Messages in this thread | | | Date | Thu, 31 Jul 2014 18:58:04 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH v4 2/5] x86,entry: Only call user_exit if TIF_NOHZ |
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On 07/31, Oleg Nesterov wrote: > > On 07/31, Frederic Weisbecker wrote: > > > > On Thu, Jul 31, 2014 at 06:42:46PM +0200, Oleg Nesterov wrote: > > > > > > And if we change this, then the code above becomes racy. The state of > > > TIF_XYZ can be changed right after the check. OK, it is racy anyway ;) > > > but still this adds more confusion. > > > > No because all running tasks have this flag set when context tracking is > > enabled. And context tracking can't be disabled on runtime. > > Yes, yes, please note that I said "if we change this".
And "it is racy anyway" connects to the problems we discuss in another thread.
Oleg.
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