linux-kernel - Re: [PATCH 1/2] mm/page_alloc: free order-0 pages through PCP in page_frag

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Message-ID: <f2d00eca-e40b-c0e9-5aae-a9a8105169b1@intel.com>
Date:   Mon, 5 Nov 2018 08:37:57 -0800
From:   Dave Hansen <dave.hansen@...el.com>
To:     Aaron Lu <aaron.lu@...el.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Paweł Staszewski <pstaszewski@...are.pl>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Eric Dumazet <eric.dumazet@...il.com>,
        Tariq Toukan <tariqt@...lanox.com>,
        Ilias Apalodimas <ilias.apalodimas@...aro.org>,
        Yoel Caspersen <yoel@...knet.dk>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Saeed Mahameed <saeedm@...lanox.com>,
        Michal Hocko <mhocko@...e.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Dave Hansen <dave.hansen@...ux.intel.com>
Subject: Re: [PATCH 1/2] mm/page_alloc: free order-0 pages through PCP in
 page_frag_free()

On 11/5/18 12:58 AM, Aaron Lu wrote:
> -	if (unlikely(put_page_testzero(page)))
> -		__free_pages_ok(page, compound_order(page));
> +	if (unlikely(put_page_testzero(page))) {
> +		unsigned int order = compound_order(page);
> +
> +		if (order == 0)
> +			free_unref_page(page);
> +		else
> +			__free_pages_ok(page, order);
> +	}
>  }

This little hunk seems repeated in __free_pages() and
__page_frag_cache_drain().  Do we need a common helper?