mirror of
https://github.com/openvswitch/ovs
synced 2025-08-22 09:58:01 +00:00
fd016ae3fb
Poll-loop is the core to implement main loop. It should be available in libopenvswitch. Signed-off-by: Xiao Liang <shaw.leon@gmail.com> Signed-off-by: Ben Pfaff <blp@ovn.org>
98 lines
2.8 KiB
C
98 lines
2.8 KiB
C
/*
|
|
* Copyright (c) 2012 Nicira, Inc.
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at:
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#include <config.h>
|
|
|
|
#include "openvswitch/token-bucket.h"
|
|
|
|
#include "openvswitch/poll-loop.h"
|
|
#include "sat-math.h"
|
|
#include "timeval.h"
|
|
#include "util.h"
|
|
|
|
/* Initializes 'tb' to accumulate 'rate' tokens per millisecond, with a
|
|
* maximum of 'burst' tokens.
|
|
*
|
|
* The token bucket is initially full.
|
|
*
|
|
* It may be more convenient to use TOKEN_BUCKET_INIT. */
|
|
void
|
|
token_bucket_init(struct token_bucket *tb,
|
|
unsigned int rate, unsigned int burst)
|
|
{
|
|
tb->rate = rate;
|
|
tb->burst = burst;
|
|
tb->tokens = 0;
|
|
tb->last_fill = LLONG_MIN;
|
|
}
|
|
|
|
/* Changes 'tb' to accumulate 'rate' tokens per millisecond, with a maximum of
|
|
* 'burst' tokens.
|
|
*
|
|
* 'tb' must already have been initialized with TOKEN_BUCKET_INIT or
|
|
* token_bucket_init(). */
|
|
void
|
|
token_bucket_set(struct token_bucket *tb,
|
|
unsigned int rate, unsigned int burst)
|
|
{
|
|
tb->rate = rate;
|
|
tb->burst = burst;
|
|
if (burst < tb->tokens) {
|
|
tb->tokens = burst;
|
|
}
|
|
}
|
|
|
|
/* Attempts to remove 'n' tokens from 'tb'. Returns true if successful, false
|
|
* if 'tb' contained fewer than 'n' tokens (and thus 'n' tokens could not be
|
|
* removed) . */
|
|
bool
|
|
token_bucket_withdraw(struct token_bucket *tb, unsigned int n)
|
|
{
|
|
if (tb->tokens < n) {
|
|
long long int now = time_msec();
|
|
if (now > tb->last_fill) {
|
|
unsigned long long int elapsed_ull
|
|
= (unsigned long long int) now - tb->last_fill;
|
|
unsigned int elapsed = MIN(UINT_MAX, elapsed_ull);
|
|
unsigned int add = sat_mul(tb->rate, elapsed);
|
|
unsigned int tokens = sat_add(tb->tokens, add);
|
|
tb->tokens = MIN(tokens, tb->burst);
|
|
tb->last_fill = now;
|
|
}
|
|
|
|
if (tb->tokens < n) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
tb->tokens -= n;
|
|
return true;
|
|
}
|
|
|
|
/* Causes the poll loop to wake up when at least 'n' tokens will be available
|
|
* for withdrawal from 'tb'. */
|
|
void
|
|
token_bucket_wait_at(struct token_bucket *tb, unsigned int n,
|
|
const char *where)
|
|
{
|
|
if (tb->tokens >= n) {
|
|
poll_immediate_wake_at(where);
|
|
} else {
|
|
unsigned int need = n - tb->tokens;
|
|
poll_timer_wait_until_at(tb->last_fill + need / tb->rate + 1, where);
|
|
}
|
|
}
|