linux-kernel - Re: [PATCH 2/2] s390/mm: use ipte range to invalidate multiple page table entries

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Message-Id: <20160706082350.5c56ca40@mschwide>
Date:	Wed, 6 Jul 2016 08:23:50 +0200
From:	Martin Schwidefsky <schwidefsky@...ibm.com>
To:	"Hillf Danton" <hillf.zj@...baba-inc.com>
Cc:	"linux-kernel" <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>
Subject: Re: [PATCH 2/2] s390/mm: use ipte range to invalidate multiple page
 table entries

On Wed, 06 Jul 2016 12:03:28 +0800
"Hillf Danton" <hillf.zj@...baba-inc.com> wrote:

> > 
> > +void ptep_invalidate_range(struct mm_struct *mm, unsigned long start,
> > +			   unsigned long end, pte_t *ptep)
> > +{
> > +	unsigned long nr;
> > +
> > +	if (!MACHINE_HAS_IPTE_RANGE || mm_has_pgste(mm))
> > +		return;
> > +	preempt_disable();
> > +	nr = (end - start) >> PAGE_SHIFT;
> > +	/* If the flush is likely to be local skip the ipte range */
> > +	if (nr && !cpumask_equal(mm_cpumask(mm),
> > +				 cpumask_of(smp_processor_id())))
> 
> s/smp/raw_smp/ to avoid adding schedule entry with page table
> lock held?

There can not be a schedule entry with either the page table lock held
or the preempt_disable() a few lines above.
 
> > +		__ptep_ipte_range(start, nr - 1, ptep);
> > +	preempt_enable();
> > +}
> > +EXPORT_SYMBOL(ptep_invalidate_range);
> > +
> 
> thanks
> Hillf
> 


-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.