Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v9 6/7] mm: Make alloc_contig_range handle in-use hugetlb
 pages
To:     Oscar Salvador <osalvador@suse.de>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Mike Kravetz <mike.kravetz@oracle.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Michal Hocko <mhocko@kernel.org>,
        Muchun Song <songmuchun@bytedance.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Michal Hocko <mhocko@suse.com>
References: <20210416070023.4742-1-osalvador@suse.de>
 <20210416070023.4742-7-osalvador@suse.de>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
Message-ID: <02de399f-1ecf-98d6-6a78-1301f9a97d5a@redhat.com>
Date:   Fri, 16 Apr 2021 10:36:01 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.8.1
MIME-Version: 1.0
In-Reply-To: <20210416070023.4742-7-osalvador@suse.de>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk


> -int isolate_or_dissolve_huge_page(struct page *page)
> +int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list)
>   {
>   	struct hstate *h;
>   	struct page *head;
> +	int ret = -EBUSY;
>   
>   	/*
>   	 * The page might have been dissolved from under our feet, so make sure
> @@ -2373,13 +2380,18 @@ int isolate_or_dissolve_huge_page(struct page *page)
>   
>   	/*
>   	 * Fence off gigantic pages as there is a cyclic dependency between
> -	 * alloc_contig_range and them. Return -ENOME as this has the effect
> +	 * alloc_contig_range and them. Return -ENOMEM as this has the effect

Nit: belongs into previous patch.

>   	 * of bailing out right away without further retrying.
>   	 */
>   	if (hstate_is_gigantic(h))
>   		return -ENOMEM;
>   
> -	return alloc_and_dissolve_huge_page(h, head);
> +	if (page_count(head) && isolate_huge_page(head, list))
> +		ret = 0;
> +	else if (!page_count(head))
> +		ret = alloc_and_dissolve_huge_page(h, head, list);
> +
> +	return ret;
>   }
>   
>   struct page *alloc_huge_page(struct vm_area_struct *vma,
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index bb8321026c0c..5199b9696bab 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1703,8 +1703,9 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone,
>   	LIST_HEAD(clean_pages);
>   
>   	list_for_each_entry_safe(page, next, page_list, lru) {
> -		if (page_is_file_lru(page) && !PageDirty(page) &&
> -		    !__PageMovable(page) && !PageUnevictable(page)) {
> +		if (!PageHuge(page) && page_is_file_lru(page) &&
> +		    !PageDirty(page) && !__PageMovable(page) &&
> +		    !PageUnevictable(page)) {

Nit: adding to the end of the list would require less modifications ;)

>   			ClearPageActive(page);
>   			list_move(&page->lru, &clean_pages);
>   		}
> 

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

-- 
Thanks,

David / dhildenb