From: Borislav Petkov <bp@alien8.de>
To: Ankur Arora <ankur.a.arora@oracle.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
Andy Lutomirski <luto@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Michal Hocko <mhocko@kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, X86 ML <x86@kernel.org>,
"H. Peter Anvin" <hpa@zytor.com>, Arnd Bergmann <arnd@arndb.de>,
Andrew Morton <akpm@linux-foundation.org>,
Ira Weiny <ira.weiny@intel.com>,
linux-arch <linux-arch@vger.kernel.org>
Subject: Re: [PATCH 5/8] x86/clear_page: add clear_page_uncached()
Date: Fri, 16 Oct 2020 20:21:40 +0200 [thread overview]
Message-ID: <20201016182140.GJ8483@zn.tnic> (raw)
In-Reply-To: <593f3b75-678c-1cd4-a7f0-55257dc84caf@oracle.com>
On Thu, Oct 15, 2020 at 02:20:36PM -0700, Ankur Arora wrote:
> The case I was thinking of was that clear_huge_page()
That loop in clear_gigantic_page() there could be optimized not to
iterate over the pages but do a NTA moves in one go, provided they're
contiguous.
> or faultin_page() would
faultin_page() goes into the bowels of mm fault handling, you'd have to
be more precise what exactly you mean with that one.
> know the size to a page unit, while the higher level function would know the
> whole extent and could optimize differently based on that.
Just don't forget that this "optimization" of yours comes at the price
of added code complexity and you're putting the onus on the people to
know which function to call. So it is not for free and needs to be
carefully weighed.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-10-16 18:21 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-14 8:32 [PATCH 0/8] Use uncached writes while clearing gigantic pages Ankur Arora
2020-10-14 8:32 ` [PATCH 1/8] x86/cpuid: add X86_FEATURE_NT_GOOD Ankur Arora
2020-10-14 8:32 ` [PATCH 2/8] x86/asm: add memset_movnti() Ankur Arora
2020-10-14 8:32 ` [PATCH 3/8] perf bench: " Ankur Arora
2020-10-14 8:32 ` [PATCH 4/8] x86/asm: add clear_page_nt() Ankur Arora
2020-10-14 19:56 ` Borislav Petkov
2020-10-14 21:11 ` Ankur Arora
2020-10-14 8:32 ` [PATCH 5/8] x86/clear_page: add clear_page_uncached() Ankur Arora
2020-10-14 11:10 ` kernel test robot
2020-10-14 13:04 ` kernel test robot
2020-10-14 15:45 ` Andy Lutomirski
2020-10-14 19:58 ` Borislav Petkov
2020-10-14 21:07 ` Andy Lutomirski
2020-10-14 21:12 ` Borislav Petkov
2020-10-15 3:37 ` Ankur Arora
2020-10-15 10:35 ` Borislav Petkov
2020-10-15 21:20 ` Ankur Arora
2020-10-16 18:21 ` Borislav Petkov [this message]
2020-10-15 3:21 ` Ankur Arora
2020-10-15 10:40 ` Borislav Petkov
2020-10-15 21:40 ` Ankur Arora
2020-10-14 20:54 ` Ankur Arora
2020-10-14 8:32 ` [PATCH 6/8] mm, clear_huge_page: use clear_page_uncached() for gigantic pages Ankur Arora
2020-10-14 15:28 ` Ingo Molnar
2020-10-14 19:15 ` Ankur Arora
2020-10-14 8:32 ` [PATCH 7/8] x86/cpu/intel: enable X86_FEATURE_NT_GOOD on Intel Broadwellx Ankur Arora
2020-10-14 15:31 ` Ingo Molnar
2020-10-14 19:23 ` Ankur Arora
2020-10-14 8:32 ` [PATCH 8/8] x86/cpu/amd: enable X86_FEATURE_NT_GOOD on AMD Zen Ankur Arora
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