From: Nitin Gupta <nitin.m.gupta@xxxxxxxxxx>
Date: Thu, 30 Mar 2017 20:12:03 -0700
> On 3/30/17 7:57 PM, David Miller wrote:
>> From: Nitin Gupta <nitin.m.gupta@xxxxxxxxxx>
>> Date: Thu, 30 Mar 2017 17:42:51 -0700
>>
>>> diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
>>> index 0a04811..bedf08b 100644
>>> --- a/arch/sparc/mm/tsb.c
>>> +++ b/arch/sparc/mm/tsb.c
>>> @@ -122,7 +122,7 @@ void flush_tsb_user(struct tlb_batch *tb)
>>>
>>> spin_lock_irqsave(&mm->context.lock, flags);
>>>
>>> - if (tb->hugepage_shift < HPAGE_SHIFT) {
>>> + if (tb->hugepage_shift < REAL_HPAGE_SHIFT) {
>>> base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
>>> nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
>>> if (tlb_type == cheetah_plus || tlb_type == hypervisor)
>>> @@ -155,7 +155,7 @@ void flush_tsb_user_page(struct mm_struct *mm,
>>> unsigned long vaddr,
>>>
>>> spin_lock_irqsave(&mm->context.lock, flags);
>>>
>>> - if (hugepage_shift < HPAGE_SHIFT) {
>>> + if (hugepage_shift < REAL_HPAGE_SHIFT) {
>>> base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
>>> nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
>>> if (tlb_type == cheetah_plus || tlb_type == hypervisor)
>>> --
>>
>> I think if we do it like this, it will only flush one half of the huge
>> page.
>>
>
> Flushing only half the 8M page is the intended behavior: after the
> initial allocation of 8M hugepage, the page is handled exactly as if two
> independent 4M hugepages were allocated (that happen to be physically
> contiguous). So, for each 4M chunk, flushing from TLB and TSB is done
> independently. For instance, in set_huge_pte_at() we added special case
> for (size == HPAGE_SIZE) to flush the "second half" of 8M page.
> Similarly in huge_ptep_get_and_clear() and in set_pmd_at().
Indeed, the set_pmd_at() code path does the same thing.
Ok so your patch is more correct.
Please submit it formally with a proper commit log message and
signoff, thanks!
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