[PATCH] mm: skip if required_kernelcore is larger than totalpages

[PATCH] mm: skip if required_kernelcore is larger than totalpages

[Xishi Qiu]

If kernelcore was not specified, or the kernelcore size is zero
(required_movablecore >= totalpages), or the kernelcore size is larger
than totalpages, there is no ZONE_MOVABLE. We should fill the zone
with both kernel memory and movable memory.

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
---
 mm/page_alloc.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index af3c9bd..6a6da0d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5674,8 +5674,11 @@ static void __init find_zone_movable_pfns_for_nodes(void)
 		required_kernelcore = max(required_kernelcore, corepages);
 	}
 
-	/* If kernelcore was not specified, there is no ZONE_MOVABLE */
-	if (!required_kernelcore)
+	/*
+	 * If kernelcore was not specified or kernelcore size is larger
+	 * than totalpages, there is no ZONE_MOVABLE.
+	 */
+	if (!required_kernelcore || required_kernelcore >= totalpages)
 		goto out;
 
 	/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
-- 
2.0.0


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Re: [PATCH] mm: skip if required_kernelcore is larger than totalpages

[Yasuaki Ishimatsu]

On Thu, 8 Oct 2015 10:21:05 +0800
Xishi Qiu <qiuxishi@huawei.com> wrote:

> If kernelcore was not specified, or the kernelcore size is zero
> (required_movablecore >= totalpages), or the kernelcore size is larger

Why does required_movablecore become larger than totalpages, when the
kernelcore size is zero? I read the code but I could not find that you
mention.

Thanks,
Yasuaki Ishimatsu

> than totalpages, there is no ZONE_MOVABLE. We should fill the zone
> with both kernel memory and movable memory.
> 
> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
> ---
>  mm/page_alloc.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index af3c9bd..6a6da0d 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5674,8 +5674,11 @@ static void __init find_zone_movable_pfns_for_nodes(void)
>  		required_kernelcore = max(required_kernelcore, corepages);
>  	}
>  
> -	/* If kernelcore was not specified, there is no ZONE_MOVABLE */
> -	if (!required_kernelcore)
> +	/*
> +	 * If kernelcore was not specified or kernelcore size is larger
> +	 * than totalpages, there is no ZONE_MOVABLE.
> +	 */
> +	if (!required_kernelcore || required_kernelcore >= totalpages)
>  		goto out;
>  
>  	/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
> -- 
> 2.0.0
> 
> 
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Re: [PATCH] mm: skip if required_kernelcore is larger than totalpages

[Xishi Qiu]

On 2015/10/9 23:41, Yasuaki Ishimatsu wrote:

> 
> On Thu, 8 Oct 2015 10:21:05 +0800
> Xishi Qiu <qiuxishi@huawei.com> wrote:
> 
>> If kernelcore was not specified, or the kernelcore size is zero
>> (required_movablecore >= totalpages), or the kernelcore size is larger
> 
> Why does required_movablecore become larger than totalpages, when the
> kernelcore size is zero? I read the code but I could not find that you
> mention.
> 

If user only set boot option movablecore, and the value is larger than
totalpages, the calculation of kernelcore is zero, but we can't fill
the zone only with kernelcore, so skip it.

I have send a patch before this patch.
"fix overflow in find_zone_movable_pfns_for_nodes()"
		...
 		required_movablecore =
 			roundup(required_movablecore, MAX_ORDER_NR_PAGES);
+		required_movablecore = min(totalpages, required_movablecore);
 		corepages = totalpages - required_movablecore;
		...

Thanks,
Xishi Qiu

> Thanks,
> Yasuaki Ishimatsu
> 
>> than totalpages, there is no ZONE_MOVABLE. We should fill the zone
>> with both kernel memory and movable memory.
>>
>> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
>> ---
>>  mm/page_alloc.c | 7 +++++--
>>  1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index af3c9bd..6a6da0d 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -5674,8 +5674,11 @@ static void __init find_zone_movable_pfns_for_nodes(void)
>>  		required_kernelcore = max(required_kernelcore, corepages);
>>  	}
>>  
>> -	/* If kernelcore was not specified, there is no ZONE_MOVABLE */
>> -	if (!required_kernelcore)
>> +	/*
>> +	 * If kernelcore was not specified or kernelcore size is larger
>> +	 * than totalpages, there is no ZONE_MOVABLE.
>> +	 */
>> +	if (!required_kernelcore || required_kernelcore >= totalpages)
>>  		goto out;
>>  
>>  	/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
>> -- 
>> 2.0.0
>>
>>
>> --
>> To unsubscribe, send a message with 'unsubscribe linux-mm' in
>> the body to majordomo@kvack.org.  For more info on Linux MM,
>> see: http://www.linux-mm.org/ .
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> 
> .
> 



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Re: [PATCH] mm: skip if required_kernelcore is larger than totalpages

[David Rientjes]

On Thu, 8 Oct 2015, Xishi Qiu wrote:

> If kernelcore was not specified, or the kernelcore size is zero
> (required_movablecore >= totalpages), or the kernelcore size is larger
> than totalpages, there is no ZONE_MOVABLE. We should fill the zone
> with both kernel memory and movable memory.
> 
> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>

Acked-by: David Rientjes <rientjes@google.com>

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Re: [PATCH] mm: skip if required_kernelcore is larger than totalpages

[Tang Chen]

Hi, Qiu

The patch seems OK to me. Only one little concern below.

