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Rethink MemoryContext creation to improve performance. 

This patch makes a number of interrelated changes to reduce the overhead
involved in creating/deleting memory contexts.  The key ideas are:

* Include the AllocSetContext header of an aset.c context in its first
malloc request, rather than allocating it separately in TopMemoryContext.
This means that we now always create an initial or "keeper" block in an
aset, even if it never receives any allocation requests.

* Create freelists in which we can save and recycle recently-destroyed
asets (this idea is due to Robert Haas).

* In the common case where the name of a context is a constant string,
just store a pointer to it in the context header, rather than copying
the string.

The first change eliminates a palloc/pfree cycle per context, and
also avoids bloat in TopMemoryContext, at the price that creating
a context now involves a malloc/free cycle even if the context never
receives any allocations.  That would be a loser for some common
usage patterns, but recycling short-lived contexts via the freelist
eliminates that pain.

Avoiding copying constant strings not only saves strlen() and strcpy()
overhead, but is an essential part of the freelist optimization because
it makes the context header size constant.  Currently we make no
attempt to use the freelist for contexts with non-constant names.
(Perhaps someday we'll need to think harder about that, but in current
usage, most contexts with custom names are long-lived anyway.)

The freelist management in this initial commit is pretty simplistic,
and we might want to refine it later --- but in common workloads that
will never matter because the freelists will never get full anyway.

To create a context with a non-constant name, one is now required to
call AllocSetContextCreateExtended and specify the MEMCONTEXT_COPY_NAME
option.  AllocSetContextCreate becomes a wrapper macro, and it includes
a test that will complain about non-string-literal context name
parameters on gcc and similar compilers.

An unfortunate side effect of making AllocSetContextCreate a macro is
that one is now *required* to use the size parameter abstraction macros
(ALLOCSET_DEFAULT_SIZES and friends) with it; the pre-9.6 habit of
writing out individual size parameters no longer works unless you
switch to AllocSetContextCreateExtended.

Internally to the memory-context-related modules, the context creation
APIs are simplified, removing the rather baroque original design whereby
a context-type module called mcxt.c which then called back into the
context-type module.  That saved a bit of code duplication, but not much,
and it prevented context-type modules from exercising control over the
allocation of context headers.

In passing, I converted the test-and-elog validation of aset size
parameters into Asserts to save a few more cycles.  The original thought
was that callers might compute size parameters on the fly, but in practice
nobody does that, so it's useless to expend cycles on checking those
numbers in production builds.

Also, mark the memory context method-pointer structs "const",
just for cleanliness.

Discussion: https://postgr.es/m/2264.1512870796@sss.pgh.pa.us
This commit is contained in:
Tom Lane 2017-12-13 13:55:12 -05:00
parent 632b03da31
commit 9fa6f00b13
21 changed files with 540 additions and 342 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
contrib/amcheck/verify_nbtree.c
View File

@ -295,9 +295,7 @@ bt_check_every_level(Relation rel, bool readonly)
/* Create context for page */
state->targetcontext = AllocSetContextCreate(CurrentMemoryContext,
"amcheck context",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
ALLOCSET_DEFAULT_SIZES);
state->checkstrategy = GetAccessStrategy(BAS_BULKREAD);
/* Get true root block from meta-page */

11
src/backend/access/transam/xact.c
View File

@ -997,11 +997,12 @@ AtStart_Memory(void)
*/
if (TransactionAbortContext == NULL)
TransactionAbortContext =
AllocSetContextCreate(TopMemoryContext,
"TransactionAbortContext",
32 * 1024,
32 * 1024,
32 * 1024);
AllocSetContextCreateExtended(TopMemoryContext,
"TransactionAbortContext",
0,
32 * 1024,
32 * 1024,
32 * 1024);
/*
* We shouldn't have a transaction context already.

7
src/backend/catalog/partition.c
View File

@ -520,9 +520,10 @@ RelationBuildPartitionDesc(Relation rel)
}
/* Now build the actual relcache partition descriptor */
rel->rd_pdcxt = AllocSetContextCreate(CacheMemoryContext,
RelationGetRelationName(rel),
ALLOCSET_DEFAULT_SIZES);
rel->rd_pdcxt = AllocSetContextCreateExtended(CacheMemoryContext,
RelationGetRelationName(rel),
MEMCONTEXT_COPY_NAME,
ALLOCSET_DEFAULT_SIZES);
oldcxt = MemoryContextSwitchTo(rel->rd_pdcxt);
result = (PartitionDescData *) palloc0(sizeof(PartitionDescData));

4
src/backend/commands/subscriptioncmds.c
View File

@ -259,9 +259,7 @@ publicationListToArray(List *publist)
/* Create memory context for temporary allocations. */
memcxt = AllocSetContextCreate(CurrentMemoryContext,
"publicationListToArray to array",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
ALLOCSET_DEFAULT_SIZES);
oldcxt = MemoryContextSwitchTo(memcxt);
datums = (Datum *) palloc(sizeof(Datum) * list_length(publist));

4
src/backend/lib/knapsack.c
View File

@ -57,9 +57,7 @@ DiscreteKnapsack(int max_weight, int num_items,
{
MemoryContext local_ctx = AllocSetContextCreate(CurrentMemoryContext,
"Knapsack",
ALLOCSET_SMALL_MINSIZE,
ALLOCSET_SMALL_INITSIZE,
ALLOCSET_SMALL_MAXSIZE);
ALLOCSET_SMALL_SIZES);
MemoryContext oldctx = MemoryContextSwitchTo(local_ctx);
double *values;
Bitmapset **sets;

4
src/backend/replication/logical/launcher.c
View File

@ -925,9 +925,7 @@ ApplyLauncherMain(Datum main_arg)
/* Use temporary context for the database list and worker info. */
subctx = AllocSetContextCreate(TopMemoryContext,
"Logical Replication Launcher sublist",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
ALLOCSET_DEFAULT_SIZES);
oldctx = MemoryContextSwitchTo(subctx);
/* search for subscriptions to start or stop. */

3
src/backend/replication/logical/reorderbuffer.c
View File

@ -237,16 +237,19 @@ ReorderBufferAllocate(void)
buffer->change_context = SlabContextCreate(new_ctx,
"Change",
0,
SLAB_DEFAULT_BLOCK_SIZE,
sizeof(ReorderBufferChange));
buffer->txn_context = SlabContextCreate(new_ctx,
"TXN",
0,
SLAB_DEFAULT_BLOCK_SIZE,
sizeof(ReorderBufferTXN));
buffer->tup_context = GenerationContextCreate(new_ctx,
"Tuples",
0,
SLAB_LARGE_BLOCK_SIZE);
hash_ctl.keysize = sizeof(TransactionId);

