linux-kernel - Re: [PATCH v5 09/12] zsmalloc: separate free_zspage from putback

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Date:	Mon, 16 May 2016 12:15:32 +0900
From:	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:	Minchan Kim <minchan@...nel.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Subject: Re: [PATCH v5 09/12] zsmalloc: separate free_zspage from
 putback_zspage

On (05/09/16 11:20), Minchan Kim wrote:
> Currently, putback_zspage does free zspage under class->lock
> if fullness become ZS_EMPTY but it makes trouble to implement
> locking scheme for new zspage migration.
> So, this patch is to separate free_zspage from putback_zspage
> and free zspage out of class->lock which is preparation for
> zspage migration.
> 
> Cc: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
> Signed-off-by: Minchan Kim <minchan@...nel.org>


Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>

	-ss

> ---
>  mm/zsmalloc.c | 27 +++++++++++----------------
>  1 file changed, 11 insertions(+), 16 deletions(-)
> 
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index 162a598a417a..5ccd83732a14 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -1685,14 +1685,12 @@ static struct zspage *isolate_zspage(struct size_class *class, bool source)
>  
>  /*
>   * putback_zspage - add @zspage into right class's fullness list
> - * @pool: target pool
>   * @class: destination class
>   * @zspage: target page
>   *
>   * Return @zspage's fullness_group
>   */
> -static enum fullness_group putback_zspage(struct zs_pool *pool,
> -			struct size_class *class,
> +static enum fullness_group putback_zspage(struct size_class *class,
>  			struct zspage *zspage)
>  {
>  	enum fullness_group fullness;
> @@ -1701,15 +1699,6 @@ static enum fullness_group putback_zspage(struct zs_pool *pool,
>  	insert_zspage(class, zspage, fullness);
>  	set_zspage_mapping(zspage, class->index, fullness);
>  
> -	if (fullness == ZS_EMPTY) {
> -		zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
> -			class->size, class->pages_per_zspage));
> -		atomic_long_sub(class->pages_per_zspage,
> -				&pool->pages_allocated);
> -
> -		free_zspage(pool, zspage);
> -	}
> -
>  	return fullness;
>  }
>  
> @@ -1755,23 +1744,29 @@ static void __zs_compact(struct zs_pool *pool, struct size_class *class)
>  			if (!migrate_zspage(pool, class, &cc))
>  				break;
>  
> -			putback_zspage(pool, class, dst_zspage);
> +			putback_zspage(class, dst_zspage);
>  		}
>  
>  		/* Stop if we couldn't find slot */
>  		if (dst_zspage == NULL)
>  			break;
>  
> -		putback_zspage(pool, class, dst_zspage);
> -		if (putback_zspage(pool, class, src_zspage) == ZS_EMPTY)
> +		putback_zspage(class, dst_zspage);
> +		if (putback_zspage(class, src_zspage) == ZS_EMPTY) {
> +			zs_stat_dec(class, OBJ_ALLOCATED, get_maxobj_per_zspage(
> +					class->size, class->pages_per_zspage));
> +			atomic_long_sub(class->pages_per_zspage,
> +					&pool->pages_allocated);
> +			free_zspage(pool, src_zspage);
>  			pool->stats.pages_compacted += class->pages_per_zspage;
> +		}
>  		spin_unlock(&class->lock);
>  		cond_resched();
>  		spin_lock(&class->lock);
>  	}
>  
>  	if (src_zspage)
> -		putback_zspage(pool, class, src_zspage);
> +		putback_zspage(class, src_zspage);
>  
>  	spin_unlock(&class->lock);
>  }
> -- 
> 1.9.1
> 
> --
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