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Subject: Re: [PATCH 2/3] mm: sparse: pass section_nr to find_memory_block
To:     Ohhoon Kwon <ohoono.kwon@samsung.com>, akpm@linux-foundation.org,
        mhocko@suse.com
Cc:     bhe@redhat.com, rppt@linux.ibm.com, ohkwon1043@gmail.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <20210702094132.6276-1-ohoono.kwon@samsung.com>
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 <20210702094132.6276-3-ohoono.kwon@samsung.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
Message-ID: <a03f502d-60e9-196a-0db8-88ce3a98a32c@redhat.com>
Date:   Fri, 2 Jul 2021 19:55:28 +0200
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On 02.07.21 11:41, Ohhoon Kwon wrote:
> With CONFIG_SPARSEMEM_EXTREME enabled, __section_nr() which converts
> mem_section to section_nr could be costly since it iterates all
> section roots to check if the given mem_section is in its range.
> 
> On the other hand, __nr_to_section() which converts section_nr to
> mem_section can be done in O(1).
> 
> Let's pass section_nr instead of mem_section ptr to
> find_memory_block() in order to reduce needless iterations.
> 
> Signed-off-by: Ohhoon Kwon <ohoono.kwon@samsung.com>


Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb