PostgreSQL Source Code  git master
generation.c File Reference
#include "postgres.h"
#include "lib/ilist.h"
#include "port/pg_bitutils.h"
#include "utils/memdebug.h"
#include "utils/memutils.h"
#include "utils/memutils_internal.h"
#include "utils/memutils_memorychunk.h"
Include dependency graph for generation.c:

Go to the source code of this file.

Data Structures

struct  GenerationContext
 
struct  GenerationBlock
 

Macros

#define Generation_BLOCKHDRSZ   MAXALIGN(sizeof(GenerationBlock))
 
#define Generation_CHUNKHDRSZ   sizeof(MemoryChunk)
 
#define Generation_CHUNK_FRACTION   8
 
#define GenerationIsValid(set)    (PointerIsValid(set) && IsA(set, GenerationContext))
 
#define GenerationBlockIsValid(block)    (PointerIsValid(block) && GenerationIsValid((block)->context))
 
#define GenerationBlockIsEmpty(b)   ((b)->nchunks == 0)
 
#define ExternalChunkGetBlock(chunk)    (GenerationBlock *) ((char *) chunk - Generation_BLOCKHDRSZ)
 
#define KeeperBlock(set)
 
#define IsKeeperBlock(set, block)   ((block) == (KeeperBlock(set)))
 

Typedefs

typedef struct GenerationBlock GenerationBlock
 
typedef void * GenerationPointer
 
typedef struct GenerationContext GenerationContext
 

Functions

static void GenerationBlockInit (GenerationContext *context, GenerationBlock *block, Size blksize)
 
static void GenerationBlockMarkEmpty (GenerationBlock *block)
 
static Size GenerationBlockFreeBytes (GenerationBlock *block)
 
static void GenerationBlockFree (GenerationContext *set, GenerationBlock *block)
 
MemoryContext GenerationContextCreate (MemoryContext parent, const char *name, Size minContextSize, Size initBlockSize, Size maxBlockSize)
 
void GenerationReset (MemoryContext context)
 
void GenerationDelete (MemoryContext context)
 
static pg_noinline void * GenerationAllocLarge (MemoryContext context, Size size, int flags)
 
static void * GenerationAllocChunkFromBlock (MemoryContext context, GenerationBlock *block, Size size, Size chunk_size)
 
static pg_noinline void * GenerationAllocFromNewBlock (MemoryContext context, Size size, int flags, Size chunk_size)
 
void * GenerationAlloc (MemoryContext context, Size size, int flags)
 
void GenerationFree (void *pointer)
 
void * GenerationRealloc (void *pointer, Size size, int flags)
 
MemoryContext GenerationGetChunkContext (void *pointer)
 
Size GenerationGetChunkSpace (void *pointer)
 
bool GenerationIsEmpty (MemoryContext context)
 
void GenerationStats (MemoryContext context, MemoryStatsPrintFunc printfunc, void *passthru, MemoryContextCounters *totals, bool print_to_stderr)
 

Macro Definition Documentation

◆ ExternalChunkGetBlock

#define ExternalChunkGetBlock (   chunk)     (GenerationBlock *) ((char *) chunk - Generation_BLOCKHDRSZ)

Definition at line 123 of file generation.c.

◆ Generation_BLOCKHDRSZ

#define Generation_BLOCKHDRSZ   MAXALIGN(sizeof(GenerationBlock))

Definition at line 46 of file generation.c.

◆ Generation_CHUNK_FRACTION

#define Generation_CHUNK_FRACTION   8

Definition at line 49 of file generation.c.

◆ Generation_CHUNKHDRSZ

#define Generation_CHUNKHDRSZ   sizeof(MemoryChunk)

Definition at line 47 of file generation.c.

◆ GenerationBlockIsEmpty

#define GenerationBlockIsEmpty (   b)    ((b)->nchunks == 0)

Definition at line 116 of file generation.c.

◆ GenerationBlockIsValid

#define GenerationBlockIsValid (   block)     (PointerIsValid(block) && GenerationIsValid((block)->context))

Definition at line 109 of file generation.c.

◆ GenerationIsValid

#define GenerationIsValid (   set)     (PointerIsValid(set) && IsA(set, GenerationContext))

Definition at line 102 of file generation.c.

◆ IsKeeperBlock

#define IsKeeperBlock (   set,
  block 
)    ((block) == (KeeperBlock(set)))

Definition at line 132 of file generation.c.

◆ KeeperBlock

#define KeeperBlock (   set)
Value:
((GenerationBlock *) (((char *) set) + \
MAXALIGN(sizeof(GenerationContext))))

Definition at line 127 of file generation.c.

Typedef Documentation

◆ GenerationBlock

Definition at line 1 of file generation.c.

◆ GenerationContext

◆ GenerationPointer

typedef void* GenerationPointer

Definition at line 53 of file generation.c.

Function Documentation

◆ GenerationAlloc()

void* GenerationAlloc ( MemoryContext  context,
Size  size,
int  flags 
)

Definition at line 527 of file generation.c.

528 {
530  GenerationBlock *block;
531  Size chunk_size;
532  Size required_size;
533 
535 
536 #ifdef MEMORY_CONTEXT_CHECKING
537  /* ensure there's always space for the sentinel byte */
538  chunk_size = MAXALIGN(size + 1);
539 #else
540  chunk_size = MAXALIGN(size);
541 #endif
542 
543  /*
544  * If requested size exceeds maximum for chunks we hand the request off to
545  * GenerationAllocLarge().
546  */
547  if (chunk_size > set->allocChunkLimit)
548  return GenerationAllocLarge(context, size, flags);
549 
550  required_size = chunk_size + Generation_CHUNKHDRSZ;
551 
552  /*
553  * Not an oversized chunk. We try to first make use of the current block,
554  * but if there's not enough space in it, instead of allocating a new
555  * block, we look to see if the empty freeblock has enough space. We
556  * don't try reusing the keeper block. If it's become empty we'll reuse
557  * that again only if the context is reset.
558  *
559  * We only try reusing the freeblock if we've no space for this allocation
560  * on the current block. When a freeblock exists, we'll switch to it once
561  * the first time we can't fit an allocation in the current block. We
562  * avoid ping-ponging between the two as we need to be careful not to
563  * fragment differently sized consecutive allocations between several
564  * blocks. Going between the two could cause fragmentation for FIFO
565  * workloads, which generation is meant to be good at.
566  */
567  block = set->block;
568 
569  if (unlikely(GenerationBlockFreeBytes(block) < required_size))
570  {
571  GenerationBlock *freeblock = set->freeblock;
572 
573  /* freeblock, if set, must be empty */
574  Assert(freeblock == NULL || GenerationBlockIsEmpty(freeblock));
575 
576  /* check if we have a freeblock and if it's big enough */
577  if (freeblock != NULL &&
578  GenerationBlockFreeBytes(freeblock) >= required_size)
579  {
580  /* make the freeblock the current block */
581  set->freeblock = NULL;
582  set->block = freeblock;
583 
585  freeblock,
586  size,
587  chunk_size);
588  }
589  else
590  {
591  /*
592  * No freeblock, or it's not big enough for this allocation. Make
593  * a new block.
594  */
595  return GenerationAllocFromNewBlock(context, size, flags, chunk_size);
596  }
597  }
598 
599  /* The current block has space, so just allocate chunk there. */
600  return GenerationAllocChunkFromBlock(context, block, size, chunk_size);
601 }
#define MAXALIGN(LEN)
Definition: c.h:811
#define Assert(condition)
Definition: c.h:858
#define unlikely(x)
Definition: c.h:311
size_t Size
Definition: c.h:605
static pg_noinline void * GenerationAllocLarge(MemoryContext context, Size size, int flags)
Definition: generation.c:343
static Size GenerationBlockFreeBytes(GenerationBlock *block)
Definition: generation.c:654
#define Generation_CHUNKHDRSZ
Definition: generation.c:47
static pg_noinline void * GenerationAllocFromNewBlock(MemoryContext context, Size size, int flags, Size chunk_size)
Definition: generation.c:461
#define GenerationBlockIsEmpty(b)
Definition: generation.c:116
static void * GenerationAllocChunkFromBlock(MemoryContext context, GenerationBlock *block, Size size, Size chunk_size)
Definition: generation.c:413
#define GenerationIsValid(set)
Definition: generation.c:102
tree context
Definition: radixtree.h:1829
static pg_noinline void Size size
Definition: slab.c:607
GenerationBlock * freeblock
Definition: generation.c:70
GenerationBlock * block
Definition: generation.c:69
uint32 allocChunkLimit
Definition: generation.c:67

References GenerationContext::allocChunkLimit, Assert, GenerationContext::block, context, GenerationContext::freeblock, Generation_CHUNKHDRSZ, GenerationAllocChunkFromBlock(), GenerationAllocFromNewBlock(), GenerationAllocLarge(), GenerationBlockFreeBytes(), GenerationBlockIsEmpty, GenerationIsValid, MAXALIGN, size, and unlikely.

Referenced by GenerationRealloc().

◆ GenerationAllocChunkFromBlock()

static void* GenerationAllocChunkFromBlock ( MemoryContext  context,
GenerationBlock block,
Size  size,
Size  chunk_size 
)
inlinestatic

Definition at line 413 of file generation.c.

415 {
416  MemoryChunk *chunk = (MemoryChunk *) (block->freeptr);
417 
418  /* validate we've been given a block with enough free space */
419  Assert(block != NULL);
420  Assert((block->endptr - block->freeptr) >=
421  Generation_CHUNKHDRSZ + chunk_size);
422 
423  /* Prepare to initialize the chunk header. */
425 
426  block->nchunks += 1;
427  block->freeptr += (Generation_CHUNKHDRSZ + chunk_size);
428 
429  Assert(block->freeptr <= block->endptr);
430 
431  MemoryChunkSetHdrMask(chunk, block, chunk_size, MCTX_GENERATION_ID);
432 #ifdef MEMORY_CONTEXT_CHECKING
433  chunk->requested_size = size;
434  /* set mark to catch clobber of "unused" space */
435  Assert(size < chunk_size);
436  set_sentinel(MemoryChunkGetPointer(chunk), size);
437 #endif
438 #ifdef RANDOMIZE_ALLOCATED_MEMORY
439  /* fill the allocated space with junk */
440  randomize_mem((char *) MemoryChunkGetPointer(chunk), size);
441 #endif
442 
443  /* Ensure any padding bytes are marked NOACCESS. */
445  chunk_size - size);
446 
447  /* Disallow access to the chunk header. */
449 
451 }
uint64 chunk
#define VALGRIND_MAKE_MEM_NOACCESS(addr, size)
Definition: memdebug.h:27
#define VALGRIND_MAKE_MEM_UNDEFINED(addr, size)
Definition: memdebug.h:28
@ MCTX_GENERATION_ID
#define MemoryChunkGetPointer(c)
static void MemoryChunkSetHdrMask(MemoryChunk *chunk, void *block, Size value, MemoryContextMethodID methodid)
char * freeptr
Definition: generation.c:94

References Assert, chunk, GenerationBlock::endptr, GenerationBlock::freeptr, Generation_CHUNKHDRSZ, MCTX_GENERATION_ID, MemoryChunkGetPointer, MemoryChunkSetHdrMask(), GenerationBlock::nchunks, size, VALGRIND_MAKE_MEM_NOACCESS, and VALGRIND_MAKE_MEM_UNDEFINED.

Referenced by GenerationAlloc(), and GenerationAllocFromNewBlock().

◆ GenerationAllocFromNewBlock()

static pg_noinline void* GenerationAllocFromNewBlock ( MemoryContext  context,
Size  size,
int  flags,
Size  chunk_size 
)
static

Definition at line 461 of file generation.c.

463 {
465  GenerationBlock *block;
466  Size blksize;
467  Size required_size;
468 
469  /*
470  * The first such block has size initBlockSize, and we double the space in
471  * each succeeding block, but not more than maxBlockSize.
472  */
473  blksize = set->nextBlockSize;
474  set->nextBlockSize <<= 1;
475  if (set->nextBlockSize > set->maxBlockSize)
476  set->nextBlockSize = set->maxBlockSize;
477 
478  /* we'll need space for the chunk, chunk hdr and block hdr */
479  required_size = chunk_size + Generation_CHUNKHDRSZ + Generation_BLOCKHDRSZ;
480 
481  /* round the size up to the next power of 2 */
482  if (blksize < required_size)
483  blksize = pg_nextpower2_size_t(required_size);
484 
485  block = (GenerationBlock *) malloc(blksize);
486 
487  if (block == NULL)
489 
490  context->mem_allocated += blksize;
491 
492  /* initialize the new block */
493  GenerationBlockInit(set, block, blksize);
494 
495  /* add it to the doubly-linked list of blocks */
496  dlist_push_head(&set->blocks, &block->node);
497 
498  /* make this the current block */
499  set->block = block;
500 
501  return GenerationAllocChunkFromBlock(context, block, size, chunk_size);
502 }
static void GenerationBlockInit(GenerationContext *context, GenerationBlock *block, Size blksize)
Definition: generation.c:609
#define Generation_BLOCKHDRSZ
Definition: generation.c:46
#define malloc(a)
Definition: header.h:50
static void dlist_push_head(dlist_head *head, dlist_node *node)
Definition: ilist.h:347
void * MemoryContextAllocationFailure(MemoryContext context, Size size, int flags)
Definition: mcxt.c:1147
#define pg_nextpower2_size_t
Definition: pg_bitutils.h:417
dlist_node node
Definition: generation.c:89
uint32 maxBlockSize
Definition: generation.c:65
uint32 nextBlockSize
Definition: generation.c:66
dlist_head blocks
Definition: generation.c:72

References GenerationContext::block, GenerationContext::blocks, context, dlist_push_head(), Generation_BLOCKHDRSZ, Generation_CHUNKHDRSZ, GenerationAllocChunkFromBlock(), GenerationBlockInit(), malloc, GenerationContext::maxBlockSize, MemoryContextAllocationFailure(), GenerationContext::nextBlockSize, GenerationBlock::node, pg_nextpower2_size_t, and size.

Referenced by GenerationAlloc().

◆ GenerationAllocLarge()

static pg_noinline void* GenerationAllocLarge ( MemoryContext  context,
Size  size,
int  flags 
)
static

Definition at line 343 of file generation.c.

344 {
346  GenerationBlock *block;
348  Size chunk_size;
349  Size required_size;
350  Size blksize;
351 
352  /* validate 'size' is within the limits for the given 'flags' */
354 
355 #ifdef MEMORY_CONTEXT_CHECKING
356  /* ensure there's always space for the sentinel byte */
357  chunk_size = MAXALIGN(size + 1);
358 #else
359  chunk_size = MAXALIGN(size);
360 #endif
361  required_size = chunk_size + Generation_CHUNKHDRSZ;
362  blksize = required_size + Generation_BLOCKHDRSZ;
363 
364  block = (GenerationBlock *) malloc(blksize);
365  if (block == NULL)
367 
368  context->mem_allocated += blksize;
369 
370  /* block with a single (used) chunk */
371  block->context = set;
372  block->blksize = blksize;
373  block->nchunks = 1;
374  block->nfree = 0;
375 
376  /* the block is completely full */
377  block->freeptr = block->endptr = ((char *) block) + blksize;
378 
379  chunk = (MemoryChunk *) (((char *) block) + Generation_BLOCKHDRSZ);
380 
381  /* mark the MemoryChunk as externally managed */
383 
384 #ifdef MEMORY_CONTEXT_CHECKING
385  chunk->requested_size = size;
386  /* set mark to catch clobber of "unused" space */
387  Assert(size < chunk_size);
388  set_sentinel(MemoryChunkGetPointer(chunk), size);
389 #endif
390 #ifdef RANDOMIZE_ALLOCATED_MEMORY
391  /* fill the allocated space with junk */
392  randomize_mem((char *) MemoryChunkGetPointer(chunk), size);
393 #endif
394 
395  /* add the block to the list of allocated blocks */
396  dlist_push_head(&set->blocks, &block->node);
397 
398  /* Ensure any padding bytes are marked NOACCESS. */
400  chunk_size - size);
401 
402  /* Disallow access to the chunk header. */
404 
406 }
static void MemoryContextCheckSize(MemoryContext context, Size size, int flags)
static void MemoryChunkSetHdrMaskExternal(MemoryChunk *chunk, MemoryContextMethodID methodid)
GenerationContext * context
Definition: generation.c:90

