From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gregory Haskins Subject: Re: [PATCH 4/4] Convert irq notifiers lists to RCU locking. Date: Mon, 13 Jul 2009 09:48:20 -0400 Message-ID: <4A5B3B24.30106@gmail.com> References: <1247400233-24243-1-git-send-email-gleb@redhat.com> <1247400233-24243-5-git-send-email-gleb@redhat.com> <20090713125640.GB10402@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig1F147F6CECFF0E2B625DB6CC" Cc: Gleb Natapov , avi@redhat.com, kvm@vger.kernel.org To: "Michael S. Tsirkin" Return-path: Received: from mail-pz0-f197.google.com ([209.85.222.197]:40408 "EHLO mail-pz0-f197.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754962AbZGMNs3 (ORCPT ); Mon, 13 Jul 2009 09:48:29 -0400 Received: by pzk35 with SMTP id 35so854120pzk.33 for ; Mon, 13 Jul 2009 06:48:28 -0700 (PDT) In-Reply-To: <20090713125640.GB10402@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig1F147F6CECFF0E2B625DB6CC Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Michael S. Tsirkin wrote: > On Sun, Jul 12, 2009 at 03:03:53PM +0300, Gleb Natapov wrote: > =20 >> Use RCU locking for mask/ack notifiers lists. >> >> Signed-off-by: Gleb Natapov >> --- >> virt/kvm/irq_comm.c | 20 +++++++++++--------- >> 1 files changed, 11 insertions(+), 9 deletions(-) >> >> diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c >> index 5dde1ef..ba3a115 100644 >> --- a/virt/kvm/irq_comm.c >> +++ b/virt/kvm/irq_comm.c >> @@ -179,18 +179,18 @@ void kvm_notify_acked_irq(struct kvm *kvm, unsig= ned irqchip, unsigned pin) >> break; >> } >> } >> - rcu_read_unlock(); >> =20 >> - hlist_for_each_entry(kian, n, &kvm->irq_ack_notifier_list, link) >> + hlist_for_each_entry_rcu(kian, n, &kvm->irq_ack_notifier_list, link)= >> if (kian->gsi =3D=3D gsi) >> kian->irq_acked(kian); >> + rcu_read_unlock(); >> } >> =20 >> void kvm_register_irq_ack_notifier(struct kvm *kvm, >> struct kvm_irq_ack_notifier *kian) >> { >> mutex_lock(&kvm->irq_lock); >> - hlist_add_head(&kian->link, &kvm->irq_ack_notifier_list); >> + hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list); >> mutex_unlock(&kvm->irq_lock); >> =20 > > I think we need synchronize_rcu here as well. If the user adds a > notifier, he expects to get notified of irqs immediately > after the function returns, not after the next rcu grace period. > =20 Agreed. > =20 >> } >> =20 >> @@ -198,8 +198,9 @@ void kvm_unregister_irq_ack_notifier(struct kvm *k= vm, >> struct kvm_irq_ack_notifier *kian) >> { >> mutex_lock(&kvm->irq_lock); >> - hlist_del_init(&kian->link); >> + hlist_del_init_rcu(&kian->link); >> mutex_unlock(&kvm->irq_lock); >> + synchronize_rcu(); >> } >> =20 >> int kvm_request_irq_source_id(struct kvm *kvm) >> @@ -246,7 +247,7 @@ void kvm_register_irq_mask_notifier(struct kvm *kv= m, int irq, >> { >> mutex_lock(&kvm->irq_lock); >> kimn->irq =3D irq; >> - hlist_add_head(&kimn->link, &kvm->mask_notifier_list); >> + hlist_add_head_rcu(&kimn->link, &kvm->mask_notifier_list); >> mutex_unlock(&kvm->irq_lock); >> } >> =20 >> @@ -254,8 +255,9 @@ void kvm_unregister_irq_mask_notifier(struct kvm *= kvm, int irq, >> struct kvm_irq_mask_notifier *kimn) >> { >> mutex_lock(&kvm->irq_lock); >> - hlist_del(&kimn->link); >> + hlist_del_rcu(&kimn->link); >> mutex_unlock(&kvm->irq_lock); >> + synchronize_rcu(); >> } >> =20 >> void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask) >> @@ -263,11 +265,11 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, in= t irq, bool mask) >> struct kvm_irq_mask_notifier *kimn; >> struct hlist_node *n; >> =20 >> - WARN_ON(!mutex_is_locked(&kvm->irq_lock)); >> - >> - hlist_for_each_entry(kimn, n, &kvm->mask_notifier_list, link) >> + rcu_read_lock(); >> + hlist_for_each_entry_rcu(kimn, n, &kvm->mask_notifier_list, link) >> if (kimn->irq =3D=3D irq) >> kimn->func(kimn, mask); >> + rcu_read_unlock(); >> } >> =20 >> void kvm_free_irq_routing(struct kvm *kvm) >> --=20 >> 1.6.2.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe kvm" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> =20 > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > =20 --------------enig1F147F6CECFF0E2B625DB6CC 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 iEYEARECAAYFAkpbOyQACgkQP5K2CMvXmqHjIgCfS2HscWY3z5q5dIWxWfCA9vlj QHYAn0Yd8YCgWbvV/EvqLQ+qVFrjrgDy =H6Qt -----END PGP SIGNATURE----- --------------enig1F147F6CECFF0E2B625DB6CC--