From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gregory Haskins Subject: Re: [GIT PULL] AlacrityVM guest drivers for 2.6.33 Date: Tue, 22 Dec 2009 14:37:28 -0500 Message-ID: <4B311FF8.7000804@gmail.com> References: <4B1D4F29.8020309@gmail.com> <20091218215107.GA14946@elte.hu> <4B2F9582.5000002@gmail.com> <20091222075742.GB26467@elte.hu> <4B3103B4.4070708@gmail.com> <4B3115C1.4070303@redhat.com> <4B311ADA.4000700@gmail.com> <4B311D20.7020400@redhat.com> <4B311ECB.6040205@gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig684F93E4DC44D9C0FAF9CB2F" Cc: Ingo Molnar , kvm@vger.kernel.org, Andrew Morton , torvalds@linux-foundation.org, "linux-kernel@vger.kernel.org" , netdev@vger.kernel.org, "alacrityvm-devel@lists.sourceforge.net" To: Avi Kivity Return-path: In-Reply-To: <4B311ECB.6040205@gmail.com> Sender: kvm-owner@vger.kernel.org List-Id: netdev.vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig684F93E4DC44D9C0FAF9CB2F Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 12/22/09 2:32 PM, Gregory Haskins wrote: > On 12/22/09 2:25 PM, Avi Kivity wrote: >> >> If you're not doing something pretty minor, you're better of waking up= a >> thread (perhaps _sync if you want to keep on the same cpu). With the >> new user return notifier thingie, that's pretty cheap. >=20 > We have exploits that take advantage of IO heuristics. When triggered > they do more work in vcpu context than normal, which reduces latency > under certain circumstances. But you definitely do _not_ want to do > them in-atomic ;) And I almost forgot: dev->call() is an RPC to the backend device. Therefore, it must be synchronous, yet we dont want it locked either. I think that was actually the primary motivation for the change, now that I think about it. -Greg --------------enig684F93E4DC44D9C0FAF9CB2F Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.11 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAksxH/gACgkQP5K2CMvXmqGV3ACfQJWsxAl29eA9aDFyBd72YK7T 8JcAnR0e2riD4WmPtnK1KmdSf/8I3Maf =tyPD -----END PGP SIGNATURE----- --------------enig684F93E4DC44D9C0FAF9CB2F--