References Assert, GenerationBlock::blksize, GenerationContext::blocks, chunk, GenerationBlock::context, context, dlist_push_head(), GenerationBlock::endptr, GenerationBlock::freeptr, Generation_BLOCKHDRSZ, Generation_CHUNKHDRSZ, malloc, MAXALIGN, MCTX_GENERATION_ID, MemoryChunkGetPointer, MemoryChunkSetHdrMaskExternal(), MemoryContextAllocationFailure(), MemoryContextCheckSize(), GenerationBlock::nchunks, GenerationBlock::nfree, GenerationBlock::node, size, and VALGRIND_MAKE_MEM_NOACCESS.

Referenced by GenerationAlloc().

◆ GenerationBlockFree()

static void GenerationBlockFree ( GenerationContext set,
GenerationBlock block 
)
inlinestatic

Definition at line 664 of file generation.c.

665 {
666  /* Make sure nobody tries to free the keeper block */
667  Assert(!IsKeeperBlock(set, block));
668  /* We shouldn't be freeing the freeblock either */
669  Assert(block != set->freeblock);
670 
671  /* release the block from the list of blocks */
672  dlist_delete(&block->node);
673 
674  ((MemoryContext) set)->mem_allocated -= block->blksize;
675 
676 #ifdef CLOBBER_FREED_MEMORY
677  wipe_mem(block, block->blksize);
678 #endif
679 
680  free(block);
681 }
#define IsKeeperBlock(set, block)
Definition: generation.c:132
#define free(a)
Definition: header.h:65
static void dlist_delete(dlist_node *node)
Definition: ilist.h:405
struct MemoryContextData * MemoryContext
Definition: palloc.h:36

References Assert, GenerationBlock::blksize, dlist_delete(), free, GenerationContext::freeblock, IsKeeperBlock, and GenerationBlock::node.

Referenced by GenerationFree(), and GenerationReset().

◆ GenerationBlockFreeBytes()

static Size GenerationBlockFreeBytes ( GenerationBlock block)
inlinestatic

Definition at line 654 of file generation.c.

655 {
656  return (block->endptr - block->freeptr);
657 }

References GenerationBlock::endptr, and GenerationBlock::freeptr.

Referenced by GenerationAlloc().

◆ GenerationBlockInit()

static void GenerationBlockInit ( GenerationContext context,
GenerationBlock block,
Size  blksize 
)
inlinestatic

Definition at line 609 of file generation.c.

611 {
612  block->context = context;
613  block->blksize = blksize;
614  block->nchunks = 0;
615  block->nfree = 0;
616 
617  block->freeptr = ((char *) block) + Generation_BLOCKHDRSZ;
618  block->endptr = ((char *) block) + blksize;
619 
620  /* Mark unallocated space NOACCESS. */
622  blksize - Generation_BLOCKHDRSZ);
623 }

References GenerationBlock::blksize, GenerationBlock::context, context, GenerationBlock::endptr, GenerationBlock::freeptr, Generation_BLOCKHDRSZ, GenerationBlock::nchunks, GenerationBlock::nfree, and VALGRIND_MAKE_MEM_NOACCESS.

Referenced by GenerationAllocFromNewBlock(), and GenerationContextCreate().

◆ GenerationBlockMarkEmpty()

static void GenerationBlockMarkEmpty ( GenerationBlock block)
inlinestatic

Definition at line 630 of file generation.c.

631 {
632 #if defined(USE_VALGRIND) || defined(CLOBBER_FREED_MEMORY)
633  char *datastart = ((char *) block) + Generation_BLOCKHDRSZ;
634 #endif
635 
636 #ifdef CLOBBER_FREED_MEMORY
637  wipe_mem(datastart, block->freeptr - datastart);
638 #else
639  /* wipe_mem() would have done this */
640  VALGRIND_MAKE_MEM_NOACCESS(datastart, block->freeptr - datastart);
641 #endif
642 
643  /* Reset the block, but don't return it to malloc */
644  block->nchunks = 0;
645  block->nfree = 0;
646  block->freeptr = ((char *) block) + Generation_BLOCKHDRSZ;
647 }

References GenerationBlock::freeptr, Generation_BLOCKHDRSZ, GenerationBlock::nchunks, GenerationBlock::nfree, and VALGRIND_MAKE_MEM_NOACCESS.

Referenced by GenerationFree(), and GenerationReset().

◆ GenerationContextCreate()

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

Definition at line 160 of file generation.c.

