memutils_internal.h File Reference

#include "utils/memutils.h"

Include dependency graph for memutils_internal.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Macros
#define	PallocAlignedExtraBytes(alignto)    ((alignto) + (sizeof(MemoryChunk) - MAXIMUM_ALIGNOF))
#define	MEMORY_CONTEXT_METHODID_BITS   3
#define	MEMORY_CONTEXT_METHODID_MASK    ((((uint64) 1) << MEMORY_CONTEXT_METHODID_BITS) - 1)

Typedefs
typedef enum MemoryContextMethodID	MemoryContextMethodID

Enumerations
enum	MemoryContextMethodID {   MCTX_UNUSED1_ID , MCTX_UNUSED2_ID , MCTX_UNUSED3_ID , MCTX_ASET_ID ,   MCTX_GENERATION_ID , MCTX_SLAB_ID , MCTX_ALIGNED_REDIRECT_ID , MCTX_UNUSED4_ID }

Functions
void *	AllocSetAlloc (MemoryContext context, Size size)
void	AllocSetFree (void *pointer)
void *	AllocSetRealloc (void *pointer, Size size)
void	AllocSetReset (MemoryContext context)
void	AllocSetDelete (MemoryContext context)
MemoryContext	AllocSetGetChunkContext (void *pointer)
Size	AllocSetGetChunkSpace (void *pointer)
bool	AllocSetIsEmpty (MemoryContext context)
void	AllocSetStats (MemoryContext context, MemoryStatsPrintFunc printfunc, void *passthru, MemoryContextCounters *totals, bool print_to_stderr)
void *	GenerationAlloc (MemoryContext context, Size size)
void	GenerationFree (void *pointer)
void *	GenerationRealloc (void *pointer, Size size)
void	GenerationReset (MemoryContext context)
void	GenerationDelete (MemoryContext context)
MemoryContext	GenerationGetChunkContext (void *pointer)
Size	GenerationGetChunkSpace (void *pointer)
bool	GenerationIsEmpty (MemoryContext context)
void	GenerationStats (MemoryContext context, MemoryStatsPrintFunc printfunc, void *passthru, MemoryContextCounters *totals, bool print_to_stderr)
void *	SlabAlloc (MemoryContext context, Size size)
void	SlabFree (void *pointer)
void *	SlabRealloc (void *pointer, Size size)
void	SlabReset (MemoryContext context)
void	SlabDelete (MemoryContext context)
MemoryContext	SlabGetChunkContext (void *pointer)
Size	SlabGetChunkSpace (void *pointer)
bool	SlabIsEmpty (MemoryContext context)
void	SlabStats (MemoryContext context, MemoryStatsPrintFunc printfunc, void *passthru, MemoryContextCounters *totals, bool print_to_stderr)
void	AlignedAllocFree (void *pointer)
void *	AlignedAllocRealloc (void *pointer, Size size)
MemoryContext	AlignedAllocGetChunkContext (void *pointer)
Size	AlignedAllocGetChunkSpace (void *pointer)
void	MemoryContextCreate (MemoryContext node, NodeTag tag, MemoryContextMethodID method_id, MemoryContext parent, const char *name)

Macro Definition Documentation

MEMORY_CONTEXT_METHODID_BITS

#define MEMORY_CONTEXT_METHODID_BITS   3

Definition at line 121 of file memutils_internal.h.

MEMORY_CONTEXT_METHODID_MASK

#define MEMORY_CONTEXT_METHODID_MASK    ((((uint64) 1) << MEMORY_CONTEXT_METHODID_BITS) - 1)

Definition at line 122 of file memutils_internal.h.

PallocAlignedExtraBytes

#define PallocAlignedExtraBytes

(

alignto

)

((alignto) + (sizeof(MemoryChunk) - MAXIMUM_ALIGNOF))

Definition at line 88 of file memutils_internal.h.

Typedef Documentation

MemoryContextMethodID

typedef enum MemoryContextMethodID MemoryContextMethodID

Enumeration Type Documentation

MemoryContextMethodID

enum MemoryContextMethodID

Enumerator
MCTX_UNUSED1_ID
MCTX_UNUSED2_ID
MCTX_UNUSED3_ID
MCTX_ASET_ID
MCTX_GENERATION_ID
MCTX_SLAB_ID
MCTX_ALIGNED_REDIRECT_ID
MCTX_UNUSED4_ID

Definition at line 105 of file memutils_internal.h.

{
    MCTX_UNUSED1_ID,            /* 000 occurs in never-used memory */
    MCTX_UNUSED2_ID,            /* glibc malloc'd chunks usually match 001 */
    MCTX_UNUSED3_ID,            /* glibc malloc'd chunks > 128kB match 010 */
    MCTX_ASET_ID,
    MCTX_GENERATION_ID,
    MCTX_SLAB_ID,
    MCTX_ALIGNED_REDIRECT_ID,
    MCTX_UNUSED4_ID,            /* 111 occurs in wipe_mem'd memory */
} MemoryContextMethodID;

Function Documentation

AlignedAllocFree()

void AlignedAllocFree

(

void *

pointer

)

Definition at line 29 of file alignedalloc.c.

{
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    void       *unaligned;
 
    VALGRIND_MAKE_MEM_DEFINED(chunk, sizeof(MemoryChunk));
 
    Assert(!MemoryChunkIsExternal(chunk));
 
    /* obtain the original (unaligned) allocated pointer */
    unaligned = MemoryChunkGetBlock(chunk);
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* Test for someone scribbling on unused space in chunk */
    if (!sentinel_ok(pointer, chunk->requested_size))
        elog(WARNING, "detected write past chunk end in %s %p",
             GetMemoryChunkContext(unaligned)->name, chunk);
#endif
 
    pfree(unaligned);
}

References Assert(), elog(), GetMemoryChunkContext(), MemoryChunkGetBlock(), MemoryChunkIsExternal(), name, pfree(), PointerGetMemoryChunk, VALGRIND_MAKE_MEM_DEFINED, and WARNING.

AlignedAllocGetChunkContext()

MemoryContext AlignedAllocGetChunkContext

(

void *

pointer

)

Definition at line 118 of file alignedalloc.c.

{
    MemoryChunk *redirchunk = PointerGetMemoryChunk(pointer);
    MemoryContext cxt;
 
    VALGRIND_MAKE_MEM_DEFINED(redirchunk, sizeof(MemoryChunk));
 
    Assert(!MemoryChunkIsExternal(redirchunk));
 
    cxt = GetMemoryChunkContext(MemoryChunkGetBlock(redirchunk));
 
    VALGRIND_MAKE_MEM_NOACCESS(redirchunk, sizeof(MemoryChunk));
 
    return cxt;
}

References Assert(), GetMemoryChunkContext(), MemoryChunkGetBlock(), MemoryChunkIsExternal(), PointerGetMemoryChunk, VALGRIND_MAKE_MEM_DEFINED, and VALGRIND_MAKE_MEM_NOACCESS.

AlignedAllocGetChunkSpace()

Size AlignedAllocGetChunkSpace

(

void *

pointer

)

Definition at line 140 of file alignedalloc.c.

{
    MemoryChunk *redirchunk = PointerGetMemoryChunk(pointer);
    void       *unaligned;
    Size        space;
 
    VALGRIND_MAKE_MEM_DEFINED(redirchunk, sizeof(MemoryChunk));
 
    unaligned = MemoryChunkGetBlock(redirchunk);
    space = GetMemoryChunkSpace(unaligned);
 
    VALGRIND_MAKE_MEM_NOACCESS(redirchunk, sizeof(MemoryChunk));
 
    return space;
}

References GetMemoryChunkSpace(), MemoryChunkGetBlock(), PointerGetMemoryChunk, VALGRIND_MAKE_MEM_DEFINED, and VALGRIND_MAKE_MEM_NOACCESS.

AlignedAllocRealloc()

void* AlignedAllocRealloc	(	void *	pointer,
		Size	size
	)

Definition at line 60 of file alignedalloc.c.

{
    MemoryChunk *redirchunk = PointerGetMemoryChunk(pointer);
    Size        alignto;
    void       *unaligned;
    MemoryContext ctx;
    Size        old_size;
    void       *newptr;
 
    VALGRIND_MAKE_MEM_DEFINED(redirchunk, sizeof(MemoryChunk));
 
    alignto = MemoryChunkGetValue(redirchunk);
    unaligned = MemoryChunkGetBlock(redirchunk);
 
    /* sanity check this is a power of 2 value */
    Assert((alignto & (alignto - 1)) == 0);
 
    /*
     * Determine the size of the original allocation.  We can't determine this
     * exactly as GetMemoryChunkSpace() returns the total space used for the
     * allocation, which for contexts like aset includes rounding up to the
     * next power of 2.  However, this value is just used to memcpy() the old
     * data into the new allocation, so we only need to concern ourselves with
     * not reading beyond the end of the original allocation's memory.  The
     * drawback here is that we may copy more bytes than we need to, which
     * only amounts to wasted effort.  We can safely subtract the extra bytes
     * that we requested to allow us to align the pointer.  We must also
     * subtract the space for the unaligned pointer's MemoryChunk since
     * GetMemoryChunkSpace should have included that.  This does assume that
     * all context types use MemoryChunk as a chunk header.
     */
    old_size = GetMemoryChunkSpace(unaligned) -
        PallocAlignedExtraBytes(alignto) - sizeof(MemoryChunk);
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* check that GetMemoryChunkSpace returned something realistic */
    Assert(old_size >= redirchunk->requested_size);
#endif
 
    ctx = GetMemoryChunkContext(unaligned);
    newptr = MemoryContextAllocAligned(ctx, size, alignto, 0);
 
    /*
     * We may memcpy beyond the end of the original allocation request size,
     * so we must mark the entire allocation as defined.
     */
    VALGRIND_MAKE_MEM_DEFINED(pointer, old_size);
    memcpy(newptr, pointer, Min(size, old_size));
    pfree(unaligned);
 
    return newptr;
}

References Assert(), GetMemoryChunkContext(), GetMemoryChunkSpace(), MemoryChunkGetBlock(), MemoryChunkGetValue(), MemoryContextAllocAligned(), Min, PallocAlignedExtraBytes, pfree(), PointerGetMemoryChunk, and VALGRIND_MAKE_MEM_DEFINED.

AllocSetAlloc()

void* AllocSetAlloc	(	MemoryContext	context,
		Size	size
	)

Definition at line 703 of file aset.c.

