From: Li Zefan Subject: [PATCH 06/10] cpuset: re-structure update_cpumask() a bit Date: Fri, 19 Apr 2013 20:27:27 +0800 Message-ID: <5171382F.709@huawei.com> References: <517137A7.4020605@huawei.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <517137A7.4020605-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Tejun Heo Cc: LKML , Cgroups , Containers , Glauber Costa Check if cpus_allowed is to be changed before calling validate_change(). This won't change any behavior, but later it will allow us to do this: # mkdir /cpuset/child # echo $$ > /cpuset/child/tasks /* empty cpuset */ # echo > /cpuset/child/cpuset.cpus /* do nothing, won't fail */ Without this patch, the last operation will fail. Signed-off-by: Li Zefan --- kernel/cpuset.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 2e4c5af..63a5343 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -855,14 +855,15 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs, if (!cpumask_subset(trialcs->cpus_allowed, cpu_active_mask)) return -EINVAL; } - retval = validate_change(cs, trialcs); - if (retval < 0) - return retval; /* Nothing to do if the cpus didn't change */ if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed)) return 0; + retval = validate_change(cs, trialcs); + if (retval < 0) + return retval; + retval = heap_init(&heap, PAGE_SIZE, GFP_KERNEL, NULL); if (retval) return retval; -- 1.8.0.2