4
src/backend/replication/pgoutput/pgoutput.c
View File

@ -152,9 +152,7 @@ pgoutput_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt,
/* Create our memory context for private allocations. */
data->context = AllocSetContextCreate(ctx->context,
"logical replication output context",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
ALLOCSET_DEFAULT_SIZES);
ctx->output_plugin_private = data;

29
src/backend/utils/cache/relcache.c vendored
View File

@ -669,9 +669,10 @@ RelationBuildRuleLock(Relation relation)
/*
* Make the private context. Assume it'll not contain much data.
*/
rulescxt = AllocSetContextCreate(CacheMemoryContext,
RelationGetRelationName(relation),
ALLOCSET_SMALL_SIZES);
rulescxt = AllocSetContextCreateExtended(CacheMemoryContext,
RelationGetRelationName(relation),
MEMCONTEXT_COPY_NAME,
ALLOCSET_SMALL_SIZES);
relation->rd_rulescxt = rulescxt;
/*
@ -984,9 +985,10 @@ RelationBuildPartitionKey(Relation relation)
ReleaseSysCache(tuple);
/* Success --- now copy to the cache memory */
partkeycxt = AllocSetContextCreate(CacheMemoryContext,
RelationGetRelationName(relation),
ALLOCSET_SMALL_SIZES);
partkeycxt = AllocSetContextCreateExtended(CacheMemoryContext,
RelationGetRelationName(relation),
MEMCONTEXT_COPY_NAME,
ALLOCSET_SMALL_SIZES);
relation->rd_partkeycxt = partkeycxt;
oldcxt = MemoryContextSwitchTo(relation->rd_partkeycxt);
relation->rd_partkey = copy_partition_key(key);
@ -1566,9 +1568,10 @@ RelationInitIndexAccessInfo(Relation relation)
* a context, and not just a couple of pallocs, is so that we won't leak
* any subsidiary info attached to fmgr lookup records.
*/
indexcxt = AllocSetContextCreate(CacheMemoryContext,
RelationGetRelationName(relation),
ALLOCSET_SMALL_SIZES);
indexcxt = AllocSetContextCreateExtended(CacheMemoryContext,
RelationGetRelationName(relation),
MEMCONTEXT_COPY_NAME,
ALLOCSET_SMALL_SIZES);
relation->rd_indexcxt = indexcxt;
/*
@ -5537,9 +5540,11 @@ load_relcache_init_file(bool shared)
* prepare index info context --- parameters should match
* RelationInitIndexAccessInfo
*/
indexcxt = AllocSetContextCreate(CacheMemoryContext,
RelationGetRelationName(rel),
ALLOCSET_SMALL_SIZES);
indexcxt =
AllocSetContextCreateExtended(CacheMemoryContext,
RelationGetRelationName(rel),
MEMCONTEXT_COPY_NAME,
ALLOCSET_SMALL_SIZES);
rel->rd_indexcxt = indexcxt;
/*

7
src/backend/utils/cache/ts_cache.c vendored
View File

@ -294,9 +294,10 @@ lookup_ts_dictionary_cache(Oid dictId)
Assert(!found); /* it wasn't there a moment ago */
/* Create private memory context the first time through */
saveCtx = AllocSetContextCreate(CacheMemoryContext,
NameStr(dict->dictname),
ALLOCSET_SMALL_SIZES);
saveCtx = AllocSetContextCreateExtended(CacheMemoryContext,
NameStr(dict->dictname),
MEMCONTEXT_COPY_NAME,
ALLOCSET_SMALL_SIZES);
}
else
{

8
src/backend/utils/hash/dynahash.c
View File

@ -340,9 +340,11 @@ hash_create(const char *tabname, long nelem, HASHCTL *info, int flags)
CurrentDynaHashCxt = info->hcxt;
else
CurrentDynaHashCxt = TopMemoryContext;
CurrentDynaHashCxt = AllocSetContextCreate(CurrentDynaHashCxt,
tabname,
ALLOCSET_DEFAULT_SIZES);
CurrentDynaHashCxt =
AllocSetContextCreateExtended(CurrentDynaHashCxt,
tabname,
MEMCONTEXT_COPY_NAME,
ALLOCSET_DEFAULT_SIZES);
}
/* Initialize the hash header, plus a copy of the table name */

12
src/backend/utils/mmgr/README
View File

@ -177,8 +177,7 @@ every other context is a direct or indirect child of this one. Allocating
here is essentially the same as "malloc", because this context will never
be reset or deleted. This is for stuff that should live forever, or for
stuff that the controlling module will take care of deleting at the
appropriate time. An example is fd.c's tables of open files, as well as
the context management nodes for memory contexts themselves. Avoid
appropriate time. An example is fd.c's tables of open files. Avoid
allocating stuff here unless really necessary, and especially avoid
running with CurrentMemoryContext pointing here.
@ -420,11 +419,10 @@ a maximum block size. Selecting smaller values can prevent wastage of
space in contexts that aren't expected to hold very much (an example
is the relcache's per-relation contexts).
Also, it is possible to specify a minimum context size. If this
value is greater than zero then a block of that size will be grabbed
immediately upon context creation, and cleared but not released during
context resets. This feature is needed for ErrorContext (see above),
but will most likely not be used for other contexts.
Also, it is possible to specify a minimum context size, in case for some
reason that should be different from the initial size for additional
blocks. An aset.c context will always contain at least one block,
of size minContextSize if that is specified, otherwise initBlockSize.
We expect that per-tuple contexts will be reset frequently and typically
will not allocate very much space per tuple cycle. To make this usage

