* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/utils/mmgr/aset.c,v 1.32 2000/11/16 05:51:02 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/mmgr/aset.c,v 1.33 2000/12/01 05:16:45 tgl Exp $
*
* NOTE:
* This is a new (Feb. 05, 1999) implementation of the allocation set
* when the caller is repeatedly repalloc()'ing a block bigger and bigger;
* the previous instances of the block were guaranteed to be wasted until
* AllocSetReset() under the old way.
+ *
+ * About CLOBBER_FREED_MEMORY:
+ *
+ * If this symbol is defined, all freed memory is overwritten with 0x7F's.
+ * This is useful for catching places that reference already-freed memory.
+ *
+ * About MEMORY_CONTEXT_CHECKING:
+ *
+ * Since we usually round request sizes up to the next power of 2, there
+ * is often some unused space immediately after a requested data area.
+ * Thus, if someone makes the common error of writing past what they've
+ * requested, the problem is likely to go unnoticed ... until the day when
+ * there *isn't* any wasted space, perhaps because of different memory
+ * alignment on a new platform, or some other effect. To catch this sort
+ * of problem, the MEMORY_CONTEXT_CHECKING option stores 0x7E just beyond
+ * the requested space whenever the request is less than the actual chunk
+ * size, and verifies that the byte is undamaged when the chunk is freed.
+ *
*-------------------------------------------------------------------------
*/
#include "utils/memutils.h"
-/* Define this to detail debug alloc information
- */
-/*#define HAVE_ALLOCINFO 1*/
+/* Define this to detail debug alloc information */
+/* #define HAVE_ALLOCINFO */
/*
* AllocSetContext is defined in nodes/memnodes.h.
typedef struct AllocChunkData
{
/* aset is the owning aset if allocated, or the freelist link if free */
- void *aset;
+ void *aset;
/* size is always the size of the usable space in the chunk */
- Size size;
+ Size size;
#ifdef MEMORY_CONTEXT_CHECKING
- Size data_size;
-#endif
+ /* when debugging memory usage, also store actual requested size */
+ Size requested_size;
+#endif
} AllocChunkData;
/*
((AllocChunk)(((char *)(ptr)) - ALLOC_CHUNKHDRSZ))
#define AllocChunkGetPointer(chk) \
((AllocPointer)(((char *)(chk)) + ALLOC_CHUNKHDRSZ))
-#define AllocPointerGetAset(ptr) ((AllocSet)(AllocPointerGetChunk(ptr)->aset))
-#define AllocPointerGetSize(ptr) (AllocPointerGetChunk(ptr)->size)
/*
* These functions implement the MemoryContext API for AllocSet contexts.
static void AllocSetInit(MemoryContext context);
static void AllocSetReset(MemoryContext context);
static void AllocSetDelete(MemoryContext context);
-
#ifdef MEMORY_CONTEXT_CHECKING
static void AllocSetCheck(MemoryContext context);
#endif
-
static void AllocSetStats(MemoryContext context);
/*
context->blocks = block;
/* Mark block as not to be released at reset time */
context->keeper = block;
-
-#ifdef MEMORY_CONTEXT_CHECKING
- /* mark memory for memory leak searching */
- memset(block->freeptr, 0x7F, blksize - ALLOC_BLOCKHDRSZ);
-#endif
}
return (MemoryContext) context;
AssertArg(AllocSetIsValid(set));
+#ifdef MEMORY_CONTEXT_CHECKING
+ /* Check for corruption and leaks before freeing */
+ AllocSetCheck(context);
+#endif
+
while (block != NULL)
{
AllocBlock next = block->next;
#ifdef CLOBBER_FREED_MEMORY
/* Wipe freed memory for debugging purposes */
- memset(datastart, 0x7F, ((char *) block->freeptr) - datastart);
+ memset(datastart, 0x7F, block->freeptr - datastart);
#endif
block->freeptr = datastart;
block->next = NULL;
/* Normal case, release the block */
