Re: Sysenter crash with Nested Task Bit set

[Ingo Molnar]

* Linus Torvalds <torvalds@xxxxxxxx> wrote:

> And sysenter really is very special because of the weak trap 
> semantics. Damn. We could either fix it in the sysenter code-path, or 
> in the task-switch one, and both of them are timing-critical, but task 
> switching perhaps just a tad less so.

agreed. Context-switching is 10 times less frequent on most workloads 
than syscalls, so if it takes 10 cycles in the context-switch path to 
eliminate a 1 cycle overhead in the syscall-entry path then we are still 
break-even on average. In this case the overhead is similar i think, so 
the switch_to() fix is preferable.

	Ingo
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