diff options
Diffstat (limited to 'src/backend/utils/mmgr/aset.c')
| -rw-r--r-- | src/backend/utils/mmgr/aset.c | 26 |
1 files changed, 21 insertions, 5 deletions
diff --git a/src/backend/utils/mmgr/aset.c b/src/backend/utils/mmgr/aset.c index bafe9153e82..e210e42049a 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 - * $Header: /cvsroot/pgsql/src/backend/utils/mmgr/aset.c,v 1.48 2002/09/04 20:31:33 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/mmgr/aset.c,v 1.49 2002/12/15 21:01:34 tgl Exp $ * * NOTE: * This is a new (Feb. 05, 1999) implementation of the allocation set @@ -371,10 +371,11 @@ AllocSetInit(MemoryContext context) * Frees all memory which is allocated in the given set. * * 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 on to any "keeper" - * block specified for the set. + * 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. */ static void AllocSetReset(MemoryContext context) @@ -697,6 +698,21 @@ 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->blocks == NULL && blksize == set->initBlockSize) + { + Assert(set->keeper == NULL); + set->keeper = block; + } + block->next = set->blocks; set->blocks = block; } |