#ifdef CLOBBER_FREED_MEMORY
/* Wipe freed memory for debugging purposes */
- memset(block, 0x7F, ((char *) block->freeptr) - ((char *) block));
+ memset(block, 0x7F, block->freeptr - ((char *) block));
#endif
free(block);
}
AssertArg(AllocSetIsValid(set));
+#ifdef MEMORY_CONTEXT_CHECKING
+ /* Check for corruption and leaks before freeing */
+ AllocSetCheck(context);
+#endif
+
while (block != NULL)
{
AllocBlock next = block->next;
#ifdef CLOBBER_FREED_MEMORY
/* Wipe freed memory for debugging purposes */
- memset(block, 0x7F, ((char *) block->endptr) - ((char *) block));
+ memset(block, 0x7F, block->freeptr - ((char *) block));
#endif
free(block);
block = next;
AllocBlock block;
AllocChunk chunk;
AllocChunk priorfree = NULL;
- int fidx;
+ int fidx;
Size chunk_size;
Size blksize;
AssertArg(AllocSetIsValid(set));
/*
- * Small size can be in free list
+ * Lookup in the corresponding free list if there is a free chunk we
+ * could reuse
*/
- if (size < ALLOC_BIGCHUNK_LIMIT)
+ fidx = AllocSetFreeIndex(size);
+ for (chunk = set->freelist[fidx]; chunk; chunk = (AllocChunk) chunk->aset)
{
- /*
- * Lookup in the corresponding free list if there is a free chunk we
- * could reuse
- */
- fidx = AllocSetFreeIndex(size);
- for (chunk = set->freelist[fidx]; chunk; chunk = (AllocChunk) chunk->aset)
- {
- if (chunk->size >= size)
- break;
- priorfree = chunk;
- }
+ if (chunk->size >= size)
+ break;
+ priorfree = chunk;
+ }
- /*
- * If one is found, remove it from the free list, make it again a
- * member of the alloc set and return its data address.
- */
- if (chunk != NULL)
- {
- if (priorfree == NULL)
- set->freelist[fidx] = (AllocChunk) chunk->aset;
- else
- priorfree->aset = chunk->aset;
-
- chunk->aset = (void *) set;
+ /*
+ * If one is found, remove it from the free list, make it again a
+ * member of the alloc set and return its data address.
+ */
+ if (chunk != NULL)
+ {
+ if (priorfree == NULL)
+ set->freelist[fidx] = (AllocChunk) chunk->aset;
+ else
+ priorfree->aset = chunk->aset;
+
+ chunk->aset = (void *) set;
#ifdef MEMORY_CONTEXT_CHECKING
- chunk->data_size = size;
+ chunk->requested_size = size;
+ /* set mark to catch clobber of "unused" space */
+ if (size < chunk->size)
+ ((char *) AllocChunkGetPointer(chunk))[size] = 0x7E;
#endif
- AllocAllocInfo(set, chunk);
- return AllocChunkGetPointer(chunk);
- }
- }
- else
- /* Big chunk
- */
- fidx = ALLOCSET_NUM_FREELISTS - 1;
+
+ AllocAllocInfo(set, chunk);
+ return AllocChunkGetPointer(chunk);
+ }
/*
* Choose the actual chunk size to allocate.
chunk = (AllocChunk) (((char *) block) + ALLOC_BLOCKHDRSZ);
chunk->aset = set;
chunk->size = chunk_size;
+#ifdef MEMORY_CONTEXT_CHECKING
+ chunk->requested_size = size;
+ /* set mark to catch clobber of "unused" space */
+ if (size < chunk->size)
+ ((char *) AllocChunkGetPointer(chunk))[size] = 0x7E;
+#endif
/*
* Try to stick the block underneath the active allocation block,
set->blocks = block;
}
-#ifdef MEMORY_CONTEXT_CHECKING
- chunk->data_size = size;
- /* mark memory for memory leak searching */
- memset(AllocChunkGetPointer(chunk), 0x7F, chunk->size);
-#endif
AllocAllocInfo(set, chunk);
return AllocChunkGetPointer(chunk);
}
}
else
{
+ /*
+ * The existing active (top) block does not have enough room
+ * for the requested allocation, but it might still have a
+ * useful amount of space in it. Once we push it down in the
+ * block list, we'll never try to allocate more space from it.
+ * So, before we do that, carve up its free space into chunks
+ * that we can put on the set's freelists.
