From: Ankur Arora <ankur.a.arora@oracle.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ankur Arora <ankur.a.arora@oracle.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
the arch/x86 maintainers <x86@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Ingo Molnar <mingo@kernel.org>,
Andrew Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Andi Kleen <ak@linux.intel.com>, Arnd Bergmann <arnd@arndb.de>,
Jason Gunthorpe <jgg@nvidia.com>,
jon.grimm@amd.com, Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Joao Martins <joao.m.martins@oracle.com>
Subject: Re: [PATCH v3 00/21] huge page clearing optimizations
Date: Thu, 09 Jun 2022 01:51:45 +0530 [thread overview]
Message-ID: <87zgimsy7a.fsf@oracle.com> (raw)
In-Reply-To: <CAHk-=wgGjmCwyrs4Druy26rUddoWj29PjAKRZD=q0pzfVNioDg@mail.gmail.com>
Linus Torvalds <torvalds@linux-foundation.org> writes:
> On Wed, Jun 8, 2022 at 12:25 PM Ankur Arora <ankur.a.arora@oracle.com> wrote:
>>
>> But, even on x86, AFAICT gigantic pages could straddle MAX_SECTION_BITS?
>> An arch specific clear_huge_page() code could, however handle 1GB pages
>> via some kind of static loop around (30 - MAX_SECTION_BITS).
>
> Even if gigantic pages straddle that area, it simply shouldn't matter.
>
> The only reason that MAX_SECTION_BITS matters is for the 'struct page *' lookup.
>
> And the only reason for *that* is because of HIGHMEM.
>
> So it's all entirely silly and pointless on any sane architecture, I think.
>
>> We'll need a preemption point there for CONFIG_PREEMPT_VOLUNTARY
>> as well, right?
>
> Ahh, yes. I should have looked at the code, and not just gone by my
> "PREEMPT_NONE vs PREEMPT" thing that entirely forgot about how we
> split that up.
>
>> Just one minor point -- seems to me that the choice of nontemporal or
>> temporal might have to be based on a hint to clear_huge_page().
>
> Quite possibly. But I'd prefer that as a separate "look, this
> improves numbers by X%" thing from the whole "let's make the
> clear_huge_page() interface at least sane".
Makes sense to me.
--
ankur
next prev parent reply other threads:[~2022-06-08 20:22 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-06 20:20 [PATCH v3 00/21] huge page clearing optimizations Ankur Arora
2022-06-06 20:20 ` [PATCH v3 01/21] mm, huge-page: reorder arguments to process_huge_page() Ankur Arora
2022-06-06 20:20 ` [PATCH v3 02/21] mm, huge-page: refactor process_subpage() Ankur Arora
2022-06-06 20:20 ` [PATCH v3 03/21] clear_page: add generic clear_user_pages() Ankur Arora
2022-06-06 20:20 ` [PATCH v3 04/21] mm, clear_huge_page: support clear_user_pages() Ankur Arora
2022-06-06 20:37 ` [PATCH v3 05/21] mm/huge_page: generalize process_huge_page() Ankur Arora
2022-06-06 20:37 ` [PATCH v3 06/21] x86/clear_page: add clear_pages() Ankur Arora
2022-06-06 20:37 ` [PATCH v3 07/21] x86/asm: add memset_movnti() Ankur Arora
2022-06-06 20:37 ` [PATCH v3 08/21] perf bench: " Ankur Arora
2022-06-06 20:37 ` [PATCH v3 09/21] x86/asm: add clear_pages_movnt() Ankur Arora
2022-06-10 22:11 ` Noah Goldstein
2022-06-10 22:15 ` Noah Goldstein
2022-06-12 11:18 ` Ankur Arora
2022-06-06 20:37 ` [PATCH v3 10/21] x86/asm: add clear_pages_clzero() Ankur Arora
2022-06-06 20:37 ` [PATCH v3 11/21] x86/cpuid: add X86_FEATURE_MOVNT_SLOW Ankur Arora
2022-06-06 20:37 ` [PATCH v3 12/21] sparse: add address_space __incoherent Ankur Arora
2022-06-06 20:37 ` [PATCH v3 13/21] clear_page: add generic clear_user_pages_incoherent() Ankur Arora
2022-06-08 0:01 ` Luc Van Oostenryck
2022-06-12 11:19 ` Ankur Arora
2022-06-06 20:37 ` [PATCH v3 14/21] x86/clear_page: add clear_pages_incoherent() Ankur Arora
2022-06-06 20:37 ` [PATCH v3 15/21] mm/clear_page: add clear_page_non_caching_threshold() Ankur Arora
2022-06-06 20:37 ` [PATCH v3 16/21] x86/clear_page: add arch_clear_page_non_caching_threshold() Ankur Arora
2022-06-06 20:37 ` [PATCH v3 17/21] clear_huge_page: use non-cached clearing Ankur Arora
2022-06-06 20:37 ` [PATCH v3 18/21] gup: add FOLL_HINT_BULK, FAULT_FLAG_NON_CACHING Ankur Arora
2022-06-06 20:37 ` [PATCH v3 19/21] gup: hint non-caching if clearing large regions Ankur Arora
2022-06-06 20:37 ` [PATCH v3 20/21] vfio_iommu_type1: specify FOLL_HINT_BULK to pin_user_pages() Ankur Arora
2022-06-06 20:37 ` [PATCH v3 21/21] x86/cpu/intel: set X86_FEATURE_MOVNT_SLOW for Skylake Ankur Arora
2022-06-06 21:53 ` [PATCH v3 00/21] huge page clearing optimizations Linus Torvalds
2022-06-07 15:08 ` Ankur Arora
2022-06-07 17:56 ` Linus Torvalds
2022-06-08 19:24 ` Ankur Arora
2022-06-08 19:39 ` Linus Torvalds
2022-06-08 20:21 ` Ankur Arora [this message]
2022-06-08 19:49 ` Matthew Wilcox
2022-06-08 19:51 ` Matthew Wilcox
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