aset.c File Reference

#include "postgres.h"
#include "utils/memdebug.h"
#include "utils/memutils.h"

Include dependency graph for aset.c:

Go to the source code of this file.

Data Structures
struct	AllocSetContext
struct	AllocBlockData
struct	AllocChunkData

Macros
#define	ALLOC_MINBITS   3 /* smallest chunk size is 8 bytes */
#define	ALLOCSET_NUM_FREELISTS   11
#define	ALLOC_CHUNK_LIMIT   (1 << (ALLOCSET_NUM_FREELISTS-1+ALLOC_MINBITS))
#define	ALLOC_CHUNK_FRACTION   4
#define	ALLOC_BLOCKHDRSZ   MAXALIGN(sizeof(AllocBlockData))
#define	ALLOC_CHUNKHDRSZ   sizeof(struct AllocChunkData)
#define	AllocPointerIsValid(pointer)   PointerIsValid(pointer)
#define	AllocSetIsValid(set)   PointerIsValid(set)
#define	AllocPointerGetChunk(ptr)   ((AllocChunk)(((char *)(ptr)) - ALLOC_CHUNKHDRSZ))
#define	AllocChunkGetPointer(chk)   ((AllocPointer)(((char *)(chk)) + ALLOC_CHUNKHDRSZ))
#define	LT16(n)   n, n, n, n, n, n, n, n, n, n, n, n, n, n, n, n
#define	AllocFreeInfo(_cxt, _chunk)
#define	AllocAllocInfo(_cxt, _chunk)

Typedefs
typedef struct AllocBlockData *	AllocBlock
typedef struct AllocChunkData *	AllocChunk
typedef void *	AllocPointer
typedef struct AllocSetContext	AllocSetContext
typedef AllocSetContext *	AllocSet
typedef struct AllocBlockData	AllocBlockData
typedef struct AllocChunkData	AllocChunkData

Functions
static void *	AllocSetAlloc (MemoryContext context, Size size)
static void	AllocSetFree (MemoryContext context, void *pointer)
static void *	AllocSetRealloc (MemoryContext context, void *pointer, Size size)
static void	AllocSetInit (MemoryContext context)
static void	AllocSetReset (MemoryContext context)
static void	AllocSetDelete (MemoryContext context)
static Size	AllocSetGetChunkSpace (MemoryContext context, void *pointer)
static bool	AllocSetIsEmpty (MemoryContext context)
static void	AllocSetStats (MemoryContext context, int level, bool print, MemoryContextCounters *totals)
static int	AllocSetFreeIndex (Size size)
MemoryContext	AllocSetContextCreate (MemoryContext parent, const char *name, Size minContextSize, Size initBlockSize, Size maxBlockSize)

Variables
static MemoryContextMethods	AllocSetMethods
static const unsigned char	LogTable256 [256]

Macro Definition Documentation

#define ALLOC_BLOCKHDRSZ   MAXALIGN(sizeof(AllocBlockData))

Definition at line 99 of file aset.c.

Referenced by AllocSetAlloc(), AllocSetContextCreate(), AllocSetFree(), AllocSetRealloc(), and AllocSetReset().

#define ALLOC_CHUNK_FRACTION   4

Definition at line 85 of file aset.c.

Referenced by AllocSetContextCreate().

#define ALLOC_CHUNK_LIMIT   (1 << (ALLOCSET_NUM_FREELISTS-1+ALLOC_MINBITS))

Definition at line 83 of file aset.c.

Referenced by AllocSetContextCreate().

#define ALLOC_CHUNKHDRSZ   sizeof(struct AllocChunkData)

Definition at line 100 of file aset.c.

Referenced by AllocSetAlloc(), AllocSetContextCreate(), AllocSetFree(), AllocSetGetChunkSpace(), AllocSetRealloc(), and AllocSetStats().

#define ALLOC_MINBITS   3 /* smallest chunk size is 8 bytes */

Definition at line 81 of file aset.c.

Referenced by AllocSetAlloc(), and AllocSetFreeIndex().

#define AllocAllocInfo	(		_cxt,
			_chunk
	)

Definition at line 259 of file aset.c.

Referenced by AllocSetAlloc().

#define AllocChunkGetPointer

(

chk

)

((AllocPointer)(((char *)(chk)) + ALLOC_CHUNKHDRSZ))

Definition at line 195 of file aset.c.

Referenced by AllocSetAlloc(), and AllocSetRealloc().

#define AllocFreeInfo	(		_cxt,
			_chunk
	)

Definition at line 258 of file aset.c.

Referenced by AllocSetFree().

