diff options
Diffstat (limited to 'src/backend/utils/mmgr/aset.c')
| -rw-r--r-- | src/backend/utils/mmgr/aset.c | 128 |
1 files changed, 62 insertions, 66 deletions
diff --git a/src/backend/utils/mmgr/aset.c b/src/backend/utils/mmgr/aset.c index 6c1b5f390da..70bcf778a14 100644 --- a/src/backend/utils/mmgr/aset.c +++ b/src/backend/utils/mmgr/aset.c @@ -11,7 +11,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/mmgr/aset.c,v 1.63 2005/09/01 18:15:42 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/mmgr/aset.c,v 1.64 2005/10/15 02:49:36 momjian Exp $ * * NOTE: * This is a new (Feb. 05, 1999) implementation of the allocation set @@ -140,8 +140,7 @@ typedef struct AllocSetContext /* Allocation parameters for this context: */ Size initBlockSize; /* initial block size */ Size maxBlockSize; /* maximum block size */ - AllocBlock keeper; /* if not NULL, keep this block over - * resets */ + AllocBlock keeper; /* if not NULL, keep this block over resets */ } AllocSetContext; typedef AllocSetContext *AllocSet; @@ -342,8 +341,8 @@ AllocSetContextCreate(MemoryContext parent, ereport(ERROR, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"), - errdetail("Failed while creating memory context \"%s\".", - name))); + errdetail("Failed while creating memory context \"%s\".", + name))); } block->aset = context; block->freeptr = ((char *) block) + ALLOC_BLOCKHDRSZ; @@ -505,8 +504,8 @@ AllocSetAlloc(MemoryContext context, Size size) AssertArg(AllocSetIsValid(set)); /* - * If requested size exceeds maximum for chunks, allocate an entire - * block for this request. + * If requested size exceeds maximum for chunks, allocate an entire block + * for this request. */ if (size > ALLOC_CHUNK_LIMIT) { @@ -536,8 +535,8 @@ AllocSetAlloc(MemoryContext context, Size size) #endif /* - * Stick the new block underneath the active allocation block, so - * that we don't lose the use of the space remaining therein. + * Stick the new block underneath the active allocation block, so that + * we don't lose the use of the space remaining therein. */ if (set->blocks != NULL) { @@ -558,8 +557,7 @@ AllocSetAlloc(MemoryContext context, Size size) /* * Request is small enough to be treated as a chunk. Look in the - * corresponding free list to see if there is a free chunk we could - * reuse. + * corresponding free list to see if there is a free chunk we could reuse. */ fidx = AllocSetFreeIndex(size); priorfree = NULL; @@ -571,8 +569,8 @@ AllocSetAlloc(MemoryContext context, Size size) } /* - * 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 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) { @@ -604,8 +602,8 @@ AllocSetAlloc(MemoryContext context, Size size) Assert(chunk_size >= size); /* - * If there is enough room in the active allocation block, we will put - * the chunk into that block. Else must start a new one. + * If there is enough room in the active allocation block, we will put the + * chunk into that block. Else must start a new one. */ if ((block = set->blocks) != NULL) { @@ -614,16 +612,16 @@ AllocSetAlloc(MemoryContext context, Size size) if (availspace < (chunk_size + ALLOC_CHUNKHDRSZ)) { /* - * The existing active (top) block does not have enough room - * for the requested allocation, but it might still have a - * useful amount of space in it. Once we push it down in the - * block list, we'll never try to allocate more space from it. - * So, before we do that, carve up its free space into chunks - * that we can put on the set's freelists. + * The existing active (top) block does not have enough room for + * the requested allocation, but it might still have a useful + * amount of space in it. Once we push it down in the block list, + * we'll never try to allocate more space from it. So, before we + * do that, carve up its free space into chunks that we can put on + * the set's freelists. * * Because we can only get here when there's less than - * ALLOC_CHUNK_LIMIT left in the block, this loop cannot - * iterate more than ALLOCSET_NUM_FREELISTS-1 times. + * ALLOC_CHUNK_LIMIT left in the block, this loop cannot iterate + * more than ALLOCSET_NUM_FREELISTS-1 times. */ while (availspace >= ((1 << ALLOC_MINBITS) + ALLOC_CHUNKHDRSZ)) { @@ -631,10 +629,9 @@ AllocSetAlloc(MemoryContext context, Size size) int a_fidx = AllocSetFreeIndex(availchunk); /* - * In most cases, we'll get back the index of the next - * larger freelist than the one we need to put this chunk - * on. The exception is when availchunk is exactly a - * power of 2. + * In most cases, we'll get back the index of the next larger + * freelist than the one we need to put this chunk on. The + * exception is when availchunk is exactly a power of 2. */ if (availchunk != (1 << (a_fidx + ALLOC_MINBITS))) { @@ -676,11 +673,11 @@ AllocSetAlloc(MemoryContext context, Size size) else { /* - * Use first power of 2 that is larger than previous block, - * but not more than the allowed limit. (We don't simply - * double