From: "Aneesh Kumar K.V" <firstname.lastname@example.org> To: Matthew Wilcox <email@example.com> Cc: linuxppc-dev <firstname.lastname@example.org>, Nick Piggin <email@example.com>, Linux-MM <firstname.lastname@example.org>, Kalesh Singh <email@example.com>, Joel Fernandes <firstname.lastname@example.org>, "Kirill A . Shutemov" <email@example.com>, Andrew Morton <firstname.lastname@example.org>, Linus Torvalds <email@example.com> Subject: Re: [PATCH 5/6] mm/mremap: Use pmd/pud_poplulate to update page table entries Date: Sun, 13 Jun 2021 16:43:50 +0530 [thread overview] Message-ID: <firstname.lastname@example.org> (raw) In-Reply-To: <YMXi6AZm4fPpPKrH@casper.infradead.org> On 6/13/21 4:20 PM, Matthew Wilcox wrote: > On Sun, Jun 13, 2021 at 02:36:13PM +0530, Aneesh Kumar K.V 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. > > That is ahistorical. See 2f569afd9ced9ebec9a6eb3dbf6f83429be0a7b4 -- > we have pgtable_t for the benefit of s390's crazy sub-page page table > sizes. That is also true with ppc64. We do sub-page page table size. I was trying to explain why it can't be pte_t * everywhere and why we have it as struct page *. > > Also, please stop numbering page tables upside down. PTEs are first > level, not fourth. > POWER ISA do name it the other way. I also see some pages explaining levels the other way https://www.bottomupcs.com/virtual_memory_linux.xhtml whereas https://en.wikipedia.org/wiki/Intel_5-level_paging#/media/File:Page_Tables_(5_levels).svg I am pretty sure I had commits that explained page table level as I did in this thread. I will switch to your suggestion in further discussions. May be the best solution is to attribute it with more details like level 1 (pte_t *)? -aneesh
next prev parent reply other threads:[~2021-06-13 11:16 UTC|newest] Thread overview: 15+ 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 2021-06-10 18:16 ` Linus Torvalds 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 [this message] 2021-06-14 5:27 ` Christophe Leroy 2021-06-13 18:53 ` Linus Torvalds 2021-06-10 8:35 ` [PATCH 6/6] mm/mremap: hold the rmap lock in write mode when moving " Aneesh Kumar K.V 2021-06-11 8:11 ` Jann Horn
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ --subject='Re: [PATCH 5/6] mm/mremap: Use pmd/pud_poplulate to update page table entries' \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).