#define AllocPointerGetChunk

(

ptr

)

((AllocChunk)(((char *)(ptr)) - ALLOC_CHUNKHDRSZ))

Definition at line 193 of file aset.c.

Referenced by AllocSetFree(), AllocSetGetChunkSpace(), and AllocSetRealloc().

#define AllocPointerIsValid

(

pointer

)

PointerIsValid(pointer)

Definition at line 185 of file aset.c.

#define ALLOCSET_NUM_FREELISTS   11

Definition at line 82 of file aset.c.

Referenced by AllocSetFreeIndex(), and AllocSetStats().

#define AllocSetIsValid

(

set

)

PointerIsValid(set)

Definition at line 191 of file aset.c.

Referenced by AllocSetAlloc(), AllocSetDelete(), and AllocSetReset().

#define LT16

(

n

)

n, n, n, n, n, n, n, n, n, n, n, n, n, n, n, n

Definition at line 237 of file aset.c.

Typedef Documentation

typedef struct AllocBlockData* AllocBlock

Definition at line 102 of file aset.c.

typedef struct AllocBlockData AllocBlockData

typedef struct AllocChunkData* AllocChunk

Definition at line 103 of file aset.c.

typedef struct AllocChunkData AllocChunkData

typedef void* AllocPointer

Definition at line 109 of file aset.c.

typedef AllocSetContext* AllocSet

Definition at line 134 of file aset.c.

typedef struct AllocSetContext AllocSetContext

Function Documentation

static void * AllocSetAlloc ( MemoryContext  context, Size  size  )

static

Definition at line 562 of file aset.c.

References ALLOC_BLOCKHDRSZ, ALLOC_CHUNKHDRSZ, ALLOC_MINBITS, AllocAllocInfo, AllocChunkGetPointer, AllocSetContext::allocChunkLimit, AllocSetFreeIndex(), AllocSetIsValid, AllocBlockData::aset, AllocChunkData::aset, Assert, AssertArg, AllocSetContext::blocks, AllocBlockData::endptr, AllocSetContext::freelist, AllocBlockData::freeptr, AllocSetContext::initBlockSize, AllocSetContext::keeper, malloc, MAXALIGN, AllocSetContext::maxBlockSize, AllocBlockData::next, AllocSetContext::nextBlockSize, NULL, AllocBlockData::prev, AllocChunkData::size, VALGRIND_MAKE_MEM_NOACCESS, and VALGRIND_MAKE_MEM_UNDEFINED.

Referenced by AllocSetRealloc().

{
    AllocSet    set = (AllocSet) context;
    AllocBlock  block;
    AllocChunk  chunk;
    int         fidx;
    Size        chunk_size;
    Size        blksize;

    AssertArg(AllocSetIsValid(set));

    /*
     * If requested size exceeds maximum for chunks, allocate an entire block
     * for this request.
     */
    if (size > set->allocChunkLimit)
    {
        chunk_size = MAXALIGN(size);
        blksize = chunk_size + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ;
        block = (AllocBlock) malloc(blksize);
        if (block == NULL)
            return NULL;
        block->aset = set;
        block->freeptr = block->endptr = ((char *) block) + blksize;

        chunk = (AllocChunk) (((char *) block) + ALLOC_BLOCKHDRSZ);
        chunk->aset = set;
        chunk->size = chunk_size;
#ifdef MEMORY_CONTEXT_CHECKING
        /* Valgrind: Will be made NOACCESS below. */
        chunk->requested_size = size;
        /* set mark to catch clobber of "unused" space */
        if (size < chunk_size)
            set_sentinel(AllocChunkGetPointer(chunk), size);
#endif
#ifdef RANDOMIZE_ALLOCATED_MEMORY
        /* fill the allocated space with junk */
        randomize_mem((char *) AllocChunkGetPointer(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;
        }

        AllocAllocInfo(set, chunk);

        /*
         * Chunk's metadata fields remain DEFINED.  The requested allocation
         * itself can be NOACCESS or UNDEFINED; our caller will soon make it
         * UNDEFINED.  Make extra space at the end of the chunk, if any,
         * NOACCESS.
         */
        VALGRIND_MAKE_MEM_NOACCESS((char *) chunk + ALLOC_CHUNKHDRSZ,
                                   chunk_size - ALLOC_CHUNKHDRSZ);

        return AllocChunkGetPointer(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.
     */
    fidx = AllocSetFreeIndex(size);
    chunk = set->freelist[fidx];
    if (chunk != NULL)
    {
        Assert(chunk->size >= size);

        set->freelist[fidx] = (AllocChunk) chunk->aset;

        chunk->aset = (void *) set;

