From: Nathan Lynch <nathanl@linux.ibm.com>
To: Juliet Kim <julietk@linux.vnet.ibm.com>
Cc: ego@linux.vnet.ibm.com, mmc <mmc@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc/rtas: retry when cpu offline races with suspend/migration
Date: Tue, 25 Jun 2019 13:51:40 -0500 [thread overview]
Message-ID: <877e99ts5f.fsf@linux.ibm.com> (raw)
In-Reply-To: <5a825cec-234a-ee8a-a776-8ba305f9cb26@linux.vnet.ibm.com>
Juliet Kim <julietk@linux.vnet.ibm.com> writes:
> There's some concern this could retry forever, resulting in live lock.
First of all the system will make progress in other areas even if there
are repeated retries; we're not indefinitely holding locks or anything
like that.
Second, Linux checks the H_VASI_STATE result on every retry. If the
platform wants to terminate the migration (say, if it imposes a
timeout), Linux will abandon it when H_VASI_STATE fails to return
H_VASI_SUSPENDING. And it seems incorrect to bail out before that
happens, absent hard errors on the Linux side such as allocation
failures.
next prev parent reply other threads:[~2019-06-25 18:53 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-21 6:05 [PATCH] powerpc/rtas: retry when cpu offline races with suspend/migration Nathan Lynch
2019-06-24 16:52 ` mmc
2019-06-24 17:23 ` Nathan Lynch
2019-06-25 1:02 ` Juliet Kim
2019-06-25 18:51 ` Nathan Lynch [this message]
2019-06-26 21:40 ` Juliet Kim
2019-06-27 5:01 ` Michael Ellerman
2019-06-27 21:59 ` Juliet Kim
2019-07-01 22:12 ` Nathan Lynch
2019-07-02 2:16 ` Michael Ellerman
2019-07-03 14:27 ` Michael Ellerman
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