Messages in this thread | | | From | Andy Lutomirski <> | Date | Fri, 30 Nov 2018 12:18:33 -0800 | Subject | Re: [PATCH v2 4/4] x86/static_call: Add inline static call implementation for x86-64 |
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On Fri, Nov 30, 2018 at 11:51 AM Linus Torvalds <torvalds@linux-foundation.org> wrote: > > On Fri, Nov 30, 2018 at 10:39 AM Josh Poimboeuf <jpoimboe@redhat.com> wrote: > > > > AFAICT, all the other proposed options seem to have major issues. > > I still absolutely detest this patch, and in fact it got worse from > the test of the config variable. > > Honestly, the entry code being legible and simple is more important > than the extra cycle from branching to a trampoline for static calls. > > Just don't do the inline case if it causes this much confusion.
With my entry maintainer hat on, I don't mind it so much, although the implementation needs some work. The #ifdef should just go away, and there should be another sanity check in the sanity check section.
Or we could replace that IPI with x86's bona fide serialize-all-cpus primitive and then we can just retry instead of emulating. It's a piece of cake -- we just trigger an SMI :) /me runs away.
--Andy
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