diff options
Diffstat (limited to 'lib/libc')
| -rw-r--r-- | lib/libc/stdlib/malloc.3 | 24 | ||||
| -rw-r--r-- | lib/libc/stdlib/malloc.c | 15 |
2 files changed, 20 insertions, 19 deletions
diff --git a/lib/libc/stdlib/malloc.3 b/lib/libc/stdlib/malloc.3 index 7138ead..466accc 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 December 27, 2007 +.Dd January 3, 2008 .Dt MALLOC 3 .Os .Sh NAME @@ -245,7 +245,7 @@ This option is not available for some configurations (non-PIC). Use .Xr mmap 2 to acquire anonymously mapped memory. -This option is disabled by default. +This option is enabled by default. If both the .Dq D and @@ -335,24 +335,24 @@ Traditionally, allocators have used to obtain memory, which is suboptimal for several reasons, including race conditions, increased fragmentation, and artificial limitations on maximum usable memory. -This allocator uses -.Xr sbrk 2 -by default in order to facilitate resource limits, but it can be configured at -run time to use +This allocator uses both .Xr sbrk 2 -and/or -.Xr mmap 2 . +and +.Xr mmap 2 +by default, but it can be configured at run time to use only one or the other. If resource limits are not a primary concern, the preferred configuration is .Ev MALLOC_OPTIONS=dM or .Ev MALLOC_OPTIONS=DM . When so configured, the .Ar datasize -resource limit has little practical effect for typical applications. -The +resource limit has little practical effect for typical applications; use +.Ev MALLOC_OPTIONS=Dm +if that is a concern. +Regardless of allocator configuration, the .Ar vmemoryuse -resource limit, however, can be used to bound the total virtual memory used by -a process, as described in +resource limit can be used to bound the total virtual memory used by a +process, as described in .Xr limits 1 . .Pp This allocator uses multiple arenas in order to reduce lock contention for diff --git a/lib/libc/stdlib/malloc.c b/lib/libc/stdlib/malloc.c index 5c987c5..abe367a 100644 --- a/lib/libc/stdlib/malloc.c +++ b/lib/libc/stdlib/malloc.c @@ -1,5 +1,5 @@ /*- - * Copyright (C) 2006,2007 Jason Evans <jasone@FreeBSD.org>. + * Copyright (C) 2006-2008 Jason Evans <jasone@FreeBSD.org>. * All rights reserved. * * Redistribution and use in source and binary forms, with or without @@ -131,7 +131,7 @@ * unnecessary, but we are burdened by history and the lack of resource limits * for anonymous mapped memory. */ -#define MALLOC_DSS +#define MALLOC_DSS #include <sys/cdefs.h> __FBSDID("$FreeBSD$"); @@ -821,7 +821,7 @@ static bool opt_junk = false; #endif #ifdef MALLOC_DSS static bool opt_dss = true; -static bool opt_mmap = false; +static bool opt_mmap = true; #endif static bool opt_hint = false; #ifdef MALLOC_LAZY_FREE @@ -1646,6 +1646,7 @@ chunk_alloc_mmap(size_t size) return (NULL); /* Clean up unneeded leading/trailing space. */ + offset = CHUNK_ADDR2OFFSET(ret); if (offset != 0) { /* Leading space. */ pages_unmap(ret, chunksize - offset); @@ -1661,11 +1662,11 @@ chunk_alloc_mmap(size_t size) pages_unmap((void *)((uintptr_t)ret + size), chunksize); } + } else { + /* Clean up unneeded leading space. */ + pages_unmap(ret, chunksize - offset); + ret = (void *)((uintptr_t)ret + (chunksize - offset)); } - - /* Clean up unneeded leading space. */ - pages_unmap(ret, chunksize - offset); - ret = (void *)((uintptr_t)ret + (chunksize - offset)); } return (ret); |
