Re: [PATCH] x86: Revert E820_PRAM change in e820_end_pfn()

From: Yinghai Lu <yinghai@kernel.org>
To: Toshi Kani <toshi.kani@hp.com>
Cc: Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-nvdimm@ml01.01.org, linux-fsdevel@vger.kernel.org,
	"the arch/x86 maintainers" <x86@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Christoph Hellwig <hch@lst.de>, Boaz Harrosh <boaz@plexistor.com>
Subject: Re: [PATCH] x86: Revert E820_PRAM change in e820_end_pfn()
Date: Mon, 6 Apr 2015 11:29:36 -0700	[thread overview]
Message-ID: <CAE9FiQXNobC1_0YFS1dgy7Ae+vZFU783ttuBsSyw67wXbz2fCg@mail.gmail.com> (raw)
In-Reply-To: <1428342439-31285-1-git-send-email-toshi.kani@hp.com>

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On Mon, Apr 6, 2015 at 10:47 AM, Toshi Kani <toshi.kani@hp.com> wrote:
> 'Commit ec776ef6bbe17 ("x86/mm: Add support for the non-standard
> protected e820 type")' added E820_PRAM ranges, which do not have
> have struct-page.  Therefore, there is no need to update max_pfn
> to cover the E820_PRAM ranges.  Revert the change made to account
> E820_PRAM as RAM in e820_end_pfn() in the commit.
>
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> Signed-off-by: Toshi Kani <toshi.kani@hp.com>
> Tested-by: Christoph Hellwig <hch@lst.de>
> ---
> The patch is based on the tip branch.
> ---
>  arch/x86/kernel/e820.c |    6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index e2ce85d..4dfe4bd 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -763,11 +763,7 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn)
>                 unsigned long start_pfn;
>                 unsigned long end_pfn;
>
> -               /*
> -                * Persistent memory is accounted as ram for purposes of
> -                * establishing max_pfn and mem_map.
> -                */
> -               if (ei->type != E820_RAM && ei->type != E820_PRAM)
> +               if (ei->type != E820_RAM)
>                         continue;
>
>                 start_pfn = ei->addr >> PAGE_SHIFT;

Please use attached for code change.

Thanks

Yinghai

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---
 arch/x86/kernel/e820.c |   12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

Index: linux-2.6/arch/x86/kernel/e820.c
===================================================================

--- linux-2.6.orig/arch/x86/kernel/e820.c
+++ linux-2.6/arch/x86/kernel/e820.c
@@ -752,7 +752,7 @@ u64 __init early_reserve_e820(u64 size,
 /*
  * Find the highest page frame number we have available
  */
-static unsigned long __init e820_end_pfn(unsigned long limit_pfn)
+static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type)
 {
 	int i;
 	unsigned long last_pfn = 0;
@@ -763,11 +763,7 @@ static unsigned long __init e820_end_pfn
 		unsigned long start_pfn;
 		unsigned long end_pfn;
 
-		/*
-		 * Persistent memory is accounted as ram for purposes of
-		 * establishing max_pfn and mem_map.
-		 */
-		if (ei->type != E820_RAM && ei->type != E820_PRAM)
+		if (ei->type != type)
 			continue;
 
 		start_pfn = ei->addr >> PAGE_SHIFT;
@@ -792,12 +788,12 @@ static unsigned long __init e820_end_pfn
 }
 unsigned long __init e820_end_of_ram_pfn(void)
 {
-	return e820_end_pfn(MAX_ARCH_PFN);
+	return e820_end_pfn(MAX_ARCH_PFN, E820_RAM);
 }
 
 unsigned long __init e820_end_of_low_ram_pfn(void)
 {
-	return e820_end_pfn(1UL << (32-PAGE_SHIFT));
+	return e820_end_pfn(1UL<<(32 - PAGE_SHIFT), E820_RAM);
 }
 
 static void early_panic(char *msg)
