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Message-ID: <19907f0c-4d83-4d85-4233-f4ee727574a0@redhat.com>
Date:   Tue, 1 Feb 2022 11:17:01 +0100
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Subject: Re: [PATCH RFC v1] drivers/base/node: consolidate node device
 subsystem initialization in node_dev_init()
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To:     Oscar Salvador <osalvador@suse.de>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Michal Hocko <mhocko@suse.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Yoshinori Sato <ysato@users.sourceforge.jp>,
        Rich Felker <dalias@libc.org>,
        "David S. Miller" <davem@davemloft.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>, x86@kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
        linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
        linux-sh@vger.kernel.org, sparclinux@vger.kernel.org
References: <20220128151540.164759-1-david@redhat.com>
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 <3be2e20c-f0b9-c080-adf4-b0e17c046eb0@redhat.com>
 <20220131094041.GA15392@linux>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <20220131094041.GA15392@linux>
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On 31.01.22 10:40, Oscar Salvador wrote:
> On Mon, Jan 31, 2022 at 08:48:54AM +0100, David Hildenbrand wrote:
>> Hi Oscar,
> 
> Hi David :-),
> 
>> Right, and the idea is that the online state of nodes (+ node/zone
>> ranges) already has to be known at that point in time, because
>> otherwise, we'd be in bigger trouble.
> 
> Yeah, I wanted to check where exactly did we mark the nodes online,
> and for the few architectures I checked it happens in setup_arch(),
> which is called very early in start_kernel(), while driver_init()
> gets called through arch_call_rest_init(), which happens at the end
> of the function.
> 
> I am not sure whether we want to remark that somehow in the changelog,
> so it is crystal clear that by the time the node_dev_init() gets called,
> we already set the nodes online.
> 
> Anyway, just saying, but is fine as is.

I'll adjust the first paragraph to:

    ... and call node_dev_init() after memory_dev_init() from driver_init(),
    so before any of the existing arch/subsys calls. All online nodes should
    be known at that point: early during boot, arch code determines node and
    zone ranges and sets the relevant nodes online; usually this happens in
    setup_arch().

Thanks!

-- 
Thanks,

David / dhildenb