165 {
166  Size firstBlockSize;
167  Size allocSize;
168  GenerationContext *set;
169  GenerationBlock *block;
170 
171  /* ensure MemoryChunk's size is properly maxaligned */
173  "sizeof(MemoryChunk) is not maxaligned");
174 
175  /*
176  * First, validate allocation parameters. Asserts seem sufficient because
177  * nobody varies their parameters at runtime. We somewhat arbitrarily
178  * enforce a minimum 1K block size. We restrict the maximum block size to
179  * MEMORYCHUNK_MAX_BLOCKOFFSET as MemoryChunks are limited to this in
180  * regards to addressing the offset between the chunk and the block that
181  * the chunk is stored on. We would be unable to store the offset between
182  * the chunk and block for any chunks that were beyond
183  * MEMORYCHUNK_MAX_BLOCKOFFSET bytes into the block if the block was to be
184  * larger than this.
185  */
186  Assert(initBlockSize == MAXALIGN(initBlockSize) &&
187  initBlockSize >= 1024);
188  Assert(maxBlockSize == MAXALIGN(maxBlockSize) &&
189  maxBlockSize >= initBlockSize &&
190  AllocHugeSizeIsValid(maxBlockSize)); /* must be safe to double */
191  Assert(minContextSize == 0 ||
192  (minContextSize == MAXALIGN(minContextSize) &&
193  minContextSize >= 1024 &&
194  minContextSize <= maxBlockSize));
195  Assert(maxBlockSize <= MEMORYCHUNK_MAX_BLOCKOFFSET);
196 
197  /* Determine size of initial block */
198  allocSize = MAXALIGN(sizeof(GenerationContext)) +
200  if (minContextSize != 0)
201  allocSize = Max(allocSize, minContextSize);
202  else
203  allocSize = Max(allocSize, initBlockSize);
204 
205  /*
206  * Allocate the initial block. Unlike other generation.c blocks, it
207  * starts with the context header and its block header follows that.
208  */
209  set = (GenerationContext *) malloc(allocSize);
210  if (set == NULL)
211  {
213  ereport(ERROR,
214  (errcode(ERRCODE_OUT_OF_MEMORY),
215  errmsg("out of memory"),
216  errdetail("Failed while creating memory context \"%s\".",
217  name)));
218  }
219 
220  /*
221  * Avoid writing code that can fail between here and MemoryContextCreate;
222  * we'd leak the header if we ereport in this stretch.
223  */
224  dlist_init(&set->blocks);
225 
226  /* Fill in the initial block's block header */
227  block = KeeperBlock(set);
228  /* determine the block size and initialize it */
229  firstBlockSize = allocSize - MAXALIGN(sizeof(GenerationContext));
230  GenerationBlockInit(set, block, firstBlockSize);
231 
232  /* add it to the doubly-linked list of blocks */
233  dlist_push_head(&set->blocks, &block->node);
234 
235  /* use it as the current allocation block */
236  set->block = block;
237 
238  /* No free block, yet */
239  set->freeblock = NULL;
240 
241  /* Fill in GenerationContext-specific header fields */
242  set->initBlockSize = (uint32) initBlockSize;
243  set->maxBlockSize = (uint32) maxBlockSize;
244  set->nextBlockSize = (uint32) initBlockSize;
245 
246  /*
247  * Compute the allocation chunk size limit for this context.
248  *
249  * Limit the maximum size a non-dedicated chunk can be so that we can fit
250  * at least Generation_CHUNK_FRACTION of chunks this big onto the maximum
251  * sized block. We must further limit this value so that it's no more
252  * than MEMORYCHUNK_MAX_VALUE. We're unable to have non-external chunks
253  * larger than that value as we store the chunk size in the MemoryChunk
254  * 'value' field in the call to MemoryChunkSetHdrMask().
255  */
256  set->allocChunkLimit = Min(maxBlockSize, MEMORYCHUNK_MAX_VALUE);
257  while ((Size) (set->allocChunkLimit + Generation_CHUNKHDRSZ) >
258  (Size) ((Size) (maxBlockSize - Generation_BLOCKHDRSZ) / Generation_CHUNK_FRACTION))
259  set->allocChunkLimit >>= 1;
260 
261  /* Finally, do the type-independent part of context creation */
263  T_GenerationContext,
265  parent,
266  name);
267 
268  ((MemoryContext) set)->mem_allocated = firstBlockSize;
269 
270  return (MemoryContext) set;
271 }
unsigned int uint32
Definition: c.h:506
#define Min(x, y)
Definition: c.h:1004
#define Max(x, y)
Definition: c.h:998
#define StaticAssertDecl(condition, errmessage)
Definition: c.h:936
int errdetail(const char *fmt,...)
Definition: elog.c:1205
int errcode(int sqlerrcode)
Definition: elog.c:859
int errmsg(const char *fmt,...)
Definition: elog.c:1072
#define ERROR
Definition: elog.h:39
#define ereport(elevel,...)
Definition: elog.h:149
#define Generation_CHUNK_FRACTION
Definition: generation.c:49
#define KeeperBlock(set)
Definition: generation.c:127
static void dlist_init(dlist_head *head)
Definition: ilist.h:314
void MemoryContextCreate(MemoryContext node, NodeTag tag, MemoryContextMethodID method_id, MemoryContext parent, const char *name)
Definition: mcxt.c:1100
MemoryContext TopMemoryContext
Definition: mcxt.c:149
void MemoryContextStats(MemoryContext context)
Definition: mcxt.c:814
#define AllocHugeSizeIsValid(size)
Definition: memutils.h:49
#define MEMORYCHUNK_MAX_BLOCKOFFSET
#define MEMORYCHUNK_MAX_VALUE
uint32 initBlockSize
Definition: generation.c:64
const char * name

References GenerationContext::allocChunkLimit, AllocHugeSizeIsValid, Assert, GenerationContext::block, GenerationContext::blocks, dlist_init(), dlist_push_head(), ereport, errcode(), errdetail(), errmsg(), ERROR, GenerationContext::freeblock, Generation_BLOCKHDRSZ, Generation_CHUNK_FRACTION, Generation_CHUNKHDRSZ, GenerationBlockInit(), GenerationContext::initBlockSize, KeeperBlock, malloc, Max, MAXALIGN, GenerationContext::maxBlockSize, MCTX_GENERATION_ID, MEMORYCHUNK_MAX_BLOCKOFFSET, MEMORYCHUNK_MAX_VALUE, MemoryContextCreate(), MemoryContextStats(), Min, name, GenerationContext::nextBlockSize, GenerationBlock::node, StaticAssertDecl, and TopMemoryContext.

