Various updates.

1 files changed, 31 insertions, 22 deletions

diff --git a/morecore.c b/morecore.c
index 023a0ea..c5249e0 100644
--- a/morecore.c
+++ b/morecore.c
@@ -13,22 +13,21 @@
 #include "libhugetlbfs_internal.h"
 
 static int heap_fd;
-static long blocksize = (16 * 1024 * 1024);
+static long blocksize;
 
 static void *heapbase;
 static void *heaptop;
 static long mapsize;
 
-
 /*
- * Our plan is to ask for pages 'roughly' at the BASE.  We expect nee require
- * the kernel to offer us sequential pages from wherever it first gave us a
- * page.  If it does not do so, we return the page and pretend there are none
- * this covers us for the case where another map is in the way.  This is 
- * required because 'morecore' must have 'sbrk' semantics, ie. return
- * sequential, contigious memory blocks.  Luckily, if it does not do so
- * and we error out malloc will happily go back to small pages and use mmap
- * to get them.  Hurrah.
+ * Our plan is to ask for pages 'roughly' at the BASE.  We expect and
+ * require the kernel to offer us sequential pages from wherever it
+ * first gave us a page.  If it does not do so, we return the page and
+ * pretend there are none this covers us for the case where another
+ * map is in the way.  This is required because 'morecore' must have
+ * 'sbrk' semantics, ie. return sequential, contigious memory blocks.
+ * Luckily, if it does not do so and we error out malloc will happily
+ * go back to small pages and use mmap to get them.  Hurrah.
  */
 
 static void *hugetlbfs_morecore(ptrdiff_t increment)
@@ -49,18 +48,21 @@ static void *hugetlbfs_morecore(ptrdiff_t increment)
 		DEBUG("Attempting to map %ld bytes\n", newsize);
 
 		p = mmap(heapbase + mapsize, newsize, PROT_READ|PROT_WRITE,
-			 MAP_PRIVATE | MAP_FIXED, heap_fd, mapsize);
+			 MAP_PRIVATE, heap_fd, mapsize);
 		if (p == MAP_FAILED) {
-			ERROR("Mapping failed in hugetlbfs_morecore()\n");
+			WARNING("Mapping failed in hugetlbfs_morecore()\n");
 			return NULL;
 		}
 
-		if (! heapbase) {
+		if (! mapsize) {
+			if (heapbase && (heapbase != p))
+				WARNING("Heap originates at %p instead of %p\n",
+					p, heapbase);
 			heapbase = heaptop = p;
 		} else if (p != (heapbase + mapsize)) {
 			/* Couldn't get the mapping where we wanted */
 			munmap(p, newsize);
-			ERROR("Mapped at %p instead of %p in hugetlbfs_morecore()\n",
+			WARNING("Mapped at %p instead of %p in hugetlbfs_morecore()\n",
 			      p, heapbase + mapsize);
 			return NULL;
 		}
@@ -78,14 +80,18 @@ static void *hugetlbfs_morecore(ptrdiff_t increment)
 static void __attribute__((constructor)) setup_morecore(void)
 {
 	char *env, *ep;
-	unsigned long heapaddr = 0;
-
-	DEBUG("setup_morecore()\n");
+	unsigned long heapaddr;
 
 	env = getenv("HUGETLB_MORECORE");
 	if (! env)
 		return;
 
+	blocksize = gethugepagesize();
+	if (! blocksize) {
+		ERROR("Hugepages unavailable\n");
+		return;
+	}
+		
 	heap_fd = hugetlbfs_unlinked_fd();
 	if (heap_fd < 0) {
 		ERROR("Couldn't open hugetlbfs file for morecore\n");
@@ -100,18 +106,21 @@ static void __attribute__((constructor)) setup_morecore(void)
 			      env);
 			return;
 		}
-	}
-
-	if (! heapaddr) {
+	} else {
 		heapaddr = (unsigned long)sbrk(0);
 		heapaddr = ALIGN(heapaddr, hugetlbfs_vaddr_granularity());
 	}
 
-	DEBUG("Placing hugepage morecore heap at 0x%lx\n", heapaddr);
+	DEBUG("setup_morecore(): heapaddr = 0x%lx\n", heapaddr);
 		
 	heaptop = heapbase = (void *)heapaddr;
 	__morecore = &hugetlbfs_morecore;
 
-	/* we always want to use our morecore, not ordinary mmap() */
+	/* Set some allocator options more appropriate for hugepages */
+	mallopt(M_TRIM_THRESHOLD, blocksize / 2);
+	mallopt(M_TOP_PAD, blocksize / 2);
+	/* we always want to use our morecore, not ordinary mmap().
+	 * This doesn't appear to prohibit malloc() from falling back
+	 * to mmap() if we run out of hugepages. */
 	mallopt(M_MMAP_MAX, 0);
 }