linux-kernel - Re: [PATCH 3/6] mm: remove return value from init_currently_empty

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Date:   Tue, 4 Apr 2017 09:30:56 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Reza Arbab <arbab@...ux.vnet.ibm.com>
Cc:     linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
        Mel Gorman <mgorman@...e.de>, Vlastimil Babka <vbabka@...e.cz>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Yasuaki Ishimatsu <yasu.isimatu@...il.com>,
        Tang Chen <tangchen@...fujitsu.com>, qiuxishi@...wei.com,
        Kani Toshimitsu <toshi.kani@....com>, slaoub@...il.com,
        Joonsoo Kim <js1304@...il.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Zhang Zhen <zhenzhang.zhang@...wei.com>,
        David Rientjes <rientjes@...gle.com>,
        Daniel Kiper <daniel.kiper@...cle.com>,
        Igor Mammedov <imammedo@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/6] mm: remove return value from
 init_currently_empty_zone

On Mon 03-04-17 16:22:32, Reza Arbab wrote:
> On Thu, Mar 30, 2017 at 01:54:51PM +0200, Michal Hocko wrote:
> >init_currently_empty_zone doesn't have any error to return yet it is
> >still an int and callers try to be defensive and try to handle potential
> >error. Remove this nonsense and simplify all callers.
> 
> Semi-related; arch_remove_memory() returns int, but callers ignore it.
> 
> Is that worth cleaning up? If so, should the implementations be simplified,
> or should we maybe do a pr_error() or something with it?

No, pr_error is not really helpful. Either that path can fail and we
should handle it properly - which will be hard because remove_memory
cannot handle that or we should just make arch_remove_memory
non-failing. I have a suspicion that this path doesn't really fail
in fact. This requires a deeper inspection though. I've put that on my
todo list.

Thanks!
-- 
Michal Hocko
SUSE Labs