Message-ID: <bea284c3-fe7c-f55a-449d-07f47a364c1c@suse.cz>
Date:   Tue, 24 Jan 2023 12:00:07 +0100
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Subject: Re: [PATCH v4 1/1] docs/mm: Physical Memory: add structure,
 introduction and nodes description
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To:     Mike Rapoport <rppt@kernel.org>, Jonathan Corbet <corbet@lwn.net>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Bagas Sanjaya <bagasdotme@gmail.com>,
        David Hildenbrand <david@redhat.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Lorenzo Stoakes <lstoakes@gmail.com>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        Mel Gorman <mgorman@suse.de>, Michal Hocko <mhocko@kernel.org>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Michal Hocko <mhocko@suse.com>
References: <20230115184212.996298-1-rppt@kernel.org>
 <20230115184212.996298-2-rppt@kernel.org>
From:   Vlastimil Babka <vbabka@suse.cz>
In-Reply-To: <20230115184212.996298-2-rppt@kernel.org>
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On 1/15/23 19:42, Mike Rapoport wrote:
> From: "Mike Rapoport (IBM)" <rppt@kernel.org>
> 
> Add structure, introduction and Nodes section to Physical Memory
> chapter.
> 
> As the new documentation references core-api/dma-api and mm/page_reclaim,
> add page labels to those documents.
> 
> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

A small bug to fix below?

<snip>

> +
> +Along with the node structures, kernel maintains an array of ``nodemask_t``
> +bitmasks called ``node_states``. Each bitmask in this array represents a set of
> +nodes with particular properties as defined by ``enum node_states``:
> +
> +``N_POSSIBLE``
> +  The node could become online at some point.
> +``N_ONLINE``
> +  The node is online.
> +``N_NORMAL_MEMORY``
> +  The node has regular memory.
> +``N_HIGH_MEMORY``
> +  The node has regular or high memory. When ``CONFIG_HIGHMEM`` is disabled
> +  aliased to ``N_NORMAL_MEMORY``.

Noted.

> +``N_MEMORY``
> +  The node has memory(regular, high, movable)
> +``N_CPU``
> +  The node has one or more CPUs
> +
> +For each node that has a property described above, the bit corresponding to the
> +node ID in the ``node_states[<property>]`` bitmask is set.
> +
> +For example, for node 2 with normal memory and CPUs, bit 2 will be set in ::
> +
> +  node_states[N_POSSIBLE]
> +  node_states[N_ONLINE]
> +  node_states[N_NORMAL_MEMORY]
> +  node_states[N_MEMORY]
> +  node_states[N_CPU]

Should it be set also in node_states[N_HIGH_MEMORY]?