the prior block size, because in some cases this - * could be a funny size, eg if very first allocation was for - * an odd-sized large chunk.) + * Use first power of 2 that is larger than previous block, but + * not more than the allowed limit. (We don't simply double the + * prior block size, because in some cases this could be a funny + * size, eg if very first allocation was for an odd-sized large + * chunk.) */ Size pblksize = set->blocks->endptr - ((char *) set->blocks); @@ -692,8 +689,8 @@ AllocSetAlloc(MemoryContext context, Size size) } /* - * If initBlockSize is less than ALLOC_CHUNK_LIMIT, we could need - * more space... but try to keep it a power of 2. + * If initBlockSize is less than ALLOC_CHUNK_LIMIT, we could need more + * space... but try to keep it a power of 2. */ required_size = chunk_size + ALLOC_BLOCKHDRSZ + ALLOC_CHUNKHDRSZ; while (blksize < required_size) @@ -703,9 +700,8 @@ AllocSetAlloc(MemoryContext context, Size size) block = (AllocBlock) malloc(blksize); /* - * We could be asking for pretty big blocks here, so cope if - * malloc fails. But give up if there's less than a meg or so - * available... + * We could be asking for pretty big blocks here, so cope if malloc + * fails. But give up if there's less than a meg or so available... */ while (block == NULL && blksize > 1024 * 1024) { @@ -730,13 +726,13 @@ AllocSetAlloc(MemoryContext context, Size size) 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 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->blocks == NULL && blksize == set->initBlockSize) { @@ -870,8 +866,8 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) /* * 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.) + * allocated area already is >= the new size. (In particular, we always + * fall out here if the requested size is a decrease.) */ if (oldsize >= size) { @@ -887,9 +883,9 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) if (oldsize > ALLOC_CHUNK_LIMIT) { /* - * The chunk must been allocated as a single-chunk block. Find - * the containing block and use realloc() to make it bigger with - * minimum space wastage. + * The chunk must been allocated as a single-chunk block. Find the + * containing block and use realloc() to make it bigger with minimum + * space wastage. */ AllocBlock block = set->blocks; AllocBlock prevblock = NULL; @@ -944,15 +940,15 @@ AllocSetRealloc(MemoryContext context, void *pointer, Size size) else { /* - * Small-chunk case. If the chunk is the last one in its block, - * there might be enough free space after it that we can just - * enlarge the chunk in-place. It's relatively painful to find - * the containing block in the general case, but we can detect - * last-ness quite cheaply for the typical case where the chunk is - * in the active (topmost) allocation block. (At least with the - * regression tests and code as of 1/2001, realloc'ing the last - * chunk of a non-topmost block hardly ever happens, so it's not - * worth scanning the block list to catch that case.) + * Small-chunk case. If the chunk is the last one in its block, there + * might be enough free space after it that we can just enlarge the + * chunk in-place. It's relatively painful to find the containing + * block in the general case, but we can detect last-ness quite + * cheaply for the typical case where the chunk is in the active + * (topmost) allocation block. (At least with the regression tests + * and code as of 1/2001, realloc'ing the last chunk of a non-topmost + * block hardly ever happens, so it's not worth scanning the block + * list to catch that case.) * * NOTE: must be careful not to create a chunk of a size that * AllocSetAlloc would not create, else we'll get confused later. @@ -1031,10 +1027,10 @@ AllocSetIsEmpty(MemoryContext context) AllocSet set = (AllocSet) context; /* - * For now, we say "empty" only if the context is new or just reset. - * We could examine the freelists to determine if all space has been - * freed, but it's not really worth the trouble for present uses of - * this functionality. + * For now, we say "empty" only if the context is new or just reset. We + * could examine the freelists to determine if all space has been freed, + * but it's not really worth the trouble for present uses of this + * functionality. */ if (set->isReset) return true; @@ -1073,7 +1069,7 @@ AllocSetStats(MemoryContext context) } } fprintf(stderr, - "%s: %ld total in %ld blocks; %ld free (%ld chunks); %ld used\n", + "%s: %ld total in %ld blocks; %ld free (%ld chunks); %ld used\n", set->header.name, totalspace, nblocks, freespace, nchunks, totalspace - freespace); } @@ -1144,9 +1140,9 @@ AllocSetCheck(MemoryContext context) name, chunk, block); /* - * 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 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 (dsize > 0 && chunk->aset != (void *) set) elog(WARNING, "problem in alloc set %s: bogus aset link in block %p, chunk %p", |