{
    AllocSet    set = (AllocSet) context;
    AllocBlock  block;
    MemoryChunk *chunk;
    int         fidx;
    Size        chunk_size;
    Size        blksize;
 
    Assert(AllocSetIsValid(set));
 
    /*
     * If requested size exceeds maximum for chunks, allocate an entire block
     * for this request.
     */
    if (size > set->allocChunkLimit)
    {
#ifdef MEMORY_CONTEXT_CHECKING
        /* ensure there's always space for the sentinel byte */
        chunk_size = MAXALIGN(size + 1);
#else
        chunk_size = MAXALIGN(size);
#endif
 
        blksize = chunk_size + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ;
        block = (AllocBlock) malloc(blksize);
        if (block == NULL)
            return NULL;
 
        context->mem_allocated += blksize;
 
        block->aset = set;
        block->freeptr = block->endptr = ((char *) block) + blksize;
 
        chunk = (MemoryChunk *) (((char *) block) + ALLOC_BLOCKHDRSZ);
 
        /* mark the MemoryChunk as externally managed */
        MemoryChunkSetHdrMaskExternal(chunk, MCTX_ASET_ID);
 
#ifdef MEMORY_CONTEXT_CHECKING
        chunk->requested_size = size;
        /* set mark to catch clobber of "unused" space */
        Assert(size < chunk_size);
        set_sentinel(MemoryChunkGetPointer(chunk), size);
#endif
#ifdef RANDOMIZE_ALLOCATED_MEMORY
        /* fill the allocated space with junk */
        randomize_mem((char *) MemoryChunkGetPointer(chunk), size);
#endif
 
        /*
         * Stick the new block underneath the active allocation block, if any,
         * so that we don't lose the use of the space remaining therein.
         */
        if (set->blocks != NULL)
        {
            block->prev = set->blocks;
            block->next = set->blocks->next;
            if (block->next)
                block->next->prev = block;
            set->blocks->next = block;
        }
        else
        {
            block->prev = NULL;
            block->next = NULL;
            set->blocks = block;
        }
 
        /* Ensure any padding bytes are marked NOACCESS. */
        VALGRIND_MAKE_MEM_NOACCESS((char *) MemoryChunkGetPointer(chunk) + size,
                                   chunk_size - size);
 
        /* Disallow access to the chunk header. */
        VALGRIND_MAKE_MEM_NOACCESS(chunk, ALLOC_CHUNKHDRSZ);
 
        return MemoryChunkGetPointer(chunk);
    }
 
    /*
     * Request is small enough to be treated as a chunk.  Look in the
     * corresponding free list to see if there is a free chunk we could reuse.
     * If one is found, remove it from the free list, make it again a member
     * of the alloc set and return its data address.
     *
     * Note that we don't attempt to ensure there's space for the sentinel
     * byte here.  We expect a large proportion of allocations to be for sizes
     * which are already a power of 2.  If we were to always make space for a
     * sentinel byte in MEMORY_CONTEXT_CHECKING builds, then we'd end up
     * doubling the memory requirements for such allocations.
     */
    fidx = AllocSetFreeIndex(size);
    chunk = set->freelist[fidx];
    if (chunk != NULL)
    {
        AllocFreeListLink *link = GetFreeListLink(chunk);
 
        /* Allow access to the chunk header. */
        VALGRIND_MAKE_MEM_DEFINED(chunk, ALLOC_CHUNKHDRSZ);
 
        Assert(fidx == MemoryChunkGetValue(chunk));
 
        /* pop this chunk off the freelist */
        VALGRIND_MAKE_MEM_DEFINED(link, sizeof(AllocFreeListLink));
        set->freelist[fidx] = link->next;
        VALGRIND_MAKE_MEM_NOACCESS(link, sizeof(AllocFreeListLink));
 
#ifdef MEMORY_CONTEXT_CHECKING
        chunk->requested_size = size;
        /* set mark to catch clobber of "unused" space */
        if (size < GetChunkSizeFromFreeListIdx(fidx))
            set_sentinel(MemoryChunkGetPointer(chunk), size);
#endif
#ifdef RANDOMIZE_ALLOCATED_MEMORY
        /* fill the allocated space with junk */
        randomize_mem((char *) MemoryChunkGetPointer(chunk), size);
#endif
 
        /* Ensure any padding bytes are marked NOACCESS. */
        VALGRIND_MAKE_MEM_NOACCESS((char *) MemoryChunkGetPointer(chunk) + size,
                                   GetChunkSizeFromFreeListIdx(fidx) - size);
 
        /* Disallow access to the chunk header. */
        VALGRIND_MAKE_MEM_NOACCESS(chunk, ALLOC_CHUNKHDRSZ);
 
        return MemoryChunkGetPointer(chunk);
    }
 
    /*
     * Choose the actual chunk size to allocate.
     */
    chunk_size = GetChunkSizeFromFreeListIdx(fidx);
    Assert(chunk_size >= size);
 
    /*
     * If there is enough room in the active allocation block, we will put the
     * chunk into that block.  Else must start a new one.
     */
    if ((block = set->blocks) != NULL)
    {
        Size        availspace = block->endptr - block->freeptr;
 
        if (availspace < (chunk_size + ALLOC_CHUNKHDRSZ))
        {
            /*
             * The existing active (top) block does not have enough room for
             * the requested allocation, but it might still have a useful
             * amount of space in it.  Once we push it down in the block list,
             * we'll never try to allocate more space from it. So, before we
             * do that, carve up its free space into chunks that we can put on
             * the set's freelists.
             *
             * Because we can only get here when there's less than
             * ALLOC_CHUNK_LIMIT left in the block, this loop cannot iterate
             * more than ALLOCSET_NUM_FREELISTS-1 times.
             */
            while (availspace >= ((1 << ALLOC_MINBITS) + ALLOC_CHUNKHDRSZ))
            {
                AllocFreeListLink *link;
                Size        availchunk = availspace - ALLOC_CHUNKHDRSZ;
                int         a_fidx = AllocSetFreeIndex(availchunk);
 
                /*
                 * In most cases, we'll get back the index of the next larger
                 * freelist than the one we need to put this chunk on.  The
                 * exception is when availchunk is exactly a power of 2.
                 */
                if (availchunk != GetChunkSizeFromFreeListIdx(a_fidx))
                {
                    a_fidx--;
                    Assert(a_fidx >= 0);
                    availchunk = GetChunkSizeFromFreeListIdx(a_fidx);
                }
 
                chunk = (MemoryChunk *) (block->freeptr);
 
                /* Prepare to initialize the chunk header. */
                VALGRIND_MAKE_MEM_UNDEFINED(chunk, ALLOC_CHUNKHDRSZ);
                block->freeptr += (availchunk + ALLOC_CHUNKHDRSZ);
                availspace -= (availchunk + ALLOC_CHUNKHDRSZ);
 
                /* store the freelist index in the value field */
                MemoryChunkSetHdrMask(chunk, block, a_fidx, MCTX_ASET_ID);
#ifdef MEMORY_CONTEXT_CHECKING
                chunk->requested_size = InvalidAllocSize;   /* mark it free */
#endif
                /* push this chunk onto the free list */
                link = GetFreeListLink(chunk);
 
                VALGRIND_MAKE_MEM_DEFINED(link, sizeof(AllocFreeListLink));
                link->next = set->freelist[a_fidx];
                VALGRIND_MAKE_MEM_NOACCESS(link, sizeof(AllocFreeListLink));
 
                set->freelist[a_fidx] = chunk;
            }
            /* Mark that we need to create a new block */
            block = NULL;
        }
    }
 
    /*
     * Time to create a new regular (multi-chunk) block?
     */
    if (block == NULL)
    {
        Size        required_size;
 
        /*
         * The first such block has size initBlockSize, and we double the
         * space in each succeeding block, but not more than maxBlockSize.
         */
        blksize = set->nextBlockSize;
        set->nextBlockSize <<= 1;
        if (set->nextBlockSize > set->maxBlockSize)
            set->nextBlockSize = set->maxBlockSize;
 
        /*
         * If initBlockSize is less than ALLOC_CHUNK_LIMIT, we could need more
         * space... but try to keep it a power of 2.
         */
        required_size = chunk_size + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ;
        while (blksize < required_size)
            blksize <<= 1;
 
        /* Try to allocate it */
        block = (AllocBlock) malloc(blksize);
 
        /*
         * We could be asking for pretty big blocks here, so cope if malloc
         * fails.  But give up if there's less than 1 MB or so available...
         */
        while (block == NULL && blksize > 1024 * 1024)
        {
            blksize >>= 1;
            if (blksize < required_size)
                break;
            block = (AllocBlock) malloc(blksize);
        }
 
        if (block == NULL)
            return NULL;
 
        context->mem_allocated += blksize;
 
        block->aset = set;
        block->freeptr = ((char *) block) + ALLOC_BLOCKHDRSZ;
        block->endptr = ((char *) block) + blksize;
 
        /* Mark unallocated space NOACCESS. */
        VALGRIND_MAKE_MEM_NOACCESS(block->freeptr,
                                   blksize - ALLOC_BLOCKHDRSZ);
 
        block->prev = NULL;
        block->next = set->blocks;
        if (block->next)
            block->next->prev = block;
        set->blocks = block;
    }
 
    /*
     * OK, do the allocation
     */
    chunk = (MemoryChunk *) (block->freeptr);
 
    /* Prepare to initialize the chunk header. */
    VALGRIND_MAKE_MEM_UNDEFINED(chunk, ALLOC_CHUNKHDRSZ);
 
    block->freeptr += (chunk_size + ALLOC_CHUNKHDRSZ);
    Assert(block->freeptr <= block->endptr);
 
    /* store the free list index in the value field */
    MemoryChunkSetHdrMask(chunk, block, fidx, MCTX_ASET_ID);
 
#ifdef MEMORY_CONTEXT_CHECKING
    chunk->requested_size = size;
    /* set mark to catch clobber of "unused" space */
    if (size < chunk_size)
        set_sentinel(MemoryChunkGetPointer(chunk), size);
#endif
#ifdef RANDOMIZE_ALLOCATED_MEMORY
    /* fill the allocated space with junk */
    randomize_mem((char *) MemoryChunkGetPointer(chunk), size);
#endif
 
    /* Ensure any padding bytes are marked NOACCESS. */
    VALGRIND_MAKE_MEM_NOACCESS((char *) MemoryChunkGetPointer(chunk) + size,
                               chunk_size - size);
 
    /* Disallow access to the chunk header. */
    VALGRIND_MAKE_MEM_NOACCESS(chunk, ALLOC_CHUNKHDRSZ);
 
    return MemoryChunkGetPointer(chunk);
}

References ALLOC_BLOCKHDRSZ, ALLOC_CHUNKHDRSZ, ALLOC_MINBITS, AllocSetContext::allocChunkLimit, AllocSetFreeIndex(), AllocSetIsValid, AllocBlockData::aset, Assert(), AllocSetContext::blocks, AllocBlockData::endptr, AllocSetContext::freelist, AllocBlockData::freeptr, GetChunkSizeFromFreeListIdx, GetFreeListLink, InvalidAllocSize, link(), malloc, MAXALIGN, AllocSetContext::maxBlockSize, MCTX_ASET_ID, MemoryContextData::mem_allocated, MemoryChunkGetPointer, MemoryChunkGetValue(), MemoryChunkSetHdrMask(), MemoryChunkSetHdrMaskExternal(), AllocBlockData::next, AllocSetContext::nextBlockSize, AllocBlockData::prev, VALGRIND_MAKE_MEM_DEFINED, VALGRIND_MAKE_MEM_NOACCESS, and VALGRIND_MAKE_MEM_UNDEFINED.

Referenced by AllocSetRealloc().

AllocSetDelete()

void AllocSetDelete

(

MemoryContext

context

)

Definition at line 607 of file aset.c.

