From: Robert Haas <rhaas@postgresql.org>
Date: Mon, 3 Feb 2014 17:49:29 +0000 (-0500)
Subject: Hack.
X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=09e1f49cc2dacf188bd71b1ca6923c198ea703d5;p=users%2Frhaas%2Fpostgres.git

Hack.
---

diff --git a/src/backend/utils/mmgr/mspan.c b/src/backend/utils/mmgr/mspan.c
index c0a81e5253..6ad8cfcd4f 100644
--- a/src/backend/utils/mmgr/mspan.c
+++ b/src/backend/utils/mmgr/mspan.c
@@ -502,6 +502,7 @@ static char *
 mspan_allocate_from_superblock(char *base, mspan *superblock)
 {
 	char   *spanbase;
+	char   *result;
 	uint16	object_size;
 	uint16	total;
 
@@ -511,27 +512,26 @@ mspan_allocate_from_superblock(char *base, mspan *superblock)
 	if (superblock->nused >= total)
 		return NULL;
 
-	/* Try to reuse a previously-freed object. */
+	/* Do the allocation. */
 	spanbase = base + superblock->first_page * MSPAN_PAGE_SIZE;
 	if (superblock->firstfree != MSPAN_FIRSTFREE_NONE)
 	{
-		uint16 *firstfree;
-
-		firstfree =
-			(uint16 *) (spanbase + (superblock->firstfree * object_size));
-		superblock->firstfree = *firstfree;
-		return (char *) firstfree;
+		/* There's a freed object available for reuse.  Allocate it. */
+		result = spanbase + (superblock->firstfree * object_size);
+		superblock->firstfree = ((uint16 *) result)[0];
+	}
+	else
+	{
+		/* Carve out an object from not-previously-used part of span. */
+		result = spanbase + (superblock->ninitialized * object_size);
+		++superblock->ninitialized;
 	}
 
-	/*
-	 * Carve out space from the uninitialized portion of the span.  This
-	 * should always work, since we already verified that nused < total.
-	 */
-
-	/*
-	 * XXX. Implementation needed.
-	 */
-	return NULL;
+	/* Update counter and return result. */
+	++superblock->nused;
+	Assert(superblock->nused <= superblock->ninitialized);
+	Assert(result < spanbase + object_size * total);
+	return result;
 }
 
 /*