Source code
Revision control
Copy as Markdown
Other Tools
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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
#ifndef _MORKZONE_
#define _MORKZONE_ 1
#ifndef _MORK_
# include "mork.h"
#endif
#ifndef _MORKNODE_
# include "morkNode.h"
#endif
#ifndef _MORKDEQUE_
# include "morkDeque.h"
#endif
// 456789_123456789_123456789_123456789_123456789_123456789_123456789_123456789
/*| CONFIG_DEBUG: do paranoid debug checks if defined.
|*/
#ifdef MORK_DEBUG
# define morkZone_CONFIG_DEBUG 1 /* debug paranoid if defined */
#endif /*MORK_DEBUG*/
/*| CONFIG_STATS: keep volume and usage statistics.
|*/
#define morkZone_CONFIG_VOL_STATS 1 /* count space used by zone instance */
/*| CONFIG_ARENA: if this is defined, then the morkZone class will alloc big
**| blocks from the zone's heap, and suballocate from these. If undefined,
**| then morkZone will just pass all calls through to the zone's heap.
|*/
#ifdef MORK_ENABLE_ZONE_ARENAS
# define morkZone_CONFIG_ARENA 1 /* be arena, if defined; otherwise no-op */
#endif /*MORK_ENABLE_ZONE_ARENAS*/
/*| CONFIG_ALIGN_8: if this is defined, then the morkZone class will give
**| blocks 8 byte alignment instead of only 4 byte alignment.
|*/
#ifdef MORK_CONFIG_ALIGN_8
# define morkZone_CONFIG_ALIGN_8 1 /* ifdef: align to 8 bytes, otherwise 4 */
#endif /*MORK_CONFIG_ALIGN_8*/
/*| CONFIG_PTR_SIZE_4: if this is defined, then the morkZone class will
**| assume sizeof(void*) == 4, so a tag slot for padding is needed.
|*/
#ifdef MORK_CONFIG_PTR_SIZE_4
# define morkZone_CONFIG_PTR_SIZE_4 1 /* ifdef: sizeof(void*) == 4 */
#endif /*MORK_CONFIG_PTR_SIZE_4*/
/*| morkZone_USE_TAG_SLOT: if this is defined, then define slot mRun_Tag
**| in order to achieve eight byte alignment after the mRun_Next slot.
|*/
#if defined(morkZone_CONFIG_ALIGN_8) && defined(morkZone_CONFIG_PTR_SIZE_4)
# define morkRun_USE_TAG_SLOT 1 /* need mRun_Tag slot inside morkRun */
# define morkHunk_USE_TAG_SLOT 1 /* need mHunk_Tag slot inside morkHunk */
#endif
// 456789_123456789_123456789_123456789_123456789_123456789_123456789_123456789
#define morkRun_kTag ((mork_u4)0x6D52754E) /* ascii 'mRuN' */
/*| morkRun: structure used by morkZone for sized blocks
|*/
class morkRun {
protected: // member variable slots
#ifdef morkRun_USE_TAG_SLOT
mork_u4 mRun_Tag; // force 8 byte alignment after mRun_Next
#endif /* morkRun_USE_TAG_SLOT */
morkRun* mRun_Next;
public: // pointer interpretation of mRun_Next (when inside a list):
morkRun* RunNext() const { return mRun_Next; }
void RunSetNext(morkRun* ioNext) { mRun_Next = ioNext; }
public: // size interpretation of mRun_Next (when not inside a list):
mork_size RunSize() const { return (mork_size)((mork_ip)mRun_Next); }
void RunSetSize(mork_size inSize) { mRun_Next = (morkRun*)((mork_ip)inSize); }
public: // maintenance and testing of optional tag magic signature slot:
#ifdef morkRun_USE_TAG_SLOT
void RunInitTag() { mRun_Tag = morkRun_kTag; }
mork_bool RunGoodTag() { return (mRun_Tag == morkRun_kTag); }
#endif /* morkRun_USE_TAG_SLOT */
public: // conversion back and forth to inline block following run instance:
void* RunAsBlock() { return (((mork_u1*)this) + sizeof(morkRun)); }
static morkRun* BlockAsRun(void* ioBlock) {
return (morkRun*)(((mork_u1*)ioBlock) - sizeof(morkRun));
}
public: // typing & errors
static void BadRunTagError(morkEnv* ev);
static void RunSizeAlignError(morkEnv* ev);
};
// 456789_123456789_123456789_123456789_123456789_123456789_123456789_123456789
/*| morkOldRun: more space to record size when run is put into old free list
|*/
class morkOldRun : public morkRun {
protected: // need another size field when mRun_Next is used for linkage:
mdb_size mOldRun_Size;
public: // size getter/setter
mork_size OldSize() const { return mOldRun_Size; }
void OldSetSize(mork_size inSize) { mOldRun_Size = inSize; }
};
// 456789_123456789_123456789_123456789_123456789_123456789_123456789_123456789
#define morkHunk_kTag ((mork_u4)0x68556E4B) /* ascii 'hUnK' */
/*| morkHunk: structure used by morkZone for heap allocations.
