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Date:   Wed, 21 Jun 2023 22:55:18 +0900
From:   Sergey Senozhatsky <senozhatsky@chromium.org>
To:     Alexey Romanov <AVRomanov@sberdevices.ru>
Cc:     Sergey Senozhatsky <senozhatsky@chromium.org>,
        Minchan Kim <minchan@kernel.org>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        kernel <kernel@sberdevices.ru>
Subject: Re: [PATCH v1 1/2] zsmalloc: add allocated objects counter for
 subpage
Message-ID: <20230621135518.GD2934656@google.com>
References: <20230619143506.45253-1-avromanov@sberdevices.ru>
 <20230619143506.45253-2-avromanov@sberdevices.ru>
 <20230620103629.GA42985@google.com>
 <20230620111635.gztldehfzvuzkdnj@cab-wsm-0029881>
 <20230621131716.GC2934656@google.com>
 <20230621134130.tm2oucg5eskelwzr@cab-wsm-0029881>
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On (23/06/21 13:41), Alexey Romanov wrote:
[..]
> > +static bool zspage_empty(struct zspage *zspage)
> > +{
> > +	return get_zspage_inuse(zspage) == 0;
> > +}
> > +
> >  /**
> >   * zs_lookup_class_index() - Returns index of the zsmalloc &size_class
> >   * that hold objects of the provided size.
> > @@ -1787,6 +1792,10 @@ static void migrate_zspage(struct zs_pool *pool, struct size_class *class,
> >  		obj_idx++;
> >  		record_obj(handle, free_obj);
> >  		obj_free(class->size, used_obj, NULL);
> > +
> > +		/* Stop if there are no more objects to migrate */
> > +		if (zspage_empty(get_zspage(s_page)))
> > +			break;
> >  	}
> 
> Yes it seems my version is not as good as I thought. Looks bad for an
> architecturally dependent PAGE_SIZE. [..]

Well, we are looking for a solution that is both reasonable (perf wise)
and is maintainable.

> I can implement this option. I'll test this and send patch this week.

Either that or, if Suggested-by: Alexey Romanov <AVRomanov@sberdevices.ru>
is good enough for you, then I can send a series tonight or tomorrow (after
some testing). I have two more patches on top of that one.