{
    AllocSet    set = (AllocSet) context;
    AllocBlock  block = set->blocks;
    Size        keepersize PG_USED_FOR_ASSERTS_ONLY;
 
    Assert(AllocSetIsValid(set));
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* Check for corruption and leaks before freeing */
    AllocSetCheck(context);
#endif
 
    /* Remember keeper block size for Assert below */
    keepersize = KeeperBlock(set)->endptr - ((char *) set);
 
    /*
     * If the context is a candidate for a freelist, put it into that freelist
     * instead of destroying it.
     */
    if (set->freeListIndex >= 0)
    {
        AllocSetFreeList *freelist = &context_freelists[set->freeListIndex];
 
        /*
         * Reset the context, if it needs it, so that we aren't hanging on to
         * more than the initial malloc chunk.
         */
        if (!context->isReset)
            MemoryContextResetOnly(context);
 
        /*
         * If the freelist is full, just discard what's already in it.  See
         * comments with context_freelists[].
         */
        if (freelist->num_free >= MAX_FREE_CONTEXTS)
        {
            while (freelist->first_free != NULL)
            {
                AllocSetContext *oldset = freelist->first_free;
 
                freelist->first_free = (AllocSetContext *) oldset->header.nextchild;
                freelist->num_free--;
 
                /* All that remains is to free the header/initial block */
                free(oldset);
            }
            Assert(freelist->num_free == 0);
        }
 
        /* Now add the just-deleted context to the freelist. */
        set->header.nextchild = (MemoryContext) freelist->first_free;
        freelist->first_free = set;
        freelist->num_free++;
 
        return;
    }
 
    /* Free all blocks, except the keeper which is part of context header */
    while (block != NULL)
    {
        AllocBlock  next = block->next;
 
        if (!IsKeeperBlock(set, block))
            context->mem_allocated -= block->endptr - ((char *) block);
 
#ifdef CLOBBER_FREED_MEMORY
        wipe_mem(block, block->freeptr - ((char *) block));
#endif
 
        if (!IsKeeperBlock(set, block))
            free(block);
 
        block = next;
    }
 
    Assert(context->mem_allocated == keepersize);
 
    /* Finally, free the context header, including the keeper block */
    free(set);
}

References AllocSetIsValid, Assert(), AllocSetContext::blocks, context_freelists, AllocBlockData::endptr, AllocSetFreeList::first_free, free, AllocSetContext::freeListIndex, AllocBlockData::freeptr, AllocSetContext::header, IsKeeperBlock, MemoryContextData::isReset, KeeperBlock, MAX_FREE_CONTEXTS, MemoryContextData::mem_allocated, MemoryContextResetOnly(), next, AllocBlockData::next, MemoryContextData::nextchild, AllocSetFreeList::num_free, and PG_USED_FOR_ASSERTS_ONLY.

AllocSetFree()

void AllocSetFree

(

void *

pointer

)

Definition at line 1002 of file aset.c.

{
    AllocSet    set;
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, ALLOC_CHUNKHDRSZ);
 
    if (MemoryChunkIsExternal(chunk))
    {
        /* Release single-chunk block. */
        AllocBlock  block = ExternalChunkGetBlock(chunk);
 
        /*
         * Try to verify that we have a sane block pointer: the block header
         * should reference an aset and the freeptr should match the endptr.
         */
        if (!AllocBlockIsValid(block) || block->freeptr != block->endptr)
            elog(ERROR, "could not find block containing chunk %p", chunk);
 
        set = block->aset;
 
#ifdef MEMORY_CONTEXT_CHECKING
        {
            /* Test for someone scribbling on unused space in chunk */
            Assert(chunk->requested_size < (block->endptr - (char *) pointer));
            if (!sentinel_ok(pointer, chunk->requested_size))
                elog(WARNING, "detected write past chunk end in %s %p",
                     set->header.name, chunk);
        }
#endif
 
        /* OK, remove block from aset's list and free it */
        if (block->prev)
            block->prev->next = block->next;
        else
            set->blocks = block->next;
        if (block->next)
            block->next->prev = block->prev;
 
        set->header.mem_allocated -= block->endptr - ((char *) block);
 
#ifdef CLOBBER_FREED_MEMORY
        wipe_mem(block, block->freeptr - ((char *) block));
#endif
        free(block);
    }
    else
    {
        AllocBlock  block = MemoryChunkGetBlock(chunk);
        int         fidx;
        AllocFreeListLink *link;
 
        /*
         * In this path, for speed reasons we just Assert that the referenced
         * block is good.  We can also Assert that the value field is sane.
         * Future field experience may show that these Asserts had better
         * become regular runtime test-and-elog checks.
         */
        Assert(AllocBlockIsValid(block));
        set = block->aset;
 
        fidx = MemoryChunkGetValue(chunk);
        Assert(FreeListIdxIsValid(fidx));
        link = GetFreeListLink(chunk);
 
#ifdef MEMORY_CONTEXT_CHECKING
        /* Test for someone scribbling on unused space in chunk */
        if (chunk->requested_size < GetChunkSizeFromFreeListIdx(fidx))
            if (!sentinel_ok(pointer, chunk->requested_size))
                elog(WARNING, "detected write past chunk end in %s %p",
                     set->header.name, chunk);
#endif
 
#ifdef CLOBBER_FREED_MEMORY
        wipe_mem(pointer, GetChunkSizeFromFreeListIdx(fidx));
#endif
        /* push this chunk onto the top of the free list */
        VALGRIND_MAKE_MEM_DEFINED(link, sizeof(AllocFreeListLink));
        link->next = set->freelist[fidx];
        VALGRIND_MAKE_MEM_NOACCESS(link, sizeof(AllocFreeListLink));
        set->freelist[fidx] = chunk;
 
#ifdef MEMORY_CONTEXT_CHECKING
 
        /*
         * Reset requested_size to InvalidAllocSize in chunks that are on free
         * list.
         */
        chunk->requested_size = InvalidAllocSize;
#endif
    }
}

References ALLOC_CHUNKHDRSZ, AllocBlockIsValid, AllocBlockData::aset, Assert(), AllocSetContext::blocks, elog(), AllocBlockData::endptr, ERROR, ExternalChunkGetBlock, free, AllocSetContext::freelist, FreeListIdxIsValid, AllocBlockData::freeptr, GetChunkSizeFromFreeListIdx, GetFreeListLink, AllocSetContext::header, InvalidAllocSize, link(), MemoryContextData::mem_allocated, MemoryChunkGetBlock(), MemoryChunkGetValue(), MemoryChunkIsExternal(), MemoryContextData::name, AllocBlockData::next, PointerGetMemoryChunk, AllocBlockData::prev, VALGRIND_MAKE_MEM_DEFINED, VALGRIND_MAKE_MEM_NOACCESS, and WARNING.

Referenced by AllocSetRealloc().

AllocSetGetChunkContext()

MemoryContext AllocSetGetChunkContext

(

void *

pointer

)

Definition at line 1370 of file aset.c.

{
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    AllocBlock  block;
    AllocSet    set;
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, ALLOC_CHUNKHDRSZ);
 
    if (MemoryChunkIsExternal(chunk))
        block = ExternalChunkGetBlock(chunk);
    else
        block = (AllocBlock) MemoryChunkGetBlock(chunk);
 
    /* Disallow access to the chunk header. */
    VALGRIND_MAKE_MEM_NOACCESS(chunk, ALLOC_CHUNKHDRSZ);
 
    Assert(AllocBlockIsValid(block));
    set = block->aset;
 
    return &set->header;
}

References ALLOC_CHUNKHDRSZ, AllocBlockIsValid, AllocBlockData::aset, Assert(), ExternalChunkGetBlock, AllocSetContext::header, MemoryChunkGetBlock(), MemoryChunkIsExternal(), PointerGetMemoryChunk, VALGRIND_MAKE_MEM_DEFINED, and VALGRIND_MAKE_MEM_NOACCESS.

AllocSetGetChunkSpace()

Size AllocSetGetChunkSpace

(

void *

pointer

)

Definition at line 1399 of file aset.c.

{
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    int         fidx;
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, ALLOC_CHUNKHDRSZ);
 
    if (MemoryChunkIsExternal(chunk))
    {
        AllocBlock  block = ExternalChunkGetBlock(chunk);
 
        /* Disallow access to the chunk header. */
        VALGRIND_MAKE_MEM_NOACCESS(chunk, ALLOC_CHUNKHDRSZ);
 
        Assert(AllocBlockIsValid(block));
 
        return block->endptr - (char *) chunk;
    }
 
    fidx = MemoryChunkGetValue(chunk);
    Assert(FreeListIdxIsValid(fidx));
 
    /* Disallow access to the chunk header. */
    VALGRIND_MAKE_MEM_NOACCESS(chunk, ALLOC_CHUNKHDRSZ);
 
    return GetChunkSizeFromFreeListIdx(fidx) + ALLOC_CHUNKHDRSZ;
}

References ALLOC_CHUNKHDRSZ, AllocBlockIsValid, Assert(), AllocBlockData::endptr, ExternalChunkGetBlock, FreeListIdxIsValid, GetChunkSizeFromFreeListIdx, MemoryChunkGetValue(), MemoryChunkIsExternal(), PointerGetMemoryChunk, VALGRIND_MAKE_MEM_DEFINED, and VALGRIND_MAKE_MEM_NOACCESS.

AllocSetIsEmpty()

bool AllocSetIsEmpty

(

MemoryContext

context

)

Definition at line 1433 of file aset.c.

{
    Assert(AllocSetIsValid(context));
 
    /*
     * For now, we say "empty" only if the context is new or just reset. We
     * could examine the freelists to determine if all space has been freed,
     * but it's not really worth the trouble for present uses of this
     * functionality.
     */
    if (context->isReset)
        return true;
    return false;
}

References AllocSetIsValid, Assert(), and MemoryContextData::isReset.

AllocSetRealloc()

void* AllocSetRealloc	(	void *	pointer,
		Size	size
	)

Definition at line 1109 of file aset.c.

{
    AllocBlock  block;
    AllocSet    set;
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    Size        oldchksize;
    int         fidx;
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, ALLOC_CHUNKHDRSZ);
 
    if (MemoryChunkIsExternal(chunk))
    {
        /*
         * The chunk must have been allocated as a single-chunk block.  Use
         * realloc() to make the containing block bigger, or smaller, with
         * minimum space wastage.
         */
        Size        chksize;
        Size        blksize;
        Size        oldblksize;
 
        block = ExternalChunkGetBlock(chunk);
 
        /*
         * Try to verify that we have a sane block pointer: the block header
         * should reference an aset and the freeptr should match the endptr.
         */
        if (!AllocBlockIsValid(block) || block->freeptr != block->endptr)
            elog(ERROR, "could not find block containing chunk %p", chunk);
 
        set = block->aset;
 
        oldchksize = block->endptr - (char *) pointer;
 
#ifdef MEMORY_CONTEXT_CHECKING
        /* Test for someone scribbling on unused space in chunk */
        Assert(chunk->requested_size < oldchksize);
        if (!sentinel_ok(pointer, chunk->requested_size))
            elog(WARNING, "detected write past chunk end in %s %p",
                 set->header.name, chunk);
#endif
 
#ifdef MEMORY_CONTEXT_CHECKING
        /* ensure there's always space for the sentinel byte */
        chksize = MAXALIGN(size + 1);
#else
        chksize = MAXALIGN(size);
#endif
 
        /* Do the realloc */
        blksize = chksize + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ;
        oldblksize = block->endptr - ((char *) block);
 
        block = (AllocBlock) realloc(block, blksize);
        if (block == NULL)
        {
            /* Disallow access to the chunk header. */
            VALGRIND_MAKE_MEM_NOACCESS(chunk, ALLOC_CHUNKHDRSZ);
            return NULL;
        }
 
        /* updated separately, not to underflow when (oldblksize > blksize) */
        set->header.mem_allocated -= oldblksize;
        set->header.mem_allocated += blksize;
 
        block->freeptr = block->endptr = ((char *) block) + blksize;
 
        /* Update pointers since block has likely been moved */
        chunk = (MemoryChunk *) (((char *) block) + ALLOC_BLOCKHDRSZ);
        pointer = MemoryChunkGetPointer(chunk);
        if (block->prev)
            block->prev->next = block;
        else
            set->blocks = block;
        if (block->next)
            block->next->prev = block;
 
