Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues

From	Yu-cheng Yu <yu-cheng.yu@intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues
Date	2016-04-29 22:10 +0200
Message-ID	<rtmTE-3yl-13@gated-at.bofh.it> (permalink)
References	<r92ut-2hO-1@gated-at.bofh.it> <rtl1w-1Wz-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Fri, Apr 29, 2016 at 11:09:23AM -0700, Dave Hansen wrote:

> Once we *HAVE* XSAVES support, it also opens up the possibilities for
> doing things like dynamic XSAVE buffer allocation.  For instance, let
> threads that are not _using_ AVX-512 not waste the 2k of space for it.

If we can somehow modify exec* system call to scan the executable binary (in user space) and pass along a bitmask containing xfeatures used in the binary, and XSAVES is enabled in the kernel, we can easily save a lot of memory.  The kernel only needs to allocate space for tasks that actually use xstates; most of them do not.

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Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Dave Hansen <dave.hansen@linux.intel.com> - 2016-04-29 20:10 +0200
  Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Ingo Molnar <mingo@kernel.org> - 2016-04-29 21:50 +0200
  Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Dave Hansen <dave.hansen@linux.intel.com> - 2016-04-29 22:10 +0200
    Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Yu-cheng Yu <yu-cheng.yu@intel.com> - 2016-04-29 22:20 +0200
      Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Andy Lutomirski <luto@amacapital.net> - 2016-04-29 22:30 +0200
        Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Dave Hansen <dave.hansen@linux.intel.com> - 2016-04-29 22:50 +0200
          Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Andy Lutomirski <luto@amacapital.net> - 2016-04-29 22:50 +0200
            Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Dave Hansen <dave.hansen@linux.intel.com> - 2016-04-30 00:50 +0200
          Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Ingo Molnar <mingo@kernel.org> - 2016-04-30 10:00 +0200
            Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Dave Hansen <dave.hansen@linux.intel.com> - 2016-05-02 18:30 +0200
              Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Ingo Molnar <mingo@kernel.org> - 2016-05-02 20:40 +0200
      Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Dave Hansen <dave.hansen@linux.intel.com> - 2016-04-29 22:40 +0200
  Re: [PATCH v4 0/10] x86/xsaves: Fix XSAVES known issues Yu-cheng Yu <yu-cheng.yu@intel.com> - 2016-04-29 22:10 +0200

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