#ifdef MEMORY_CONTEXT_CHECKING
        /* Valgrind: Free list requested_size should be DEFINED. */
        chunk->requested_size = size;
        VALGRIND_MAKE_MEM_NOACCESS(&chunk->requested_size,
                                   sizeof(chunk->requested_size));
        /* set mark to catch clobber of "unused" space */
        if (size < chunk->size)
            set_sentinel(AllocChunkGetPointer(chunk), size);
#endif
#ifdef RANDOMIZE_ALLOCATED_MEMORY
        /* fill the allocated space with junk */
        randomize_mem((char *) AllocChunkGetPointer(chunk), size);
#endif

        AllocAllocInfo(set, chunk);
        return AllocChunkGetPointer(chunk);
    }

    /*
     * Choose the actual chunk size to allocate.
     */
    chunk_size = (1 << ALLOC_MINBITS) << 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))
            {
                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 != ((Size) 1 << (a_fidx + ALLOC_MINBITS)))
                {
                    a_fidx--;
                    Assert(a_fidx >= 0);
                    availchunk = ((Size) 1 << (a_fidx + ALLOC_MINBITS));
                }

                chunk = (AllocChunk) (block->freeptr);

                /* Prepare to initialize the chunk header. */
                VALGRIND_MAKE_MEM_UNDEFINED(chunk, ALLOC_CHUNKHDRSZ);

                block->freeptr += (availchunk + ALLOC_CHUNKHDRSZ);
                availspace -= (availchunk + ALLOC_CHUNKHDRSZ);

                chunk->size = availchunk;
#ifdef MEMORY_CONTEXT_CHECKING
                chunk->requested_size = 0;      /* mark it free */
#endif
                chunk->aset = (void *) set->freelist[a_fidx];
                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 a meg 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;

        block->aset = set;
        block->freeptr = ((char *) block) + ALLOC_BLOCKHDRSZ;
        block->endptr = ((char *) block) + blksize;

        /*
         * If this is the first block of the set, make it the "keeper" block.
         * Formerly, a keeper block could only be created during context
         * creation, but allowing it to happen here lets us have fast reset
         * cycling even for contexts created with minContextSize = 0; that way
         * we don't have to force space to be allocated in contexts that might
         * never need any space.  Don't mark an oversize block as a keeper,
         * however.
         */
        if (set->keeper == NULL && blksize == set->initBlockSize)
            set->keeper = block;

        /* 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 = (AllocChunk) (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);

    chunk->aset = (void *) set;
    chunk->size = chunk_size;
#ifdef MEMORY_CONTEXT_CHECKING
    chunk->requested_size = size;
    VALGRIND_MAKE_MEM_NOACCESS(&chunk->requested_size,
                               sizeof(chunk->requested_size));
    /* set mark to catch clobber of "unused" space */
    if (size < chunk->size)
        set_sentinel(AllocChunkGetPointer(chunk), size);
#endif
#ifdef RANDOMIZE_ALLOCATED_MEMORY
    /* fill the allocated space with junk */
    randomize_mem((char *) AllocChunkGetPointer(chunk), size);
#endif

    AllocAllocInfo(set, chunk);
    return AllocChunkGetPointer(chunk);
}

MemoryContext AllocSetContextCreate	(	MemoryContext	parent,
		const char *	name,
		Size	minContextSize,
		Size	initBlockSize,
		Size	maxBlockSize
	)

Definition at line 322 of file aset.c.

References ALLOC_BLOCKHDRSZ, ALLOC_CHUNK_FRACTION, ALLOC_CHUNK_LIMIT, ALLOC_CHUNKHDRSZ, AllocSetContext::allocChunkLimit, AllocHugeSizeIsValid, ALLOCSET_SEPARATE_THRESHOLD, AllocSetMethods, AllocBlockData::aset, AllocSetContext::blocks, elog, AllocBlockData::endptr, ereport, errcode(), errdetail(), errmsg(), ERROR, AllocBlockData::freeptr, AllocSetContext::initBlockSize, AllocSetContext::keeper, malloc, MAXALIGN, AllocSetContext::maxBlockSize, MemoryContextCreate(), MemoryContextStats(), name, AllocBlockData::next, AllocSetContext::nextBlockSize, NULL, offsetof, AllocBlockData::prev, StaticAssertStmt, T_AllocSetContext, TopMemoryContext, and VALGRIND_MAKE_MEM_NOACCESS.