+ */
+ Size availspace = set->blocks->endptr - set->blocks->freeptr;
+
+ while (availspace >= ((1 << ALLOC_MINBITS) + ALLOC_CHUNKHDRSZ))
+ {
+ Size availchunk = availspace - ALLOC_CHUNKHDRSZ;
+ int x_fidx = AllocSetFreeIndex(availchunk);
+
+ /*
+ * In most cases, we'll get back the index of the next larger
+ * freelist than the one we need to put this chunk on. The
+ * exceptions are when availchunk is exactly a power of 2,
+ * or is large enough that we're dealing with the last
+ * (variable-chunk-size) freelist. This test detects both:
+ */
+ if (availchunk < (1 << (x_fidx + ALLOC_MINBITS)))
+ {
+ x_fidx--;
+ Assert(x_fidx >= 0);
+ availchunk = (1 << (x_fidx + ALLOC_MINBITS));
+ }
+
+ chunk = (AllocChunk) (set->blocks->freeptr);
+ chunk->size = availchunk;
+#ifdef MEMORY_CONTEXT_CHECKING
+ chunk->requested_size = 0; /* mark it free */
+#endif
+ chunk->aset = (void *) set->freelist[x_fidx];
+ set->freelist[x_fidx] = chunk;
+
+ set->blocks->freeptr += (availchunk + ALLOC_CHUNKHDRSZ);
+ availspace -= (availchunk + ALLOC_CHUNKHDRSZ);
+ }
+
/* Get size of prior block */
blksize = set->blocks->endptr - ((char *) set->blocks);
block->freeptr = ((char *) block) + ALLOC_BLOCKHDRSZ;
block->endptr = ((char *) block) + blksize;
-#ifdef MEMORY_CONTEXT_CHECKING
- /* mark memory for memory leak searching */
- memset(block->freeptr, 0x7F, blksize - ALLOC_BLOCKHDRSZ);
-#endif
block->next = set->blocks;
-
set->blocks = block;
}
chunk = (AllocChunk) (block->freeptr);
chunk->aset = (void *) set;
chunk->size = chunk_size;
-
#ifdef MEMORY_CONTEXT_CHECKING
- chunk->data_size = size;
+ chunk->requested_size = size;
+ /* set mark to catch clobber of "unused" space */
+ if (size < chunk->size)
+ ((char *) AllocChunkGetPointer(chunk))[size] = 0x7E;
#endif
+
block->freeptr += (chunk_size + ALLOC_CHUNKHDRSZ);
Assert(block->freeptr <= block->endptr);
AllocSet set = (AllocSet) context;
AllocChunk chunk = AllocPointerGetChunk(pointer);
-#if defined(CLOBBER_FREED_MEMORY) || defined(MEMORY_CONTEXT_CHECKING)
- /* Wipe freed memory for debugging purposes or for memory leak
- * searching (in freelist[] must be mark memory
- */
- memset(pointer, 0x7F, chunk->size);
-#endif
-
AllocFreeInfo(set, chunk);
+#ifdef MEMORY_CONTEXT_CHECKING
+ /* Test for someone scribbling on unused space in chunk */
+ if (chunk->requested_size < chunk->size)
+ if (((char *) pointer)[chunk->requested_size] != 0x7E)
+ elog(ERROR, "AllocSetFree: detected write past chunk end in %p",
+ chunk);
+#endif
+
if (chunk->size >= ALLOC_BIGCHUNK_LIMIT)
{
/*
prevblock->next = block->next;
#ifdef CLOBBER_FREED_MEMORY
/* Wipe freed memory for debugging purposes */
- memset(block, 0x7F, ((char *) block->endptr) - ((char *) block));
+ memset(block, 0x7F, block->freeptr - ((char *) block));
#endif
free(block);
}
chunk->aset = (void *) set->freelist[fidx];
+#ifdef CLOBBER_FREED_MEMORY
+ /* Wipe freed memory for debugging purposes */
+ memset(pointer, 0x7F, chunk->size);
+#endif
+
#ifdef MEMORY_CONTEXT_CHECKING
- chunk->data_size = 0;
+ /* Reset requested_size to 0 in chunks that are on freelist */
+ chunk->requested_size = 0;
#endif
set->freelist[fidx] = chunk;
}
AllocSetRealloc(MemoryContext context, void *pointer, Size size)
{
AllocSet set = (AllocSet) context;
- Size oldsize;
+ AllocChunk chunk = AllocPointerGetChunk(pointer);
+ Size oldsize = chunk->size;
+
+#ifdef MEMORY_CONTEXT_CHECKING
+ /* Test for someone scribbling on unused space in chunk */
+ if (chunk->requested_size < oldsize)
+ if (((char *) pointer)[chunk->requested_size] != 0x7E)
+ elog(ERROR, "AllocSetRealloc: detected write past chunk end in %p",
+ chunk);
+#endif
/*
* Chunk sizes are aligned to power of 2 in AllocSetAlloc(). Maybe the
* allocated area already is >= the new size. (In particular, we
* always fall out here if the requested size is a decrease.)
