On Mon, Sep 21, 2015 at 9:49 AM, Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> wrote: >> >> How many msr reads are <i>so</i> critical that the function call >> overhead would matter? > > if anything qualifies it'd be switch_to() and friends. Is there anything else than the FS/GS_BASE thing (possibly hidden behind inlines etc that I didn't get from a quick grep)? And why is that sometimes using the "safe" version (in do_arch_prctl()), and sometimes not (switch_to())? I'm not convinced that mess is a good argument for the status quo ;) > note that I'm not entirely happy about the notion of "safe" MSRs. > They're safe as in "won't fault". I wouldn't object to renaming them. Linus -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html