Referenced by _bt_preprocess_array_keys(), _SPI_make_plan_non_temp(), _SPI_save_plan(), afterTriggerAddEvent(), afterTriggerInvokeEvents(), AllocateSnapshotBuilder(), ApplyLauncherMain(), ApplyWorkerMain(), AtStart_Memory(), AtSubStart_Memory(), AutoVacLauncherMain(), BackgroundWriterMain(), begin_heap_rewrite(), BeginCopy(), blbuild(), blinsert(), brin_build_desc(), brin_new_memtuple(), bringetbitmap(), brininsert(), bt_check_every_level(), btvacuumscan(), BuildCachedPlan(), BuildEventTriggerCache(), BuildRelationExtStatistics(), CheckpointerMain(), cluster(), compile_plperl_function(), compile_pltcl_function(), CompleteCachedPlan(), compute_index_stats(), CopyCachedPlan(), CopyTo(), CreateCachedPlan(), CreateCacheMemoryContext(), CreateExecutorState(), CreateExprContext(), CreatePortal(), CreateStandaloneExprContext(), createTempGistContext(), createTrgmNFA(), DiscreteKnapsack(), do_analyze_rel(), do_autovacuum(), do_compile(), do_start_worker(), each_worker(), each_worker_jsonb(), elements_worker(), elements_worker_jsonb(), EnablePortalManager(), EventTriggerBeginCompleteQuery(), EventTriggerInvoke(), exec_parse_message(), exec_replication_command(), ExecHashTableCreate(), ExecInitFunctionScan(), ExecInitRecursiveUnion(), ExecInitSetOp(), ExecInitSubPlan(), ExecInitTableFuncScan(), ExecInitUnique(), ExecInitWindowAgg(), expand_array(), file_acquire_sample_rows(), fill_hba_view(), geqo_eval(), get_stmt_mcontext(), GetLocalBufferStorage(), gin_xlog_startup(), ginbeginscan(), ginbuild(), ginbulkdelete(), gininsert(), ginInsertCleanup(), ginPlaceToPage(), gistrescan(), HandleParallelMessages(), hash_create(), index_register(), init_MultiFuncCall(), init_sql_fcache(), initArrayResult(), initArrayResultArr(), initGISTstate(), initialize_peragg(), InitXLogInsert(), inline_function(), inline_set_returning_function(), libpqrcv_processTuples(), load_domaintype_info(), load_hba(), load_ident(), load_relcache_init_file(), load_tzoffsets(), logicalrep_relmap_init(), LogicalRepApplyLoop(), lookup_ts_dictionary_cache(), materializeQueryResult(), mdinit(), MemoryContextInit(), mXactCachePut(), NIStartBuild(), ParallelWorkerMain(), PerformAuthentication(), pg_decode_startup(), pgoutput_startup(), pgstat_setup_memcxt(), plperl_return_next(), plperl_spi_prepare(), plpgsql_compile_inline(), plpgsql_estate_setup(), plpython_inline_handler(), pltcl_SPI_prepare(), PLy_cursor_plan(), PLy_cursor_query(), PLy_get_scratch_context(), PLy_procedure_create(), PLy_spi_execute_fetch_result(), PLy_spi_prepare(), PLyObject_ToComposite(), PLyString_ToComposite(), PortalCreateHoldStore(), postgresAcquireSampleRowsFunc(), postgresBeginDirectModify(), postgresBeginForeignModify(), postgresBeginForeignScan(), PostgresMain(), PostmasterMain(), printtup_startup(), publicationListToArray(), rebuild_database_list(), ReindexMultipleTables(), RelationBuildPartitionDesc(), RelationBuildPartitionKey(), RelationBuildRowSecurity(), RelationBuildRuleLock(), RelationInitIndexAccessInfo(), ReorderBufferAllocate(), ResetUnloggedRelations(), RevalidateCachedQuery(), sepgsql_avc_init(), spg_xlog_startup(), spgbeginscan(), spgbuild(), spginsert(), SPI_connect(), spi_dest_startup(), StartupDecodingContext(), strlist_to_textarray(), tokenize_file(), tqueueReceiveSlot(), tuplesort_begin_common(), union_tuples(), vacuum(), WalWriterMain(), and XLOGShmemInit().

