mirror/glibc
2
0
Fork 0
mirror of git://sourceware.org/git/glibc.git synced 2025-02-17 13:00:43 +08:00
Code Issues Packages Projects Releases Wiki Activity

Update.

Browse Source 
2000-02-28  Ulrich Drepper  <drepper@redhat.com>

	* stdlib/msort.c (qsort): Limit the amount of memory spend on a
	temporary array for the mergesort.
This commit is contained in:
Ulrich Drepper 2000-02-28 08:14:33 +00:00
parent e5aa91c34a
commit 8358825c70
2 changed files with 54 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
ChangeLog
View File

@ -1,3 +1,8 @@
2000-02-28 Ulrich Drepper <drepper@redhat.com>
* stdlib/msort.c (qsort): Limit the amount of memory spend on a
temporary array for the mergesort.
2000-02-28 Andreas Jaeger <aj@suse.de>
* stdlib/canonicalize.c: Include <stddef.h> for ptrdiff_t.

60
stdlib/msort.c
View File

@ -1,6 +1,6 @@
/* An alternative to qsort, with an identical interface.
This file is part of the GNU C Library.
Copyright (C) 1992, 1995, 1996, 1997, 1999 Free Software Foundation, Inc.
Copyright (C) 1992, 1995-1997, 1999, 2000 Free Software Foundation, Inc.
Written by Mike Haertel, September 1988.
The GNU C Library is free software; you can redistribute it and/or
@ -21,6 +21,7 @@
#include <alloca.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <memcopy.h>
#include <errno.h>
@ -94,20 +95,57 @@ qsort (void *b, size_t n, size_t s, __compar_fn_t cmp)
msort_with_tmp (b, n, s, cmp, __alloca (size));
else
{
/* It's somewhat large, so malloc it. */
int save = errno;
char *tmp = malloc (size);
if (tmp == NULL)
/* We should avoid allocating too much memory since this might
have to be backed up by swap space. */
static long int phys_pages;
static int pagesize;
if (phys_pages == 0)
{
/* Couldn't get space, so use the slower algorithm
that doesn't need a temporary array. */
_quicksort (b, n, s, cmp);
phys_pages = __sysconf (_SC_PHYS_PAGES);
if (phys_pages == -1)
/* Error while determining the memory size. So let's
assume there is enough memory. Otherwise the
implementer should provide a complete implementation of
the `sysconf' function. */
phys_pages = (long int) (~0ul >> 1);
/* The following determines that we will never use more than
a quarter of the physical memory. */
phys_pages /= 4;
pagesize = __sysconf (_SC_PAGESIZE);
}
/* Just a comment here. We cannot compute
phys_pages * pagesize
and compare the needed amount of memory against this value.
The problem is that some systems might have more physical
memory then can be represented with a `size_t' value (when
measured in bytes. */
/* If the memory requirements are too high don't allocate memory. */
if (size / pagesize > phys_pages)
_quicksort (b, n, s, cmp);
else
{
msort_with_tmp (b, n, s, cmp, tmp);
free (tmp);
/* It's somewhat large, so malloc it. */
int save = errno;
char *tmp = malloc (size);
if (tmp == NULL)
{
/* Couldn't get space, so use the slower algorithm
that doesn't need a temporary array. */
__set_errno (save);
_quicksort (b, n, s, cmp);
}
else
{
__set_errno (save);
msort_with_tmp (b, n, s, cmp, tmp);
free (tmp);
}
}
__set_errno (save);
}
}