Re: [RFC PATCH 06/14] sparc64: general shared context tsb creation and support

From	Mike Kravetz <mike.kravetz@oracle.com>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 06/14] sparc64: general shared context tsb creation and support
Date	2016-12-19 02:00 +0100
Message-ID	<sPUt4-Gv-7@gated-at.bofh.it> (permalink)
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On 12/16/2016 11:53 PM, Sam Ravnborg wrote:
> Hi Mike
> 
>> --- a/arch/sparc/mm/hugetlbpage.c
>> +++ b/arch/sparc/mm/hugetlbpage.c
>> @@ -162,8 +162,14 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
>>  {
>>  	pte_t orig;
>>  
>> -	if (!pte_present(*ptep) && pte_present(entry))
>> -		mm->context.hugetlb_pte_count++;
>> +	if (!pte_present(*ptep) && pte_present(entry)) {
>> +#if defined(CONFIG_SHARED_MMU_CTX)
>> +		if (pte_val(entry) | _PAGE_SHR_CTX_4V)
>> +			mm->context.shared_hugetlb_pte_count++;
>> +		else
>> +#endif
>> +			mm->context.hugetlb_pte_count++;
>> +	}
> 
> This kind of conditional code it just too ugly to survive...
> Could a static inline be used to help you here?
> The compiler will inline it so there should not be any run-time cost

Yes, this can be cleaned up in that way.

> 
>>  
>>  	mm_rss -= saved_thp_pte_count * (HPAGE_SIZE / PAGE_SIZE);
>>  #endif
>> @@ -544,8 +576,10 @@ int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
>>  	 * us, so we need to zero out the TSB pointer or else tsb_grow()
>>  	 * will be confused and think there is an older TSB to free up.
>>  	 */
>> -	for (i = 0; i < MM_NUM_TSBS; i++)
>> +	for (i = 0; i < MM_NUM_TSBS; i++) {
>>  		mm->context.tsb_block[i].tsb = NULL;
>> +		mm->context.tsb_descr[i].tsb_base = 0UL;
>> +	}
> This change seems un-related to the rest?

Correct.  I was experimenting with some other ways of managing the tsb_descr
array that got dropped, but forgot to remove this.

-- 
Mike Kravetz

> 
> 	Sam
>

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[RFC PATCH 06/14] sparc64: general shared context tsb creation and support Mike Kravetz <mike.kravetz@oracle.com> - 2016-12-16 19:40 +0100
  Re: [RFC PATCH 06/14] sparc64: general shared context tsb creation  and support Sam Ravnborg <sam@ravnborg.org> - 2016-12-17 09:00 +0100
    Re: [RFC PATCH 06/14] sparc64: general shared context tsb creation  and support Mike Kravetz <mike.kravetz@oracle.com> - 2016-12-19 02:00 +0100

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