#ifdef MEMORY_CONTEXT_CHECKING
#ifdef RANDOMIZE_ALLOCATED_MEMORY
 
        /*
         * We can only randomize the extra space if we know the prior request.
         * When using Valgrind, randomize_mem() also marks memory UNDEFINED.
         */
        if (size > chunk->requested_size)
            randomize_mem((char *) pointer + chunk->requested_size,
                          size - chunk->requested_size);
#else
 
        /*
         * If this is an increase, realloc() will have marked any
         * newly-allocated part (from oldchksize to chksize) UNDEFINED, but we
         * also need to adjust trailing bytes from the old allocation (from
         * chunk->requested_size to oldchksize) as they are marked NOACCESS.
         * Make sure not to mark too many bytes in case chunk->requested_size
         * < size < oldchksize.
         */
#ifdef USE_VALGRIND
        if (Min(size, oldchksize) > chunk->requested_size)
            VALGRIND_MAKE_MEM_UNDEFINED((char *) pointer + chunk->requested_size,
                                        Min(size, oldchksize) - chunk->requested_size);
#endif
#endif
 
        chunk->requested_size = size;
        /* set mark to catch clobber of "unused" space */
        Assert(size < chksize);
        set_sentinel(pointer, size);
#else                           /* !MEMORY_CONTEXT_CHECKING */
 
        /*
         * We may need to adjust marking of bytes from the old allocation as
         * some of them may be marked NOACCESS.  We don't know how much of the
         * old chunk size was the requested size; it could have been as small
         * as one byte.  We have to be conservative and just mark the entire
         * old portion DEFINED.  Make sure not to mark memory beyond the new
         * allocation in case it's smaller than the old one.
         */
        VALGRIND_MAKE_MEM_DEFINED(pointer, Min(size, oldchksize));
#endif
 
        /* Ensure any padding bytes are marked NOACCESS. */
        VALGRIND_MAKE_MEM_NOACCESS((char *) pointer + size, chksize - size);
 
        /* Disallow access to the chunk header . */
        VALGRIND_MAKE_MEM_NOACCESS(chunk, ALLOC_CHUNKHDRSZ);
 
        return pointer;
    }
 
    block = MemoryChunkGetBlock(chunk);
 
    /*
     * In this path, for speed reasons we just Assert that the referenced
     * block is good. We can also Assert that the value field is sane. Future
     * field experience may show that these Asserts had better become regular
     * runtime test-and-elog checks.
     */
    Assert(AllocBlockIsValid(block));
    set = block->aset;
 
    fidx = MemoryChunkGetValue(chunk);
    Assert(FreeListIdxIsValid(fidx));
    oldchksize = GetChunkSizeFromFreeListIdx(fidx);
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* Test for someone scribbling on unused space in chunk */
    if (chunk->requested_size < oldchksize)
        if (!sentinel_ok(pointer, chunk->requested_size))
            elog(WARNING, "detected write past chunk end in %s %p",
                 set->header.name, chunk);
#endif
 
    /*
     * Chunk sizes are aligned to power of 2 in AllocSetAlloc().  Maybe the
     * allocated area already is >= the new size.  (In particular, we will
     * fall out here if the requested size is a decrease.)
     */
    if (oldchksize >= size)
    {
#ifdef MEMORY_CONTEXT_CHECKING
        Size        oldrequest = chunk->requested_size;
 
#ifdef RANDOMIZE_ALLOCATED_MEMORY
        /* We can only fill the extra space if we know the prior request */
        if (size > oldrequest)
            randomize_mem((char *) pointer + oldrequest,
                          size - oldrequest);
#endif
 
        chunk->requested_size = size;
 
        /*
         * If this is an increase, mark any newly-available part UNDEFINED.
         * Otherwise, mark the obsolete part NOACCESS.
         */
        if (size > oldrequest)
            VALGRIND_MAKE_MEM_UNDEFINED((char *) pointer + oldrequest,
                                        size - oldrequest);
        else
            VALGRIND_MAKE_MEM_NOACCESS((char *) pointer + size,
                                       oldchksize - size);
 
        /* set mark to catch clobber of "unused" space */
        if (size < oldchksize)
            set_sentinel(pointer, size);
#else                           /* !MEMORY_CONTEXT_CHECKING */
 
        /*
         * We don't have the information to determine whether we're growing
         * the old request or shrinking it, so we conservatively mark the
         * entire new allocation DEFINED.
         */
        VALGRIND_MAKE_MEM_NOACCESS(pointer, oldchksize);
        VALGRIND_MAKE_MEM_DEFINED(pointer, size);
#endif
 
        /* Disallow access to the chunk header. */
        VALGRIND_MAKE_MEM_NOACCESS(chunk, ALLOC_CHUNKHDRSZ);
 
        return pointer;
    }
    else
    {
        /*
         * Enlarge-a-small-chunk case.  We just do this by brute force, ie,
         * allocate a new chunk and copy the data.  Since we know the existing
         * data isn't huge, this won't involve any great memcpy expense, so
         * it's not worth being smarter.  (At one time we tried to avoid
         * memcpy when it was possible to enlarge the chunk in-place, but that
         * turns out to misbehave unpleasantly for repeated cycles of
         * palloc/repalloc/pfree: the eventually freed chunks go into the
         * wrong freelist for the next initial palloc request, and so we leak
         * memory indefinitely.  See pgsql-hackers archives for 2007-08-11.)
         */
        AllocPointer newPointer;
        Size        oldsize;
 
        /* allocate new chunk */
        newPointer = AllocSetAlloc((MemoryContext) set, size);
 
        /* leave immediately if request was not completed */
        if (newPointer == NULL)
        {
            /* Disallow access to the chunk header. */
            VALGRIND_MAKE_MEM_NOACCESS(chunk, ALLOC_CHUNKHDRSZ);
            return NULL;
        }
 
        /*
         * AllocSetAlloc() may have returned a region that is still NOACCESS.
         * Change it to UNDEFINED for the moment; memcpy() will then transfer
         * definedness from the old allocation to the new.  If we know the old
         * allocation, copy just that much.  Otherwise, make the entire old
         * chunk defined to avoid errors as we copy the currently-NOACCESS
         * trailing bytes.
         */
        VALGRIND_MAKE_MEM_UNDEFINED(newPointer, size);
#ifdef MEMORY_CONTEXT_CHECKING
        oldsize = chunk->requested_size;
#else
        oldsize = oldchksize;
        VALGRIND_MAKE_MEM_DEFINED(pointer, oldsize);
#endif
 
        /* transfer existing data (certain to fit) */
        memcpy(newPointer, pointer, oldsize);
 
        /* free old chunk */
        AllocSetFree(pointer);
 
        return newPointer;
    }
}

References ALLOC_BLOCKHDRSZ, ALLOC_CHUNKHDRSZ, AllocBlockIsValid, AllocSetAlloc(), AllocSetFree(), AllocBlockData::aset, Assert(), AllocSetContext::blocks, elog(), AllocBlockData::endptr, ERROR, ExternalChunkGetBlock, FreeListIdxIsValid, AllocBlockData::freeptr, GetChunkSizeFromFreeListIdx, AllocSetContext::header, MAXALIGN, MemoryContextData::mem_allocated, MemoryChunkGetBlock(), MemoryChunkGetPointer, MemoryChunkGetValue(), MemoryChunkIsExternal(), Min, MemoryContextData::name, AllocBlockData::next, PointerGetMemoryChunk, AllocBlockData::prev, realloc, VALGRIND_MAKE_MEM_DEFINED, VALGRIND_MAKE_MEM_NOACCESS, VALGRIND_MAKE_MEM_UNDEFINED, and WARNING.

AllocSetReset()

void AllocSetReset

(

MemoryContext

context

)

Definition at line 537 of file aset.c.

{
    AllocSet    set = (AllocSet) context;
    AllocBlock  block;
    Size        keepersize PG_USED_FOR_ASSERTS_ONLY;
 
    Assert(AllocSetIsValid(set));
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* Check for corruption and leaks before freeing */
    AllocSetCheck(context);
#endif
 
    /* Remember keeper block size for Assert below */
    keepersize = KeeperBlock(set)->endptr - ((char *) set);
 
    /* Clear chunk freelists */
    MemSetAligned(set->freelist, 0, sizeof(set->freelist));
 
    block = set->blocks;
 
    /* New blocks list will be just the keeper block */
    set->blocks = KeeperBlock(set);
 
    while (block != NULL)
    {
        AllocBlock  next = block->next;
 
        if (IsKeeperBlock(set, block))
        {
            /* Reset the block, but don't return it to malloc */
            char       *datastart = ((char *) block) + ALLOC_BLOCKHDRSZ;
 
#ifdef CLOBBER_FREED_MEMORY
            wipe_mem(datastart, block->freeptr - datastart);
#else
            /* wipe_mem() would have done this */
            VALGRIND_MAKE_MEM_NOACCESS(datastart, block->freeptr - datastart);
#endif
            block->freeptr = datastart;
            block->prev = NULL;
            block->next = NULL;
        }
        else
        {
            /* Normal case, release the block */
            context->mem_allocated -= block->endptr - ((char *) block);
 
#ifdef CLOBBER_FREED_MEMORY
            wipe_mem(block, block->freeptr - ((char *) block));
#endif
            free(block);
        }
        block = next;
    }
 
    Assert(context->mem_allocated == keepersize);
 
    /* Reset block size allocation sequence, too */
    set->nextBlockSize = set->initBlockSize;
}

References ALLOC_BLOCKHDRSZ, AllocSetIsValid, Assert(), AllocSetContext::blocks, AllocBlockData::endptr, free, AllocSetContext::freelist, AllocBlockData::freeptr, AllocSetContext::initBlockSize, IsKeeperBlock, KeeperBlock, MemoryContextData::mem_allocated, MemSetAligned, next, AllocBlockData::next, AllocSetContext::nextBlockSize, PG_USED_FOR_ASSERTS_ONLY, AllocBlockData::prev, and VALGRIND_MAKE_MEM_NOACCESS.

AllocSetStats()

void AllocSetStats	(	MemoryContext	context,
		MemoryStatsPrintFunc	printfunc,
		void *	passthru,
		MemoryContextCounters *	totals,
		bool	print_to_stderr
	)

Definition at line 1458 of file aset.c.

{
    AllocSet    set = (AllocSet) context;
    Size        nblocks = 0;
    Size        freechunks = 0;
    Size        totalspace;
    Size        freespace = 0;
    AllocBlock  block;
    int         fidx;
 
    Assert(AllocSetIsValid(set));
 
    /* Include context header in totalspace */
    totalspace = MAXALIGN(sizeof(AllocSetContext));
 
    for (block = set->blocks; block != NULL; block = block->next)
    {
        nblocks++;
        totalspace += block->endptr - ((char *) block);
        freespace += block->endptr - block->freeptr;
    }
    for (fidx = 0; fidx < ALLOCSET_NUM_FREELISTS; fidx++)
    {
        Size        chksz = GetChunkSizeFromFreeListIdx(fidx);
        MemoryChunk *chunk = set->freelist[fidx];
 
        while (chunk != NULL)
        {
            AllocFreeListLink *link = GetFreeListLink(chunk);
 
            /* Allow access to the chunk header. */
            VALGRIND_MAKE_MEM_DEFINED(chunk, ALLOC_CHUNKHDRSZ);
            Assert(MemoryChunkGetValue(chunk) == fidx);
            VALGRIND_MAKE_MEM_NOACCESS(chunk, ALLOC_CHUNKHDRSZ);
 
            freechunks++;
            freespace += chksz + ALLOC_CHUNKHDRSZ;
 
            VALGRIND_MAKE_MEM_DEFINED(link, sizeof(AllocFreeListLink));
            chunk = link->next;
            VALGRIND_MAKE_MEM_NOACCESS(link, sizeof(AllocFreeListLink));
        }
    }
 
    if (printfunc)
    {
        char        stats_string[200];
 
        snprintf(stats_string, sizeof(stats_string),
                 "%zu total in %zu blocks; %zu free (%zu chunks); %zu used",
                 totalspace, nblocks, freespace, freechunks,
                 totalspace - freespace);
        printfunc(context, passthru, stats_string, print_to_stderr);
    }
 
    if (totals)
    {
        totals->nblocks += nblocks;
        totals->freechunks += freechunks;
        totals->totalspace += totalspace;
        totals->freespace += freespace;
    }
}

References ALLOC_CHUNKHDRSZ, ALLOCSET_NUM_FREELISTS, AllocSetIsValid, Assert(), AllocSetContext::blocks, AllocBlockData::endptr, MemoryContextCounters::freechunks, AllocSetContext::freelist, AllocBlockData::freeptr, MemoryContextCounters::freespace, GetChunkSizeFromFreeListIdx, GetFreeListLink, MAXALIGN, MemoryChunkGetValue(), MemoryContextCounters::nblocks, AllocBlockData::next, snprintf, MemoryContextCounters::totalspace, VALGRIND_MAKE_MEM_DEFINED, and VALGRIND_MAKE_MEM_NOACCESS.

