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From: Thomas Gleixner <tglx@linutronix.de>
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To: Shrikanth Hegde <sshegde@linux.ibm.com>, LKML
 <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>, Gabriele Monaco
 <gmonaco@redhat.com>, Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
 Michael Jeanson <mjeanson@efficios.com>, Jens Axboe <axboe@kernel.dk>,
 "Paul E. McKenney" <paulmck@kernel.org>, "Gautham R. Shenoy"
 <gautham.shenoy@amd.com>, Florian Weimer <fweimer@redhat.com>, Tim Chen
 <tim.c.chen@intel.com>, Yury Norov <yury.norov@gmail.com>
Subject: Re: [patch V2 10/20] sched/mmcid: Convert mm CID mask to a bitmap
In-Reply-To: <6f7b0688-6c92-4901-ab18-d348e667703e@linux.ibm.com>
References: <20251022104005.907410538@linutronix.de>
 <20251022110556.029862568@linutronix.de>
 <6f7b0688-6c92-4901-ab18-d348e667703e@linux.ibm.com>
Date: Mon, 27 Oct 2025 09:57:09 +0100
Message-ID: <87ikg0wwm2.ffs@tglx>
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On Mon, Oct 27 2025 at 11:15, Shrikanth Hegde wrote:
> On 10/22/25 6:25 PM, Thomas Gleixner wrote:
>>   static inline void mm_init_cid(struct mm_struct *mm, struct task_struct *p)
>> @@ -1363,7 +1363,7 @@ static inline void mm_init_cid(struct mm
>>   	mm->mm_cid.nr_cpus_allowed = p->nr_cpus_allowed;
>>   	raw_spin_lock_init(&mm->mm_cid.lock);
>>   	cpumask_copy(mm_cpus_allowed(mm), &p->cpus_mask);
>> -	cpumask_clear(mm_cidmask(mm));
>> +	bitmap_zero(mm_cidmask(mm), cpumask_size());
>
> Could use num_possible_cpus() here? CID are bound to be less than it no?

Probably.