366
src/backend/utils/mmgr/aset.c
View File

@ -93,6 +93,9 @@
*
* Blocks allocated to hold oversize chunks do not follow this rule, however;
* they are just however big they need to be to hold that single chunk.
*
* Also, if a minContextSize is specified, the first block has that size,
* and then initBlockSize is used for the next one.
*--------------------
*/
@ -113,7 +116,7 @@ typedef void *AllocPointer;
*
* Note: header.isReset means there is nothing for AllocSetReset to do.
* This is different from the aset being physically empty (empty blocks list)
* because we may still have a keeper block. It's also different from the set
* because we will still have a keeper block. It's also different from the set
* being logically empty, because we don't attempt to detect pfree'ing the
* last active chunk.
*/
@ -127,8 +130,11 @@ typedef struct AllocSetContext
Size initBlockSize; /* initial block size */
Size maxBlockSize; /* maximum block size */
Size nextBlockSize; /* next block size to allocate */
Size headerSize; /* allocated size of context header */
Size allocChunkLimit; /* effective chunk size limit */
AllocBlock keeper; /* if not NULL, keep this block over resets */
AllocBlock keeper; /* keep this block over resets */
/* freelist this context could be put in, or -1 if not a candidate: */
int freeListIndex; /* index in context_freelists[], or -1 */
} AllocSetContext;
typedef AllocSetContext *AllocSet;
@ -215,13 +221,57 @@ typedef struct AllocChunkData
#define AllocChunkGetPointer(chk) \
((AllocPointer)(((char *)(chk)) + ALLOC_CHUNKHDRSZ))
/*
* Rather than repeatedly creating and deleting memory contexts, we keep some
* freed contexts in freelists so that we can hand them out again with little
* work. Before putting a context in a freelist, we reset it so that it has
* only its initial malloc chunk and no others. To be a candidate for a
* freelist, a context must have the same minContextSize/initBlockSize as
* other contexts in the list; but its maxBlockSize is irrelevant since that
* doesn't affect the size of the initial chunk. Also, candidate contexts
* *must not* use MEMCONTEXT_COPY_NAME since that would make their header size
* variable. (We currently insist that all flags be zero, since other flags
* would likely make the contexts less interchangeable, too.)
*
* We currently provide one freelist for ALLOCSET_DEFAULT_SIZES contexts
* and one for ALLOCSET_SMALL_SIZES contexts; the latter works for
* ALLOCSET_START_SMALL_SIZES too, since only the maxBlockSize differs.
*
* Ordinarily, we re-use freelist contexts in last-in-first-out order, in
* hopes of improving locality of reference. But if there get to be too
* many contexts in the list, we'd prefer to drop the most-recently-created
* contexts in hopes of keeping the process memory map compact.
* We approximate that by simply deleting all existing entries when the list
* overflows, on the assumption that queries that allocate a lot of contexts
* will probably free them in more or less reverse order of allocation.
*
* Contexts in a freelist are chained via their nextchild pointers.
*/
#define MAX_FREE_CONTEXTS 100 /* arbitrary limit on freelist length */
typedef struct AllocSetFreeList
{
int num_free; /* current list length */
AllocSetContext *first_free; /* list header */
} AllocSetFreeList;
/* context_freelists[0] is for default params, [1] for small params */
static AllocSetFreeList context_freelists[2] =
{
{
0, NULL
},
{
0, NULL
}
};
/*
* These functions implement the MemoryContext API for AllocSet contexts.
*/
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);
@ -236,11 +286,10 @@ static void AllocSetCheck(MemoryContext context);
/*
* This is the virtual function table for AllocSet contexts.
*/
static MemoryContextMethods AllocSetMethods = {
static const MemoryContextMethods AllocSetMethods = {
AllocSetAlloc,
AllocSetFree,
AllocSetRealloc,
AllocSetInit,
AllocSetReset,
AllocSetDelete,
AllocSetGetChunkSpace,
@ -325,27 +374,35 @@ AllocSetFreeIndex(Size size)
/*
* AllocSetContextCreate
* AllocSetContextCreateExtended
* Create a new AllocSet context.
*
* parent: parent context, or NULL if top-level context
* name: name of context (for debugging only, need not be unique)
* flags: bitmask of MEMCONTEXT_XXX option flags
* minContextSize: minimum context size
* initBlockSize: initial allocation block size
* maxBlockSize: maximum allocation block size
*
* Notes: the name string will be copied into context-lifespan storage.
* Notes: if flags & MEMCONTEXT_COPY_NAME, the name string will be copied into
* context-lifespan storage; otherwise, it had better be statically allocated.
* Most callers should abstract the context size parameters using a macro
* such as ALLOCSET_DEFAULT_SIZES.
* such as ALLOCSET_DEFAULT_SIZES. (This is now *required* when going
* through the AllocSetContextCreate macro.)
*/
MemoryContext
AllocSetContextCreate(MemoryContext parent,
const char *name,
Size minContextSize,
Size initBlockSize,
Size maxBlockSize)
AllocSetContextCreateExtended(MemoryContext parent,
const char *name,
int flags,
Size minContextSize,
Size initBlockSize,
Size maxBlockSize)
{
int freeListIndex;
Size headerSize;
Size firstBlockSize;
AllocSet set;
AllocBlock block;
/* Assert we padded AllocChunkData properly */
StaticAssertStmt(ALLOC_CHUNKHDRSZ == MAXALIGN(ALLOC_CHUNKHDRSZ),
@ -355,36 +412,125 @@ AllocSetContextCreate(MemoryContext parent,
"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.
* First, validate allocation parameters. Once these were regular runtime
* test and elog's, but in practice Asserts seem sufficient because nobody
* varies their parameters at runtime. 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);
Assert(initBlockSize == MAXALIGN(initBlockSize) &&
initBlockSize >= 1024);
Assert(maxBlockSize == MAXALIGN(maxBlockSize) &&
maxBlockSize >= initBlockSize &&
AllocHugeSizeIsValid(maxBlockSize)); /* must be safe to double */
Assert(minContextSize == 0 ||
(minContextSize == MAXALIGN(minContextSize) &&
minContextSize >= 1024 &&
minContextSize <= maxBlockSize));
/* Do the type-independent part of context creation */
set = (AllocSet) MemoryContextCreate(T_AllocSetContext,
sizeof(AllocSetContext),
&AllocSetMethods,
parent,
name);
/*
* Check whether the parameters match either available freelist. We do
* not need to demand a match of maxBlockSize.
*/
if (flags == 0 &&
minContextSize == ALLOCSET_DEFAULT_MINSIZE &&
initBlockSize == ALLOCSET_DEFAULT_INITSIZE)
freeListIndex = 0;
else if (flags == 0 &&
