linux-kernel - Re: [PATCH linux-next] mm: workingset: simplify the calculation of workingset size

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Message-ID: <ZBMWHUJfFnIX7F9y@casper.infradead.org>
Date:   Thu, 16 Mar 2023 13:14:05 +0000
From:   Matthew Wilcox <willy@...radead.org>
To:     yang.yang29@....com.cn
Cc:     akpm@...ux-foundation.org, hannes@...xchg.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        iamjoonsoo.kim@....com
Subject: Re:  [PATCH linux-next] mm: workingset: simplify the calculation of workingset size

On Thu, Mar 16, 2023 at 05:23:05PM +0800, yang.yang29@....com.cn wrote:
>  	 * Compare the distance to the existing workingset size. We
>  	 * don't activate pages that couldn't stay resident even if
> -	 * all the memory was available to the workingset. Whether
> -	 * workingset competition needs to consider anon or not depends
> -	 * on having swap.
> +	 * all the memory was available to the workingset. For page
> +	 * cache whether workingset competition needs to consider
> +	 * anon or not depends on having swap.

I don't mind this change

>  	 */
>  	workingset_size = lruvec_page_state(eviction_lruvec, NR_ACTIVE_FILE);
> +	/* For anonymous page */

This comment adds no value

>  	if (!file) {
> +		workingset_size += lruvec_page_state(eviction_lruvec,
> +						     NR_ACTIVE_ANON);
>  		workingset_size += lruvec_page_state(eviction_lruvec,
>  						     NR_INACTIVE_FILE);
> -	}
> -	if (mem_cgroup_get_nr_swap_pages(eviction_memcg) > 0) {
> +	/* For page cache */

Nor this one

> +	} else if (mem_cgroup_get_nr_swap_pages(eviction_memcg) > 0) {
>  		workingset_size += lruvec_page_state(eviction_lruvec,
>  						     NR_ACTIVE_ANON);
> -		if (file) {
> -			workingset_size += lruvec_page_state(eviction_lruvec,
> +		workingset_size += lruvec_page_state(eviction_lruvec,
>  						     NR_INACTIVE_ANON);
> -		}
>  	}

I don't have an opinion on the actual code changes.