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stream: move rate limiting to a separate header file

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Make the code reusable.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Paolo Bonzini 2012-05-09 16:09:46 +02:00 committed by Kevin Wolf
parent 188a7bbf94
commit 6ef228fc0d
2 changed files with 50 additions and 29 deletions
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31
block/stream.c
View File

@ -13,6 +13,7 @@
#include "trace.h"
#include "block_int.h"
#include "qemu/ratelimit.h"
enum {
/*
@ -25,34 +26,6 @@ enum {
#define SLICE_TIME 100000000ULL /* ns */
typedef struct {
int64_t next_slice_time;
uint64_t slice_quota;
uint64_t dispatched;
} RateLimit;
static int64_t ratelimit_calculate_delay(RateLimit *limit, uint64_t n)
{
int64_t now = qemu_get_clock_ns(rt_clock);
if (limit->next_slice_time < now) {
limit->next_slice_time = now + SLICE_TIME;
limit->dispatched = 0;
}
if (limit->dispatched == 0 || limit->dispatched + n <= limit->slice_quota) {
limit->dispatched += n;
return 0;
} else {
limit->dispatched = n;
return limit->next_slice_time - now;
}
}
static void ratelimit_set_speed(RateLimit *limit, uint64_t speed)
{
limit->slice_quota = speed / (1000000000ULL / SLICE_TIME);
}
typedef struct StreamBlockJob {
BlockJob common;
RateLimit limit;
@ -198,7 +171,7 @@ static void stream_set_speed(BlockJob *job, int64_t speed, Error **errp)
error_set(errp, QERR_INVALID_PARAMETER, "speed");
return;
}
ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE);
ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME);
}
static BlockJobType stream_job_type = {

48
include/qemu/ratelimit.h Normal file
View File

@ -0,0 +1,48 @@
/*
* Ratelimiting calculations
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#ifndef QEMU_RATELIMIT_H
#define QEMU_RATELIMIT_H 1
typedef struct {
int64_t next_slice_time;
uint64_t slice_quota;
uint64_t slice_ns;
uint64_t dispatched;
} RateLimit;
static inline int64_t ratelimit_calculate_delay(RateLimit *limit, uint64_t n)
{
int64_t now = qemu_get_clock_ns(rt_clock);
if (limit->next_slice_time < now) {
limit->next_slice_time = now + limit->slice_ns;
limit->dispatched = 0;
}
if (limit->dispatched == 0 || limit->dispatched + n <= limit->slice_quota) {
limit->dispatched += n;
return 0;
} else {
limit->dispatched = n;
return limit->next_slice_time - now;
}
}
static inline void ratelimit_set_speed(RateLimit *limit, uint64_t speed,
uint64_t slice_ns)
{
limit->slice_ns = slice_ns;
limit->slice_quota = ((double)speed * 1000000000ULL) / slice_ns;
}
#endif