mirror of
https://github.com/zerotier/ZeroTierOne.git
synced 2025-04-25 16:36:54 +02:00
99 lines
1.9 KiB
C++
99 lines
1.9 KiB
C++
/*
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* Copyright (c)2013-2020 ZeroTier, Inc.
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file in the project's root directory.
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*
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* Change Date: 2024-01-01
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2.0 of the Apache License.
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*/
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/****/
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#include "Buf.hpp"
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#ifdef __WINDOWS__
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#define sched_yield() Sleep(0)
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#endif
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namespace ZeroTier {
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static std::atomic<uintptr_t> s_pool(0);
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static std::atomic<long> s_allocated(0);
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// uintptr_max can never be a valid pointer, so use it to indicate that s_pool is locked (very short duration spinlock)
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#define ZT_ATOMIC_PTR_LOCKED (~((uintptr_t)0))
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void *Buf::operator new(std::size_t sz)
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{
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uintptr_t bb;
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for (;;) {
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bb = s_pool.exchange(ZT_ATOMIC_PTR_LOCKED);
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if (bb != ZT_ATOMIC_PTR_LOCKED)
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break;
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sched_yield();
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}
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Buf *b;
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if (bb) {
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s_pool.store(((Buf *) bb)->__nextInPool);
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b = (Buf *) bb;
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} else {
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s_pool.store(0);
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b = (Buf *) malloc(sz);
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if (!b)
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throw std::bad_alloc();
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++s_allocated;
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}
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b->__refCount.store(0);
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return (void *) b;
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}
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void Buf::operator delete(void *ptr)
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{
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if (ptr) {
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if (s_allocated.load() > ZT_BUF_MAX_POOL_SIZE) {
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--s_allocated;
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free(ptr);
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} else {
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uintptr_t bb;
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for (;;) {
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bb = s_pool.exchange(ZT_ATOMIC_PTR_LOCKED);
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if (bb != ZT_ATOMIC_PTR_LOCKED)
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break;
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sched_yield();
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}
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((Buf *) ptr)->__nextInPool.store(bb);
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s_pool.store((uintptr_t) ptr);
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}
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}
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}
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void Buf::freePool() noexcept
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{
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uintptr_t bb;
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for (;;) {
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bb = s_pool.exchange(ZT_ATOMIC_PTR_LOCKED);
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if (bb != ZT_ATOMIC_PTR_LOCKED)
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break;
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sched_yield();
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}
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s_pool.store(0);
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while (bb != 0) {
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const uintptr_t next = ((Buf *) bb)->__nextInPool;
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--s_allocated;
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free((void *) bb);
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bb = next;
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}
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}
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long Buf::poolAllocated() noexcept
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{
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return s_allocated.load();
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}
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} // namespace ZeroTier
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