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Subject: Re: [lustre-devel] staging: lustre: One function call less in class_register_type() after error detection
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From: Oleg Drokin <oleg.drokin@intel.com>
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Date: Fri, 29 Jul 2016 11:28:46 -0400
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        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
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To: SF Markus Elfring <elfring@users.sourceforge.net>
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On Jul 28, 2016, at 1:53 AM, SF Markus Elfring wrote:

>> This function is called several times during lustre module insert.
>> Namely it's called 5 times for 5 types:
>> osc, mdc, lov, lmv, mgc.
> 
> Will any extra memory accesses matter for the successful execution
> in this use case?

I doubt it.

In typical deployments outside of testing environment, this function is
called 5 times every system boot and never again.

>> It's not called any more than that, so it's not exactly a super hot-path function
>> to overoptimize it, and the failure is presumed to never happen too
>> (or the module would be non-functional).
> 
> Did the assignment for the local variable "rc" with a well-known error code
> influence the run-time characteristics in unwanted ways?
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/drivers/staging/lustre/lustre/obdclass/genops.c?id=6a5b99a46bedc2cfbba96dec6d255c4b90af9ff8#n140

I am not sure what do you mean here.