77 lines
2.2 KiB
C
77 lines
2.2 KiB
C
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/*
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* Helper functionality for distributing a fixed total amount of
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* an abstract resource among multiple coroutines.
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*
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* Copyright (c) 2019 Virtuozzo International GmbH
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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#include "qemu/coroutine.h"
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#include "qemu/co-shared-resource.h"
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struct SharedResource {
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uint64_t total;
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uint64_t available;
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CoQueue queue;
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};
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SharedResource *shres_create(uint64_t total)
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{
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SharedResource *s = g_new0(SharedResource, 1);
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s->total = s->available = total;
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qemu_co_queue_init(&s->queue);
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return s;
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}
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void shres_destroy(SharedResource *s)
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{
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assert(s->available == s->total);
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g_free(s);
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}
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bool co_try_get_from_shres(SharedResource *s, uint64_t n)
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{
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if (s->available >= n) {
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s->available -= n;
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return true;
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}
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return false;
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}
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void coroutine_fn co_get_from_shres(SharedResource *s, uint64_t n)
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{
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assert(n <= s->total);
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while (!co_try_get_from_shres(s, n)) {
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qemu_co_queue_wait(&s->queue, NULL);
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}
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}
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void coroutine_fn co_put_to_shres(SharedResource *s, uint64_t n)
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{
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assert(s->total - s->available >= n);
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s->available += n;
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qemu_co_queue_restart_all(&s->queue);
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}
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