From: Robert Haas <rhaas@postgresql.org>
Date: Thu, 10 Apr 2014 16:43:56 +0000 (+0000)
Subject: Fix bugs.
X-Git-Url: http://waps.l3s.uni-hannover.de/gitweb/?a=commitdiff_plain;h=2dad5598ac2b17bf001c8ebeec203a3bbea3b6eb;p=users%2Frhaas%2Fpostgres.git

Fix bugs.
---

diff --git a/src/backend/utils/mmgr/sb_alloc.c b/src/backend/utils/mmgr/sb_alloc.c
index 69ca093383..760839bb56 100644
--- a/src/backend/utils/mmgr/sb_alloc.c
+++ b/src/backend/utils/mmgr/sb_alloc.c
@@ -43,7 +43,7 @@ struct sb_span
 	relptr(sb_heap) parent;		/* Containing heap. */
 	relptr(sb_span) prevspan;	/* Previous span. */
 	relptr(sb_span) nextspan;	/* Next span. */
-	Size		first_page;		/* Starting page number. */
+	relptr(char)	start;		/* Starting page number. */
 	Size		npages;			/* Length of span in pages. */
 	uint16		size_class;		/* Size class. */
 	uint16		ninitialized;	/* Maximum number of objects ever allocated. */
@@ -312,27 +312,19 @@ sb_reset_allocator(sb_allocator *a)
 			sb_region *region;
 			char *superblock;
 			sb_span *span;
-			char *fpm_base;
-			Size first_page;
 
 			span = relptr_access(base, heap->spans[fclass]);
 			while (span != NULL)
 			{
-				superblock = base + span->first_page * FPM_PAGE_SIZE;
+				Size	offset;
+
+				superblock = relptr_access(base, span->start);
 				region = sb_lookup_region(superblock);
 				Assert(region != NULL);
-				fpm_base = fpm_segment_base(region->fpm);
-
-				/*
-				 * XXX.  Here's where the wheels are going to come
-				 * off if it turns out that malloc returns somethign that isn't
-				 * page-aligned.... what do we do about this?  Maybe we should
-				 * rejigger things so that the fpm base is NULL for all private
-				 * stuff.
-				 */
-				first_page = (superblock - fpm_base) / FPM_PAGE_SIZE;
-				FreePageManagerPut(region->fpm, first_page, span->npages);
-
+				offset = superblock - fpm_segment_base(region->fpm);
+				Assert(offset % FPM_PAGE_SIZE == 0);
+				FreePageManagerPut(region->fpm, offset / FPM_PAGE_SIZE,
+								   span->npages);
 				span = relptr_access(base, span->nextspan);
 			}
 		}
@@ -441,18 +433,21 @@ sb_alloc_from_heap(char *base, sb_heap *heap, Size obsize, Size nmax)
 	 * free list or, failing that, initialize a new object.
 	 */
 	active_sb = relptr_access(base, heap->spans[1]);
-	superblock = base + active_sb->first_page * FPM_PAGE_SIZE;
+	superblock = relptr_access(base, active_sb->start);
 	Assert(active_sb != NULL);
 	Assert(active_sb->nused < nmax);
 	Assert(active_sb->nused <= active_sb->ninitialized);
 	if (active_sb->firstfree < nmax)
 	{
 		result = superblock + active_sb->firstfree * obsize;
+		elog(FATAL, "superblock at %p points to %p reallocating %d of %zu result %p",
+			active_sb, superblock, active_sb->firstfree, nmax, result);
 		active_sb->firstfree = * (Size *) result;
 	}
 	else
 	{
 		Assert(active_sb->ninitialized < nmax);
+		Assert(active_sb->ninitialized == active_sb->nused);
 		result = superblock + active_sb->ninitialized * obsize;
 		++active_sb->ninitialized;
 	}
@@ -598,7 +593,7 @@ sb_init_span(char *base, sb_span *span, sb_heap *heap, char *ptr,
 	relptr_store(base, span->nextspan, head);
 	relptr_store(base, span->prevspan, (sb_span *) NULL);
 	relptr_store(base, heap->spans[1], span);
-	span->first_page = (ptr - base) / FPM_PAGE_SIZE;
+	relptr_store(base, span->start, ptr);
 	span->npages = npages;
 	span->size_class = size_class;
 	span->ninitialized = 0;