GenerationAlloc()

void* GenerationAlloc	(	MemoryContext	context,
		Size	size
	)

Definition at line 345 of file generation.c.

{
    GenerationContext *set = (GenerationContext *) context;
    GenerationBlock *block;
    MemoryChunk *chunk;
    Size        chunk_size;
    Size        required_size;
 
    Assert(GenerationIsValid(set));
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* ensure there's always space for the sentinel byte */
    chunk_size = MAXALIGN(size + 1);
#else
    chunk_size = MAXALIGN(size);
#endif
    required_size = chunk_size + Generation_CHUNKHDRSZ;
 
    /* is it an over-sized chunk? if yes, allocate special block */
    if (chunk_size > set->allocChunkLimit)
    {
        Size        blksize = required_size + Generation_BLOCKHDRSZ;
 
        block = (GenerationBlock *) malloc(blksize);
        if (block == NULL)
            return NULL;
 
        context->mem_allocated += blksize;
 
        /* block with a single (used) chunk */
        block->context = set;
        block->blksize = blksize;
        block->nchunks = 1;
        block->nfree = 0;
 
        /* the block is completely full */
        block->freeptr = block->endptr = ((char *) block) + blksize;
 
        chunk = (MemoryChunk *) (((char *) block) + Generation_BLOCKHDRSZ);
 
        /* mark the MemoryChunk as externally managed */
        MemoryChunkSetHdrMaskExternal(chunk, MCTX_GENERATION_ID);
 
#ifdef MEMORY_CONTEXT_CHECKING
        chunk->requested_size = size;
        /* set mark to catch clobber of "unused" space */
        Assert(size < chunk_size);
        set_sentinel(MemoryChunkGetPointer(chunk), size);
#endif
#ifdef RANDOMIZE_ALLOCATED_MEMORY
        /* fill the allocated space with junk */
        randomize_mem((char *) MemoryChunkGetPointer(chunk), size);
#endif
 
        /* add the block to the list of allocated blocks */
        dlist_push_head(&set->blocks, &block->node);
 
        /* Ensure any padding bytes are marked NOACCESS. */
        VALGRIND_MAKE_MEM_NOACCESS((char *) MemoryChunkGetPointer(chunk) + size,
                                   chunk_size - size);
 
        /* Disallow access to the chunk header. */
        VALGRIND_MAKE_MEM_NOACCESS(chunk, Generation_CHUNKHDRSZ);
 
        return MemoryChunkGetPointer(chunk);
    }
 
    /*
     * Not an oversized chunk.  We try to first make use of the current block,
     * but if there's not enough space in it, instead of allocating a new
     * block, we look to see if the freeblock is empty and has enough space.
     * If not, we'll also try the same using the keeper block.  The keeper
     * block may have become empty and we have no other way to reuse it again
     * if we don't try to use it explicitly here.
     *
     * We don't want to start filling the freeblock before the current block
     * is full, otherwise we may cause fragmentation in FIFO type workloads.
     * We only switch to using the freeblock or keeper block if those blocks
     * are completely empty.  If we didn't do that we could end up fragmenting
     * consecutive allocations over multiple blocks which would be a problem
     * that would compound over time.
     */
    block = set->block;
 
    if (block == NULL ||
        GenerationBlockFreeBytes(block) < required_size)
    {
        Size        blksize;
        GenerationBlock *freeblock = set->freeblock;
 
        if (freeblock != NULL &&
            GenerationBlockIsEmpty(freeblock) &&
            GenerationBlockFreeBytes(freeblock) >= required_size)
        {
            block = freeblock;
 
            /*
             * Zero out the freeblock as we'll set this to the current block
             * below
             */
            set->freeblock = NULL;
        }
        else if (GenerationBlockIsEmpty(KeeperBlock(set)) &&
                 GenerationBlockFreeBytes(KeeperBlock(set)) >= required_size)
        {
            block = KeeperBlock(set);
        }
        else
        {
            /*
             * The first such block has size initBlockSize, and we double the
             * space in each succeeding block, but not more than maxBlockSize.
             */
            blksize = set->nextBlockSize;
            set->nextBlockSize <<= 1;
            if (set->nextBlockSize > set->maxBlockSize)
                set->nextBlockSize = set->maxBlockSize;
 
            /* we'll need a block hdr too, so add that to the required size */
            required_size += Generation_BLOCKHDRSZ;
 
            /* round the size up to the next power of 2 */
            if (blksize < required_size)
                blksize = pg_nextpower2_size_t(required_size);
 
            block = (GenerationBlock *) malloc(blksize);
 
            if (block == NULL)
                return NULL;
 
            context->mem_allocated += blksize;
 
            /* initialize the new block */
            GenerationBlockInit(set, block, blksize);
 
            /* add it to the doubly-linked list of blocks */
            dlist_push_head(&set->blocks, &block->node);
 
            /* Zero out the freeblock in case it's become full */
            set->freeblock = NULL;
        }
 
        /* and also use it as the current allocation block */
        set->block = block;
    }
 
    /* we're supposed to have a block with enough free space now */
    Assert(block != NULL);
    Assert((block->endptr - block->freeptr) >= Generation_CHUNKHDRSZ + chunk_size);
 
    chunk = (MemoryChunk *) block->freeptr;
 
    /* Prepare to initialize the chunk header. */
    VALGRIND_MAKE_MEM_UNDEFINED(chunk, Generation_CHUNKHDRSZ);
 
    block->nchunks += 1;
    block->freeptr += (Generation_CHUNKHDRSZ + chunk_size);
 
    Assert(block->freeptr <= block->endptr);
 
    MemoryChunkSetHdrMask(chunk, block, chunk_size, MCTX_GENERATION_ID);
#ifdef MEMORY_CONTEXT_CHECKING
    chunk->requested_size = size;
    /* set mark to catch clobber of "unused" space */
    Assert(size < chunk_size);
    set_sentinel(MemoryChunkGetPointer(chunk), size);
#endif
#ifdef RANDOMIZE_ALLOCATED_MEMORY
    /* fill the allocated space with junk */
    randomize_mem((char *) MemoryChunkGetPointer(chunk), size);
#endif
 
    /* Ensure any padding bytes are marked NOACCESS. */
    VALGRIND_MAKE_MEM_NOACCESS((char *) MemoryChunkGetPointer(chunk) + size,
                               chunk_size - size);
 
    /* Disallow access to the chunk header. */
    VALGRIND_MAKE_MEM_NOACCESS(chunk, Generation_CHUNKHDRSZ);
 
    return MemoryChunkGetPointer(chunk);
}

References GenerationContext::allocChunkLimit, Assert(), GenerationBlock::blksize, GenerationContext::block, GenerationContext::blocks, GenerationBlock::context, dlist_push_head(), GenerationBlock::endptr, GenerationContext::freeblock, GenerationBlock::freeptr, Generation_BLOCKHDRSZ, Generation_CHUNKHDRSZ, GenerationBlockFreeBytes(), GenerationBlockInit(), GenerationBlockIsEmpty(), GenerationIsValid, KeeperBlock, malloc, MAXALIGN, GenerationContext::maxBlockSize, MCTX_GENERATION_ID, MemoryContextData::mem_allocated, MemoryChunkGetPointer, MemoryChunkSetHdrMask(), MemoryChunkSetHdrMaskExternal(), GenerationBlock::nchunks, GenerationContext::nextBlockSize, GenerationBlock::nfree, GenerationBlock::node, pg_nextpower2_size_t, VALGRIND_MAKE_MEM_NOACCESS, and VALGRIND_MAKE_MEM_UNDEFINED.

Referenced by GenerationRealloc().

GenerationDelete()

void GenerationDelete

(

MemoryContext

context

)

Definition at line 323 of file generation.c.

{
    /* Reset to release all releasable GenerationBlocks */
    GenerationReset(context);
    /* And free the context header and keeper block */
    free(context);
}

References free, and GenerationReset().

GenerationFree()

void GenerationFree

(

void *

pointer

)

Definition at line 623 of file generation.c.

{
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    GenerationBlock *block;
    GenerationContext *set;
#if (defined(MEMORY_CONTEXT_CHECKING) && defined(USE_ASSERT_CHECKING)) \
    || defined(CLOBBER_FREED_MEMORY)
    Size        chunksize;
#endif
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, Generation_CHUNKHDRSZ);
 
    if (MemoryChunkIsExternal(chunk))
    {
        block = ExternalChunkGetBlock(chunk);
 
        /*
         * Try to verify that we have a sane block pointer: the block header
         * should reference a generation context.
         */
        if (!GenerationBlockIsValid(block))
            elog(ERROR, "could not find block containing chunk %p", chunk);
 
#if (defined(MEMORY_CONTEXT_CHECKING) && defined(USE_ASSERT_CHECKING)) \
    || defined(CLOBBER_FREED_MEMORY)
        chunksize = block->endptr - (char *) pointer;
#endif
    }
    else
    {
        block = MemoryChunkGetBlock(chunk);
 
        /*
         * In this path, for speed reasons we just Assert that the referenced
         * block is good.  Future field experience may show that this Assert
         * had better become a regular runtime test-and-elog check.
         */
        Assert(GenerationBlockIsValid(block));
 
#if (defined(MEMORY_CONTEXT_CHECKING) && defined(USE_ASSERT_CHECKING)) \
    || defined(CLOBBER_FREED_MEMORY)
        chunksize = MemoryChunkGetValue(chunk);
#endif
    }
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* Test for someone scribbling on unused space in chunk */
    Assert(chunk->requested_size < chunksize);
    if (!sentinel_ok(pointer, chunk->requested_size))
        elog(WARNING, "detected write past chunk end in %s %p",
             ((MemoryContext) block->context)->name, chunk);
#endif
 
#ifdef CLOBBER_FREED_MEMORY
    wipe_mem(pointer, chunksize);
#endif
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* Reset requested_size to InvalidAllocSize in freed chunks */
    chunk->requested_size = InvalidAllocSize;
#endif
 
    block->nfree += 1;
 
    Assert(block->nchunks > 0);
    Assert(block->nfree <= block->nchunks);
 
    /* If there are still allocated chunks in the block, we're done. */
    if (block->nfree < block->nchunks)
        return;
 
    set = block->context;
 
    /* Don't try to free the keeper block, just mark it empty */
    if (IsKeeperBlock(set, block))
    {
        GenerationBlockMarkEmpty(block);
        return;
    }
 
    /*
     * If there is no freeblock set or if this is the freeblock then instead
     * of freeing this memory, we keep it around so that new allocations have
     * the option of recycling it.
     */
    if (set->freeblock == NULL || set->freeblock == block)
    {
        /* XXX should we only recycle maxBlockSize sized blocks? */
        set->freeblock = block;
        GenerationBlockMarkEmpty(block);
        return;
    }
 
    /* Also make sure the block is not marked as the current block. */
    if (set->block == block)
        set->block = NULL;
 
    /*
     * The block is empty, so let's get rid of it. First remove it from the
     * list of blocks, then return it to malloc().
     */
    dlist_delete(&block->node);
 
    set->header.mem_allocated -= block->blksize;
    free(block);
}

References Assert(), GenerationBlock::blksize, GenerationContext::block, GenerationBlock::context, dlist_delete(), elog(), GenerationBlock::endptr, ERROR, ExternalChunkGetBlock, free, GenerationContext::freeblock, Generation_CHUNKHDRSZ, GenerationBlockIsValid, GenerationBlockMarkEmpty(), GenerationContext::header, InvalidAllocSize, IsKeeperBlock, MemoryContextData::mem_allocated, MemoryChunkGetBlock(), MemoryChunkGetValue(), MemoryChunkIsExternal(), GenerationBlock::nchunks, GenerationBlock::nfree, GenerationBlock::node, PointerGetMemoryChunk, VALGRIND_MAKE_MEM_DEFINED, and WARNING.

