Date:   Thu, 2 Dec 2021 14:59:14 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Charan Teja Reddy <quic_charante@quicinc.com>
Cc:     hughd@google.com, akpm@linux-foundation.org, vbabka@suse.cz,
        rientjes@google.com, david@redhat.com, mhocko@suse.com,
        surenb@google.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Charan Teja Reddy <charante@codeaurora.org>
Subject: Re: [PATCH v2] mm: shmem: implement POSIX_FADV_[WILL|DONT]NEED for
 shmem
Message-ID: <YajfQiEHYA6E5CeY@casper.infradead.org>
References: <1638442253-1591-1-git-send-email-quic_charante@quicinc.com>
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On Thu, Dec 02, 2021 at 04:20:53PM +0530, Charan Teja Reddy wrote:
> +static void shmem_isolate_pages_range(struct address_space *mapping, loff_t start,
> +				loff_t end, struct list_head *list)
> +{
> +	XA_STATE(xas, &mapping->i_pages, start);
> +	struct page *page;
> +
> +	rcu_read_lock();
> +	xas_for_each(&xas, page, end) {
> +		if (xas_retry(&xas, page))
> +			continue;
> +		if (xa_is_value(page))
> +			continue;
> +		if (!get_page_unless_zero(page))
> +			continue;
> +		if (isolate_lru_page(page))
> +			continue;
> +
> +		list_add(&page->lru, list);
> +		inc_node_page_state(page, NR_ISOLATED_ANON +
> +						page_is_file_lru(page));

... what if the page is a THP?