minContextSize == ALLOCSET_SMALL_MINSIZE &&
initBlockSize == ALLOCSET_SMALL_INITSIZE)
freeListIndex = 1;
else
freeListIndex = -1;
/*
* If a suitable freelist entry exists, just recycle that context.
*/
if (freeListIndex >= 0)
{
AllocSetFreeList *freelist = &context_freelists[freeListIndex];
if (freelist->first_free != NULL)
{
/* Remove entry from freelist */
set = freelist->first_free;
freelist->first_free = (AllocSet) set->header.nextchild;
freelist->num_free--;
/* Update its maxBlockSize; everything else should be OK */
set->maxBlockSize = maxBlockSize;
/* Reinitialize its header, installing correct name and parent */
MemoryContextCreate((MemoryContext) set,
T_AllocSetContext,
set->headerSize,
sizeof(AllocSetContext),
&AllocSetMethods,
parent,
name,
flags);
return (MemoryContext) set;
}
}
/* Size of the memory context header, including name storage if needed */
if (flags & MEMCONTEXT_COPY_NAME)
headerSize = MAXALIGN(sizeof(AllocSetContext) + strlen(name) + 1);
else
headerSize = MAXALIGN(sizeof(AllocSetContext));
/* Determine size of initial block */
firstBlockSize = headerSize + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ;
if (minContextSize != 0)
firstBlockSize = Max(firstBlockSize, minContextSize);
else
firstBlockSize = Max(firstBlockSize, initBlockSize);
/*
* Allocate the initial block. Unlike other aset.c blocks, it starts with
* the context header and its block header follows that.
*/
set = (AllocSet) malloc(firstBlockSize);
if (set == NULL)
{
if (TopMemoryContext)
MemoryContextStats(TopMemoryContext);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory"),
errdetail("Failed while creating memory context \"%s\".",
name)));
}
/*
* Avoid writing code that can fail between here and MemoryContextCreate;
* we'd leak the header/initial block if we ereport in this stretch.
*/
/* Fill in the initial block's block header */
block = (AllocBlock) (((char *) set) + headerSize);
block->aset = set;
block->freeptr = ((char *) block) + ALLOC_BLOCKHDRSZ;
block->endptr = ((char *) set) + firstBlockSize;
block->prev = NULL;
block->next = NULL;
/* Mark unallocated space NOACCESS; leave the block header alone. */
VALGRIND_MAKE_MEM_NOACCESS(block->freeptr, block->endptr - block->freeptr);
/* Remember block as part of block list */
set->blocks = block;
/* Mark block as not to be released at reset time */
set->keeper = block;
/* Finish filling in aset-specific parts of the context header */
MemSetAligned(set->freelist, 0, sizeof(set->freelist));
/* Save allocation parameters */
set->initBlockSize = initBlockSize;
set->maxBlockSize = maxBlockSize;
set->nextBlockSize = initBlockSize;
set->headerSize = headerSize;
set->freeListIndex = freeListIndex;
/*
* Compute the allocation chunk size limit for this context. It can't be
@ -410,64 +556,19 @@ AllocSetContextCreate(MemoryContext parent,
(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);
}
/* Finally, do the type-independent part of context creation */
MemoryContextCreate((MemoryContext) set,
T_AllocSetContext,
headerSize,
sizeof(AllocSetContext),
&AllocSetMethods,
parent,
name,
flags);
return (MemoryContext) set;
}
/*
* AllocSetInit
* Context-type-specific initialization routine.
*
* This is called by MemoryContextCreate() after setting up the
* generic MemoryContext fields and before linking the new context
* into the context tree. We must do whatever is needed to make the
* new context minimally valid for deletion. We must *not* risk
* failure --- thus, for example, allocating more memory is not cool.
* (AllocSetContextCreate can allocate memory when it gets control
* back, however.)
*/
static void
AllocSetInit(MemoryContext context)
{
/*
* Since MemoryContextCreate already zeroed the context node, we don't
* have to do anything here: it's already OK.
*/
}
/*
* AllocSetReset
* Frees all memory which is allocated in the given set.
@ -475,9 +576,10 @@ AllocSetInit(MemoryContext context)
* Actually, this routine has some discretion about what to do.
* It should mark all allocated chunks freed, but it need not necessarily
* give back all the resources the set owns. Our actual implementation is
* that we hang onto any "keeper" block specified for the set. In this way,
* we don't thrash malloc() when a context is repeatedly reset after small
* allocations, which is typical behavior for per-tuple contexts.
* that we give back all but the "keeper" block (which we must keep, since
* it shares a malloc chunk with the context header). In this way, we don't
* thrash malloc() when a context is repeatedly reset after small allocations,
* which is typical behavior for per-tuple contexts.
*/
static void
AllocSetReset(MemoryContext context)
@ -497,7 +599,7 @@ AllocSetReset(MemoryContext context)
block = set->blocks;
/* New blocks list is either empty or just the keeper block */
/* New blocks list will be just the keeper block */
set->blocks = set->keeper;
while (block != NULL)
@ -540,7 +642,6 @@ AllocSetReset(MemoryContext context)
* in preparation for deletion of the set.
*
* Unlike AllocSetReset, this *must* free all resources of the set.
* But note we are not responsible for deleting the context node itself.
*/
static void
AllocSetDelete(MemoryContext context)
@ -555,11 +656,49 @@ AllocSetDelete(MemoryContext context)
AllocSetCheck(context);
#endif
/* Make it look empty, just in case... */
MemSetAligned(set->freelist, 0, sizeof(set->freelist));
set->blocks = NULL;
set->keeper = NULL;
/*
* 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;
@ -567,9 +706,15 @@ AllocSetDelete(MemoryContext context)
#ifdef CLOBBER_FREED_MEMORY
wipe_mem(block, block->freeptr - ((char *) block));
#endif
free(block);
if (block != set->keeper)
free(block);
block = next;
}
/* Finally, free the context header, including the keeper block */
free(set);
}
/*
@ -807,18 +952,6 @@ AllocSetAlloc(MemoryContext context, Size size)
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);
@ -1205,11 +1338,14 @@ AllocSetStats(MemoryContext context, int level, bool print,
AllocSet set = (AllocSet) context;
Size nblocks = 0;
Size freechunks = 0;
Size totalspace = 0;
Size totalspace;
Size freespace = 0;
AllocBlock block;
int fidx;
/* Include context header in totalspace */
totalspace = set->headerSize;
for (block = set->blocks; block != NULL; block = block->next)
{
nblocks++;
@ -1264,7 +1400,7 @@ static void
AllocSetCheck(MemoryContext context)
{
AllocSet set = (AllocSet) context;
char *name = set->header.name;
const char *name = set->header.name;
AllocBlock prevblock;
AllocBlock block;

