From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx106.postini.com [74.125.245.106]) by kanga.kvack.org (Postfix) with SMTP id 5AFF16B0044 for ; Tue, 14 Aug 2012 10:20:05 -0400 (EDT) Received: by eaaf11 with SMTP id f11so190837eaa.14 for ; Tue, 14 Aug 2012 07:20:03 -0700 (PDT) From: Michal Nazarewicz Subject: Re: [RFC 2/2] cma: support MIGRATE_DISCARD In-Reply-To: <1344934627-8473-3-git-send-email-minchan@kernel.org> References: <1344934627-8473-1-git-send-email-minchan@kernel.org> <1344934627-8473-3-git-send-email-minchan@kernel.org> Date: Tue, 14 Aug 2012 16:19:55 +0200 Message-ID: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="=-=-=" Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim , Marek Szyprowski Cc: Mel Gorman , Rik van Riel , Kamezawa Hiroyuki , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Minchan Kim writes: > This patch introudes MIGRATE_DISCARD mode in migration. > It drop clean cache pages instead of migration so that > migration latency could be reduced. Of course, it could > evict code pages but latency of big contiguous memory > is more important than some background application's slow down > in mobile embedded enviroment. > > Signed-off-by: Minchan Kim This looks good to me. > --- > include/linux/migrate_mode.h | 11 +++++++--- > mm/migrate.c | 50 +++++++++++++++++++++++++++++++++---= ------ > mm/page_alloc.c | 2 +- > 3 files changed, 49 insertions(+), 14 deletions(-) > > diff --git a/include/linux/migrate_mode.h b/include/linux/migrate_mode.h > index ebf3d89..04ca19c 100644 > --- a/include/linux/migrate_mode.h > +++ b/include/linux/migrate_mode.h > @@ -6,11 +6,16 @@ > * on most operations but not ->writepage as the potential stall time > * is too significant > * MIGRATE_SYNC will block when migrating pages > + * MIGRTATE_DISCARD will discard clean cache page instead of migration > + * > + * MIGRATE_ASYNC, MIGRATE_SYNC_LIGHT, MIGRATE_SYNC shouldn't be used > + * together as OR flag. > */ > enum migrate_mode { > - MIGRATE_ASYNC, > - MIGRATE_SYNC_LIGHT, > - MIGRATE_SYNC, > + MIGRATE_ASYNC =3D 1 << 0, > + MIGRATE_SYNC_LIGHT =3D 1 << 1, > + MIGRATE_SYNC =3D 1 << 2, > + MIGRATE_DISCARD =3D 1 << 3, > }; Since CMA is the only user of MIGRATE_DISCARD it may be worth it to guard it inside an #ifdef, eg: #ifdef CONFIG_CMA MIGRATE_DISCARD =3D 1 << 3, #define is_migrate_discard(mode) (((mode) & MIGRATE_DISCARD) =3D=3D MIGRATE= _DISCARD) #endif =20=20 > #endif /* MIGRATE_MODE_H_INCLUDED */ > diff --git a/mm/migrate.c b/mm/migrate.c > index 77ed2d7..8119a59 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -685,9 +685,12 @@ static int __unmap_and_move(struct page *page, struc= t page *newpage, > int remap_swapcache =3D 1; > struct mem_cgroup *mem; > struct anon_vma *anon_vma =3D NULL; > + enum ttu_flags ttu_flags; > + bool discard_mode =3D false; > + bool file =3D false; >=20=20 > if (!trylock_page(page)) { > - if (!force || mode =3D=3D MIGRATE_ASYNC) > + if (!force || mode & MIGRATE_ASYNC) + if (!force || (mode & MIGRATE_ASYNC)) > goto out; >=20=20 > /* --=20 Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=3D./ `o ..o | Computer Science, Micha=C5=82 =E2=80=9Cmina86=E2=80=9D Nazarewicz = (o o) ooo +------------------ooO--(_)--Ooo-- --=-=-= Content-Type: multipart/signed; boundary="==-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" --==-=-= Content-Type: text/plain --==-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQIcBAEBAgAGBQJQKl6LAAoJECBgQBJQdR/0goYP/0/hPtydiXAf13PcPR+dWLrx UhGN2//ZkV8KnA11/q/1fLJ7mIuUoR84gGi9PPkQUOdos5iOxoVj9yMB+UWlok68 qwrsOeBwJZLcYzpeLP3UAyuElxUBWCs4A/zvRXjA9Sb8Bnk0p7W/ONqfIjeYQsyN phpxS8dEZkwLff4QOaQpHNYopTxDyBfjzbL2F0vlnXfP0NuLVEYk6BDE1d1oCXWt 7t61/34i3e5fNYGCybgxcmMWG32vzg6i1a1MTt4kXFVg+H8PtC8iM2u+/o0Ma2oW 76le3gW1P3zGFreBABKYViyu3MUEdS5yNzjspvCM7d20nTLlxKN7ZnqZF2Pmldwb VU/eCmWTNbA3aCH+2zjbuV1M08CS4TmQcQa+T2Txp6PctRM6zfoM1v/kxdTgHKIW PdtXiYN1yryjHGb6RDt34W9VGhEmiJ4wOtVb1taDHODM/VzrWe8YRIqvyqDjqTD8 PoyeoP4lqA71KZelHJh5KY7YXw0owROkesoADZcxWJ01D4jRo5m6G+ZkyfiAwVgj IE3g4T5wcG4BxVPGazIni3HqoPX0HbSdbb7SnI4MHoSK1LypBGmuKsaoAqSb3o28 8qXxNNfPO2Cj6TNxyJDAkBnUXGL5b2nQYF1FR2Ha4t79ljqsMAX+54JqkOErWMtE 1MeBYF5Gv4LtAgQONM6c =v1Nm -----END PGP SIGNATURE----- --==-=-=-- --=-=-=-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org