Referenced by gistvacuumscan(), and ReorderBufferAllocate().

◆ GenerationDelete()

void GenerationDelete ( MemoryContext  context)

Definition at line 328 of file generation.c.

329 {
330  /* Reset to release all releasable GenerationBlocks */
332  /* And free the context header and keeper block */
333  free(context);
334 }
void GenerationReset(MemoryContext context)
Definition: generation.c:283

References context, free, and GenerationReset().

◆ GenerationFree()

void GenerationFree ( void *  pointer)

Definition at line 689 of file generation.c.

690 {
692  GenerationBlock *block;
693  GenerationContext *set;
694 #if (defined(MEMORY_CONTEXT_CHECKING) && defined(USE_ASSERT_CHECKING)) \
695  || defined(CLOBBER_FREED_MEMORY)
696  Size chunksize;
697 #endif
698 
699  /* Allow access to the chunk header. */
701 
703  {
704  block = ExternalChunkGetBlock(chunk);
705 
706  /*
707  * Try to verify that we have a sane block pointer: the block header
708  * should reference a generation context.
709  */
710  if (!GenerationBlockIsValid(block))
711  elog(ERROR, "could not find block containing chunk %p", chunk);
712 
713 #if (defined(MEMORY_CONTEXT_CHECKING) && defined(USE_ASSERT_CHECKING)) \
714  || defined(CLOBBER_FREED_MEMORY)
715  chunksize = block->endptr - (char *) pointer;
716 #endif
717  }
718  else
719  {
720  block = MemoryChunkGetBlock(chunk);
721 
722  /*
723  * In this path, for speed reasons we just Assert that the referenced
724  * block is good. Future field experience may show that this Assert
725  * had better become a regular runtime test-and-elog check.
726  */
728 
729 #if (defined(MEMORY_CONTEXT_CHECKING) && defined(USE_ASSERT_CHECKING)) \
730  || defined(CLOBBER_FREED_MEMORY)
731  chunksize = MemoryChunkGetValue(chunk);
732 #endif
733  }
734 
735 #ifdef MEMORY_CONTEXT_CHECKING
736  /* Test for someone scribbling on unused space in chunk */
737  Assert(chunk->requested_size < chunksize);
738  if (!sentinel_ok(pointer, chunk->requested_size))
739  elog(WARNING, "detected write past chunk end in %s %p",
740  ((MemoryContext) block->context)->name, chunk);
741 #endif
742 
743 #ifdef CLOBBER_FREED_MEMORY
744  wipe_mem(pointer, chunksize);
745 #endif
746 
747 #ifdef MEMORY_CONTEXT_CHECKING
748  /* Reset requested_size to InvalidAllocSize in freed chunks */
749  chunk->requested_size = InvalidAllocSize;
750 #endif
751 
752  block->nfree += 1;
753 
754  Assert(block->nchunks > 0);
755  Assert(block->nfree <= block->nchunks);
756  Assert(block != block->context->freeblock);
757 
758  /* If there are still allocated chunks in the block, we're done. */
759  if (likely(block->nfree < block->nchunks))
760  return;
761 
762  set = block->context;
763 
764  /*-----------------------
765  * The block this allocation was on has now become completely empty of
766  * chunks. In the general case, we can now return the memory for this
767  * block back to malloc. However, there are cases where we don't want to
768  * do that:
769  *
770  * 1) If it's the keeper block. This block was malloc'd in the same
771  * allocation as the context itself and can't be free'd without
772  * freeing the context.
773  * 2) If it's the current block. We could free this, but doing so would
774  * leave us nothing to set the current block to, so we just mark the
775  * block as empty so new allocations can reuse it again.
776  * 3) If we have no "freeblock" set, then we save a single block for
777  * future allocations to avoid having to malloc a new block again.
778  * This is useful for FIFO workloads as it avoids continual
779  * free/malloc cycles.
780  */
781  if (IsKeeperBlock(set, block) || set->block == block)
782  GenerationBlockMarkEmpty(block); /* case 1 and 2 */
783  else if (set->freeblock == NULL)
784  {
785  /* case 3 */
787  set->freeblock = block;
788  }
789  else
790  GenerationBlockFree(set, block); /* Otherwise, free it */
791 }
#define likely(x)
Definition: c.h:310
#define WARNING
Definition: elog.h:36
#define elog(elevel,...)
Definition: elog.h:224
static void GenerationBlockFree(GenerationContext *set, GenerationBlock *block)
Definition: generation.c:664
static void GenerationBlockMarkEmpty(GenerationBlock *block)
Definition: generation.c:630
#define GenerationBlockIsValid(block)
Definition: generation.c:109
#define ExternalChunkGetBlock(chunk)
Definition: generation.c:123
#define VALGRIND_MAKE_MEM_DEFINED(addr, size)
Definition: memdebug.h:26
#define InvalidAllocSize
Definition: memutils.h:47
static Size MemoryChunkGetValue(MemoryChunk *chunk)
static bool MemoryChunkIsExternal(MemoryChunk *chunk)
static void * MemoryChunkGetBlock(MemoryChunk *chunk)
#define PointerGetMemoryChunk(p)