Referenced by GenerationRealloc().

GenerationGetChunkContext()

MemoryContext GenerationGetChunkContext

(

void *

pointer

)

Definition at line 880 of file generation.c.

{
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    GenerationBlock *block;
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, Generation_CHUNKHDRSZ);
 
    if (MemoryChunkIsExternal(chunk))
        block = ExternalChunkGetBlock(chunk);
    else
        block = (GenerationBlock *) MemoryChunkGetBlock(chunk);
 
    /* Disallow access to the chunk header. */
    VALGRIND_MAKE_MEM_NOACCESS(chunk, Generation_CHUNKHDRSZ);
 
    Assert(GenerationBlockIsValid(block));
    return &block->context->header;
}

References Assert(), GenerationBlock::context, ExternalChunkGetBlock, Generation_CHUNKHDRSZ, GenerationBlockIsValid, GenerationContext::header, MemoryChunkGetBlock(), MemoryChunkIsExternal(), PointerGetMemoryChunk, VALGRIND_MAKE_MEM_DEFINED, and VALGRIND_MAKE_MEM_NOACCESS.

GenerationGetChunkSpace()

Size GenerationGetChunkSpace

(

void *

pointer

)

Definition at line 906 of file generation.c.

{
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    Size        chunksize;
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, Generation_CHUNKHDRSZ);
 
    if (MemoryChunkIsExternal(chunk))
    {
        GenerationBlock *block = ExternalChunkGetBlock(chunk);
 
        Assert(GenerationBlockIsValid(block));
        chunksize = block->endptr - (char *) pointer;
    }
    else
        chunksize = MemoryChunkGetValue(chunk);
 
    /* Disallow access to the chunk header. */
    VALGRIND_MAKE_MEM_NOACCESS(chunk, Generation_CHUNKHDRSZ);
 
    return Generation_CHUNKHDRSZ + chunksize;
}

References Assert(), GenerationBlock::endptr, ExternalChunkGetBlock, Generation_CHUNKHDRSZ, GenerationBlockIsValid, MemoryChunkGetValue(), MemoryChunkIsExternal(), PointerGetMemoryChunk, VALGRIND_MAKE_MEM_DEFINED, and VALGRIND_MAKE_MEM_NOACCESS.

GenerationIsEmpty()

bool GenerationIsEmpty

(

MemoryContext

context

)

Definition at line 935 of file generation.c.

{
    GenerationContext *set = (GenerationContext *) context;
    dlist_iter  iter;
 
    Assert(GenerationIsValid(set));
 
    dlist_foreach(iter, &set->blocks)
    {
        GenerationBlock *block = dlist_container(GenerationBlock, node, iter.cur);
 
        if (block->nchunks > 0)
            return false;
    }
 
    return true;
}

References Assert(), GenerationContext::blocks, dlist_iter::cur, dlist_container, dlist_foreach, GenerationIsValid, and GenerationBlock::nchunks.

GenerationRealloc()

void* GenerationRealloc	(	void *	pointer,
		Size	size
	)

Definition at line 738 of file generation.c.

{
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    GenerationContext *set;
    GenerationBlock *block;
    GenerationPointer newPointer;
    Size        oldsize;
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, Generation_CHUNKHDRSZ);
 
    if (MemoryChunkIsExternal(chunk))
    {
        block = ExternalChunkGetBlock(chunk);
 
        /*
         * Try to verify that we have a sane block pointer: the block header
         * should reference a generation context.
         */
        if (!GenerationBlockIsValid(block))
            elog(ERROR, "could not find block containing chunk %p", chunk);
 
        oldsize = block->endptr - (char *) pointer;
    }
    else
    {
        block = MemoryChunkGetBlock(chunk);
 
        /*
         * In this path, for speed reasons we just Assert that the referenced
         * block is good.  Future field experience may show that this Assert
         * had better become a regular runtime test-and-elog check.
         */
        Assert(GenerationBlockIsValid(block));
 
        oldsize = MemoryChunkGetValue(chunk);
    }
 
    set = block->context;
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* Test for someone scribbling on unused space in chunk */
    Assert(chunk->requested_size < oldsize);
    if (!sentinel_ok(pointer, chunk->requested_size))
        elog(WARNING, "detected write past chunk end in %s %p",
             ((MemoryContext) set)->name, chunk);
#endif
 
    /*
     * Maybe the allocated area already is >= the new size.  (In particular,
     * we always fall out here if the requested size is a decrease.)
     *
     * This memory context does not use power-of-2 chunk sizing and instead
     * carves the chunks to be as small as possible, so most repalloc() calls
     * will end up in the palloc/memcpy/pfree branch.
     *
     * XXX Perhaps we should annotate this condition with unlikely()?
     */
    if (oldsize >= size)
    {
#ifdef MEMORY_CONTEXT_CHECKING
        Size        oldrequest = chunk->requested_size;
 
#ifdef RANDOMIZE_ALLOCATED_MEMORY
        /* We can only fill the extra space if we know the prior request */
        if (size > oldrequest)
            randomize_mem((char *) pointer + oldrequest,
                          size - oldrequest);
#endif
 
        chunk->requested_size = size;
 
        /*
         * If this is an increase, mark any newly-available part UNDEFINED.
         * Otherwise, mark the obsolete part NOACCESS.
         */
        if (size > oldrequest)
            VALGRIND_MAKE_MEM_UNDEFINED((char *) pointer + oldrequest,
                                        size - oldrequest);
        else
            VALGRIND_MAKE_MEM_NOACCESS((char *) pointer + size,
                                       oldsize - size);
 
        /* set mark to catch clobber of "unused" space */
        set_sentinel(pointer, size);
#else                           /* !MEMORY_CONTEXT_CHECKING */
 
        /*
         * We don't have the information to determine whether we're growing
         * the old request or shrinking it, so we conservatively mark the
         * entire new allocation DEFINED.
         */
        VALGRIND_MAKE_MEM_NOACCESS(pointer, oldsize);
        VALGRIND_MAKE_MEM_DEFINED(pointer, size);
#endif
 
        /* Disallow access to the chunk header. */
        VALGRIND_MAKE_MEM_NOACCESS(chunk, Generation_CHUNKHDRSZ);
 
        return pointer;
    }
 
    /* allocate new chunk */
    newPointer = GenerationAlloc((MemoryContext) set, size);
 
    /* leave immediately if request was not completed */
    if (newPointer == NULL)
    {
        /* Disallow access to the chunk header. */
        VALGRIND_MAKE_MEM_NOACCESS(chunk, Generation_CHUNKHDRSZ);
        return NULL;
    }
 
    /*
     * GenerationAlloc() may have returned a region that is still NOACCESS.
     * Change it to UNDEFINED for the moment; memcpy() will then transfer
     * definedness from the old allocation to the new.  If we know the old
     * allocation, copy just that much.  Otherwise, make the entire old chunk
     * defined to avoid errors as we copy the currently-NOACCESS trailing
     * bytes.
     */
    VALGRIND_MAKE_MEM_UNDEFINED(newPointer, size);
#ifdef MEMORY_CONTEXT_CHECKING
    oldsize = chunk->requested_size;
#else
    VALGRIND_MAKE_MEM_DEFINED(pointer, oldsize);
#endif
 
    /* transfer existing data (certain to fit) */
    memcpy(newPointer, pointer, oldsize);
 
    /* free old chunk */
    GenerationFree(pointer);
 
    return newPointer;
}

References Assert(), GenerationBlock::context, elog(), GenerationBlock::endptr, ERROR, ExternalChunkGetBlock, Generation_CHUNKHDRSZ, GenerationAlloc(), GenerationBlockIsValid, GenerationFree(), MemoryChunkGetBlock(), MemoryChunkGetValue(), MemoryChunkIsExternal(), name, PointerGetMemoryChunk, VALGRIND_MAKE_MEM_DEFINED, VALGRIND_MAKE_MEM_NOACCESS, VALGRIND_MAKE_MEM_UNDEFINED, and WARNING.

GenerationReset()

void GenerationReset

(

MemoryContext

context

)

Definition at line 278 of file generation.c.

{
    GenerationContext *set = (GenerationContext *) context;
    dlist_mutable_iter miter;
 
    Assert(GenerationIsValid(set));
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* Check for corruption and leaks before freeing */
    GenerationCheck(context);
#endif
 
    /*
     * NULLify the free block pointer.  We must do this before calling
     * GenerationBlockFree as that function never expects to free the
     * freeblock.
     */
    set->freeblock = NULL;
 
    dlist_foreach_modify(miter, &set->blocks)
    {
        GenerationBlock *block = dlist_container(GenerationBlock, node, miter.cur);
 
        if (IsKeeperBlock(set, block))
            GenerationBlockMarkEmpty(block);
        else
            GenerationBlockFree(set, block);
    }
 
    /* set it so new allocations to make use of the keeper block */
    set->block = KeeperBlock(set);
 
    /* Reset block size allocation sequence, too */
    set->nextBlockSize = set->initBlockSize;
 
    /* Ensure there is only 1 item in the dlist */
    Assert(!dlist_is_empty(&set->blocks));
    Assert(!dlist_has_next(&set->blocks, dlist_head_node(&set->blocks)));
}

References Assert(), GenerationContext::block, GenerationContext::blocks, dlist_mutable_iter::cur, dlist_container, dlist_foreach_modify, dlist_has_next(), dlist_head_node(), dlist_is_empty(), GenerationContext::freeblock, GenerationBlockFree(), GenerationBlockMarkEmpty(), GenerationIsValid, GenerationContext::initBlockSize, IsKeeperBlock, KeeperBlock, and GenerationContext::nextBlockSize.

Referenced by GenerationDelete().

GenerationStats()

void GenerationStats	(	MemoryContext	context,
		MemoryStatsPrintFunc	printfunc,
		void *	passthru,
		MemoryContextCounters *	totals,
		bool	print_to_stderr
	)

Definition at line 966 of file generation.c.