85
src/backend/utils/mmgr/generation.c
View File

@ -61,6 +61,7 @@ typedef struct GenerationContext
/* Generational context parameters */
Size blockSize; /* standard block size */
Size headerSize; /* allocated size of context header */
GenerationBlock *block; /* current (most recently allocated) block */
dlist_head blocks; /* list of blocks */
@ -149,7 +150,6 @@ struct GenerationChunk
static void *GenerationAlloc(MemoryContext context, Size size);
static void GenerationFree(MemoryContext context, void *pointer);
static void *GenerationRealloc(MemoryContext context, void *pointer, Size size);
static void GenerationInit(MemoryContext context);
static void GenerationReset(MemoryContext context);
static void GenerationDelete(MemoryContext context);
static Size GenerationGetChunkSpace(MemoryContext context, void *pointer);
@ -164,11 +164,10 @@ static void GenerationCheck(MemoryContext context);
/*
* This is the virtual function table for Generation contexts.
*/
static MemoryContextMethods GenerationMethods = {
static const MemoryContextMethods GenerationMethods = {
GenerationAlloc,
GenerationFree,
GenerationRealloc,
GenerationInit,
GenerationReset,
GenerationDelete,
GenerationGetChunkSpace,
@ -208,8 +207,10 @@ static MemoryContextMethods GenerationMethods = {
MemoryContext
GenerationContextCreate(MemoryContext parent,
const char *name,
int flags,
Size blockSize)
{
Size headerSize;
GenerationContext *set;
/* Assert we padded GenerationChunk properly */
@ -231,29 +232,51 @@ GenerationContextCreate(MemoryContext parent,
elog(ERROR, "invalid blockSize for memory context: %zu",
blockSize);
/* Do the type-independent part of context creation */
set = (GenerationContext *) MemoryContextCreate(T_GenerationContext,
sizeof(GenerationContext),
&GenerationMethods,
parent,
name);
/*
* Allocate the context header. Unlike aset.c, we never try to combine
* this with the first regular block, since that would prevent us from
* freeing the first generation of allocations.
*/
/* Size of the memory context header, including name storage if needed */
if (flags & MEMCONTEXT_COPY_NAME)
headerSize = MAXALIGN(sizeof(GenerationContext) + strlen(name) + 1);
else
headerSize = MAXALIGN(sizeof(GenerationContext));
set = (GenerationContext *) malloc(headerSize);
if (set == NULL)
{
MemoryContextStats(TopMemoryContext);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory"),
errdetail("Failed while creating memory context \"%s\".",
name)));
}
/*
* Avoid writing code that can fail between here and MemoryContextCreate;
* we'd leak the header if we ereport in this stretch.
*/
/* Fill in GenerationContext-specific header fields */
set->blockSize = blockSize;
return (MemoryContext) set;
}
/*
* GenerationInit
* Context-type-specific initialization routine.
*/
static void
GenerationInit(MemoryContext context)
{
GenerationContext *set = (GenerationContext *) context;
set->headerSize = headerSize;
set->block = NULL;
dlist_init(&set->blocks);
/* Finally, do the type-independent part of context creation */
MemoryContextCreate((MemoryContext) set,
T_GenerationContext,
headerSize,
sizeof(GenerationContext),
&GenerationMethods,
parent,
name,
flags);
return (MemoryContext) set;
}
/*
@ -296,16 +319,15 @@ GenerationReset(MemoryContext context)
/*
* GenerationDelete
* Frees all memory which is allocated in the given set, in preparation
* for deletion of the set. We simply call GenerationReset() which does
* all the dirty work.
* Free all memory which is allocated in the given context.
*/
static void
GenerationDelete(MemoryContext context)
{
/* just reset to release all the GenerationBlocks */
/* Reset to release all the GenerationBlocks */
GenerationReset(context);
/* we are not responsible for deleting the context node itself */
/* And free the context header */
free(context);
}
/*
@ -659,7 +681,7 @@ GenerationIsEmpty(MemoryContext context)
/*
* GenerationStats
* Compute stats about memory consumption of an Generation.
* Compute stats about memory consumption of a Generation context.
*
* level: recursion level (0 at top level); used for print indentation.
* print: true to print stats to stderr.
@ -676,10 +698,13 @@ GenerationStats(MemoryContext context, int level, bool print,
Size nblocks = 0;
Size nchunks = 0;
Size nfreechunks = 0;
Size totalspace = 0;
Size totalspace;
Size freespace = 0;
dlist_iter iter;
/* Include context header in totalspace */
totalspace = set->headerSize;
dlist_foreach(iter, &set->blocks)
{
GenerationBlock *block = dlist_container(GenerationBlock, node, iter.cur);
@ -727,7 +752,7 @@ static void
GenerationCheck(MemoryContext context)
{
GenerationContext *gen = (GenerationContext *) context;
char *name = context->name;
const char *name = context->name;
dlist_iter iter;
/* walk all blocks in this context */

