Messages in this thread | | | Date | Tue, 6 Jan 2009 11:09:06 +0100 | From | Ingo Molnar <> | Subject | Re: [RFC -tip 0/4] x86: reduce fixup of uaccess |
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* Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> wrote:
> This is my second try to reduce fixup code size for exceptions of uaccess. > > This patch series reduces fixup code for exceptions of uaccess in signal. > > I gave up to make direct jump to end of function when an exception occurs. > However, I thought fixup code could be reduced. The concept is that to add > uaccess_err in thread_info and set it to -EFAULT on exception, finally check > this value on the last of function. > > Is this good to reduce code size? > > The code size reductions are below; > $ size *signal*.o.* > text data bss dec hex filename > 4741 0 0 4741 1285 ia32_signal.o.new > 6006 0 0 6006 1776 ia32_signal.o.old > 3577 0 0 3577 df9 signal.o.new > 4540 0 0 4540 11bc signal.o.old > 3855 0 0 3855 f0f signal32.o.new > 4876 0 0 4876 130c signal32.o.old
looks very nice! Since kernel execution is i-cache-cold in the typical case, this will probably transform into a performance improvement as well.
Ingo
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