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| author | Jack Steiner <steiner@sgi.com> | 2006-02-01 03:05:18 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-02-01 08:53:13 -0800 |
| commit | 2f7016d917faef8f1e016b4a7bd7f594694480b6 (patch) | |
| tree | 06aa6181a5609ad1e3815a08cf9a67df4ab08137 /kernel/sched.c | |
| parent | 0f07496144c270f10d0ad06b70b9c9387d5527fd (diff) | |
| download | lwn-2f7016d917faef8f1e016b4a7bd7f594694480b6.tar.gz lwn-2f7016d917faef8f1e016b4a7bd7f594694480b6.zip | |
[PATCH] sys_sched_getaffinity() & hotplug
Change sched_getaffinity() so that it returns a bitmap that indicates the
legally schedulable cpus that a task is allowed to run on.
Without this patch, if CONFIG_HOTPLUG_CPU is enabled, sched_getaffinity()
unconditionally returns (at least on IA64) a mask with NR_CPUS bits set.
This conveys no useful infornmation except for a kernel compile option.
This fixes a breakage we obseved running recent kernels. We have MPI jobs
that use sched_getaffinity() to determine where to place their threads.
Placing them on non-existant cpus is problematic :-)
Signed-off-by: Jack Steiner <steiner@sgi.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Nathan Lynch <ntl@pobox.com>
Cc: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index ec7fd9cee306..f77f23f8f479 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4031,7 +4031,7 @@ long sched_getaffinity(pid_t pid, cpumask_t *mask) goto out_unlock; retval = 0; - cpus_and(*mask, p->cpus_allowed, cpu_possible_map); + cpus_and(*mask, p->cpus_allowed, cpu_online_map); out_unlock: read_unlock(&tasklist_lock); |