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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Peter Xu <peterx@redhat.com>
Cc: Nathan Chancellor <nathan@kernel.org>,
	linux-mm@kvack.org, akpm@linux-foundation.org,
	mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org,
	kaleshsingh@google.com, npiggin@gmail.com,
	joel@joelfernandes.org,
	Christophe Leroy <christophe.leroy@csgroup.eu>
Subject: Re: [PATCH v5 3/9] mm/mremap: Use pmd/pud_poplulate to update page table entries
Date: Thu, 20 May 2021 18:53:01 +0530	[thread overview]
Message-ID: <e6525655-2e51-a0c0-fe54-596cfae9ce21@linux.ibm.com> (raw)
In-Reply-To: <YKZaLHurH9nJWvbj@t490s>

On 5/20/21 6:16 PM, Peter Xu wrote:
> On Thu, May 20, 2021 at 01:56:54PM +0530, Aneesh Kumar K.V wrote:
>>> This seems to work at least for my userfaultfd test on shmem, however I don't
>>> fully understand the commit message [1] on: How do we guarantee we're not
>>> moving a thp pte?
>>>
>>
>> move_page_tables() checks for pmd_trans_huge() and ends up calling
>> move_huge_pmd if it is a THP entry.
> 
> Sorry to be unclear: what if a huge pud thp?
> 

I am still checking. Looking at the code before commit 
c49dd340180260c6239e453263a9a244da9a7c85, I don't see kernel handling 
huge pud thp. I haven't studied huge pud thp enough to understand 
whether c49dd340180260c6239e453263a9a244da9a7c85 intent to add that 
support.

We can do a move_huge_pud() like we do for huge pmd thp. But I am not 
sure whether we handle those VMA's earlier and restrict mremap on them?

Are huge pud thp only allowed with DAX vmas?


-aneesh


  reply	other threads:[~2021-05-20 13:23 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-22  5:43 [PATCH v5 0/9] Speedup mremap on ppc64 Aneesh Kumar K.V
2021-04-22  5:43 ` [PATCH v5 1/9] selftest/mremap_test: Update the test to handle pagesize other than 4K Aneesh Kumar K.V
2021-04-22  5:43 ` [PATCH v5 2/9] selftest/mremap_test: Avoid crash with static build Aneesh Kumar K.V
2021-04-22  5:43 ` [PATCH v5 3/9] mm/mremap: Use pmd/pud_poplulate to update page table entries Aneesh Kumar K.V
2021-05-18 20:04   ` Nathan Chancellor
2021-05-19  4:46     ` Aneesh Kumar K.V
2021-05-19 18:02       ` Nathan Chancellor
2021-05-20  2:18       ` Peter Xu
2021-05-20  8:26         ` Aneesh Kumar K.V
2021-05-20 12:46           ` Peter Xu
2021-05-20 13:23             ` Aneesh Kumar K.V [this message]
2021-05-20 13:37               ` Aneesh Kumar K.V
2021-05-20 14:57                 ` Peter Xu
2021-05-20 19:06                   ` Zi Yan
2021-05-20 20:01                     ` Peter Xu
2021-05-20 20:25                       ` Kalesh Singh
2021-04-22  5:43 ` [PATCH v5 4/9] powerpc/mm/book3s64: Fix possible build error Aneesh Kumar K.V
2021-04-22  5:43 ` [PATCH v5 5/9] powerpc/mm/book3s64: Update tlb flush routines to take a page walk cache flush argument Aneesh Kumar K.V
2021-05-15 16:35   ` Guenter Roeck
2021-05-15 20:41     ` Andrew Morton
2021-05-15 23:05       ` Guenter Roeck
2021-05-17  8:40     ` Aneesh Kumar K.V
2021-05-17 13:38       ` Guenter Roeck
2021-05-17 13:55         ` Aneesh Kumar K.V
2021-05-17 14:18           ` Guenter Roeck
2021-05-19  0:26             ` Michael Ellerman
2021-05-19  0:45               ` Segher Boessenkool
2021-05-19 12:03                 ` Segher Boessenkool
2021-05-19 13:37                   ` Guenter Roeck
2021-05-19 14:20                     ` Segher Boessenkool
2021-05-19 15:28                       ` Guenter Roeck
2021-05-20  7:37                   ` Michael Ellerman
2021-05-20 12:17                     ` Segher Boessenkool
2021-05-19  1:08               ` Guenter Roeck
2021-05-20 11:38                 ` Michael Ellerman
2021-05-20 11:56                   ` Guenter Roeck
2021-04-22  5:43 ` [PATCH v5 6/9] mm/mremap: Use range flush that does TLB and page walk cache flush Aneesh Kumar K.V
2021-04-22  5:43 ` [PATCH v5 7/9] mm/mremap: Move TLB flush outside page table lock Aneesh Kumar K.V
2021-05-20 15:26   ` Aneesh Kumar K.V
2021-05-20 16:57     ` Aneesh Kumar K.V
2021-05-21  2:40       ` Linus Torvalds
2021-05-21  3:03         ` Aneesh Kumar K.V
2021-05-21  3:28           ` Aneesh Kumar K.V
2021-05-21  6:13           ` Linus Torvalds
2021-05-21 12:50             ` Aneesh Kumar K.V
2021-05-21 13:03               ` Aneesh Kumar K.V
2021-05-21 16:03                 ` Linus Torvalds
2021-05-21 16:29                   ` Aneesh Kumar K.V
2021-05-24 14:24                   ` Aneesh Kumar K.V
2021-05-21 15:24               ` Liam Howlett
2021-05-21 16:02                 ` Aneesh Kumar K.V
2021-05-21 16:05                 ` Linus Torvalds
2021-04-22  5:43 ` [PATCH v5 8/9] mm/mremap: Allow arch runtime override Aneesh Kumar K.V
2021-04-22  5:43 ` [PATCH v5 9/9] powerpc/mm: Enable move pmd/pud Aneesh Kumar K.V
2021-05-11 22:19   ` Andrew Morton

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