161
src/backend/utils/mmgr/mcxt.c
View File

@ -91,9 +91,7 @@ MemoryContextInit(void)
AssertState(TopMemoryContext == NULL);
/*
* First, initialize TopMemoryContext, which will hold the MemoryContext
* nodes for all other contexts. (There is special-case code in
* MemoryContextCreate() to handle this call.)
* First, initialize TopMemoryContext, which is the parent of all others.
*/
TopMemoryContext = AllocSetContextCreate((MemoryContext) NULL,
"TopMemoryContext",
@ -118,11 +116,12 @@ MemoryContextInit(void)
* This should be the last step in this function, as elog.c assumes memory
* management works once ErrorContext is non-null.
*/
ErrorContext = AllocSetContextCreate(TopMemoryContext,
"ErrorContext",
8 * 1024,
8 * 1024,
8 * 1024);
ErrorContext = AllocSetContextCreateExtended(TopMemoryContext,
"ErrorContext",
0,
8 * 1024,
8 * 1024,
8 * 1024);
MemoryContextAllowInCriticalSection(ErrorContext, true);
}
@ -191,10 +190,9 @@ MemoryContextResetChildren(MemoryContext context)
* Delete a context and its descendants, and release all space
* allocated therein.
*
* The type-specific delete routine removes all subsidiary storage
* for the context, but we have to delete the context node itself,
* as well as recurse to get the children. We must also delink the
* node from its parent, if it has one.
* The type-specific delete routine removes all storage for the context,
* but we have to recurse to handle the children.
* We must also delink the context from its parent, if it has one.
*/
void
MemoryContextDelete(MemoryContext context)
@ -205,7 +203,9 @@ MemoryContextDelete(MemoryContext context)
/* And not CurrentMemoryContext, either */
Assert(context != CurrentMemoryContext);
MemoryContextDeleteChildren(context);
/* save a function call in common case where there are no children */
if (context->firstchild != NULL)
MemoryContextDeleteChildren(context);
/*
* It's not entirely clear whether 'tis better to do this before or after
@ -223,8 +223,8 @@ MemoryContextDelete(MemoryContext context)
MemoryContextSetParent(context, NULL);
context->methods->delete_context(context);
VALGRIND_DESTROY_MEMPOOL(context);
pfree(context);
}
/*
@ -587,100 +587,85 @@ MemoryContextContains(MemoryContext context, void *pointer)
return ptr_context == context;
}
/*--------------------
/*
* MemoryContextCreate
* Context-type-independent part of context creation.
*
* This is only intended to be called by context-type-specific
* context creation routines, not by the unwashed masses.
*
* The context creation procedure is a little bit tricky because
* we want to be sure that we don't leave the context tree invalid
* in case of failure (such as insufficient memory to allocate the
* context node itself). The procedure goes like this:
* 1. Context-type-specific routine first calls MemoryContextCreate(),
* passing the appropriate tag/size/methods values (the methods
* pointer will ordinarily point to statically allocated data).
* The parent and name parameters usually come from the caller.
* 2. MemoryContextCreate() attempts to allocate the context node,
* plus space for the name. If this fails we can ereport() with no
* damage done.
* 3. We fill in all of the type-independent MemoryContext fields.
* 4. We call the type-specific init routine (using the methods pointer).
* The init routine is required to make the node minimally valid
* with zero chance of failure --- it can't allocate more memory,
* for example.
* 5. Now we have a minimally valid node that can behave correctly
* when told to reset or delete itself. We link the node to its
* parent (if any), making the node part of the context tree.
* 6. We return to the context-type-specific routine, which finishes
* The memory context creation procedure goes like this:
* 1. Context-type-specific routine makes some initial space allocation,
* including enough space for the context header. If it fails,
* it can ereport() with no damage done.
* 2. Context-type-specific routine sets up all type-specific fields of
* the header (those beyond MemoryContextData proper), as well as any
* other management fields it needs to have a fully valid context.
* Usually, failure in this step is impossible, but if it's possible
* the initial space allocation should be freed before ereport'ing.
* 3. Context-type-specific routine calls MemoryContextCreate() to fill in
* the generic header fields and link the context into the context tree.
* 4. We return to the context-type-specific routine, which finishes
* up type-specific initialization. This routine can now do things
* that might fail (like allocate more memory), so long as it's
* sure the node is left in a state that delete will handle.
*
* This protocol doesn't prevent us from leaking memory if step 6 fails
* during creation of a top-level context, since there's no parent link
* in that case. However, if you run out of memory while you're building
* a top-level context, you might as well go home anyway...
* node: the as-yet-uninitialized common part of the context header node.
* tag: NodeTag code identifying the memory context type.
* size: total size of context header including context-type-specific fields,
* as well as space for the context name if MEMCONTEXT_COPY_NAME is set.
* nameoffset: where within the "size" space to insert the context name.
* methods: context-type-specific methods (usually statically allocated).
* parent: parent context, or NULL if this will be a top-level context.
* name: name of context (for debugging only, need not be unique).
* flags: bitmask of MEMCONTEXT_XXX option flags.
*
* Normally, the context node and the name are allocated from
* TopMemoryContext (NOT from the parent context, since the node must
* survive resets of its parent context!). However, this routine is itself
* used to create TopMemoryContext! If we see that TopMemoryContext is NULL,
* we assume we are creating TopMemoryContext and use malloc() to allocate
* the node.
*
* Note that the name field of a MemoryContext does not point to
* separately-allocated storage, so it should not be freed at context
* deletion.
*--------------------
* Context routines generally assume that MemoryContextCreate can't fail,
* so this can contain Assert but not elog/ereport.
*/
MemoryContext
MemoryContextCreate(NodeTag tag, Size size,
MemoryContextMethods *methods,
void
MemoryContextCreate(MemoryContext node,
NodeTag tag, Size size, Size nameoffset,
const MemoryContextMethods *methods,
MemoryContext parent,
const char *name)
const char *name,
int flags)
{
MemoryContext node;
Size needed = size + strlen(name) + 1;
/* creating new memory contexts is not allowed in a critical section */
/* Creating new memory contexts is not allowed in a critical section */
Assert(CritSectionCount == 0);
/* Get space for node and name */
if (TopMemoryContext != NULL)
/* Check size is sane */
Assert(nameoffset >= sizeof(MemoryContextData));
Assert((flags & MEMCONTEXT_COPY_NAME) ?
size >= nameoffset + strlen(name) + 1 :
size >= nameoffset);
/* Initialize all standard fields of memory context header */
node->type = tag;
node->isReset = true;
node->methods = methods;
node->parent = parent;
node->firstchild = NULL;
node->prevchild = NULL;
node->reset_cbs = NULL;
if (flags & MEMCONTEXT_COPY_NAME)
{
/* Normal case: allocate the node in TopMemoryContext */
node = (MemoryContext) MemoryContextAlloc(TopMemoryContext,
needed);
/* Insert context name into space reserved for it */
char *namecopy = ((char *) node) + nameoffset;
node->name = namecopy;
strcpy(namecopy, name);
}
else
{
/* Special case for startup: use good ol' malloc */
node = (MemoryContext) malloc(needed);
Assert(node != NULL);
/* Assume the passed-in name is statically allocated */
node->name = name;
}
/* Initialize the node as best we can */
MemSet(node, 0, size);
node->type = tag;
node->methods = methods;
node->parent = NULL; /* for the moment */
node->firstchild = NULL;
node->prevchild = NULL;
node->nextchild = NULL;
node->isReset = true;
node->name = ((char *) node) + size;
strcpy(node->name, name);
/* Type-specific routine finishes any other essential initialization */
node->methods->init(node);
/* OK to link node to parent (if any) */
/* Could use MemoryContextSetParent here, but doesn't seem worthwhile */
/* OK to link node into context tree */
if (parent)
{
node->parent = parent;
node->nextchild = parent->firstchild;
if (parent->firstchild != NULL)
parent->firstchild->prevchild = node;
@ -688,11 +673,13 @@ MemoryContextCreate(NodeTag tag, Size size,
/* inherit allowInCritSection flag from parent */
node->allowInCritSection = parent->allowInCritSection;
}
else
{
node->nextchild = NULL;
node->allowInCritSection = false;
}
VALGRIND_CREATE_MEMPOOL(node, 0, false);
/* Return to type-specific creation routine to finish up */
return node;
}
/*