References Assert, GenerationContext::block, chunk, GenerationBlock::context, elog, GenerationBlock::endptr, ERROR, ExternalChunkGetBlock, GenerationContext::freeblock, Generation_CHUNKHDRSZ, GenerationBlockFree(), GenerationBlockIsValid, GenerationBlockMarkEmpty(), InvalidAllocSize, IsKeeperBlock, likely, MemoryChunkGetBlock(), MemoryChunkGetValue(), MemoryChunkIsExternal(), GenerationBlock::nchunks, GenerationBlock::nfree, PointerGetMemoryChunk, VALGRIND_MAKE_MEM_DEFINED, and WARNING.

Referenced by GenerationRealloc().

◆ GenerationGetChunkContext()

MemoryContext GenerationGetChunkContext ( void *  pointer)

Definition at line 942 of file generation.c.

943 {
945  GenerationBlock *block;
946 
947  /* Allow access to the chunk header. */
949 
951  block = ExternalChunkGetBlock(chunk);
952  else
954 
955  /* Disallow access to the chunk header. */
957 
959  return &block->context->header;
960 }
MemoryContextData header
Definition: generation.c:61

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

◆ GenerationGetChunkSpace()

Size GenerationGetChunkSpace ( void *  pointer)

Definition at line 968 of file generation.c.

969 {
971  Size chunksize;
972 
973  /* Allow access to the chunk header. */
975 
977  {
979 
981  chunksize = block->endptr - (char *) pointer;
982  }
983  else
984  chunksize = MemoryChunkGetValue(chunk);
985 
986  /* Disallow access to the chunk header. */
988 
989  return Generation_CHUNKHDRSZ + chunksize;
990 }

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

◆ GenerationIsEmpty()

bool GenerationIsEmpty ( MemoryContext  context)

Definition at line 997 of file generation.c.

998 {
1000  dlist_iter iter;
1001 
1002  Assert(GenerationIsValid(set));
1003 
1004  dlist_foreach(iter, &set->blocks)
1005  {
1006  GenerationBlock *block = dlist_container(GenerationBlock, node, iter.cur);
1007 
1008  if (block->nchunks > 0)
1009  return false;
1010  }
1011 
1012  return true;
1013 }
#define dlist_foreach(iter, lhead)
Definition: ilist.h:623
#define dlist_container(type, membername, ptr)
Definition: ilist.h:593
dlist_node * cur
Definition: ilist.h:179

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

◆ GenerationRealloc()

void* GenerationRealloc ( void *  pointer,
Size  size,
int  flags 
)

Definition at line 800 of file generation.c.

801 {
803  GenerationContext *set;
804  GenerationBlock *block;
805  GenerationPointer newPointer;
806  Size oldsize;
807 
808  /* Allow access to the chunk header. */
810 
812  {
813  block = ExternalChunkGetBlock(chunk);
814 
815  /*
816  * Try to verify that we have a sane block pointer: the block header
817  * should reference a generation context.
818  */
819  if (!GenerationBlockIsValid(block))
820  elog(ERROR, "could not find block containing chunk %p", chunk);
821 
822  oldsize = block->endptr - (char *) pointer;
823  }
824  else
825  {
826  block = MemoryChunkGetBlock(chunk);
827 
828  /*
829  * In this path, for speed reasons we just Assert that the referenced
830  * block is good. Future field experience may show that this Assert
831  * had better become a regular runtime test-and-elog check.
832  */
834 
835  oldsize = MemoryChunkGetValue(chunk);
836  }
837 
838  set = block->context;
839 
840 #ifdef MEMORY_CONTEXT_CHECKING
841  /* Test for someone scribbling on unused space in chunk */
842  Assert(chunk->requested_size < oldsize);
843  if (!sentinel_ok(pointer, chunk->requested_size))
844  elog(WARNING, "detected write past chunk end in %s %p",
845  ((MemoryContext) set)->name, chunk);
846 #endif
847 
848  /*
849  * Maybe the allocated area already is >= the new size. (In particular,
850  * we always fall out here if the requested size is a decrease.)
851  *
852  * This memory context does not use power-of-2 chunk sizing and instead
853  * carves the chunks to be as small as possible, so most repalloc() calls
854  * will end up in the palloc/memcpy/pfree branch.
855  *
856  * XXX Perhaps we should annotate this condition with unlikely()?
857  */
858  if (oldsize >= size)
859  {
860 #ifdef MEMORY_CONTEXT_CHECKING
861  Size oldrequest = chunk->requested_size;
862 
863 #ifdef RANDOMIZE_ALLOCATED_MEMORY
864  /* We can only fill the extra space if we know the prior request */
865  if (size > oldrequest)
866  randomize_mem((char *) pointer + oldrequest,
867  size - oldrequest);
868 #endif
869 
870  chunk->requested_size = size;
871 
872  /*
873  * If this is an increase, mark any newly-available part UNDEFINED.
874  * Otherwise, mark the obsolete part NOACCESS.
875  */
876  if (size > oldrequest)
877  VALGRIND_MAKE_MEM_UNDEFINED((char *) pointer + oldrequest,
878  size - oldrequest);
879  else
880  VALGRIND_MAKE_MEM_NOACCESS((char *) pointer + size,
881  oldsize - size);
882 
883  /* set mark to catch clobber of "unused" space */
884  set_sentinel(pointer, size);
885 #else /* !MEMORY_CONTEXT_CHECKING */
886 
887  /*
888  * We don't have the information to determine whether we're growing
889  * the old request or shrinking it, so we conservatively mark the
890  * entire new allocation DEFINED.
891  */
892  VALGRIND_MAKE_MEM_NOACCESS(pointer, oldsize);
894 #endif
895 
896  /* Disallow access to the chunk header. */
898 
899  return pointer;
900  }
901 
902  /* allocate new chunk (this also checks size is valid) */
903  newPointer = GenerationAlloc((MemoryContext) set, size, flags);
904 
905  /* leave immediately if request was not completed */
906  if (newPointer == NULL)
907  {
908  /* Disallow access to the chunk header. */
910  return MemoryContextAllocationFailure((MemoryContext) set, size, flags);
911  }
912 
913  /*
914  * GenerationAlloc() may have returned a region that is still NOACCESS.
915  * Change it to UNDEFINED for the moment; memcpy() will then transfer
916  * definedness from the old allocation to the new. If we know the old
917  * allocation, copy just that much. Otherwise, make the entire old chunk
918  * defined to avoid errors as we copy the currently-NOACCESS trailing
919  * bytes.
920  */
921  VALGRIND_MAKE_MEM_UNDEFINED(newPointer, size);
922 #ifdef MEMORY_CONTEXT_CHECKING
923  oldsize = chunk->requested_size;
924 #else
925  VALGRIND_MAKE_MEM_DEFINED(pointer, oldsize);
926 #endif
927 
928  /* transfer existing data (certain to fit) */
929  memcpy(newPointer, pointer, oldsize);
930 
931  /* free old chunk */
932  GenerationFree(pointer);
933 
934  return newPointer;
935 }
void * GenerationAlloc(MemoryContext context, Size size, int flags)
Definition: generation.c:527
void GenerationFree(void *pointer)
Definition: generation.c:689
void * GenerationPointer
Definition: generation.c:53

