Allocator.h

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/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */
 
#ifndef SQUID_SRC_MEM_ALLOCATOR_H
#define SQUID_SRC_MEM_ALLOCATOR_H
 
#include "base/TypeTraits.h"
#include "mem/forward.h"
#include "mem/Meter.h"
 
namespace Mem
{
 
class Allocator : public Interface
{
public:
    static const size_t FlushLimit = 1000;
 
    Allocator(const char * const aLabel, const size_t sz):
        label(aLabel),
        objectSize(RoundedSize(sz))
    {}
 
    // TODO make this method const
    virtual size_t getStats(PoolStats &) = 0;
 
    void *alloc() {
        if (++countAlloc == FlushLimit)
            flushCounters();
        return allocate();
    }
 
    void freeOne(void *obj) {
        assert(obj != nullptr);
        (void) VALGRIND_CHECK_MEM_IS_ADDRESSABLE(obj, objectSize);
        deallocate(obj);
        ++countFreeOne;
    }
 
    int getInUseCount() const { return meter.inuse.currentLevel(); }
 
    void zeroBlocks(const bool doIt) { doZero = doIt; }
 
    virtual void setChunkSize(size_t) {}
 
    virtual bool idleTrigger(int shift) const = 0;
 
    virtual void clean(time_t maxage) = 0;
 
    void flushCounters() {
        if (countFreeOne) {
            meter.gb_freed.update(countFreeOne, objectSize);
            countFreeOne = 0;
        }
        if (countAlloc) {
            meter.gb_allocated.update(countAlloc, objectSize);
            countAlloc = 0;
        }
        if (countSavedAllocs) {
            meter.gb_saved.update(countSavedAllocs, objectSize);
            countSavedAllocs = 0;
        }
    }
 
    static size_t RoundedSize(const size_t minSize) { return ((minSize + sizeof(void*) - 1) / sizeof(void*)) * sizeof(void*); }
 
public:
 
    size_t countAlloc = 0;
 
    size_t countSavedAllocs = 0;
 
    size_t countFreeOne = 0;
 
    // XXX: no counter for the number of free() calls avoided
 
    const char *const label;
 
    const size_t objectSize;
 
    PoolMeter meter;
 
protected:
    virtual void *allocate() = 0;
    virtual void deallocate(void *) = 0;
 
    bool doZero = true;
};
 
} // namespace Mem
 
#endif /* SQUID_SRC_MEM_ALLOCATOR_H */