linux-kernel - Re: [PATCH 1/4] mm/hugetlb: Enable PUD level huge page migration

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Message-ID: <a6b96126-5571-2aa2-6deb-09a457afd781@arm.com>
Date:   Wed, 3 Oct 2018 11:22:59 +0100
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Anshuman Khandual <anshuman.khandual@....com>, linux-mm@...ck.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     punit.agrawal@....com, will.deacon@....com, Steven.Price@....com,
        catalin.marinas@....com, mhocko@...nel.org,
        mike.kravetz@...cle.com, n-horiguchi@...jp.nec.com
Subject: Re: [PATCH 1/4] mm/hugetlb: Enable PUD level huge page migration



On 02/10/18 13:56, Anshuman Khandual wrote:
> 
> 
> On 10/02/2018 06:08 PM, Suzuki K Poulose wrote:
>> Hi Anshuman
>>
>> On 02/10/18 13:15, Anshuman Khandual wrote:
>>> Architectures like arm64 have PUD level HugeTLB pages for certain configs
>>> (1GB huge page is PUD based on ARM64_4K_PAGES base page size) that can be
>>> enabled for migration. It can be achieved through checking for PUD_SHIFT
>>> order based HugeTLB pages during migration.
>>>
>>> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
>>> ---
>>>    include/linux/hugetlb.h | 3 ++-
>>>    1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
>>> index 6b68e34..9c1b77f 100644
>>> --- a/include/linux/hugetlb.h
>>> +++ b/include/linux/hugetlb.h
>>> @@ -483,7 +483,8 @@ static inline bool hugepage_migration_supported(struct hstate *h)
>>>    {
>>>    #ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
>>>        if ((huge_page_shift(h) == PMD_SHIFT) ||
>>> -        (huge_page_shift(h) == PGDIR_SHIFT))
>>> +        (huge_page_shift(h) == PUD_SHIFT) ||
>>
>>
>>> +            (huge_page_shift(h) == PGDIR_SHIFT))
>>
>> nit: Extra Tab ^^.
> 
> The tab is in there when you apply this patch and all three checks are tab separated
> in a newline.

Well, with the patch applied, at least I can see 2 tabs for the
PUD_SHIFT check and 3 tabs for PGDIR_SHIFT check. Which seems
inconsistent. Is it just me (my mail client) ?

Suzuki