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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=8 et ft=cpp : */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/ShmemPool.h"
#include <utility>
#include "mozilla/Assertions.h"
#include "mozilla/Logging.h"
mozilla::LazyLogModule sShmemPoolLog("ShmemPool");
#define SHMEMPOOL_LOG_VERBOSE(args) \
MOZ_LOG(sShmemPoolLog, mozilla::LogLevel::Verbose, args)
namespace mozilla {
ShmemPool::ShmemPool(size_t aPoolSize, PoolType aPoolType)
: mPoolType(aPoolType),
mMutex("mozilla::ShmemPool"),
mPoolFree(aPoolSize),
mErrorLogged(false)
#ifdef DEBUG
,
mMaxPoolUse(0)
#endif
{
mShmemPool.SetLength(aPoolSize);
}
mozilla::ShmemBuffer ShmemPool::GetIfAvailable(size_t aSize) {
MutexAutoLock lock(mMutex);
// Pool is empty, don't block caller.
if (mPoolFree == 0) {
if (!mErrorLogged) {
// log "out of pool" once as error to avoid log spam
mErrorLogged = true;
SHMEMPOOL_LOG_ERROR(
("ShmemPool is empty, future occurrences "
"will be logged as warnings"));
} else {
SHMEMPOOL_LOG_WARN(("ShmemPool is empty"));
}
// This isn't initialized, so will be understood as an error.
return ShmemBuffer();
}
ShmemBuffer& res = mShmemPool[mPoolFree - 1];
if (!res.mInitialized) {
SHMEMPOOL_LOG(("No free preallocated Shmem"));
return ShmemBuffer();
}
MOZ_ASSERT(res.mShmem.IsWritable(), "Pool in Shmem is not writable?");
if (res.mShmem.Size<uint8_t>() < aSize) {
SHMEMPOOL_LOG(("Free Shmem but not of the right size"));
return ShmemBuffer();
}
mPoolFree--;
#ifdef DEBUG
size_t poolUse = mShmemPool.Length() - mPoolFree;
if (poolUse > mMaxPoolUse) {
mMaxPoolUse = poolUse;
SHMEMPOOL_LOG(
("Maximum ShmemPool use increased: %zu buffers", mMaxPoolUse));
}
#endif
return std::move(res);
}
void ShmemPool::Put(ShmemBuffer&& aShmem) {
MutexAutoLock lock(mMutex);
MOZ_ASSERT(mPoolFree < mShmemPool.Length());
mShmemPool[mPoolFree] = std::move(aShmem);
mPoolFree++;
#ifdef DEBUG
size_t poolUse = mShmemPool.Length() - mPoolFree;
if (poolUse > 0) {
SHMEMPOOL_LOG_VERBOSE(("ShmemPool usage reduced to %zu buffers", poolUse));
}
#endif
}
ShmemPool::~ShmemPool() {
#ifdef DEBUG
for (size_t i = 0; i < mShmemPool.Length(); i++) {
MOZ_ASSERT(!mShmemPool[i].Valid());
}
#endif
}
} // namespace mozilla
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