
>> #define BLOCK_OPT_COMPAT6 "compat6"
>> @@ -46,6 +53,16 @@ typedef struct AIOPool {
>> BlockDriverAIOCB *free_aiocb;
>> } AIOPool;
>>
>> +typedef struct BlockIOLimit {
>> + uint64_t bps[3];
>> + uint64_t iops[3];
>> +} BlockIOLimit;
>> +
>> +typedef struct BlockIODisp {
>> + uint64_t bytes[2];
>> + uint64_t ios[2];
>> +} BlockIODisp;
>> +
>> struct BlockDriver {
>> const char *format_name;
>> int instance_size;
>> @@ -175,6 +192,16 @@ struct BlockDriverState {
>>
>> void *sync_aiocb;
>>
>> + /* the time for latest disk I/O */
>> + int64_t slice_start[2];
>> + int64_t slice_end[2];
>> + BlockIOLimit io_limits;
>> + BlockIODisp io_disps;
>> + BlockQueue *block_queue;
>> + QEMUTimer *block_timer;
>> + bool io_limits_enabled;
>> + bool req_from_queue;
>> +
>> /* I/O stats (display with "info blockstats"). */
>> uint64_t rd_bytes;
>> uint64_t wr_bytes;
>> @@ -222,6 +249,9 @@ void qemu_aio_release(void *p);
>>
>> void *qemu_blockalign(BlockDriverState *bs, size_t size);
>>
>> +void bdrv_set_io_limits(BlockDriverState *bs,
>> + BlockIOLimit *io_limits);
>> +
>> #ifdef _WIN32
>> int is_windows_drive(const char *filename);
>> #endif
>> --
>> 1.7.2.3
>>
>> --
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>>
>
--
Regards,
Zhi Yong Wu
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