From: Matt Mackall <mpm@selenic.com>
Eep. cpuset uses bubble sort on a data set that's potentially O(# processes).
Switch to lib/sort.
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/kernel/cpuset.c | 19 ++++---------------
1 files changed, 4 insertions(+), 15 deletions(-)
diff -puN kernel/cpuset.c~lib-sort-replace-open-coded-opids2-bubblesort-in-cpusets kernel/cpuset.c
--- 25/kernel/cpuset.c~lib-sort-replace-open-coded-opids2-bubblesort-in-cpusets 2005-02-02 15:56:31.556990232 -0800
+++ 25-akpm/kernel/cpuset.c 2005-02-02 15:56:36.404253336 -0800
@@ -47,6 +47,7 @@
#include <linux/string.h>
#include <linux/time.h>
#include <linux/backing-dev.h>
+#include <linux/sort.h>
#include <asm/uaccess.h>
#include <asm/atomic.h>
@@ -1003,21 +1004,9 @@ array_full:
return n;
}
-/*
- * In place bubble sort pidarray of npids pid_t's.
- */
-static inline void pid_array_sort(pid_t *pidarray, int npids)
+static int cmppid(const void *a, const void *b)
{
- int i, j;
-
- for (i = 0; i < npids - 1; i++) {
- for (j = 0; j < npids - 1 - i; j++)
- if (pidarray[j + 1] < pidarray[j]) {
- pid_t tmp = pidarray[j];
- pidarray[j] = pidarray[j + 1];
- pidarray[j + 1] = tmp;
- }
- }
+ return *(pid_t *)a - *(pid_t *)b;
}
/*
@@ -1059,7 +1048,7 @@ static inline struct ctr_struct *cpuset_
goto err1;
npids = pid_array_load(pidarray, npids, cs);
- pid_array_sort(pidarray, npids);
+ sort(pidarray, npids, sizeof(pid_t), cmppid, NULL);
/* Call pid_array_to_buf() twice, first just to get bufsz */
ctr->bufsz = pid_array_to_buf(&c, sizeof(c), pidarray, npids) + 1;
_