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From: Wei Yang <richardw.yang@linux.intel.com>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Wei Yang <richardw.yang@linux.intel.com>,
	aarcange@redhat.com, hughd@google.com, linux-mm@kvack.org
Subject: Re: [PATCH v2 1/3] userfaultfd: use vma_pagesize for all huge page size calculation
Date: Sat, 5 Oct 2019 08:34:50 +0800	[thread overview]
Message-ID: <20191005003450.GA16122@richard> (raw)
In-Reply-To: <d1415004-3775-6e75-0141-ff3db05f793e@oracle.com>

On Fri, Sep 27, 2019 at 03:21:38PM -0700, Mike Kravetz wrote:
>On 9/27/19 3:10 PM, Andrew Morton wrote:
>> On Fri, 27 Sep 2019 15:00:30 +0800 Wei Yang <richardw.yang@linux.intel.com> wrote:
>> 
>>> In function __mcopy_atomic_hugetlb, we use two variables to deal with
>>> huge page size: vma_hpagesize and huge_page_size.
>>>
>>> Since they are the same, it is not necessary to use two different
>>> mechanism. This patch makes it consistent by all using vma_hpagesize.
>>>
>>> --- a/mm/userfaultfd.c
>>> +++ b/mm/userfaultfd.c
>>> @@ -262,7 +262,7 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
>>>  		pte_t dst_pteval;
>>>  
>>>  		BUG_ON(dst_addr >= dst_start + len);
>>> -		VM_BUG_ON(dst_addr & ~huge_page_mask(h));
>>> +		VM_BUG_ON(dst_addr & (vma_hpagesize - 1));
>>>  
>>>  		/*
>>>  		 * Serialize via hugetlb_fault_mutex
>>> @@ -273,7 +273,7 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
>>>  		mutex_lock(&hugetlb_fault_mutex_table[hash]);
>>>  
>>>  		err = -ENOMEM;
>>> -		dst_pte = huge_pte_alloc(dst_mm, dst_addr, huge_page_size(h));
>>> +		dst_pte = huge_pte_alloc(dst_mm, dst_addr, vma_hpagesize);
>>>  		if (!dst_pte) {
>>>  			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
>>>  			goto out_unlock;
>>> @@ -300,7 +300,8 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
>>>  
>>>  			err = copy_huge_page_from_user(page,
>>>  						(const void __user *)src_addr,
>>> -						pages_per_huge_page(h), true);
>>> +						vma_hpagesize / PAGE_SIZE,
>>> +						true);
>>>  			if (unlikely(err)) {
>>>  				err = -EFAULT;
>>>  				goto out;
>> 
>> Looks right.
>> 
>> We could go ahead and remove local variable `h', given that
>> hugetlb_fault_mutex_hash() doesn't actually use its first arg..
>
>Good catch Andrew.  I missed that, but I also wrote the original code that
>is being cleaned up. :)
>

I did a cleanup to remove the first parameter of function
hugetlb_fault_mutex_hash(). Look forward your comment.

>You can add,
>Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
>to the series.
>-- 
>Mike Kravetz

-- 
Wei Yang
Help you, Help me


  reply	other threads:[~2019-10-05  0:35 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-27  7:00 Wei Yang
2019-09-27  7:00 ` [PATCH v2 2/3] userfaultfd: remove unnecessary warn_on in __mcopy_atomic_hugetlb Wei Yang
2019-09-27  7:00 ` [PATCH v2 3/3] userfaultfd: wrap the common dst_vma check into an inlined function Wei Yang
2019-09-27 22:10 ` [PATCH v2 1/3] userfaultfd: use vma_pagesize for all huge page size calculation Andrew Morton
2019-09-27 22:21   ` Mike Kravetz
2019-10-05  0:34     ` Wei Yang [this message]
2019-09-29  0:45   ` Wei Yang
2019-10-07 22:55     ` Mike Kravetz
2019-10-08  0:57       ` Wei Yang
2019-10-05  0:33   ` [PATCH] hugetlb: remove unused hstate in hugetlb_fault_mutex_hash() Wei Yang
2019-10-05  5:42     ` kbuild test robot
2019-10-05  5:43     ` kbuild test robot
2019-10-06  2:25     ` kbuild test robot

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