{
    GenerationContext *set = (GenerationContext *) context;
    Size        nblocks = 0;
    Size        nchunks = 0;
    Size        nfreechunks = 0;
    Size        totalspace;
    Size        freespace = 0;
    dlist_iter  iter;
 
    Assert(GenerationIsValid(set));
 
    /* Include context header in totalspace */
    totalspace = MAXALIGN(sizeof(GenerationContext));
 
    dlist_foreach(iter, &set->blocks)
    {
        GenerationBlock *block = dlist_container(GenerationBlock, node, iter.cur);
 
        nblocks++;
        nchunks += block->nchunks;
        nfreechunks += block->nfree;
        totalspace += block->blksize;
        freespace += (block->endptr - block->freeptr);
    }
 
    if (printfunc)
    {
        char        stats_string[200];
 
        snprintf(stats_string, sizeof(stats_string),
                 "%zu total in %zu blocks (%zu chunks); %zu free (%zu chunks); %zu used",
                 totalspace, nblocks, nchunks, freespace,
                 nfreechunks, totalspace - freespace);
        printfunc(context, passthru, stats_string, print_to_stderr);
    }
 
    if (totals)
    {
        totals->nblocks += nblocks;
        totals->freechunks += nfreechunks;
        totals->totalspace += totalspace;
        totals->freespace += freespace;
    }
}

References Assert(), GenerationBlock::blksize, GenerationContext::blocks, dlist_iter::cur, dlist_container, dlist_foreach, GenerationBlock::endptr, MemoryContextCounters::freechunks, GenerationBlock::freeptr, MemoryContextCounters::freespace, GenerationIsValid, MAXALIGN, MemoryContextCounters::nblocks, GenerationBlock::nchunks, GenerationBlock::nfree, snprintf, and MemoryContextCounters::totalspace.

MemoryContextCreate()

void MemoryContextCreate	(	MemoryContext	node,
		NodeTag	tag,
		MemoryContextMethodID	method_id,
		MemoryContext	parent,
		const char *	name
	)

Definition at line 973 of file mcxt.c.

{
    /* Creating new memory contexts is not allowed in a critical section */
    Assert(CritSectionCount == 0);
 
    /* Initialize all standard fields of memory context header */
    node->type = tag;
    node->isReset = true;
    node->methods = &mcxt_methods[method_id];
    node->parent = parent;
    node->firstchild = NULL;
    node->mem_allocated = 0;
    node->prevchild = NULL;
    node->name = name;
    node->ident = NULL;
    node->reset_cbs = NULL;
 
    /* OK to link node into context tree */
    if (parent)
    {
        node->nextchild = parent->firstchild;
        if (parent->firstchild != NULL)
            parent->firstchild->prevchild = node;
        parent->firstchild = node;
        /* inherit allowInCritSection flag from parent */
        node->allowInCritSection = parent->allowInCritSection;
    }
    else
    {
        node->nextchild = NULL;
        node->allowInCritSection = false;
    }
 
    VALGRIND_CREATE_MEMPOOL(node, 0, false);
}

References MemoryContextData::allowInCritSection, Assert(), CritSectionCount, MemoryContextData::firstchild, MemoryContextData::ident, MemoryContextData::isReset, mcxt_methods, MemoryContextData::mem_allocated, MemoryContextData::methods, name, MemoryContextData::name, MemoryContextData::nextchild, MemoryContextData::parent, MemoryContextData::prevchild, MemoryContextData::reset_cbs, and VALGRIND_CREATE_MEMPOOL.

Referenced by AllocSetContextCreateInternal(), GenerationContextCreate(), and SlabContextCreate().

SlabAlloc()

void* SlabAlloc	(	MemoryContext	context,
		Size	size
	)

Definition at line 499 of file slab.c.

{
    SlabContext *slab = (SlabContext *) context;
    SlabBlock  *block;
    MemoryChunk *chunk;
 
    Assert(SlabIsValid(slab));
 
    /* sanity check that this is pointing to a valid blocklist */
    Assert(slab->curBlocklistIndex >= 0);
    Assert(slab->curBlocklistIndex <= SlabBlocklistIndex(slab, slab->chunksPerBlock));
 
    /* make sure we only allow correct request size */
    if (unlikely(size != slab->chunkSize))
        elog(ERROR, "unexpected alloc chunk size %zu (expected %u)",
             size, slab->chunkSize);
 
    /*
     * Handle the case when there are no partially filled blocks available.
     * SlabFree() will have updated the curBlocklistIndex setting it to zero
     * to indicate that it has freed the final block.  Also later in
     * SlabAlloc() we will set the curBlocklistIndex to zero if we end up
     * filling the final block.
     */
    if (unlikely(slab->curBlocklistIndex == 0))
    {
        dlist_head *blocklist;
        int         blocklist_idx;
 
        /* to save allocating a new one, first check the empty blocks list */
        if (dclist_count(&slab->emptyblocks) > 0)
        {
            dlist_node *node = dclist_pop_head_node(&slab->emptyblocks);
 
            block = dlist_container(SlabBlock, node, node);
 
            /*
             * SlabFree() should have left this block in a valid state with
             * all chunks free.  Ensure that's the case.
             */
            Assert(block->nfree == slab->chunksPerBlock);
 
            /* fetch the next chunk from this block */
            chunk = SlabGetNextFreeChunk(slab, block);
        }
        else
        {
            block = (SlabBlock *) malloc(slab->blockSize);
 
            if (unlikely(block == NULL))
                return NULL;
 
            block->slab = slab;
            context->mem_allocated += slab->blockSize;
 
            /* use the first chunk in the new block */
            chunk = SlabBlockGetChunk(slab, block, 0);
 
            block->nfree = slab->chunksPerBlock - 1;
            block->unused = SlabBlockGetChunk(slab, block, 1);
            block->freehead = NULL;
            block->nunused = slab->chunksPerBlock - 1;
        }
 
        /* find the blocklist element for storing blocks with 1 used chunk */
        blocklist_idx = SlabBlocklistIndex(slab, block->nfree);
        blocklist = &slab->blocklist[blocklist_idx];
 
        /* this better be empty.  We just added a block thinking it was */
        Assert(dlist_is_empty(blocklist));
 
        dlist_push_head(blocklist, &block->node);
 
        slab->curBlocklistIndex = blocklist_idx;
    }
    else
    {
        dlist_head *blocklist = &slab->blocklist[slab->curBlocklistIndex];
        int         new_blocklist_idx;
 
        Assert(!dlist_is_empty(blocklist));
 
        /* grab the block from the blocklist */
        block = dlist_head_element(SlabBlock, node, blocklist);
 
        /* make sure we actually got a valid block, with matching nfree */
        Assert(block != NULL);
        Assert(slab->curBlocklistIndex == SlabBlocklistIndex(slab, block->nfree));
        Assert(block->nfree > 0);
 
        /* fetch the next chunk from this block */
        chunk = SlabGetNextFreeChunk(slab, block);
 
        /* get the new blocklist index based on the new free chunk count */
        new_blocklist_idx = SlabBlocklistIndex(slab, block->nfree);
 
        /*
         * Handle the case where the blocklist index changes.  This also deals
         * with blocks becoming full as only full blocks go at index 0.
         */
        if (unlikely(slab->curBlocklistIndex != new_blocklist_idx))
        {
            dlist_delete_from(blocklist, &block->node);
            dlist_push_head(&slab->blocklist[new_blocklist_idx], &block->node);
 
            if (dlist_is_empty(blocklist))
                slab->curBlocklistIndex = SlabFindNextBlockListIndex(slab);
        }
    }
 
    /*
     * Check that the chunk pointer is actually somewhere on the block and is
     * aligned as expected.
     */
    Assert(chunk >= SlabBlockGetChunk(slab, block, 0));
    Assert(chunk <= SlabBlockGetChunk(slab, block, slab->chunksPerBlock - 1));
    Assert(SlabChunkMod(slab, block, chunk) == 0);
 
    /* Prepare to initialize the chunk header. */
    VALGRIND_MAKE_MEM_UNDEFINED(chunk, Slab_CHUNKHDRSZ);
 
    MemoryChunkSetHdrMask(chunk, block, MAXALIGN(slab->chunkSize),
                          MCTX_SLAB_ID);
#ifdef MEMORY_CONTEXT_CHECKING
    /* slab mark to catch clobber of "unused" space */
    Assert(slab->chunkSize < (slab->fullChunkSize - Slab_CHUNKHDRSZ));
    set_sentinel(MemoryChunkGetPointer(chunk), size);
    VALGRIND_MAKE_MEM_NOACCESS(((char *) chunk) +
                               Slab_CHUNKHDRSZ + slab->chunkSize,
                               slab->fullChunkSize -
                               (slab->chunkSize + Slab_CHUNKHDRSZ));
#endif
 
#ifdef RANDOMIZE_ALLOCATED_MEMORY
    /* fill the allocated space with junk */
    randomize_mem((char *) MemoryChunkGetPointer(chunk), size);
#endif
 
    /* Disallow access to the chunk header. */
    VALGRIND_MAKE_MEM_NOACCESS(chunk, Slab_CHUNKHDRSZ);
 
    return MemoryChunkGetPointer(chunk);
}

References Assert(), SlabContext::blocklist, SlabContext::blockSize, SlabContext::chunkSize, SlabContext::chunksPerBlock, SlabContext::curBlocklistIndex, dclist_count(), dclist_pop_head_node(), dlist_container, dlist_delete_from(), dlist_head_element, dlist_is_empty(), dlist_push_head(), elog(), SlabContext::emptyblocks, ERROR, SlabBlock::freehead, SlabContext::fullChunkSize, malloc, MAXALIGN, MCTX_SLAB_ID, MemoryContextData::mem_allocated, MemoryChunkGetPointer, MemoryChunkSetHdrMask(), SlabBlock::nfree, SlabBlock::node, SlabBlock::nunused, SlabBlock::slab, Slab_CHUNKHDRSZ, SlabBlockGetChunk, SlabBlocklistIndex(), SlabFindNextBlockListIndex(), SlabGetNextFreeChunk(), SlabIsValid, unlikely, SlabBlock::unused, VALGRIND_MAKE_MEM_NOACCESS, and VALGRIND_MAKE_MEM_UNDEFINED.

SlabDelete()

void SlabDelete

(

MemoryContext

context

)

Definition at line 485 of file slab.c.

{
    /* Reset to release all the SlabBlocks */
    SlabReset(context);
    /* And free the context header */
    free(context);
}

References free, and SlabReset().

SlabFree()

void SlabFree

(

void *

pointer

)

Definition at line 648 of file slab.c.