{
    AllocSet    set;

    StaticAssertStmt(offsetof(AllocChunkData, aset) + sizeof(MemoryContext) ==
                     MAXALIGN(sizeof(AllocChunkData)),
                     "padding calculation in AllocChunkData is wrong");

    /*
     * First, validate allocation parameters.  (If we're going to throw an
     * error, we should do so before the context is created, not after.)  We
     * somewhat arbitrarily enforce a minimum 1K block size.
     */
    if (initBlockSize != MAXALIGN(initBlockSize) ||
        initBlockSize < 1024)
        elog(ERROR, "invalid initBlockSize for memory context: %zu",
             initBlockSize);
    if (maxBlockSize != MAXALIGN(maxBlockSize) ||
        maxBlockSize < initBlockSize ||
        !AllocHugeSizeIsValid(maxBlockSize))    /* must be safe to double */
        elog(ERROR, "invalid maxBlockSize for memory context: %zu",
             maxBlockSize);
    if (minContextSize != 0 &&
        (minContextSize != MAXALIGN(minContextSize) ||
         minContextSize <= ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ))
        elog(ERROR, "invalid minContextSize for memory context: %zu",
             minContextSize);

    /* Do the type-independent part of context creation */
    set = (AllocSet) MemoryContextCreate(T_AllocSetContext,
                                         sizeof(AllocSetContext),
                                         &AllocSetMethods,
                                         parent,
                                         name);

    /* Save allocation parameters */
    set->initBlockSize = initBlockSize;
    set->maxBlockSize = maxBlockSize;
    set->nextBlockSize = initBlockSize;

    /*
     * Compute the allocation chunk size limit for this context.  It can't be
     * more than ALLOC_CHUNK_LIMIT because of the fixed number of freelists.
     * If maxBlockSize is small then requests exceeding the maxBlockSize, or
     * even a significant fraction of it, should be treated as large chunks
     * too.  For the typical case of maxBlockSize a power of 2, the chunk size
     * limit will be at most 1/8th maxBlockSize, so that given a stream of
     * requests that are all the maximum chunk size we will waste at most
     * 1/8th of the allocated space.
     *
     * We have to have allocChunkLimit a power of two, because the requested
     * and actually-allocated sizes of any chunk must be on the same side of
     * the limit, else we get confused about whether the chunk is "big".
     *
     * Also, allocChunkLimit must not exceed ALLOCSET_SEPARATE_THRESHOLD.
     */
    StaticAssertStmt(ALLOC_CHUNK_LIMIT == ALLOCSET_SEPARATE_THRESHOLD,
                     "ALLOC_CHUNK_LIMIT != ALLOCSET_SEPARATE_THRESHOLD");

    set->allocChunkLimit = ALLOC_CHUNK_LIMIT;
    while ((Size) (set->allocChunkLimit + ALLOC_CHUNKHDRSZ) >
           (Size) ((maxBlockSize - ALLOC_BLOCKHDRSZ) / ALLOC_CHUNK_FRACTION))
        set->allocChunkLimit >>= 1;

    /*
     * Grab always-allocated space, if requested
     */
    if (minContextSize > 0)
    {
        Size        blksize = minContextSize;
        AllocBlock  block;

        block = (AllocBlock) malloc(blksize);
        if (block == NULL)
        {
            MemoryContextStats(TopMemoryContext);
            ereport(ERROR,
                    (errcode(ERRCODE_OUT_OF_MEMORY),
                     errmsg("out of memory"),
                     errdetail("Failed while creating memory context \"%s\".",
                               name)));
        }
        block->aset = set;
        block->freeptr = ((char *) block) + ALLOC_BLOCKHDRSZ;
        block->endptr = ((char *) block) + blksize;
        block->prev = NULL;
        block->next = set->blocks;
        if (block->next)
            block->next->prev = block;
        set->blocks = block;
        /* Mark block as not to be released at reset time */
        set->keeper = block;

        /* Mark unallocated space NOACCESS; leave the block header alone. */
        VALGRIND_MAKE_MEM_NOACCESS(block->freeptr,
                                   blksize - ALLOC_BLOCKHDRSZ);
    }

    return (MemoryContext) set;
}

static void AllocSetDelete ( MemoryContext  context )

static

Definition at line 523 of file aset.c.

References AllocSetIsValid, AssertArg, AllocSetContext::blocks, free, AllocSetContext::freelist, AllocBlockData::freeptr, AllocSetContext::keeper, MemSetAligned, AllocBlockData::next, next, and NULL.

{
    AllocSet    set = (AllocSet) context;
    AllocBlock  block = set->blocks;

    AssertArg(AllocSetIsValid(set));

#ifdef MEMORY_CONTEXT_CHECKING
    /* Check for corruption and leaks before freeing */
    AllocSetCheck(context);
#endif

    /* Make it look empty, just in case... */
    MemSetAligned(set->freelist, 0, sizeof(set->freelist));
    set->blocks = NULL;
    set->keeper = NULL;

    while (block != NULL)
    {
        AllocBlock  next = block->next;

#ifdef CLOBBER_FREED_MEMORY
        wipe_mem(block, block->freeptr - ((char *) block));
#endif
        free(block);
        block = next;
    }
}

static void AllocSetFree ( MemoryContext  context, void *  pointer  )

static

Definition at line 839 of file aset.c.

