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Date:   Thu, 10 Dec 2020 14:16:08 +0100
From:   Oscar Salvador <osalvador@suse.de>
To:     Muchun Song <songmuchun@bytedance.com>
Cc:     Jonathan Corbet <corbet@lwn.net>,
        Mike Kravetz <mike.kravetz@oracle.com>,
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Subject: Re: [External] Re: [PATCH v8 12/12] mm/hugetlb: Optimize the code
 with the help of the compiler
Message-ID: <20201210131608.GA7811@localhost.localdomain>
References: <20201210035526.38938-1-songmuchun@bytedance.com>
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On Thu, Dec 10, 2020 at 08:14:18PM +0800, Muchun Song wrote:
> Yeah, you are right. But if we do this check can make the code simple.
> 
> For example, here is a code snippet.
> 
> void func(void)
> {
>         if (free_vmemmap_pages_per_hpage())
>                 return;
>         /* Do something */
> }
> 
> With this patch, the func will be optimized to null when is_power_of_2
> returns false.
> 
> void func(void)
> {
> }
> 
> Without this patch, the compiler cannot do this optimization.

Ok, I misread the changelog.

So, then is_hugetlb_free_vmemmap_enabled, free_huge_page_vmemmap, 
free_vmemmap_pages_per_hpage and hugetlb_vmemmap_init are optimized
out, right?

-- 
Oscar Salvador
SUSE L3