On 10/12/2015 09:37 AM, Xishi Qiu wrote:
> On 2015/10/9 23:41, Yasuaki Ishimatsu wrote:
>
>> On Thu, 8 Oct 2015 10:21:05 +0800
>> Xishi Qiu <qiuxishi@huawei.com> wrote:
>>
>>> If kernelcore was not specified, or the kernelcore size is zero
>>> (required_movablecore >= totalpages), or the kernelcore size is larger
>> Why does required_movablecore become larger than totalpages, when the
>> kernelcore size is zero? I read the code but I could not find that you
>> mention.
>>
> If user only set boot option movablecore, and the value is larger than
> totalpages, the calculation of kernelcore is zero, but we can't fill
> the zone only with kernelcore, so skip it.
>
> I have send a patch before this patch.
> "fix overflow in find_zone_movable_pfns_for_nodes()"
> 		...
>   		required_movablecore =
>   			roundup(required_movablecore, MAX_ORDER_NR_PAGES);
> +		required_movablecore = min(totalpages, required_movablecore);
>   		corepages = totalpages - required_movablecore;
> 		...


So if required_movablecore >= totalpages, there won't be any ZONE_MOVABLE.
How about add a warning or debug info to tell the user he has specified a
too large movablecore, and it is ignored ?

Thanks.


>
> Thanks,
> Xishi Qiu
>
>> Thanks,
>> Yasuaki Ishimatsu
>>
>>> than totalpages, there is no ZONE_MOVABLE. We should fill the zone
>>> with both kernel memory and movable memory.
>>>
>>> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
>>> ---
>>>   mm/page_alloc.c | 7 +++++--
>>>   1 file changed, 5 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>> index af3c9bd..6a6da0d 100644
>>> --- a/mm/page_alloc.c
>>> +++ b/mm/page_alloc.c
>>> @@ -5674,8 +5674,11 @@ static void __init find_zone_movable_pfns_for_nodes(void)
>>>   		required_kernelcore = max(required_kernelcore, corepages);
>>>   	}
>>>   
>>> -	/* If kernelcore was not specified, there is no ZONE_MOVABLE */
>>> -	if (!required_kernelcore)
>>> +	/*
>>> +	 * If kernelcore was not specified or kernelcore size is larger
>>> +	 * than totalpages, there is no ZONE_MOVABLE.
>>> +	 */
>>> +	if (!required_kernelcore || required_kernelcore >= totalpages)
>>>   		goto out;
>>>   
>>>   	/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
>>> -- 
>>> 2.0.0
>>>
>>>
>>> --
>>> To unsubscribe, send a message with 'unsubscribe linux-mm' in
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>>> see: http://www.linux-mm.org/ .
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>> .
>>
>
>
> .
>

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Re: [PATCH] mm: skip if required_kernelcore is larger than totalpages

[Xishi Qiu]

On 2015/10/14 10:50, Tang Chen wrote:

> Hi, Qiu
> 
> The patch seems OK to me. Only one little concern below.
> 
> On 10/12/2015 09:37 AM, Xishi Qiu wrote:
>> On 2015/10/9 23:41, Yasuaki Ishimatsu wrote:
>>
>>> On Thu, 8 Oct 2015 10:21:05 +0800
>>> Xishi Qiu <qiuxishi@huawei.com> wrote:
>>>
>>>> If kernelcore was not specified, or the kernelcore size is zero
>>>> (required_movablecore >= totalpages), or the kernelcore size is larger
>>> Why does required_movablecore become larger than totalpages, when the
>>> kernelcore size is zero? I read the code but I could not find that you
>>> mention.
>>>
>> If user only set boot option movablecore, and the value is larger than
>> totalpages, the calculation of kernelcore is zero, but we can't fill
>> the zone only with kernelcore, so skip it.
>>
>> I have send a patch before this patch.
>> "fix overflow in find_zone_movable_pfns_for_nodes()"
>>         ...
>>           required_movablecore =
>>               roundup(required_movablecore, MAX_ORDER_NR_PAGES);
>> +        required_movablecore = min(totalpages, required_movablecore);
>>           corepages = totalpages - required_movablecore;
>>         ...
> 
> 
> So if required_movablecore >= totalpages, there won't be any ZONE_MOVABLE.
> How about add a warning or debug info to tell the user he has specified a
> too large movablecore, and it is ignored ?
> 
> Thanks.

Yes, but I don't think is is necessary, user should know the total memory
before he set the boot option.

