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From: Mike Rapoport <rppt@linux.ibm.com>
To: Vladimir Isaev <Vladimir.Isaev@synopsys.com>
Cc: "linux-snps-arc@lists.infradead.org" 
	<linux-snps-arc@lists.infradead.org>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ARC: Use max_high_pfn as a HIGHMEM zone border
Date: Mon, 26 Apr 2021 19:15:55 +0300	[thread overview]
Message-ID: <YIbnO3BhOeUSRU0E@linux.ibm.com> (raw)
In-Reply-To: <BY5PR12MB41318EB561C2E936B0371B5EDF429@BY5PR12MB4131.namprd12.prod.outlook.com>

On Mon, Apr 26, 2021 at 11:55:00AM +0000, Vladimir Isaev wrote:
> Hi Mike,
> 
> On Mon, April 26, 2021 2:29 PM, Mike Rapoport wrote:
> > On Mon, Apr 26, 2021 at 01:10:04PM +0300, Vladimir Isaev wrote:
> > > -	max_zone_pfn[ZONE_HIGHMEM] = min_low_pfn;
> > > +	max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn;
> > 
> > This is correct with PAE40, but it will break !PAE40 when "highmem" has lower
> > addresses than lowmem.
> > 
> > It rather should be something like:
> > 
> >         if (IS_ENABLED(CONFIG_ARC_HAS_PAE40))
> >                 max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn;
> >         else
> >             	max_zone_pfn[ZONE_HIGHMEM] = min_low_pfn;
> > 
> 
> Not sure if I understand why we should have min_low_pfn here. In !PAE40
> case max_high_pfn just will be smaller than min_low_pfn.

Hmm, actually, you are right. This should be fine.

-- 
Sincerely yours,
Mike.

WARNING: multiple messages have this Message-ID (diff)
From: Mike Rapoport <rppt@linux.ibm.com>
To: Vladimir Isaev <Vladimir.Isaev@synopsys.com>
Cc: "linux-snps-arc@lists.infradead.org"
	<linux-snps-arc@lists.infradead.org>,
	 "linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ARC: Use max_high_pfn as a HIGHMEM zone border
Date: Mon, 26 Apr 2021 19:15:55 +0300	[thread overview]
Message-ID: <YIbnO3BhOeUSRU0E@linux.ibm.com> (raw)
In-Reply-To: <BY5PR12MB41318EB561C2E936B0371B5EDF429@BY5PR12MB4131.namprd12.prod.outlook.com>

On Mon, Apr 26, 2021 at 11:55:00AM +0000, Vladimir Isaev wrote:
> Hi Mike,
> 
> On Mon, April 26, 2021 2:29 PM, Mike Rapoport wrote:
> > On Mon, Apr 26, 2021 at 01:10:04PM +0300, Vladimir Isaev wrote:
> > > -	max_zone_pfn[ZONE_HIGHMEM] = min_low_pfn;
> > > +	max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn;
> > 
> > This is correct with PAE40, but it will break !PAE40 when "highmem" has lower
> > addresses than lowmem.
> > 
> > It rather should be something like:
> > 
> >         if (IS_ENABLED(CONFIG_ARC_HAS_PAE40))
> >                 max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn;
> >         else
> >             	max_zone_pfn[ZONE_HIGHMEM] = min_low_pfn;
> > 
> 
> Not sure if I understand why we should have min_low_pfn here. In !PAE40
> case max_high_pfn just will be smaller than min_low_pfn.

Hmm, actually, you are right. This should be fine.

-- 
Sincerely yours,
Mike.

_______________________________________________
linux-snps-arc mailing list
linux-snps-arc@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-snps-arc

  reply	other threads:[~2021-04-26 16:16 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-26 10:10 [PATCH] ARC: Use max_high_pfn as a HIGHMEM zone border Vladimir Isaev
2021-04-26 10:10 ` Vladimir Isaev
2021-04-26 11:29 ` Mike Rapoport
2021-04-26 11:29   ` Mike Rapoport
2021-04-26 11:55   ` Vladimir Isaev
2021-04-26 11:55     ` Vladimir Isaev
2021-04-26 16:15     ` Mike Rapoport [this message]
2021-04-26 16:15       ` Mike Rapoport
2021-04-26 16:31       ` Vineet Gupta
2021-04-26 16:31         ` Vineet Gupta

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