|*/
class morkHunk {
protected: // member variable slots
#ifdef morkHunk_USE_TAG_SLOT
mork_u4 mHunk_Tag; // force 8 byte alignment after mHunk_Next
#endif /* morkHunk_USE_TAG_SLOT */
morkHunk* mHunk_Next;
morkRun mHunk_Run;
public: // setters
void HunkSetNext(morkHunk* ioNext) { mHunk_Next = ioNext; }
public: // getters
morkHunk* HunkNext() const { return mHunk_Next; }
morkRun* HunkRun() { return &mHunk_Run; }
public: // maintenance and testing of optional tag magic signature slot:
#ifdef morkHunk_USE_TAG_SLOT
void HunkInitTag() { mHunk_Tag = morkHunk_kTag; }
mork_bool HunkGoodTag() { return (mHunk_Tag == morkHunk_kTag); }
#endif /* morkHunk_USE_TAG_SLOT */
public: // typing & errors
static void BadHunkTagWarning(morkEnv* ev);
};
// 456789_123456789_123456789_123456789_123456789_123456789_123456789_123456789
/*| kNewHunkSize: the default size for a hunk, assuming we must allocate
**| a new one whenever the free hunk list does not already have. Note this
**| number should not be changed without also considering suitable changes
**| in the related kMaxHunkWaste and kMinHunkSize constants.
|*/
#define morkZone_kNewHunkSize ((mork_size)(64 * 1024)) /* 64K per hunk */
/*| kMaxFreeVolume: some number of bytes of free space in the free hunk list
**| over which we no longer want to add more free hunks to the list, for fear
**| of accumulating too much unused, fragmented free space. This should be a
**| small multiple of kNewHunkSize, say about two to four times as great, to
**| allow for no more free hunk space than fits in a handful of new hunks.
**| This strategy will let us usefully accumulate "some" free space in the
**| free hunk list, but without accumulating "too much" free space that way.
|*/
#define morkZone_kMaxFreeVolume (morkZone_kNewHunkSize * 3)
/*| kMaxHunkWaste: if a current request is larger than this, and we cannot
**| satisfy the request with the current hunk, then we just allocate the
**| block from the heap without changing the current hunk. Basically this
**| number represents the largest amount of memory we are willing to waste,
**| since a block request barely less than this can cause the current hunk
**| to be retired (with any unused space wasted) as well get a new hunk.
|*/
#define morkZone_kMaxHunkWaste ((mork_size)4096) /* 1/16 kNewHunkSize */
/*| kRound*: the algorithm for rounding up allocation sizes for caching
**| in free lists works like the following. We add kRoundAdd to any size
**| requested, and then bitwise AND with kRoundMask, and this will give us
**| the smallest multiple of kRoundSize that is at least as large as the
**| requested size. Then if we rightshift this number by kRoundBits, we
**| will have the index into the mZone_FreeRuns array which will hold any
**| cache runs of that size. So 4 bits of shift gives us a granularity
**| of 16 bytes, so that free lists will hold successive runs that are
**| 16 bytes greater than the next smaller run size. If we have 256 free
**| lists of nonzero sized runs altogether, then the largest run that can
**| be cached is 4096, or 4K (since 4096 == 16 * 256). A larger run that
**| gets freed will go in to the free hunk list (or back to the heap).
|*/
#define morkZone_kRoundBits 4 /* bits to round-up size for free lists */
#define morkZone_kRoundSize (1 << morkZone_kRoundBits)
#define morkZone_kRoundAdd ((1 << morkZone_kRoundBits) - 1)
#define morkZone_kRoundMask (~((mork_ip)morkZone_kRoundAdd))
#define morkZone_kBuckets 256 /* number of distinct free lists */
/*| kMaxCachedRun: the largest run that will be stored inside a free
**| list of old zapped runs. A run larger than this cannot be put in
**| a free list, and must be allocated from the heap at need, and put
**| into the free hunk list when discarded.
|*/
#define morkZone_kMaxCachedRun (morkZone_kBuckets * morkZone_kRoundSize)
#define morkDerived_kZone /*i*/ 0x5A6E /* ascii 'Zn' */
/*| morkZone: a pooled memory allocator like an NSPR arena. The term 'zone'
**| is roughly synonymous with 'heap'. I avoid calling this class a "heap"
**| to avoid any confusion with nsIMdbHeap, and I avoid calling this class
**| an arean to avoid confusion with NSPR usage.
|*/
class morkZone : public morkNode, public nsIMdbHeap {
// public: // slots inherited from morkNode (meant to inform only)
// nsIMdbHeap* mNode_Heap;
// mork_base mNode_Base; // must equal morkBase_kNode
// mork_derived mNode_Derived; // depends on specific node subclass
// mork_access mNode_Access; // kOpen, kClosing, kShut, or kDead
// mork_usage mNode_Usage; // kHeap, kStack, kMember, kGlobal, kNone
// mork_able mNode_Mutable; // can this node be modified?