Thanks,
Xishi Qiu

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Re: [PATCH] mm: skip if required_kernelcore is larger than totalpages

[Tang Chen]

On 10/14/2015 11:28 AM, Xishi Qiu wrote:
> On 2015/10/14 10:50, Tang Chen wrote:
>
>> Hi, Qiu
>>
>> The patch seems OK to me. Only one little concern below.
>>
>> On 10/12/2015 09:37 AM, Xishi Qiu wrote:
>>> On 2015/10/9 23:41, Yasuaki Ishimatsu wrote:
>>>
>>>> On Thu, 8 Oct 2015 10:21:05 +0800
>>>> Xishi Qiu <qiuxishi@huawei.com> wrote:
>>>>
>>>>> If kernelcore was not specified, or the kernelcore size is zero
>>>>> (required_movablecore >= totalpages), or the kernelcore size is larger
>>>> Why does required_movablecore become larger than totalpages, when the
>>>> kernelcore size is zero? I read the code but I could not find that you
>>>> mention.
>>>>
>>> If user only set boot option movablecore, and the value is larger than
>>> totalpages, the calculation of kernelcore is zero, but we can't fill
>>> the zone only with kernelcore, so skip it.
>>>
>>> I have send a patch before this patch.
>>> "fix overflow in find_zone_movable_pfns_for_nodes()"
>>>          ...
>>>            required_movablecore =
>>>                roundup(required_movablecore, MAX_ORDER_NR_PAGES);
>>> +        required_movablecore = min(totalpages, required_movablecore);
>>>            corepages = totalpages - required_movablecore;
>>>          ...
>>
>> So if required_movablecore >= totalpages, there won't be any ZONE_MOVABLE.
>> How about add a warning or debug info to tell the user he has specified a
>> too large movablecore, and it is ignored ?
>>
>> Thanks.
> Yes, but I don't think is is necessary, user should know the total memory
> before he set the boot option.

Well, I'm just thinking if I set a too large movablecore, but I didn't 
realize it.
And when the system boots up, there is no ZONE_MOVABLE. It may confuse me.

Thanks.

>
> Thanks,
> Xishi Qiu
>
> .
>

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Re: [PATCH] mm: skip if required_kernelcore is larger than totalpages

[Yasuaki Ishimatsu]

On Mon, 12 Oct 2015 09:37:17 +0800
Xishi Qiu <qiuxishi@huawei.com> wrote:

> On 2015/10/9 23:41, Yasuaki Ishimatsu wrote:
> 
> > 
> > On Thu, 8 Oct 2015 10:21:05 +0800
> > Xishi Qiu <qiuxishi@huawei.com> wrote:
> > 
> >> If kernelcore was not specified, or the kernelcore size is zero
> >> (required_movablecore >= totalpages), or the kernelcore size is larger
> > 
> > Why does required_movablecore become larger than totalpages, when the
> > kernelcore size is zero? I read the code but I could not find that you
> > mention.
> > 
> 
> If user only set boot option movablecore, and the value is larger than
> totalpages, the calculation of kernelcore is zero, but we can't fill
> the zone only with kernelcore, so skip it.

Thank you for the explantion. Your patch looks good to me.

Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

Thanks,
Yasuaki Ishimatsu

> 
> I have send a patch before this patch.
> "fix overflow in find_zone_movable_pfns_for_nodes()"
> 		...
>  		required_movablecore =
>  			roundup(required_movablecore, MAX_ORDER_NR_PAGES);
> +		required_movablecore = min(totalpages, required_movablecore);
>  		corepages = totalpages - required_movablecore;
> 		...
> 
> Thanks,
> Xishi Qiu
> 
> > Thanks,
> > Yasuaki Ishimatsu
> > 
> >> than totalpages, there is no ZONE_MOVABLE. We should fill the zone
> >> with both kernel memory and movable memory.
> >>
> >> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
> >> ---
> >>  mm/page_alloc.c | 7 +++++--
> >>  1 file changed, 5 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> >> index af3c9bd..6a6da0d 100644
> >> --- a/mm/page_alloc.c
> >> +++ b/mm/page_alloc.c
> >> @@ -5674,8 +5674,11 @@ static void __init find_zone_movable_pfns_for_nodes(void)
> >>  		required_kernelcore = max(required_kernelcore, corepages);
> >>  	}
> >>  
> >> -	/* If kernelcore was not specified, there is no ZONE_MOVABLE */
> >> -	if (!required_kernelcore)
> >> +	/*
> >> +	 * If kernelcore was not specified or kernelcore size is larger
> >> +	 * than totalpages, there is no ZONE_MOVABLE.
> >> +	 */
> >> +	if (!required_kernelcore || required_kernelcore >= totalpages)
> >>  		goto out;
> >>  
> >>  	/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
> >> -- 
> >> 2.0.0
> >>
> >>
> >> --
> >> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> >> the body to majordomo@kvack.org.  For more info on Linux MM,
> >> see: http://www.linux-mm.org/ .
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> > 
> > .
> > 
> 
> 
> 

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