References ALLOC_BLOCKHDRSZ, ALLOC_CHUNKHDRSZ, AllocSetContext::allocChunkLimit, AllocFreeInfo, AllocPointerGetChunk, AllocSetFreeIndex(), AllocBlockData::aset, AllocChunkData::aset, AllocSetContext::blocks, elog, AllocBlockData::endptr, ERROR, free, AllocSetContext::freelist, AllocBlockData::freeptr, AllocSetContext::header, MemoryContextData::name, AllocBlockData::next, AllocBlockData::prev, AllocChunkData::size, VALGRIND_MAKE_MEM_DEFINED, and WARNING.

Referenced by AllocSetRealloc().

{
    AllocSet    set = (AllocSet) context;
    AllocChunk  chunk = AllocPointerGetChunk(pointer);

    AllocFreeInfo(set, chunk);

#ifdef MEMORY_CONTEXT_CHECKING
    VALGRIND_MAKE_MEM_DEFINED(&chunk->requested_size,
                              sizeof(chunk->requested_size));
    /* Test for someone scribbling on unused space in chunk */
    if (chunk->requested_size < chunk->size)
        if (!sentinel_ok(pointer, chunk->requested_size))
            elog(WARNING, "detected write past chunk end in %s %p",
                 set->header.name, chunk);
#endif

    if (chunk->size > set->allocChunkLimit)
    {
        /*
         * Big chunks are certain to have been allocated as single-chunk
         * blocks.  Just unlink that block and return it to malloc().
         */
        AllocBlock  block = (AllocBlock) (((char *) chunk) - ALLOC_BLOCKHDRSZ);

        /*
         * Try to verify that we have a sane block pointer: it should
         * reference the correct aset, and freeptr and endptr should point
         * just past the chunk.
         */
        if (block->aset != set ||
            block->freeptr != block->endptr ||
            block->freeptr != ((char *) block) +
            (chunk->size + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ))
            elog(ERROR, "could not find block containing chunk %p", chunk);

        /* 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;
#ifdef CLOBBER_FREED_MEMORY
        wipe_mem(block, block->freeptr - ((char *) block));
#endif
        free(block);
    }
    else
    {
        /* Normal case, put the chunk into appropriate freelist */
        int         fidx = AllocSetFreeIndex(chunk->size);

        chunk->aset = (void *) set->freelist[fidx];

#ifdef CLOBBER_FREED_MEMORY
        wipe_mem(pointer, chunk->size);
#endif

#ifdef MEMORY_CONTEXT_CHECKING
        /* Reset requested_size to 0 in chunks that are on freelist */
        chunk->requested_size = 0;
#endif
        set->freelist[fidx] = chunk;
    }
}

static int AllocSetFreeIndex ( Size  size )

inlinestatic

Definition at line 271 of file aset.c.

References ALLOC_MINBITS, ALLOCSET_NUM_FREELISTS, Assert, idx(), and LogTable256.

Referenced by AllocSetAlloc(), and AllocSetFree().

{
    int         idx;
    unsigned int t,
                tsize;

    if (size > (1 << ALLOC_MINBITS))
    {
        tsize = (size - 1) >> ALLOC_MINBITS;

        /*
         * At this point we need to obtain log2(tsize)+1, ie, the number of
         * not-all-zero bits at the right.  We used to do this with a
         * shift-and-count loop, but this function is enough of a hotspot to
         * justify micro-optimization effort.  The best approach seems to be
         * to use a lookup table.  Note that this code assumes that
         * ALLOCSET_NUM_FREELISTS <= 17, since we only cope with two bytes of
         * the tsize value.
         */
        t = tsize >> 8;
        idx = t ? LogTable256[t] + 8 : LogTable256[tsize];

        Assert(idx < ALLOCSET_NUM_FREELISTS);
    }
    else
        idx = 0;

    return idx;
}

static Size AllocSetGetChunkSpace ( MemoryContext  context, void *  pointer  )

static

Definition at line 1114 of file aset.c.

References ALLOC_CHUNKHDRSZ, AllocPointerGetChunk, and AllocChunkData::size.

{
    AllocChunk  chunk = AllocPointerGetChunk(pointer);

    return chunk->size + ALLOC_CHUNKHDRSZ;
}

static void AllocSetInit ( MemoryContext  context )

static

Definition at line 440 of file aset.c.

