Re: [RFC PATCH] mm: set cache_trim_mode when inactive ratio is undesired

[Matthew Wilcox]

On Thu, Jul 21, 2022 at 03:06:48PM +0800, zhaoyang.huang wrote:
> @@ -3198,7 +3215,8 @@ static void shrink_node(pg_data_t *pgdat, struct scan_control *sc)
>  	 * anonymous pages.
>  	 */
>  	file = lruvec_page_state(target_lruvec, NR_INACTIVE_FILE);
> -	if (file >> sc->priority && !(sc->may_deactivate & DEACTIVATE_FILE))
> +	if (file >> sc->priority && (!(sc->may_deactivate & DEACTIVATE_FILE)
> +		|| inactive_is_high(target_lruvec, LRU_INACTIVE_FILE)))

Indentation is weird here.  When splitting a line, put the operator at
the end, and then indent the rest by something *other* than a single
tab, so it doesn't look like it's part of the following statement.  ie
either:

	if (file >> sc->priority && (!(sc->may_deactivate & DEACTIVATE_FILE) ||
	    inactive_is_high(target_lruvec, LRU_INACTIVE_FILE)))

or:

	if (file >> sc->priority && (!(sc->may_deactivate & DEACTIVATE_FILE) ||
			inactive_is_high(target_lruvec, LRU_INACTIVE_FILE)))

Some people like to use the indentation to illustrate the precendence.
That would look like this:

	if (file >> sc->priority &&
	    (!(sc->may_deactivate & DEACTIVATE_FILE) ||
	     inactive_is_high(target_lruvec, LRU_INACTIVE_FILE)))

(I have a mild preference for the third option in this instance)

>  		sc->cache_trim_mode = 1;
>  	else
>  		sc->cache_trim_mode = 0;
> -- 
> 1.9.1
> 
>