102
src/backend/utils/mmgr/slab.c
View File

@ -67,6 +67,7 @@ typedef struct SlabContext
Size chunkSize; /* chunk size */
Size fullChunkSize; /* chunk size including header and alignment */
Size blockSize; /* block size */
Size headerSize; /* allocated size of context header */
int chunksPerBlock; /* number of chunks per block */
int minFreeChunks; /* min number of free chunks in any block */
int nblocks; /* number of blocks allocated */
@ -126,7 +127,6 @@ typedef struct SlabChunk
static void *SlabAlloc(MemoryContext context, Size size);
static void SlabFree(MemoryContext context, void *pointer);
static void *SlabRealloc(MemoryContext context, void *pointer, Size size);
static void SlabInit(MemoryContext context);
static void SlabReset(MemoryContext context);
static void SlabDelete(MemoryContext context);
static Size SlabGetChunkSpace(MemoryContext context, void *pointer);
@ -140,11 +140,10 @@ static void SlabCheck(MemoryContext context);
/*
* This is the virtual function table for Slab contexts.
*/
static MemoryContextMethods SlabMethods = {
static const MemoryContextMethods SlabMethods = {
SlabAlloc,
SlabFree,
SlabRealloc,
SlabInit,
SlabReset,
SlabDelete,
SlabGetChunkSpace,
@ -177,24 +176,30 @@ static MemoryContextMethods SlabMethods = {
* Create a new Slab context.
*
* parent: parent context, or NULL if top-level context
* name: name of context (for debugging --- string will be copied)
* name: name of context (for debugging only, need not be unique)
* flags: bitmask of MEMCONTEXT_XXX option flags
* blockSize: allocation block size
* chunkSize: allocation chunk size
*
* Notes: if flags & MEMCONTEXT_COPY_NAME, the name string will be copied into
* context-lifespan storage; otherwise, it had better be statically allocated.
* The chunkSize may not exceed:
* MAXALIGN_DOWN(SIZE_MAX) - MAXALIGN(sizeof(SlabBlock)) - SLAB_CHUNKHDRSZ
*
*/
MemoryContext
SlabContextCreate(MemoryContext parent,
const char *name,
int flags,
Size blockSize,
Size chunkSize)
{
int chunksPerBlock;
Size fullChunkSize;
Size freelistSize;
Size nameOffset;
Size headerSize;
SlabContext *slab;
int i;
/* Assert we padded SlabChunk properly */
StaticAssertStmt(sizeof(SlabChunk) == MAXALIGN(sizeof(SlabChunk)),
@ -211,7 +216,7 @@ SlabContextCreate(MemoryContext parent,
fullChunkSize = sizeof(SlabChunk) + MAXALIGN(chunkSize);
/* Make sure the block can store at least one chunk. */
if (blockSize - sizeof(SlabBlock) < fullChunkSize)
if (blockSize < fullChunkSize + sizeof(SlabBlock))
elog(ERROR, "block size %zu for slab is too small for %zu chunks",
blockSize, chunkSize);
@ -221,45 +226,58 @@ SlabContextCreate(MemoryContext parent,
/* The freelist starts with 0, ends with chunksPerBlock. */
freelistSize = sizeof(dlist_head) * (chunksPerBlock + 1);
/* if we can't fit at least one chunk into the block, we're hosed */
Assert(chunksPerBlock > 0);
/*
* Allocate the context header. Unlike aset.c, we never try to combine
* this with the first regular block; not worth the extra complication.
*/
/* make sure the chunks actually fit on the block */
Assert((fullChunkSize * chunksPerBlock) + sizeof(SlabBlock) <= blockSize);
/* Size of the memory context header, including name storage if needed */
nameOffset = offsetof(SlabContext, freelist) + freelistSize;
if (flags & MEMCONTEXT_COPY_NAME)
headerSize = nameOffset + strlen(name) + 1;
else
headerSize = nameOffset;
/* Do the type-independent part of context creation */
slab = (SlabContext *)
MemoryContextCreate(T_SlabContext,
(offsetof(SlabContext, freelist) + freelistSize),
&SlabMethods,
parent,
name);
slab = (SlabContext *) malloc(headerSize);
if (slab == NULL)
{
MemoryContextStats(TopMemoryContext);
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory"),
errdetail("Failed while creating memory context \"%s\".",
name)));
}
slab->blockSize = blockSize;
/*
* Avoid writing code that can fail between here and MemoryContextCreate;
* we'd leak the header if we ereport in this stretch.
*/
/* Fill in SlabContext-specific header fields */
slab->chunkSize = chunkSize;
slab->fullChunkSize = fullChunkSize;
slab->blockSize = blockSize;
slab->headerSize = headerSize;
slab->chunksPerBlock = chunksPerBlock;
slab->nblocks = 0;
slab->minFreeChunks = 0;
return (MemoryContext) slab;
}
/*
* SlabInit
* Context-type-specific initialization routine.
*/
static void
SlabInit(MemoryContext context)
{
int i;
SlabContext *slab = castNode(SlabContext, context);
Assert(slab);
slab->nblocks = 0;
/* initialize the freelist slots */
for (i = 0; i < (slab->chunksPerBlock + 1); i++)
dlist_init(&slab->freelist[i]);
/* Finally, do the type-independent part of context creation */
MemoryContextCreate((MemoryContext) slab,
T_SlabContext,
headerSize,
nameOffset,
&SlabMethods,
parent,
name,
flags);
return (MemoryContext) slab;
}
/*
@ -308,14 +326,15 @@ SlabReset(MemoryContext context)
/*
* SlabDelete
* Frees all memory which is allocated in the given slab, in preparation
* for deletion of the slab. We simply call SlabReset().
* Free all memory which is allocated in the given context.
*/
static void
SlabDelete(MemoryContext context)
{
/* just reset the context */
/* Reset to release all the SlabBlocks */
SlabReset(context);
/* And free the context header */
free(context);
}
/*
@ -613,7 +632,7 @@ SlabIsEmpty(MemoryContext context)
/*
* SlabStats
* Compute stats about memory consumption of an Slab.
* Compute stats about memory consumption of a Slab context.
*
* level: recursion level (0 at top level); used for print indentation.
* print: true to print stats to stderr.
@ -626,11 +645,12 @@ SlabStats(MemoryContext context, int level, bool print,
SlabContext *slab = castNode(SlabContext, context);
Size nblocks = 0;
Size freechunks = 0;
Size totalspace = 0;
Size totalspace;
Size freespace = 0;
int i;
Assert(slab);
/* Include context header in totalspace */
totalspace = slab->headerSize;
for (i = 0; i <= slab->chunksPerBlock; i++)
{
@ -682,7 +702,7 @@ SlabCheck(MemoryContext context)
{
int i;
SlabContext *slab = castNode(SlabContext, context);
char *name = slab->header.name;
const char *name = slab->header.name;
char *freechunks;
Assert(slab);

