src/mem/PoolChunked.h

   1 /*
   2  * Copyright (C) 1996-2015 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef _MEM_POOL_CHUNKED_H_
  10 #define _MEM_POOL_CHUNKED_H_
  11
  12 #include "mem/Pool.h"
  13
  14 #define MEM_CHUNK_SIZE        4 * 4096  /* 16KB ... 4 * VM_PAGE_SZ */
  15 #define MEM_CHUNK_MAX_SIZE  256 * 1024  /* 2MB */
  16
  17 class MemChunk;
  18
  19 /// \ingroup MemPoolsAPI
  20 class MemPoolChunked : public MemImplementingAllocator
  21 {
  22 public:
  23     friend class MemChunk;
  24     MemPoolChunked(const char *label, size_t obj_size);
  25     ~MemPoolChunked();
  26     void convertFreeCacheToChunkFreeCache();
  27     virtual void clean(time_t maxage);
  28
  29     /**
  30      \param stats   Object to be filled with statistical data about pool.
  31      \retval        Number of objects in use, ie. allocated.
  32      */
  33     virtual int getStats(MemPoolStats * stats, int accumulate);
  34
  35     void createChunk();
  36     void *get();
  37     void push(void *obj);
  38     virtual int getInUseCount();
  39 protected:
  40     virtual void *allocate();
  41     virtual void deallocate(void *, bool aggressive);
  42 public:
  43     /**
  44      * Allows you tune chunk size of pooling. Objects are allocated in chunks
  45      * instead of individually. This conserves memory, reduces fragmentation.
  46      * Because of that memory can be freed also only in chunks. Therefore
  47      * there is tradeoff between memory conservation due to chunking and free
  48      * memory fragmentation.
  49      *
  50      \note  As a general guideline, increase chunk size only for pools that keep
  51      *      very many items for relatively long time.
  52      */
  53     virtual void setChunkSize(size_t chunksize);
  54
  55     virtual bool idleTrigger(int shift) const;
  56
  57     size_t chunk_size;
  58     int chunk_capacity;
  59     int chunkCount;
  60     void *freeCache;
  61     MemChunk *nextFreeChunk;
  62     MemChunk *Chunks;
  63     Splay<MemChunk *> allChunks;
  64 };
  65
  66 /// \ingroup MemPoolsAPI
  67 class MemChunk
  68 {
  69 public:
  70     MemChunk(MemPoolChunked *pool);
  71     ~MemChunk();
  72     void *freeList;
  73     void *objCache;
  74     int inuse_count;
  75     MemChunk *nextFreeChunk;
  76     MemChunk *next;
  77     time_t lastref;
  78     MemPoolChunked *pool;
  79 };
  80
  81 #endif /* _MEM_POOL_CHUNKED_H_ */
  82