From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: [patch 3/3] raid5: relieve lock contention in get_active_stripe() Date: Wed, 28 Aug 2013 14:32:52 +1000 Message-ID: <20130828143252.1d48b04b@notabene.brown> References: <20130812022434.507702228@kernel.org> <20130812022549.013010221@kernel.org> <20130827131752.4d5ba375@notabene.brown> <20130827085330.GA30133@kernel.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/eUrdUSVhcxkt8ZYAjqVpjo."; protocol="application/pgp-signature" Return-path: In-Reply-To: <20130827085330.GA30133@kernel.org> Sender: linux-raid-owner@vger.kernel.org To: Shaohua Li Cc: linux-raid@vger.kernel.org, djbw@fb.com List-Id: linux-raid.ids --Sig_/eUrdUSVhcxkt8ZYAjqVpjo. Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Tue, 27 Aug 2013 16:53:30 +0800 Shaohua Li wrote: > On Tue, Aug 27, 2013 at 01:17:52PM +1000, NeilBrown wrote: >=20 > > Then get_active_stripe wouldn't need to worry about device_lock at all = and > > would only need to get the hash lock for the particular sector. That s= hould > > make it a lot simpler. >=20 > did you mean get_active_stripe() doesn't need device_lock for any code pa= th? > How could it be safe? device_lock still protects something like handle_li= st, > delayed_list, which release_stripe() will use while a get_active_stripe c= an run > concurrently. Yes you will still need device_lock to protect list_del_init(&sh->lru), as well as the hash lock. Do you need device_lock anywhere else in there? NeilBrown --Sig_/eUrdUSVhcxkt8ZYAjqVpjo. Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iQIVAwUBUh19dDnsnt1WYoG5AQJrPxAAq8hv19R3A2fS1pvlTO9Thr7fnA4XJn9u KLfOR/m8MqlFjzj4NaLHDH7U8kPSNf1SlD6D5Nc3raInnD5dledIUcu15jFvMPRf xvczkBwawx6ueMFBND2tiqytFdJvIWkiyBtVzeiXLo9uvxixP/3QBluXLxlNm1st ziO+HWbjZnVKxjtMNh+8pqbq86z3Nld3HU35aY7hAOBBujrv3n6MvTWVuESMdE/z ijlh3YbQYHc8PDLAPKqeamqxOi6yR2nRLuXW+e0mzYAT/RfUNrApegNdYagbUgyp 2IAB3FgJ/OrwTch/wLbQI3Z1nUb4HqzP5QYoxqtKsiJJVZmmtLw85FKpmZ2xXPBC z3F2QSJGTfd+SM/nBXbij5ffWV6p8tmbPuKB8QN2ffXC68gU0ch+9YyVbpZiwJ7c DoTWD0Nuo7apaDLKFTdR0Z56leed+zNKIdksefCA1kesSBXHCmJybbqprNu0QECv SoRa5eVdZ6rbtt+C8FfCDEMxHb13T5td2dYzOoEhK4tZupQ9sdgGu2MDe5v8uyVi Tmex5KMUY9KloXxGmf8AgeyreesuAJMQN2BrJshp2BRYpKPxKtu4oH1ZdYiVBJhQ nteUEoJGWiuka8flX8hrbxdKAKh7biyMNU/c/ceJy/frV652pFa8pzmMAKM5oXF3 f0ERxp7hjew= =qpRa -----END PGP SIGNATURE----- --Sig_/eUrdUSVhcxkt8ZYAjqVpjo.--