*/
- oldsize = AllocPointerGetSize(pointer);
if (oldsize >= size)
{
#ifdef MEMORY_CONTEXT_CHECKING
- AllocChunk chunk = AllocPointerGetChunk(pointer);
-
- /* mark memory for memory leak searching */
- memset(((char *) chunk) + (ALLOC_CHUNKHDRSZ + size),
- 0x7F, chunk->size - size);
- chunk->data_size = size;
+ chunk->requested_size = size;
+ /* set mark to catch clobber of "unused" space */
+ if (size < chunk->size)
+ ((char *) pointer)[size] = 0x7E;
#endif
return pointer;
}
* block and use realloc() to make it bigger with minimum space
* wastage.
*/
- AllocChunk chunk = AllocPointerGetChunk(pointer);
AllocBlock block = set->blocks;
AllocBlock prevblock = NULL;
+ Size chksize;
Size blksize;
-#ifdef MEMORY_CONTEXT_CHECKING
- Size data_size = size;
-#endif
while (block != NULL)
{
(chunk->size + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ));
/* Do the realloc */
- size = MAXALIGN(size);
- blksize = size + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ;
+ chksize = MAXALIGN(size);
+ blksize = chksize + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ;
block = (AllocBlock) realloc(block, blksize);
if (block == NULL)
elog(ERROR, "Memory exhausted in AllocSetReAlloc()");
set->blocks = block;
else
prevblock->next = block;
- chunk->size = size;
+ chunk->size = chksize;
#ifdef MEMORY_CONTEXT_CHECKING
- /* mark memory for memory leak searching */
- memset(((char *) chunk) + (ALLOC_CHUNKHDRSZ + data_size),
- 0x7F, size - data_size);
- chunk->data_size = data_size;
+ chunk->requested_size = size;
+ /* set mark to catch clobber of "unused" space */
+ if (size < chunk->size)
+ ((char *) AllocChunkGetPointer(chunk))[size] = 0x7E;
#endif
+
return AllocChunkGetPointer(chunk);
}
else
}
+#ifdef MEMORY_CONTEXT_CHECKING
+
/*
* AllocSetCheck
- * Walk on chunks and check consistence of memory.
+ * Walk through chunks and check consistency of memory.
*/
-#ifdef MEMORY_CONTEXT_CHECKING
-
static void
AllocSetCheck(MemoryContext context)
{
AllocSet set = (AllocSet) context;
- AllocBlock block = NULL;
- AllocChunk chunk = NULL;
char *name = set->header.name;
+ AllocBlock block;
for (block = set->blocks; block != NULL; block = block->next)
{
char *bpoz = ((char *) block) + ALLOC_BLOCKHDRSZ;
- /* long blk_size = block->endptr - ((char *) block);*/
- long blk_free = block->endptr - block->freeptr;
long blk_used = block->freeptr - bpoz;
long blk_data = 0;
long nchunks = 0;
*/
if (!blk_used)
{
- if (set->keeper == block)
- continue;
- else
- elog(ERROR, "AllocSetCheck(): %s: empty block %p",
- name, block);
+ if (set->keeper != block)
+ elog(NOTICE, "AllocSetCheck(): %s: empty block %p",
+ name, block);
}
/*
* Chunk walker
*/
- do {
- Size chsize,
- dsize;
- char *chdata_end,
- *chend;
-
- chunk = (AllocChunk) bpoz;
-
- chsize = chunk->size; /* align chunk size */
- dsize = chunk->data_size; /* real data */
+ while (bpoz < block->freeptr)
+ {
+ AllocChunk chunk = (AllocChunk) bpoz;
+ Size chsize,
+ dsize;
+ char *chdata_end;
+ chsize = chunk->size; /* aligned chunk size */
+ dsize = chunk->requested_size; /* real data */
chdata_end = ((char *) chunk) + (ALLOC_CHUNKHDRSZ + dsize);
- chend = ((char *) chunk) + (ALLOC_CHUNKHDRSZ + chsize);
- if (!dsize && chsize < dsize)
