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Date: Tue, 30 Jun 2015 08:41:24 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [RFC][PATCHv3 2/7] zsmalloc: partial page ordering within a
 fullness_list
Message-ID: <20150629234124.GB7301@swordfish>
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Hello,

Sorry for long reply.

On (06/29/15 15:52), Minchan Kim wrote:
[..]
> >  	head = &class->fullness_list[fullness];
> > -	if (*head)
> > -		list_add_tail(&page->lru, &(*head)->lru);
> > +	if (*head) {
> > +		/*
> > +		 * We want to see more ZS_FULL pages and less almost
> > +		 * empty/full. Put pages with higher ->inuse first.
> > +		 */
> > +		if (page->inuse < (*head)->inuse)
> > +			list_add_tail(&page->lru, &(*head)->lru);
> > +		else
> > +			list_add(&page->lru, &(*head)->lru);
> > +	}
> 
> >  
> >  	*head = page;
> 
> Why do you want to always put @page in the head?
> How about this?


Yeah, right. Looks OK to me. How do we want to handle it? Do you want
to submit it with Suggested-by: ss (I'm fine) or you want me to submit
it later today with Suggested-by: Minchan Kim?

	-ss

> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index e8cb31c..1c5fde9 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -658,21 +658,25 @@ static void insert_zspage(struct page *page, struct size_class *class,
>         if (fullness >= _ZS_NR_FULLNESS_GROUPS)
>                 return;
> 
> +       zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ?
> +                       CLASS_ALMOST_EMPTY : CLASS_ALMOST_FULL, 1);
> +
>         head = &class->fullness_list[fullness];
> -       if (*head) {
> -               /*
> -                * We want to see more ZS_FULL pages and less almost
> -                * empty/full. Put pages with higher ->inuse first.
> -                */
> -               if (page->inuse < (*head)->inuse)
> -                       list_add_tail(&page->lru, &(*head)->lru);
> -               else
> -                       list_add(&page->lru, &(*head)->lru);
> +       if (!*head) {
> +               *head = page;
> +               return;
>         }
> 
> -       *head = page;
> -       zs_stat_inc(class, fullness == ZS_ALMOST_EMPTY ?
> -                       CLASS_ALMOST_EMPTY : CLASS_ALMOST_FULL, 1);
> +       /*
> +        * We want to see more ZS_FULL pages and less almost
> +        * empty/full. Put pages with higher ->inuse first.
> +        */
> +       list_add_tail(&page->lru, &(*head)->lru);
> +       if (page->inuse >= (*head)->inuse)
> +               *head = page;
>  }