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From:   Michael Ellerman <mpe@ellerman.id.au>
To:     Michal Hocko <mhocko@kernel.org>, John Allen <jallen@linux.ibm.com>
Cc:     n-horiguchi@ah.jp.nec.com, linuxppc-dev@lists.ozlabs.org,
        linux-kernel@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com,
        mgorman@suse.de
Subject: Re: Infinite looping observed in __offline_pages
In-Reply-To: <20180725200336.GP28386@dhcp22.suse.cz>
References: <20180725181115.hmlyd3tmnu3mn3sf@p50.austin.ibm.com> <20180725200336.GP28386@dhcp22.suse.cz>
Date:   Wed, 01 Aug 2018 21:09:39 +1000
Message-ID: <87r2jifimk.fsf@concordia.ellerman.id.au>
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Michal Hocko <mhocko@kernel.org> writes:
> On Wed 25-07-18 13:11:15, John Allen wrote:
> [...]
>> Does a failure in do_migrate_range indicate that the range is unmigratable
>> and the loop in __offline_pages should terminate and goto failed_removal? Or
>> should we allow a certain number of retrys before we
>> give up on migrating the range?
>
> Unfortunatelly not. Migration code doesn't tell a difference between
> ephemeral and permanent failures.

What's to stop an ephemeral failure happening repeatedly?

cheers