linux-kernel - Re: [PATCH v1 1/2] zsmalloc: add allocated objects counter for subpage

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Date:   Wed, 21 Jun 2023 22:55:18 +0900
From:   Sergey Senozhatsky <senozhatsky@...omium.org>
To:     Alexey Romanov <AVRomanov@...rdevices.ru>
Cc:     Sergey Senozhatsky <senozhatsky@...omium.org>,
        Minchan Kim <minchan@...nel.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        kernel <kernel@...rdevices.ru>
Subject: Re: [PATCH v1 1/2] zsmalloc: add allocated objects counter for
 subpage

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@...rdevices.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.