From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
x86@kernel.org, Kostya Serebryany <kcc@google.com>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Alexander Potapenko <glider@google.com>,
Taras Madan <tarasmadan@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
"H . J . Lu" <hjl.tools@gmail.com>,
Andi Kleen <ak@linux.intel.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Bharata B Rao <bharata@amd.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Ashok Raj <ashok.raj@intel.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Sami Tolvanen <samitolvanen@google.com>,
ndesaulniers@google.com, joao@overdrivepizza.com
Subject: Re: [PATCHv14 08/17] x86/mm: Reduce untagged_addr() overhead until the first LAM user
Date: Tue, 17 Jan 2023 19:21:18 +0100 [thread overview]
Message-ID: <Y8bnHnLe2a+vzHDd@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAHk-=wiwiA7FdSww9fTg59r5S7G-DZHtzAcq9u5zBJKYXc1agQ@mail.gmail.com>
On Tue, Jan 17, 2023 at 09:18:01AM -0800, Linus Torvalds wrote:
> But maybe even those aren't worth worrying about. At least they do the
> unmasking outside the loop - although then in the case of execve(),
> the string copies themselves are obviously done in a loop anyway.
>
> Kirill, do you have clear numbers for that static key being a noticeable win?
Numbers would be good; I think this all started as a precaution, but
clearly that's not really working out so well :/
next prev parent reply other threads:[~2023-01-17 19:10 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-11 12:37 [PATCHv14 00/17] Linear Address Masking enabling Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 01/17] x86/mm: Rework address range check in get_user() and put_user() Kirill A. Shutemov
2023-01-18 15:49 ` Peter Zijlstra
2023-01-18 15:59 ` Linus Torvalds
2023-01-18 16:48 ` Peter Zijlstra
2023-01-18 17:01 ` Linus Torvalds
2023-01-11 12:37 ` [PATCHv14 02/17] x86: Allow atomic MM_CONTEXT flags setting Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 03/17] x86: CPUID and CR3/CR4 flags for Linear Address Masking Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 04/17] x86/mm: Handle LAM on context switch Kirill A. Shutemov
[not found] ` <CAHk-=whb1_6qwb=BSpj1KkTfJiTiahAnvTBh_=fnGyrnKAW19A@mail.gmail.com>
2023-01-11 14:14 ` Kirill A. Shutemov
2023-01-11 14:37 ` [PATCHv14.1 " Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 05/17] mm: Introduce untagged_addr_remote() Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 06/17] x86/uaccess: Provide untagged_addr() and remove tags before address check Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 07/17] x86/mm: Provide arch_prctl() interface for LAM Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 08/17] x86/mm: Reduce untagged_addr() overhead until the first LAM user Kirill A. Shutemov
2023-01-17 13:05 ` Peter Zijlstra
2023-01-17 13:57 ` Kirill A. Shutemov
2023-01-17 15:02 ` Peter Zijlstra
2023-01-17 17:18 ` Linus Torvalds
2023-01-17 17:28 ` Linus Torvalds
2023-01-17 18:26 ` Nick Desaulniers
2023-01-17 18:33 ` Linus Torvalds
2023-01-17 19:17 ` Nick Desaulniers
2023-01-17 20:10 ` Linus Torvalds
2023-01-17 20:43 ` Linus Torvalds
2023-01-17 18:14 ` Peter Zijlstra
2023-01-17 18:21 ` Peter Zijlstra [this message]
2023-01-19 23:06 ` Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 09/17] mm: Expose untagging mask in /proc/$PID/status Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 10/17] iommu/sva: Replace pasid_valid() helper with mm_valid_pasid() Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 11/17] x86/mm/iommu/sva: Make LAM and SVA mutually exclusive Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 12/17] selftests/x86/lam: Add malloc and tag-bits test cases for linear-address masking Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 13/17] selftests/x86/lam: Add mmap and SYSCALL " Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 14/17] selftests/x86/lam: Add io_uring " Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 15/17] selftests/x86/lam: Add inherit " Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 16/17] selftests/x86/lam: Add ARCH_FORCE_TAGGED_SVA " Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 17/17] selftests/x86/lam: Add test cases for LAM vs thread creation Kirill A. Shutemov
2023-01-18 16:49 ` [PATCHv14 00/17] Linear Address Masking enabling Peter Zijlstra
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