// mork_load mNode_Load; // is this node clean or dirty?
// mork_uses mNode_Uses; // refcount for strong refs
// mork_refs mNode_Refs; // refcount for strong refs + weak refs
public: // state is public because the entire Mork system is private
nsIMdbHeap* mZone_Heap; // strong ref to heap allocating all space
mork_size mZone_HeapVolume; // total bytes allocated from heap
mork_size mZone_BlockVolume; // total bytes in all zone blocks
mork_size mZone_RunVolume; // total bytes in all zone runs
mork_size mZone_ChipVolume; // total bytes in all zone chips
mork_size mZone_FreeOldRunVolume; // total bytes in all used hunks
mork_count mZone_HunkCount; // total number of used hunks
mork_count mZone_FreeOldRunCount; // total free old runs
morkHunk* mZone_HunkList; // linked list of all used hunks
morkRun* mZone_FreeOldRunList; // linked list of free old runs
// note mZone_At is a byte pointer for single byte address arithmetic:
mork_u1* mZone_At; // current position in most recent hunk
mork_size mZone_AtSize; // number of bytes remaining in this hunk
// kBuckets+1 so indexes zero through kBuckets are all okay to use:
morkRun* mZone_FreeRuns[morkZone_kBuckets + 1];
// Each piece of memory stored in list mZone_FreeRuns[ i ] has an
// allocation size equal to sizeof(morkRun) + (i * kRoundSize), so
// that callers can be given a piece of memory with (i * kRoundSize)
// bytes of writeable space while reserving the first sizeof(morkRun)
// bytes to keep track of size information for later re-use. Note
// that mZone_FreeRuns[ 0 ] is unused because no run will be zero
// bytes in size (and morkZone plans to complain about zero sizes).
protected: // zone utilities
mork_size zone_grow_at(morkEnv* ev, mork_size inNeededSize);
void* zone_new_chip(morkEnv* ev, mdb_size inSize); // alloc
morkHunk* zone_new_hunk(morkEnv* ev, mdb_size inRunSize); // alloc
// { ===== begin nsIMdbHeap methods =====
public:
NS_IMETHOD Alloc(
nsIMdbEnv* ev, // allocate a piece of memory
mdb_size inSize, // requested size of new memory block
void** outBlock) override; // memory block of inSize bytes, or nil
NS_IMETHOD Free(nsIMdbEnv* ev, // free block allocated earlier by Alloc()
void* inBlock) override;
virtual size_t GetUsedSize() override { return mZone_Heap->GetUsedSize(); }
// } ===== end nsIMdbHeap methods =====
// { ===== begin morkNode interface =====
public: // morkNode virtual methods
virtual void CloseMorkNode(morkEnv* ev) override; // CloseZone() only if open
virtual ~morkZone(); // assert that CloseMap() executed earlier
public: // morkMap construction & destruction
morkZone(morkEnv* ev, const morkUsage& inUsage, nsIMdbHeap* ioNodeHeap,
nsIMdbHeap* ioZoneHeap);
void CloseZone(morkEnv* ev); // called by CloseMorkNode()
public: // dynamic type identification
mork_bool IsZone() const {
return IsNode() && mNode_Derived == morkDerived_kZone;
}
// } ===== end morkNode methods =====
// { ===== begin morkZone methods =====
public: // chips do not know how big they are...
void* ZoneNewChip(morkEnv* ev, mdb_size inSize); // alloc
public: // ...but runs do indeed know how big they are
void* ZoneNewRun(morkEnv* ev, mdb_size inSize); // alloc
void ZoneZapRun(morkEnv* ev, void* ioRunBody); // free
void* ZoneGrowRun(morkEnv* ev, void* ioRunBody, mdb_size inSize); // realloc
// } ===== end morkZone methods =====
public: // typing & errors
static void NonZoneTypeError(morkEnv* ev);
static void NilZoneHeapError(morkEnv* ev);
static void BadZoneTagError(morkEnv* ev);
};
// 456789_123456789_123456789_123456789_123456789_123456789_123456789_123456789
#endif /* _MORKZONE_ */