From: Peter Zijlstra <peterz@infradead•org>
To: Salil Mehta <salil.mehta@huawei•com>
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Subject: Re: [PATCH v2 2/9] x86: numa: check the node id consistently for x86
Date: Tue, 3 Sep 2019 16:28:52 +0200 [thread overview]
Message-ID: <20190903142852.GT2349@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <3bc19c01095545ddbe2ba424f5488b4d@huawei.com>
On Tue, Sep 03, 2019 at 12:15:24PM +0000, Salil Mehta wrote:
> > From: Linuxarm [mailto:linuxarm-bounces@huawei•com] On Behalf Of Peter Zijlstra
> > On Tue, Sep 03, 2019 at 02:19:04PM +0800, Yunsheng Lin wrote:
> > > Is it possible that the node id set by device_add() become invalid
> > > if the node is offlined, then dev_to_node() may return a invalid
> > > node id.
> >
> > In that case I would expect the device to go away too. Once the memory
> > controller goes away, the PCI bus connected to it cannot continue to
> > function.
>
> I am not sure if this is *exactly* true on our system as NUMA nodes are
> part of the SoCs and devices could still be used even if all the memory
> and CPUs part of the node are turned off. Although, it is highly unlikely
> anybody would do that(maybe could be debated for the Power Management case?)
Cute; anyway, we never change nr_node_ids (after boot), so once a node
is deemed valid it always is.
The worst that can happen in the above case, is that cpumask_of_node()
returns an empty mask, which, if all CPUs (of said node) are offline, is
an accurate representation.
next prev parent reply other threads:[~2019-09-03 14:35 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-31 5:58 [PATCH v2 0/9] check the node id consistently across different arches Yunsheng Lin
2019-08-31 5:58 ` [PATCH v2 1/9] arm64: numa: check the node id consistently for arm64 Yunsheng Lin
2019-08-31 5:58 ` [PATCH v2 2/9] x86: numa: check the node id consistently for x86 Yunsheng Lin
2019-08-31 8:55 ` Peter Zijlstra
2019-08-31 10:09 ` Yunsheng Lin
2019-08-31 16:12 ` Peter Zijlstra
2019-09-02 5:46 ` Yunsheng Lin
2019-09-02 7:25 ` Peter Zijlstra
2019-09-02 12:25 ` Yunsheng Lin
2019-09-02 12:56 ` Peter Zijlstra
2019-09-02 18:22 ` Ingo Molnar
2019-09-02 19:14 ` Peter Zijlstra
2019-09-03 6:19 ` Yunsheng Lin
2019-09-03 7:11 ` Peter Zijlstra
2019-09-03 8:31 ` Yunsheng Lin
2019-09-03 12:15 ` Salil Mehta
2019-09-03 14:28 ` Peter Zijlstra [this message]
2019-09-02 18:17 ` Ingo Molnar
2019-09-03 7:53 ` [PATCH] x86/mm: Fix cpumask_of_node() error condition Peter Zijlstra
2019-08-31 5:58 ` [PATCH v2 3/9] alpha: numa: check the node id consistently for alpha Yunsheng Lin
2019-08-31 5:58 ` [PATCH v2 4/9] powerpc: numa: check the node id consistently for powerpc Yunsheng Lin
2019-08-31 5:58 ` [PATCH v2 5/9] s390: numa: check the node id consistently for s390 Yunsheng Lin
2019-09-02 4:05 ` kbuild test robot
2019-08-31 5:58 ` [PATCH v2 6/9] sh: numa: check the node id consistently for sh Yunsheng Lin
2019-08-31 5:58 ` [PATCH v2 7/9] sparc64: numa: check the node id consistently for sparc64 Yunsheng Lin
2019-08-31 6:53 ` David Miller
2019-08-31 8:57 ` Yunsheng Lin
2019-08-31 20:02 ` David Miller
2019-09-02 6:08 ` Yunsheng Lin
2019-09-02 15:17 ` David Miller
2019-08-31 5:58 ` [PATCH v2 8/9] mips: numa: check the node id consistently for mips ip27 Yunsheng Lin
2019-08-31 15:45 ` Paul Burton
2019-09-02 6:11 ` Yunsheng Lin
2019-08-31 5:58 ` [PATCH v2 9/9] mips: numa: check the node id consistently for mips loongson64 Yunsheng Lin
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