Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Alexey Romanov <AVRomanov@sberdevices.ru>
To:     Sergey Senozhatsky <senozhatsky@chromium.org>
CC:     Minchan Kim <minchan@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] zsmalloc: do not scan for allocated objects in empty
 zspage
Thread-Topic: [PATCH 1/2] zsmalloc: do not scan for allocated objects in empty
 zspage
Thread-Index: AQHZpYzRyNUr9zsPBkK5T8L0XRRTxK+YA1KAgAEGooCAA7ITgA==
Date:   Mon, 26 Jun 2023 10:54:50 +0000
Message-ID: <20230626105502.kqjrgtrvwp4ro3vu@cab-wsm-0029881>
References: <20230623044016.366793-1-senozhatsky@chromium.org>
 <20230623044016.366793-2-senozhatsky@chromium.org>
 <20230623104917.2n6vcxvhvlwmjm2m@cab-wsm-0029881>
 <20230624022917.GF2934656@google.com>
In-Reply-To: <20230624022917.GF2934656@google.com>
Accept-Language: ru-RU, en-US
Content-Language: en-US
Content-Type: text/plain; charset="us-ascii"
Content-ID: <2198C4204FD0134A9CBF6183F56DC4C3@sberdevices.ru>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Precedence: bulk

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) =3D=3D 0;
> > > +}
> > > +
> > >  /**
> > >   * zs_lookup_class_index() - Returns index of the zsmalloc &size_cla=
ss
> > >   * that hold objects of the provided size.
> > > @@ -1625,6 +1630,10 @@ static void migrate_zspage(struct zs_pool *poo=
l, 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;
> > >  	}
> > > =20
> > >  	/* Remember last position in this iteration */
> > > --=20
> > > 2.41.0.162.gfafddb0af9-goog
> > >=20
> >=20
> > I think we can add similar check in zs_reclaim_page() function.
> > There we also scan zspage to find the allocated object.
>=20
> 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.

--=20
Thank you,
Alexey=