From: Linus Torvalds <torvalds@linux-foundation.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Nick Piggin <npiggin@gmail.com>, Linux-MM <linux-mm@kvack.org>,
Kalesh Singh <kaleshsingh@google.com>,
Joel Fernandes <joel@joelfernandes.org>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH 5/6] mm/mremap: Use pmd/pud_poplulate to update page table entries
Date: Sun, 13 Jun 2021 11:53:20 -0700 [thread overview]
Message-ID: <CAHk-=wj+VM6meE26x+UegDdL_F3daMB_7HzA+16D10KYsBJwAQ@mail.gmail.com> (raw)
In-Reply-To: <87wnqy9lru.fsf@linux.ibm.com>
On Sun, Jun 13, 2021 at 2:06 AM Aneesh Kumar K.V
<aneesh.kumar@linux.ibm.com> wrote:
>
> IIUC the reason why we do have pmd_pgtable() is that pgtable_t type
> is arch dependent. On some architecture it is pte_t * and on the other
> struct page *. The reason being highmem and level 4 page table can
> be located in highmem.
Honestly, the same confusion is real - in a different way - about
pud_page_vaddr().
I really hate that function.
Just grep for the uses, and the definitions, to see what I mean. It's crazy.
I'm perfectly happy not having a "pud_pagetable()" function, but that
cast on pud_page_vaddr() is indicative of real problems.
One solution might be to just say "pud_page_vaddr()" must return a "pmd_t *".
I think it's what all the users actually want anyway.
Linus
next prev parent reply other threads:[~2021-06-13 18:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-10 8:35 [PATCH 0/6] mremap fixes Aneesh Kumar K.V
2021-06-10 8:35 ` [PATCH 1/6] selftest/mremap_test: Update the test to handle pagesize other than 4K Aneesh Kumar K.V
2021-06-10 8:35 ` [PATCH 2/6] selftest/mremap_test: Avoid crash with static build Aneesh Kumar K.V
2021-06-10 8:35 ` [PATCH 3/6] mm/mremap: Convert huge PUD move to separate helper Aneesh Kumar K.V
2021-06-10 22:03 ` Hugh Dickins
2021-06-10 8:35 ` [PATCH 4/6] mm/mremap: Don't enable optimized PUD move if page table levels is 2 Aneesh Kumar K.V
2021-06-10 8:35 ` [PATCH 5/6] mm/mremap: Use pmd/pud_poplulate to update page table entries Aneesh Kumar K.V
[not found] ` <CAHk-=wi+J+iodze9FtjM3Zi4j4OeS+qqbKxME9QN4roxPEXH9Q@mail.gmail.com>
2021-06-13 9:06 ` Aneesh Kumar K.V
2021-06-13 10:50 ` Matthew Wilcox
2021-06-13 11:13 ` Aneesh Kumar K.V
2021-06-14 5:27 ` Christophe Leroy
2021-06-13 18:53 ` Linus Torvalds [this message]
2021-06-10 8:35 ` [PATCH 6/6] mm/mremap: hold the rmap lock in write mode when moving " Aneesh Kumar K.V
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