linux-kernel - Re: [PATCH 1/2] zsmalloc: do not scan for allocated objects in empty zspage

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Date:   Mon, 26 Jun 2023 10:54:50 +0000
From:   Alexey Romanov <AVRomanov@...rdevices.ru>
To:     Sergey Senozhatsky <senozhatsky@...omium.org>
CC:     Minchan Kim <minchan@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] zsmalloc: do not scan for allocated objects in empty
 zspage

On Sat, Jun 24, 2023 at 11:29:17AM +0900, Sergey Senozhatsky wrote:
> On (23/06/23 10:49), 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.
> > > @@ -1625,6 +1630,10 @@ 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);
> > > +
> > > +		/* Stop if there are no more objects to migrate */
> > > +		if (zspage_empty(get_zspage(s_page)))
> > > +			break;
> > >  	}
> > >  
> > >  	/* Remember last position in this iteration */
> > > -- 
> > > 2.41.0.162.gfafddb0af9-goog
> > > 
> > 
> > I think we can add similar check in zs_reclaim_page() function.
> > There we also scan zspage to find the allocated object.
> 
> LRU was moved to zswap, so zs_reclaim_page() doesn't exist any longer
> (in linux-next).

Yeah, sorry. Just looking in current linux master.

-- 
Thank you,
Alexey