Sync from head.

2 files changed, 19 insertions, 2 deletions

diff --git a/lib/libc/stdlib/malloc.3 b/lib/libc/stdlib/malloc.3
index a621a24..308ba7b 100644
--- a/lib/libc/stdlib/malloc.3
+++ b/lib/libc/stdlib/malloc.3
@@ -32,7 +32,7 @@
 .\"     @(#)malloc.3	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\"
-.Dd August 26, 2008
+.Dd September 26, 2009
 .Dt MALLOC 3
 .Os
 .Sh NAME
@@ -245,7 +245,8 @@ will be initialized to 0x5a.
 This is intended for debugging and will impact performance negatively.
 .It K
 Double/halve the virtual memory chunk size.
-The default chunk size is 1 MB.
+The default chunk size is the maximum of 1 MB and the largest
+page size that is less than or equal to 4 MB.
 .It M
 Use
 .Xr mmap 2
@@ -561,6 +562,7 @@ _malloc_options = "X";
 .Xr alloca 3 ,
 .Xr atexit 3 ,
 .Xr getpagesize 3 ,
+.Xr getpagesizes 3 ,
 .Xr memory 3 ,
 .Xr posix_memalign 3
 .Sh STANDARDS
diff --git a/lib/libc/stdlib/malloc.c b/lib/libc/stdlib/malloc.c
index b56b003..bdc26b6 100644
--- a/lib/libc/stdlib/malloc.c
+++ b/lib/libc/stdlib/malloc.c
@@ -4795,6 +4795,21 @@ malloc_init_hard(void)
 		}
 	}
 
+	/*
+	 * Increase the chunk size to the largest page size that is greater
+	 * than the default chunk size and less than or equal to 4MB.
+	 */
+	{
+		size_t pagesizes[MAXPAGESIZES];
+		int k, nsizes;
+
+		nsizes = getpagesizes(pagesizes, MAXPAGESIZES);
+		for (k = 0; k < nsizes; k++)
+			if (pagesizes[k] <= (1LU << 22))
+				while ((1LU << opt_chunk_2pow) < pagesizes[k])
+					opt_chunk_2pow++;
+	}
+
 	for (i = 0; i < 3; i++) {
 		unsigned j;