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

◆ GenerationReset()

void GenerationReset ( MemoryContext  context)

Definition at line 283 of file generation.c.

284 {
286  dlist_mutable_iter miter;
287 
289 
290 #ifdef MEMORY_CONTEXT_CHECKING
291  /* Check for corruption and leaks before freeing */
292  GenerationCheck(context);
293 #endif
294 
295  /*
296  * NULLify the free block pointer. We must do this before calling
297  * GenerationBlockFree as that function never expects to free the
298  * freeblock.
299  */
300  set->freeblock = NULL;
301 
302  dlist_foreach_modify(miter, &set->blocks)
303  {
304  GenerationBlock *block = dlist_container(GenerationBlock, node, miter.cur);
305 
306  if (IsKeeperBlock(set, block))
308  else
309  GenerationBlockFree(set, block);
310  }
311 
312  /* set it so new allocations to make use of the keeper block */
313  set->block = KeeperBlock(set);
314 
315  /* Reset block size allocation sequence, too */
316  set->nextBlockSize = set->initBlockSize;
317 
318  /* Ensure there is only 1 item in the dlist */
319  Assert(!dlist_is_empty(&set->blocks));
321 }
static bool dlist_has_next(const dlist_head *head, const dlist_node *node)
Definition: ilist.h:503
#define dlist_foreach_modify(iter, lhead)
Definition: ilist.h:640
static bool dlist_is_empty(const dlist_head *head)
Definition: ilist.h:336
static dlist_node * dlist_head_node(dlist_head *head)
Definition: ilist.h:565
dlist_node * cur
Definition: ilist.h:200

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

Referenced by GenerationDelete().

◆ GenerationStats()

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

Definition at line 1028 of file generation.c.

1031 {
1033  Size nblocks = 0;
1034  Size nchunks = 0;
1035  Size nfreechunks = 0;
1036  Size totalspace;
1037  Size freespace = 0;
1038  dlist_iter iter;
1039 
1040  Assert(GenerationIsValid(set));
1041 
1042  /* Include context header in totalspace */
1043  totalspace = MAXALIGN(sizeof(GenerationContext));
1044 
1045  dlist_foreach(iter, &set->blocks)
1046  {
1047  GenerationBlock *block = dlist_container(GenerationBlock, node, iter.cur);
1048 
1049  nblocks++;
1050  nchunks += block->nchunks;
1051  nfreechunks += block->nfree;
1052  totalspace += block->blksize;
1053  freespace += (block->endptr - block->freeptr);
1054  }
1055 
1056  if (printfunc)
1057  {
1058  char stats_string[200];
1059 
1060  snprintf(stats_string, sizeof(stats_string),
1061  "%zu total in %zu blocks (%zu chunks); %zu free (%zu chunks); %zu used",
1062  totalspace, nblocks, nchunks, freespace,
1063  nfreechunks, totalspace - freespace);
1064  printfunc(context, passthru, stats_string, print_to_stderr);
1065  }
1066 
1067  if (totals)
1068  {
1069  totals->nblocks += nblocks;
1070  totals->freechunks += nfreechunks;
1071  totals->totalspace += totalspace;
1072  totals->freespace += freespace;
1073  }
1074 }
#define snprintf
Definition: port.h:238

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