[04/25] sched_setaffinity (Linux variant): Rewrite to use VLA instead of alloca
Commit Message
On 03/01/2015 03:05 PM, Florian Weimer wrote:
> extend_alloca was used to emulate VLA deallocation.
This new version of the patch follows the changes to the patch
“pthread_setaffinity (Linux variant): Rewrite to use VLA instead of
alloca” (same thread).
2015-03-16 Florian Weimer <fweimer@redhat.com>
* sysdeps/unix/sysv/linux/sched_setaffinity.c
(__sched_setaffinity_new): Replace extend_alloca with a
variable-length array. Do not treat res == 0 as an error.
From 2db0ecba2b3d71adfb0fe1620bfb1658901aff10 Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Sun, 1 Mar 2015 15:05:41 +0100
Subject: [PATCH] sched_setaffinity (Linux variant): Rewrite to use VLA instead
of alloca
extend_alloca was used to emulate VLA deallocation. In addition,
the system call error code from sched_getaffinity is no longer used
if there is no error.
---
sysdeps/unix/sysv/linux/sched_setaffinity.c | 34 ++++++++++++++++-------------
1 file changed, 19 insertions(+), 15 deletions(-)
@@ -22,7 +22,6 @@
#include <unistd.h>
#include <sys/types.h>
#include <shlib-compat.h>
-#include <alloca.h>
#ifdef __NR_sched_setaffinity
@@ -34,25 +33,30 @@ __sched_setaffinity_new (pid_t pid, size_t cpusetsize, const cpu_set_t *cpuset)
{
if (__glibc_unlikely (__kernel_cpumask_size == 0))
{
- INTERNAL_SYSCALL_DECL (err);
+ size_t psize;
int res;
- size_t psize = 128;
- void *p = alloca (psize);
-
- while (res = INTERNAL_SYSCALL (sched_getaffinity, err, 3, getpid (),
- psize, p),
- INTERNAL_SYSCALL_ERROR_P (res, err)
- && INTERNAL_SYSCALL_ERRNO (res, err) == EINVAL)
- p = extend_alloca (p, psize, 2 * psize);
-
- if (res == 0 || INTERNAL_SYSCALL_ERROR_P (res, err))
+ for (psize = 128; ; psize *= 2)
{
- __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
- return -1;
+ char buf[psize];
+ INTERNAL_SYSCALL_DECL (err);
+
+ res = INTERNAL_SYSCALL (sched_getaffinity, err, 3, getpid (),
+ psize, buf);
+ if (INTERNAL_SYSCALL_ERROR_P (res, err))
+ {
+ if (INTERNAL_SYSCALL_ERRNO (res, err) != EINVAL)
+ {
+ __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
+ return -1;
+ }
+ }
+ else
+ break;
}
- __kernel_cpumask_size = res;
+ if (res > 0)
+ __kernel_cpumask_size = res;
}
/* We now know the size of the kernel cpumask_t. Make sure the user
--
2.1.0