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From: Andi Kleen <ak@linux.intel.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>,
	peterz@infradead.org, linux-mm@kvack.org,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Don't touch single threaded PTEs which are on the right node
Date: Thu, 13 Oct 2016 11:04:02 -0700	[thread overview]
Message-ID: <20161013180402.GI3078@tassilo.jf.intel.com> (raw)
In-Reply-To: <20161013083910.GC20573@suse.de>

> >  	do {
> >  		oldpte = *pte;
> > @@ -94,6 +100,13 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
> >  				/* Avoid TLB flush if possible */
> >  				if (pte_protnone(oldpte))
> >  					continue;
> > +
> > +				/*
> > +				 * Don't mess with PTEs if page is already on the node
> > +				 * a single-threaded process is running on.
> > +				 */
> > +				if (target_node == page_to_nid(page))
> > +					continue;
> >  			}
> >  
> 
> Check target_node != NUMA_NODE && target_node == page_to_nid(page) to
> avoid unnecessary page->flag masking and shifts?

I didn't do this last change because I expect a potentially mispredicted
check is more expensive than some shifting/masking.

-Andi

WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <ak@linux.intel.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>,
	peterz@infradead.org, linux-mm@kvack.org,
	akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Don't touch single threaded PTEs which are on the right node
Date: Thu, 13 Oct 2016 11:04:02 -0700	[thread overview]
Message-ID: <20161013180402.GI3078@tassilo.jf.intel.com> (raw)
In-Reply-To: <20161013083910.GC20573@suse.de>

> >  	do {
> >  		oldpte = *pte;
> > @@ -94,6 +100,13 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
> >  				/* Avoid TLB flush if possible */
> >  				if (pte_protnone(oldpte))
> >  					continue;
> > +
> > +				/*
> > +				 * Don't mess with PTEs if page is already on the node
> > +				 * a single-threaded process is running on.
> > +				 */
> > +				if (target_node == page_to_nid(page))
> > +					continue;
> >  			}
> >  
> 
> Check target_node != NUMA_NODE && target_node == page_to_nid(page) to
> avoid unnecessary page->flag masking and shifts?

I didn't do this last change because I expect a potentially mispredicted
check is more expensive than some shifting/masking.

-Andi

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  reply	other threads:[~2016-10-13 18:04 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-12 16:15 [PATCH] Don't touch single threaded PTEs which are on the right node Andi Kleen
2016-10-12 16:15 ` Andi Kleen
2016-10-13  8:39 ` Mel Gorman
2016-10-13  8:39   ` Mel Gorman
2016-10-13 18:04   ` Andi Kleen [this message]
2016-10-13 18:04     ` Andi Kleen
2016-10-13 18:16     ` Mel Gorman
2016-10-13 18:16       ` Mel Gorman
  -- strict thread matches above, loose matches on Subject: below --
2016-10-13 18:08 Andi Kleen
2016-10-13 18:08 ` Andi Kleen
2016-10-11 20:28 Andi Kleen
2016-10-11 20:28 ` Andi Kleen
2016-10-12  5:49 ` Mel Gorman
2016-10-12  5:49   ` Mel Gorman
2016-10-12 15:40   ` Andi Kleen
2016-10-12 15:40     ` Andi Kleen

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