linux-kernel - Re: staging: lustre: One function call less in class_register

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Message-ID: <db6cbbce-d3ff-2b92-199b-a8e5fd99dd40@users.sourceforge.net>
Date:	Thu, 28 Jul 2016 07:53:18 +0200
From:	SF Markus Elfring <elfring@...rs.sourceforge.net>
To:	Oleg Drokin <oleg.drokin@...el.com>
Cc:	devel@...verdev.osuosl.org, lustre-devel@...ts.lustre.org,
	Andreas Dilger <andreas.dilger@...el.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	kernel-janitors@...r.kernel.org,
	Julia Lawall <julia.lawall@...6.fr>,
	Bhumika Goyal <bhumirks@...il.com>
Subject: Re: staging: lustre: One function call less in class_register_type()
 after error detection

> 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?


> 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

Regards,
Markus