{
    /*
     * Since MemoryContextCreate already zeroed the context node, we don't
     * have to do anything here: it's already OK.
     */
}

static bool AllocSetIsEmpty ( MemoryContext  context )

static

Definition at line 1126 of file aset.c.

References MemoryContextData::isReset.

{
    /*
     * 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;
}

static void * AllocSetRealloc ( MemoryContext  context, void *  pointer, Size  size  )

static

Definition at line 919 of file aset.c.

References ALLOC_BLOCKHDRSZ, ALLOC_CHUNKHDRSZ, AllocChunkGetPointer, AllocSetContext::allocChunkLimit, AllocPointerGetChunk, AllocSetAlloc(), AllocSetFree(), AllocBlockData::aset, AllocSetContext::blocks, elog, AllocBlockData::endptr, ERROR, AllocBlockData::freeptr, AllocSetContext::header, MAXALIGN, MemoryContextData::name, AllocBlockData::next, NULL, AllocBlockData::prev, realloc, AllocChunkData::size, VALGRIND_MAKE_MEM_DEFINED, VALGRIND_MAKE_MEM_NOACCESS, VALGRIND_MAKE_MEM_UNDEFINED, and WARNING.

{
    AllocSet    set = (AllocSet) context;
    AllocChunk  chunk = AllocPointerGetChunk(pointer);
    Size        oldsize = chunk->size;

#ifdef MEMORY_CONTEXT_CHECKING
    VALGRIND_MAKE_MEM_DEFINED(&chunk->requested_size,
                              sizeof(chunk->requested_size));
    /* Test for someone scribbling on unused space in chunk */
    if (chunk->requested_size < oldsize)
        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 always
     * fall out here if the requested size is a decrease.)
     */
    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;
        VALGRIND_MAKE_MEM_NOACCESS(&chunk->requested_size,
                                   sizeof(chunk->requested_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 */
        if (size < oldsize)
            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

        return pointer;
    }

    if (oldsize > set->allocChunkLimit)
    {
        /*
         * The chunk must have been allocated as a single-chunk block.  Use
         * realloc() to make the containing block bigger with minimum space
         * wastage.
         */
        AllocBlock  block = (AllocBlock) (((char *) chunk) - ALLOC_BLOCKHDRSZ);
        Size        chksize;
        Size        blksize;

        /*
         * Try to verify that we have a sane block pointer: it should
         * reference the correct aset, and freeptr and endptr should point
         * just past the chunk.
         */
        if (block->aset != set ||
            block->freeptr != block->endptr ||
            block->freeptr != ((char *) block) +
            (chunk->size + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ))
            elog(ERROR, "could not find block containing chunk %p", chunk);

        /* Do the realloc */
        chksize = MAXALIGN(size);
        blksize = chksize + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ;
        block = (AllocBlock) realloc(block, blksize);
        if (block == NULL)
            return NULL;
        block->freeptr = block->endptr = ((char *) block) + blksize;

        /* Update pointers since block has likely been moved */
        chunk = (AllocChunk) (((char *) block) + ALLOC_BLOCKHDRSZ);
        pointer = AllocChunkGetPointer(chunk);
        if (block->prev)
            block->prev->next = block;
        else
            set->blocks = block;
        if (block->next)
            block->next->prev = block;
        chunk->size = chksize;

#ifdef MEMORY_CONTEXT_CHECKING
#ifdef RANDOMIZE_ALLOCATED_MEMORY
        /* We can only fill the extra space if we know the prior request */
        randomize_mem((char *) pointer + chunk->requested_size,
                      size - chunk->requested_size);
#endif

        /*
         * realloc() (or randomize_mem()) will have left the newly-allocated
         * part UNDEFINED, but we may need to adjust trailing bytes from the
         * old allocation.
         */
        VALGRIND_MAKE_MEM_UNDEFINED((char *) pointer + chunk->requested_size,
                                    oldsize - chunk->requested_size);

        chunk->requested_size = size;
        VALGRIND_MAKE_MEM_NOACCESS(&chunk->requested_size,
                                   sizeof(chunk->requested_size));

        /* set mark to catch clobber of "unused" space */
        if (size < chunk->size)
            set_sentinel(pointer, size);
#else                           /* !MEMORY_CONTEXT_CHECKING */

        /*
         * We don't know how much of the old chunk size was the actual
         * allocation; it could have been as small as one byte.  We have to be
         * conservative and just mark the entire old portion DEFINED.
         */
        VALGRIND_MAKE_MEM_DEFINED(pointer, oldsize);
#endif

        /* Make any trailing alignment padding NOACCESS. */
        VALGRIND_MAKE_MEM_NOACCESS((char *) pointer + size, chksize - size);

        return pointer;
    }
    else
    {
        /*
         * 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;

        /* allocate new chunk */
        newPointer = AllocSetAlloc((MemoryContext) set, size);

        /* leave immediately if request was not completed */
        if (newPointer == NULL)
            return NULL;

        /*
         * AllocSetAlloc() just made the region 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 */
        AllocSetFree((MemoryContext) set, pointer);

        return newPointer;
    }
}

static void AllocSetReset ( MemoryContext  context )

static

Definition at line 460 of file aset.c.

