linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Vineet Gupta <vgupta@kernel.org>
To: Mike Rapoport <rppt@kernel.org>
Cc: linux-snps-arc@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, Anshuman Khandual <anshuman.khandual@arm.com>
Subject: Re: [PATCH 09/18] ARC: mm: non-functional code cleanup ahead of 3 levels
Date: Wed, 11 Aug 2021 18:37:19 -0700	[thread overview]
Message-ID: <7d022d55-c70b-b3ac-4f0b-1faa26c0d4bd@kernel.org> (raw)
In-Reply-To: <YRPDL90Qr5RLDmnT@kernel.org>

On 8/11/21 5:31 AM, Mike Rapoport wrote:
>> +/*
>> + * For ARC, pgtable_t is not struct page *, but pte_t * (to avoid
>> + * extraneous page_address() calculations) hence can't use
>> + * use asm-generic/pgalloc.h which assumes it being struct page *
>> + */
> Another reason to leave ARC without asm-generic/pgalloc.h was
> __get_order_pte() that other arches don't have.
> So this and pgtable_t aliased to pte_t * seemed to me too much to bother
> then, but probably it's worth reconsidering with addition of 3rd and 4th
> levels.

I agree that savings of not havign page_address() might not be huge. 
However asm-generic/pgalloc.h only has pte allocation routines and all 
other allocation levels come from arch file

Also for ARCv2, given the arbitrary address split and ensuing paging 
levels (as well as support for different page sizes) we will need to 
make sure that one page is enough to hold any level's paging using say 
BUILD_BUG_ON. In fact that should also be done for 3rd and 4th levels 
for sanity.

-Vineet



  reply	other threads:[~2021-08-12  1:37 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-11  0:42 [PATCH 00/18] ARC mm updates to support 3 or 4 levels of paging Vineet Gupta
2021-08-11  0:42 ` [PATCH 01/18] ARC: mm: simplify mmu scratch register assingment to mmu needs Vineet Gupta
2021-08-11  0:42 ` [PATCH 02/18] ARC: mm: remove tlb paranoid code Vineet Gupta
2021-08-11  0:42 ` [PATCH 03/18] ARC: mm: move mmu/cache externs out to setup.h Vineet Gupta
2021-08-11  5:10   ` Mike Rapoport
2021-08-11 18:46     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 04/18] ARC: mm: remove pgd_offset_fast Vineet Gupta
2021-08-11  5:12   ` Mike Rapoport
2021-08-11 18:54     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 05/18] ARC: mm: Fixes to allow STRICT_MM_TYPECHECKS Vineet Gupta
2021-08-11  0:42 ` [PATCH 06/18] ARC: mm: Enable STRICT_MM_TYPECHECKS Vineet Gupta
2021-08-11 12:04   ` Mike Rapoport
2021-08-11 19:01     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 07/18] ARC: ioremap: use more commonly used PAGE_KERNEL based uncached flag Vineet Gupta
2021-08-11  5:18   ` Mike Rapoport
2021-08-11 18:58     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 08/18] ARC: mm: pmd_populate* to use the canonical set_pmd (and drop pmd_set) Vineet Gupta
2021-08-11  0:42 ` [PATCH 09/18] ARC: mm: non-functional code cleanup ahead of 3 levels Vineet Gupta
2021-08-11 12:31   ` Mike Rapoport
2021-08-12  1:37     ` Vineet Gupta [this message]
2021-08-12  6:18       ` Mike Rapoport
2021-08-12 18:58         ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 10/18] ARC: mm: move MMU specific bits out of ASID allocator Vineet Gupta
2021-08-11  0:42 ` [PATCH 11/18] ARC: mm: move MMU specific bits out of entry code Vineet Gupta
2021-08-11 12:15   ` Mike Rapoport
2021-08-11 19:30     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 12/18] ARC: mm: disintegrate mmu.h (arcv2 bits out) Vineet Gupta
2021-08-11  0:42 ` [PATCH 13/18] ARC: mm: disintegrate pgtable.h into levels and flags Vineet Gupta
2021-08-11  0:42 ` [PATCH 14/18] ARC: mm: hack to allow 2 level build with 4 level code Vineet Gupta
2021-08-11  0:42 ` [PATCH 15/18] ARC: mm: support 3 levels of page tables Vineet Gupta
2021-08-11 12:24   ` Mike Rapoport
2021-08-11 22:15     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 16/18] ARC: mm: support 4 " Vineet Gupta
2021-08-11 12:28   ` Mike Rapoport
2021-08-11 22:17     ` Vineet Gupta
2021-08-11  0:42 ` [PATCH 17/18] ARC: mm: vmalloc sync from kernel to user table to update PMD Vineet Gupta
2021-08-11  0:42 ` [PATCH 18/18] ARC: mm: introduce _PAGE_TABLE to explicitly link pgd,pud,pmd entries Vineet Gupta

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 \
    --in-reply-to=7d022d55-c70b-b3ac-4f0b-1faa26c0d4bd@kernel.org \
    --to=vgupta@kernel.org \
    --cc=anshuman.khandual@arm.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-snps-arc@lists.infradead.org \
    --cc=rppt@kernel.org \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
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).