- elog(ERROR, "AllocSetCheck(): %s: internal error for chunk %p in block %p",
- name, chunk, block);
/*
* Check chunk size
*/
+ if (dsize > chsize)
+ elog(ERROR, "AllocSetCheck(): %s: req size > alloc size for chunk %p in block %p",
+ name, chunk, block);
if (chsize < (1 << ALLOC_MINBITS))
- elog(ERROR, "AllocSetCheck(): %s: bad size '%lu' for chunk %p in block %p",
- name, (unsigned long)chsize, chunk, block);
+ elog(ERROR, "AllocSetCheck(): %s: bad size %lu for chunk %p in block %p",
+ name, (unsigned long) chsize, chunk, block);
- /* single-chunk block */
+ /* single-chunk block? */
if (chsize >= ALLOC_BIGCHUNK_LIMIT &&
chsize + ALLOC_CHUNKHDRSZ != blk_used)
- elog(ERROR, "AllocSetCheck(): %s: bad singel-chunk %p in block %p",
- name, chunk, block);
-
- /*
- * Check in-chunk leak
- */
- if (dsize < chsize && *chdata_end != 0x7F)
- {
- fprintf(stderr, "\n--- Leak %p ---\n", chdata_end);
- fprintf(stderr, "Chunk dump size: %ld (chunk-header %ld + chunk-size: %lu), data must be: %lu\n--- dump begin ---\n",
- chsize + ALLOC_CHUNKHDRSZ,
- ALLOC_CHUNKHDRSZ, (unsigned long)chsize, (unsigned long)dsize);
-
- fwrite((void *) chunk, chsize+ALLOC_CHUNKHDRSZ, sizeof(char), stderr);
- fputs("\n--- dump end ---\n", stderr);
-
- elog(ERROR, "AllocSetCheck(): %s: found in-chunk memory leak (block %p; chunk %p; leak at %p",
- name, block, chunk, chdata_end);
- }
-
+ elog(ERROR, "AllocSetCheck(): %s: bad single-chunk %p in block %p",
+ name, chunk, block);
+
/*
- * Check block-freeptr leak
+ * If chunk is allocated, check for correct aset pointer.
+ * (If it's free, the aset is the freelist pointer, which we
+ * can't check as easily...)
*/
- if (chend == block->freeptr && blk_free &&
- *chdata_end != 0x7F) {
-
- fprintf(stderr, "\n--- Leak %p ---\n", chdata_end);
- fprintf(stderr, "Dump size: %ld (chunk-header %ld + chunk-size: %lu + block-freespace: %ld), data must be: %lu\n--- dump begin ---\n",
- chsize + ALLOC_CHUNKHDRSZ + blk_free,
- ALLOC_CHUNKHDRSZ, (unsigned long)chsize, blk_free, (unsigned long)dsize);
-
- fwrite((void *) chunk, chsize+ALLOC_CHUNKHDRSZ+blk_free, sizeof(char), stderr);
- fputs("\n--- dump end ---\n", stderr);
-
- elog(ERROR, "AllocSetCheck(): %s: found block-freeptr memory leak (block %p; chunk %p; leak at %p",
- name, block, chunk, chdata_end);
- }
+ if (dsize > 0 && chunk->aset != (void *) set)
+ elog(ERROR, "AllocSetCheck(): %s: bogus aset link in block %p, chunk %p",
+ name, block, chunk);
+
+ /*
+ * Check for overwrite of "unallocated" space in chunk
+ */
+ if (dsize > 0 && dsize < chsize && *chdata_end != 0x7E)
+ elog(ERROR, "AllocSetCheck(): %s: detected write past chunk end in block %p, chunk %p",
+ name, block, chunk);
blk_data += chsize;
nchunks++;
- if (chend < block->freeptr)
- bpoz += ALLOC_CHUNKHDRSZ + chsize;
- else
- break;
+ bpoz += ALLOC_CHUNKHDRSZ + chsize;
+ }
- } while(block->freeptr > bpoz); /* chunk walker */
-
-
if ((blk_data + (nchunks * ALLOC_CHUNKHDRSZ)) != blk_used)
-
- elog(ERROR, "AllocSetCheck(): %s: found non-consistent memory block %p",
- name, block);
+ elog(ERROR, "AllocSetCheck(): %s: found inconsistent memory block %p",
+ name, block);
}
}
-#endif
+
+#endif /* MEMORY_CONTEXT_CHECKING */
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