Re: [PATCH] x86/signal: Deinline get_sigframe, save 240 bytes

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From	Davidlohr Bueso <dave@stgolabs.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH] x86/signal: Deinline get_sigframe, save 240 bytes
Date	Mon, 28 Sep 2015 22:30:01 +0200
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On Mon, 28 Sep 2015, Denys Vlasenko wrote:

>On 09/28/2015 02:33 PM, H. Peter Anvin wrote:
>> This one makes me slightly nervous, because it isn't clear
>> that these aren't potentially performance sensitive.
>
>CALL instruction is not a crime :)
>It costs about the same as one read-modify-write
>operation on a memory operand.
>
>This function is used in signal delivery code.
>If performance critical code uses massive numbers
>of signals, it already has a problem, Unix signals
>are too inefficient. That's why we have futexes etc...

True, but in general I don't think that justifies anything -- and not only
referring to this particular signal patch.

Nothing really against or in favor of these patches, but I don't think that
saving 240 bytes (or whatever) is worth such changes, in fact we have Josh's
tinyfication project for those systems that do in fact care.

Thanks,
Davidlohr
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Thread

[PATCH] x86/apic: Deinline __x2apic_disable, save 467 bytes Denys Vlasenko <dvlasenk@redhat.com> - 2015-09-28 14:30 +0200
  [PATCH] x86/signal: Deinline get_sigframe, save 240 bytes Denys Vlasenko <dvlasenk@redhat.com> - 2015-09-28 14:30 +0200
    Re: [PATCH] x86/signal: Deinline get_sigframe, save 240 bytes "H. Peter Anvin" <hpa@zytor.com> - 2015-09-28 14:40 +0200
      Re: [PATCH] x86/signal: Deinline get_sigframe, save 240 bytes Denys Vlasenko <dvlasenk@redhat.com> - 2015-09-28 15:50 +0200
        Re: [PATCH] x86/signal: Deinline get_sigframe, save 240 bytes Davidlohr Bueso <dave@stgolabs.net> - 2015-09-28 22:30 +0200
          Re: [PATCH] x86/signal: Deinline get_sigframe, save 240 bytes Thomas Gleixner <tglx@linutronix.de> - 2015-09-29 21:00 +0200
    [tip:x86/cleanups] x86/signal: Deinline get_sigframe,   save 240 bytes tip-bot for Denys Vlasenko <tipbot@zytor.com> - 2015-09-30 22:00 +0200
  [PATCH] x86: Deinline e820_type_to_string, save 126 bytes Denys Vlasenko <dvlasenk@redhat.com> - 2015-09-28 14:30 +0200
    [tip:x86/cleanups] x86/e820: Deinline e820_type_to_string,   save 126 bytes tip-bot for Denys Vlasenko <tipbot@zytor.com> - 2015-09-30 22:00 +0200
  [PATCH] x86: Deinline early_console_register, save 403 bytes Denys Vlasenko <dvlasenk@redhat.com> - 2015-09-28 14:30 +0200
    [tip:x86/cleanups] x86: Deinline early_console_register,   save 403 bytes tip-bot for Denys Vlasenko <tipbot@zytor.com> - 2015-09-30 22:00 +0200

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