Messages in this thread | | | Date | Sat, 2 Sep 2017 12:32:21 +0200 | From | Ingo Molnar <> | Subject | Re: [RFC PATCH 3/4] x86/asm: Make alternative macro interfaces more clear and consistent |
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* Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> On Thu, Aug 31, 2017 at 12:25:42PM -0500, Josh Poimboeuf wrote: > > 2) Put "sp" in the clobbers list instead of as an i/o constraint. This > > mostly works for GCC, and doesn't break clang. However, it causes > > GCC to insert a "lea -0x10(%rbp),%rsp" in the epilogue of every > > affected function. > > And maybe this extra instruction is negligible for performance and not a > big deal? I might look at this one after the holiday too.
Please do statistics of how many functions are affected, on a defconfig-ish kernel.
Thanks,
Ingo
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