5
src/include/nodes/memnodes.h
View File

@ -57,7 +57,6 @@ typedef struct MemoryContextMethods
/* call this free_p in case someone #define's free() */
void (*free_p) (MemoryContext context, void *pointer);
void *(*realloc) (MemoryContext context, void *pointer, Size size);
void (*init) (MemoryContext context);
void (*reset) (MemoryContext context);
void (*delete_context) (MemoryContext context);
Size (*get_chunk_space) (MemoryContext context, void *pointer);
@ -76,12 +75,12 @@ typedef struct MemoryContextData
/* these two fields are placed here to minimize alignment wastage: */
bool isReset; /* T = no space alloced since last reset */
bool allowInCritSection; /* allow palloc in critical section */
MemoryContextMethods *methods; /* virtual function table */
const MemoryContextMethods *methods; /* virtual function table */
MemoryContext parent; /* NULL if no parent (toplevel context) */
MemoryContext firstchild; /* head of linked list of children */
MemoryContext prevchild; /* previous child of same parent */
MemoryContext nextchild; /* next child of same parent */
char *name; /* context name (just for debugging) */
const char *name; /* context name (just for debugging) */
MemoryContextCallback *reset_cbs; /* list of reset/delete callbacks */
} MemoryContextData;

43
src/include/utils/memutils.h
View File

@ -132,10 +132,12 @@ GetMemoryChunkContext(void *pointer)
* context creation. It's intended to be called from context-type-
* specific creation routines, and noplace else.
*/
extern MemoryContext MemoryContextCreate(NodeTag tag, Size size,
MemoryContextMethods *methods,
extern void MemoryContextCreate(MemoryContext node,
NodeTag tag, Size size, Size nameoffset,
const MemoryContextMethods *methods,
MemoryContext parent,
const char *name);
const char *name,
int flags);
/*
@ -143,23 +145,48 @@ extern MemoryContext MemoryContextCreate(NodeTag tag, Size size,
*/
/* aset.c */
extern MemoryContext AllocSetContextCreate(MemoryContext parent,
const char *name,
Size minContextSize,
Size initBlockSize,
Size maxBlockSize);
extern MemoryContext AllocSetContextCreateExtended(MemoryContext parent,
const char *name,
int flags,
Size minContextSize,
Size initBlockSize,
Size maxBlockSize);
/*
* This backwards compatibility macro only works for constant context names,
* and you must specify block sizes with one of the abstraction macros below.
*/
#ifdef HAVE__BUILTIN_CONSTANT_P
#define AllocSetContextCreate(parent, name, allocparams) \
(StaticAssertExpr(__builtin_constant_p(name), \
"Use AllocSetContextCreateExtended with MEMCONTEXT_COPY_NAME for non-constant context names"), \
AllocSetContextCreateExtended(parent, name, 0, allocparams))
#else
#define AllocSetContextCreate(parent, name, allocparams) \
AllocSetContextCreateExtended(parent, name, 0, allocparams)
#endif
/* slab.c */
extern MemoryContext SlabContextCreate(MemoryContext parent,
const char *name,
int flags,
Size blockSize,
Size chunkSize);
/* generation.c */
extern MemoryContext GenerationContextCreate(MemoryContext parent,
const char *name,
int flags,
Size blockSize);
/*
* Flag option bits for FooContextCreate functions.
* In future, some of these might be relevant to only some context types.
*
* COPY_NAME: FooContextCreate's name argument is not a constant string
*/
#define MEMCONTEXT_COPY_NAME 0x0001 /* is passed name transient? */
/*
* Recommended default alloc parameters, suitable for "ordinary" contexts
* that might hold quite a lot of data.

7
src/pl/plperl/plperl.c
View File

@ -2777,9 +2777,10 @@ compile_plperl_function(Oid fn_oid, bool is_trigger, bool is_event_trigger)
/************************************************************
* Allocate a context that will hold all PG data for the procedure.
************************************************************/
proc_cxt = AllocSetContextCreate(TopMemoryContext,
NameStr(procStruct->proname),
ALLOCSET_SMALL_SIZES);
proc_cxt = AllocSetContextCreateExtended(TopMemoryContext,
NameStr(procStruct->proname),
MEMCONTEXT_COPY_NAME,
ALLOCSET_SMALL_SIZES);
/************************************************************
* Allocate and fill a new procedure description block.

7
src/pl/plpython/plpy_procedure.c
View File

@ -166,9 +166,10 @@ PLy_procedure_create(HeapTuple procTup, Oid fn_oid, bool is_trigger)
}
/* Create long-lived context that all procedure info will live in */
cxt = AllocSetContextCreate(TopMemoryContext,
procName,
ALLOCSET_DEFAULT_SIZES);
cxt = AllocSetContextCreateExtended(TopMemoryContext,
procName,
MEMCONTEXT_COPY_NAME,
ALLOCSET_DEFAULT_SIZES);
oldcxt = MemoryContextSwitchTo(cxt);

9
src/pl/tcl/pltcl.c
View File

@ -146,7 +146,7 @@ typedef struct pltcl_proc_desc
Oid result_typid; /* OID of fn's result type */
FmgrInfo result_in_func; /* input function for fn's result type */
Oid result_typioparam; /* param to pass to same */
bool fn_is_procedure;/* true if this is a procedure */
bool fn_is_procedure; /* true if this is a procedure */
bool fn_retisset; /* true if function returns a set */
bool fn_retistuple; /* true if function returns composite */
bool fn_retisdomain; /* true if function returns domain */
@ -1471,9 +1471,10 @@ compile_pltcl_function(Oid fn_oid, Oid tgreloid,
* Allocate a context that will hold all PG data for the procedure.
* We use the internal proc name as the context name.
************************************************************/
proc_cxt = AllocSetContextCreate(TopMemoryContext,
internal_proname,
ALLOCSET_SMALL_SIZES);
proc_cxt = AllocSetContextCreateExtended(TopMemoryContext,
internal_proname,
MEMCONTEXT_COPY_NAME,
ALLOCSET_SMALL_SIZES);
/************************************************************
* Allocate and fill a new procedure description block.