References ALLOC_BLOCKHDRSZ, AllocSetIsValid, AssertArg, AllocSetContext::blocks, free, AllocSetContext::freelist, AllocBlockData::freeptr, AllocSetContext::initBlockSize, AllocSetContext::keeper, MemSetAligned, AllocBlockData::next, next, AllocSetContext::nextBlockSize, NULL, AllocBlockData::prev, and VALGRIND_MAKE_MEM_NOACCESS.

{
    AllocSet    set = (AllocSet) context;
    AllocBlock  block;

    AssertArg(AllocSetIsValid(set));

#ifdef MEMORY_CONTEXT_CHECKING
    /* Check for corruption and leaks before freeing */
    AllocSetCheck(context);
#endif

    /* Clear chunk freelists */
    MemSetAligned(set->freelist, 0, sizeof(set->freelist));

    block = set->blocks;

    /* New blocks list is either empty or just the keeper block */
    set->blocks = set->keeper;

    while (block != NULL)
    {
        AllocBlock  next = block->next;

        if (block == set->keeper)
        {
            /* 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 */
#ifdef CLOBBER_FREED_MEMORY
            wipe_mem(block, block->freeptr - ((char *) block));
#endif
            free(block);
        }
        block = next;
    }

    /* Reset block size allocation sequence, too */
    set->nextBlockSize = set->initBlockSize;
}

static void AllocSetStats ( MemoryContext  context, int  level, bool  print, MemoryContextCounters *  totals  )

static

Definition at line 1148 of file aset.c.

References ALLOC_CHUNKHDRSZ, ALLOCSET_NUM_FREELISTS, AllocChunkData::aset, AllocSetContext::blocks, AllocBlockData::endptr, MemoryContextCounters::freechunks, AllocSetContext::freelist, AllocBlockData::freeptr, MemoryContextCounters::freespace, AllocSetContext::header, i, MemoryContextData::name, MemoryContextCounters::nblocks, AllocBlockData::next, NULL, AllocChunkData::size, and MemoryContextCounters::totalspace.

{
    AllocSet    set = (AllocSet) context;
    Size        nblocks = 0;
    Size        freechunks = 0;
    Size        totalspace = 0;
    Size        freespace = 0;
    AllocBlock  block;
    int         fidx;

    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++)
    {
        AllocChunk  chunk;

        for (chunk = set->freelist[fidx]; chunk != NULL;
             chunk = (AllocChunk) chunk->aset)
        {
            freechunks++;
            freespace += chunk->size + ALLOC_CHUNKHDRSZ;
        }
    }

    if (print)
    {
        int         i;

        for (i = 0; i < level; i++)
            fprintf(stderr, "  ");
        fprintf(stderr,
            "%s: %zu total in %zd blocks; %zu free (%zd chunks); %zu used\n",
                set->header.name, totalspace, nblocks, freespace, freechunks,
                totalspace - freespace);
    }

    if (totals)
    {
        totals->nblocks += nblocks;
        totals->freechunks += freechunks;
        totals->totalspace += totalspace;
        totals->freespace += freespace;
    }
}

Variable Documentation

MemoryContextMethods AllocSetMethods

static

Initial value:

= {
    AllocSetAlloc,
    AllocSetFree,
    AllocSetRealloc,
    AllocSetInit,
    AllocSetReset,
    AllocSetDelete,
    AllocSetGetChunkSpace,
    AllocSetIsEmpty,
    AllocSetStats



}

Definition at line 219 of file aset.c.

Referenced by AllocSetContextCreate().

const unsigned char LogTable256[256]

static

Initial value:

=
{
    0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
    LT16(5), LT16(6), LT16(6), LT16(7), LT16(7), LT16(7), LT16(7),
    LT16(8), LT16(8), LT16(8), LT16(8), LT16(8), LT16(8), LT16(8), LT16(8)
}

Definition at line 239 of file aset.c.

Referenced by AllocSetFreeIndex().