{
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    SlabBlock  *block;
    SlabContext *slab;
    int         curBlocklistIdx;
    int         newBlocklistIdx;
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, Slab_CHUNKHDRSZ);
 
    block = MemoryChunkGetBlock(chunk);
 
    /*
     * For speed reasons we just Assert that the referenced block is good.
     * Future field experience may show that this Assert had better become a
     * regular runtime test-and-elog check.
     */
    Assert(SlabBlockIsValid(block));
    slab = block->slab;
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* Test for someone scribbling on unused space in chunk */
    Assert(slab->chunkSize < (slab->fullChunkSize - Slab_CHUNKHDRSZ));
    if (!sentinel_ok(pointer, slab->chunkSize))
        elog(WARNING, "detected write past chunk end in %s %p",
             slab->header.name, chunk);
#endif
 
    /* push this chunk onto the head of the block's free list */
    *(MemoryChunk **) pointer = block->freehead;
    block->freehead = chunk;
 
    block->nfree++;
 
    Assert(block->nfree > 0);
    Assert(block->nfree <= slab->chunksPerBlock);
 
#ifdef CLOBBER_FREED_MEMORY
    /* don't wipe the free list MemoryChunk pointer stored in the chunk */
    wipe_mem((char *) pointer + sizeof(MemoryChunk *),
             slab->chunkSize - sizeof(MemoryChunk *));
#endif
 
    curBlocklistIdx = SlabBlocklistIndex(slab, block->nfree - 1);
    newBlocklistIdx = SlabBlocklistIndex(slab, block->nfree);
 
    /*
     * Check if the block needs to be moved to another element on the
     * blocklist based on it now having 1 more free chunk.
     */
    if (unlikely(curBlocklistIdx != newBlocklistIdx))
    {
        /* do the move */
        dlist_delete_from(&slab->blocklist[curBlocklistIdx], &block->node);
        dlist_push_head(&slab->blocklist[newBlocklistIdx], &block->node);
 
        /*
         * The blocklist[curBlocklistIdx] may now be empty or we may now be
         * able to use a lower-element blocklist.  We'll need to redetermine
         * what the slab->curBlocklistIndex is if the current blocklist was
         * changed or if a lower element one was changed.  We must ensure we
         * use the list with the fullest block(s).
         */
        if (slab->curBlocklistIndex >= curBlocklistIdx)
        {
            slab->curBlocklistIndex = SlabFindNextBlockListIndex(slab);
 
            /*
             * We know there must be a block with at least 1 unused chunk as
             * we just pfree'd one.  Ensure curBlocklistIndex reflects this.
             */
            Assert(slab->curBlocklistIndex > 0);
        }
    }
 
    /* Handle when a block becomes completely empty */
    if (unlikely(block->nfree == slab->chunksPerBlock))
    {
        /* remove the block */
        dlist_delete_from(&slab->blocklist[newBlocklistIdx], &block->node);
 
        /*
         * To avoid thrashing malloc/free, we keep a list of empty blocks that
         * we can reuse again instead of having to malloc a new one.
         */
        if (dclist_count(&slab->emptyblocks) < SLAB_MAXIMUM_EMPTY_BLOCKS)
            dclist_push_head(&slab->emptyblocks, &block->node);
        else
        {
            /*
             * When we have enough empty blocks stored already, we actually
             * free the block.
             */
#ifdef CLOBBER_FREED_MEMORY
            wipe_mem(block, slab->blockSize);
#endif
            free(block);
            slab->header.mem_allocated -= slab->blockSize;
        }
 
        /*
         * Check if we need to reset the blocklist index.  This is required
         * when the blocklist this block is on has become completely empty.
         */
        if (slab->curBlocklistIndex == newBlocklistIdx &&
            dlist_is_empty(&slab->blocklist[newBlocklistIdx]))
            slab->curBlocklistIndex = SlabFindNextBlockListIndex(slab);
    }
}

References Assert(), SlabContext::blocklist, SlabContext::blockSize, SlabContext::chunkSize, SlabContext::chunksPerBlock, SlabContext::curBlocklistIndex, dclist_count(), dclist_push_head(), dlist_delete_from(), dlist_is_empty(), dlist_push_head(), elog(), SlabContext::emptyblocks, free, SlabBlock::freehead, SlabContext::fullChunkSize, SlabContext::header, MemoryContextData::mem_allocated, MemoryChunkGetBlock(), MemoryContextData::name, SlabBlock::nfree, SlabBlock::node, PointerGetMemoryChunk, SlabBlock::slab, Slab_CHUNKHDRSZ, SLAB_MAXIMUM_EMPTY_BLOCKS, SlabBlockIsValid, SlabBlocklistIndex(), SlabFindNextBlockListIndex(), unlikely, VALGRIND_MAKE_MEM_DEFINED, and WARNING.

SlabGetChunkContext()

MemoryContext SlabGetChunkContext

(

void *

pointer

)

Definition at line 810 of file slab.c.

{
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    SlabBlock  *block;
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, Slab_CHUNKHDRSZ);
 
    block = MemoryChunkGetBlock(chunk);
 
    /* Disallow access to the chunk header. */
    VALGRIND_MAKE_MEM_NOACCESS(chunk, Slab_CHUNKHDRSZ);
 
    Assert(SlabBlockIsValid(block));
 
    return &block->slab->header;
}

References Assert(), SlabContext::header, MemoryChunkGetBlock(), PointerGetMemoryChunk, SlabBlock::slab, Slab_CHUNKHDRSZ, SlabBlockIsValid, VALGRIND_MAKE_MEM_DEFINED, and VALGRIND_MAKE_MEM_NOACCESS.

SlabGetChunkSpace()

Size SlabGetChunkSpace

(

void *

pointer

)

Definition at line 834 of file slab.c.

{
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    SlabBlock  *block;
    SlabContext *slab;
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, Slab_CHUNKHDRSZ);
 
    block = MemoryChunkGetBlock(chunk);
 
    /* Disallow access to the chunk header. */
    VALGRIND_MAKE_MEM_NOACCESS(chunk, Slab_CHUNKHDRSZ);
 
    Assert(SlabBlockIsValid(block));
    slab = block->slab;
 
    return slab->fullChunkSize;
}

References Assert(), SlabContext::fullChunkSize, MemoryChunkGetBlock(), PointerGetMemoryChunk, SlabBlock::slab, Slab_CHUNKHDRSZ, SlabBlockIsValid, VALGRIND_MAKE_MEM_DEFINED, and VALGRIND_MAKE_MEM_NOACCESS.

SlabIsEmpty()

bool SlabIsEmpty

(

MemoryContext

context

)

Definition at line 859 of file slab.c.

{
    Assert(SlabIsValid((SlabContext *) context));
 
    return (context->mem_allocated == 0);
}

References Assert(), MemoryContextData::mem_allocated, and SlabIsValid.

SlabRealloc()

void* SlabRealloc	(	void *	pointer,
		Size	size
	)

Definition at line 773 of file slab.c.

{
    MemoryChunk *chunk = PointerGetMemoryChunk(pointer);
    SlabBlock  *block;
    SlabContext *slab;
 
    /* Allow access to the chunk header. */
    VALGRIND_MAKE_MEM_DEFINED(chunk, Slab_CHUNKHDRSZ);
 
    block = MemoryChunkGetBlock(chunk);
 
    /* Disallow access to the chunk header. */
    VALGRIND_MAKE_MEM_NOACCESS(chunk, Slab_CHUNKHDRSZ);
 
    /*
     * Try to verify that we have a sane block pointer: the block header
     * should reference a slab context.  (We use a test-and-elog, not just
     * Assert, because it seems highly likely that we're here in error in the
     * first place.)
     */
    if (!SlabBlockIsValid(block))
        elog(ERROR, "could not find block containing chunk %p", chunk);
    slab = block->slab;
 
    /* can't do actual realloc with slab, but let's try to be gentle */
    if (size == slab->chunkSize)
        return pointer;
 
    elog(ERROR, "slab allocator does not support realloc()");
    return NULL;                /* keep compiler quiet */
}

References SlabContext::chunkSize, elog(), ERROR, MemoryChunkGetBlock(), PointerGetMemoryChunk, SlabBlock::slab, Slab_CHUNKHDRSZ, SlabBlockIsValid, VALGRIND_MAKE_MEM_DEFINED, and VALGRIND_MAKE_MEM_NOACCESS.

SlabReset()

void SlabReset

(

MemoryContext

context

)

Definition at line 431 of file slab.c.

{
    SlabContext *slab = (SlabContext *) context;
    dlist_mutable_iter miter;
    int         i;
 
    Assert(SlabIsValid(slab));
 
#ifdef MEMORY_CONTEXT_CHECKING
    /* Check for corruption and leaks before freeing */
    SlabCheck(context);
#endif
 
    /* release any retained empty blocks */
    dclist_foreach_modify(miter, &slab->emptyblocks)
    {
        SlabBlock  *block = dlist_container(SlabBlock, node, miter.cur);
 
        dclist_delete_from(&slab->emptyblocks, miter.cur);
 
#ifdef CLOBBER_FREED_MEMORY
        wipe_mem(block, slab->blockSize);
#endif
        free(block);
        context->mem_allocated -= slab->blockSize;
    }
 
    /* walk over blocklist and free the blocks */
    for (i = 0; i < SLAB_BLOCKLIST_COUNT; i++)
    {
        dlist_foreach_modify(miter, &slab->blocklist[i])
        {
            SlabBlock  *block = dlist_container(SlabBlock, node, miter.cur);
 
            dlist_delete(miter.cur);
 
#ifdef CLOBBER_FREED_MEMORY
            wipe_mem(block, slab->blockSize);
#endif
            free(block);
            context->mem_allocated -= slab->blockSize;
        }
    }
 
    slab->curBlocklistIndex = 0;
 
    Assert(context->mem_allocated == 0);
}

References Assert(), SlabContext::blocklist, SlabContext::blockSize, dlist_mutable_iter::cur, SlabContext::curBlocklistIndex, dclist_delete_from(), dclist_foreach_modify, dlist_container, dlist_delete(), dlist_foreach_modify, SlabContext::emptyblocks, free, i, MemoryContextData::mem_allocated, SLAB_BLOCKLIST_COUNT, and SlabIsValid.

Referenced by SlabDelete().

SlabStats()

void SlabStats	(	MemoryContext	context,
		MemoryStatsPrintFunc	printfunc,
		void *	passthru,
		MemoryContextCounters *	totals,
		bool	print_to_stderr
	)

Definition at line 876 of file slab.c.

{
    SlabContext *slab = (SlabContext *) context;
    Size        nblocks = 0;
    Size        freechunks = 0;
    Size        totalspace;
    Size        freespace = 0;
    int         i;
 
    Assert(SlabIsValid(slab));
 
    /* Include context header in totalspace */
    totalspace = Slab_CONTEXT_HDRSZ(slab->chunksPerBlock);
 
    /* Add the space consumed by blocks in the emptyblocks list */
    totalspace += dclist_count(&slab->emptyblocks) * slab->blockSize;
 
    for (i = 0; i < SLAB_BLOCKLIST_COUNT; i++)
    {
        dlist_iter  iter;
 
        dlist_foreach(iter, &slab->blocklist[i])
        {
            SlabBlock  *block = dlist_container(SlabBlock, node, iter.cur);
 
            nblocks++;
            totalspace += slab->blockSize;
            freespace += slab->fullChunkSize * block->nfree;
            freechunks += block->nfree;
        }
    }
 
    if (printfunc)
    {
        char        stats_string[200];
 
        /* XXX should we include free chunks on empty blocks? */
        snprintf(stats_string, sizeof(stats_string),
                 "%zu total in %zu blocks; %u empty blocks; %zu free (%zu chunks); %zu used",
                 totalspace, nblocks, dclist_count(&slab->emptyblocks),
                 freespace, freechunks, totalspace - freespace);
        printfunc(context, passthru, stats_string, print_to_stderr);
    }
 
    if (totals)
    {
        totals->nblocks += nblocks;
        totals->freechunks += freechunks;
        totals->totalspace += totalspace;
        totals->freespace += freespace;
    }
}

References Assert(), SlabContext::blocklist, SlabContext::blockSize, SlabContext::chunksPerBlock, dlist_iter::cur, dclist_count(), dlist_container, dlist_foreach, SlabContext::emptyblocks, MemoryContextCounters::freechunks, MemoryContextCounters::freespace, SlabContext::fullChunkSize, i, MemoryContextCounters::nblocks, SlabBlock::nfree, SLAB_BLOCKLIST_COUNT, Slab_CONTEXT_HDRSZ, SlabIsValid, snprintf, and MemoryContextCounters::totalspace.