| Message ID | 1490607072-21610-16-git-send-email-eric.auger@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Mar 27 2017 at 10:31:05 AM, Eric Auger <eric.auger@redhat.com> wrote: > Natively sort the device and ITE lists in ascending > deviceId/eventid order. This paves the way to optimized > DTE and ITE scan in guest RAM table where entries are chained > together using a next ID offset. > > Signed-off-by: Eric Auger <eric.auger@redhat.com> > Reviewed-by: Andre Przywara <andre.przywara@arm.com> > > --- > > v3 -> v4: > - added Andre's R-b > --- > virt/kvm/arm/vgic/vgic-its.c | 36 ++++++++++++++++++++++++++++++++++-- > 1 file changed, 34 insertions(+), 2 deletions(-) > > diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c > index 2a1ccbf..7364b7d 100644 > --- a/virt/kvm/arm/vgic/vgic-its.c > +++ b/virt/kvm/arm/vgic/vgic-its.c > @@ -726,6 +726,21 @@ static void vgic_its_free_collection(struct vgic_its *its, u32 coll_id) > kfree(collection); > } > > +static void ite_list_insert_sorted(struct list_head *h, struct its_ite *ite) > +{ > + struct list_head *pos = h->next; > + u32 id = ite->event_id; > + > + while (pos != h) { > + struct its_ite *iter = > + list_entry(pos, struct its_ite, ite_list); > + if (id < iter->event_id) > + break; > + pos = pos->next; > + } > + list_add_tail(&ite->ite_list, pos); > +} > + > /* Must be called with its_lock mutex held */ > static int vgic_its_alloc_ite(struct its_device *device, > struct its_ite **itep, > @@ -742,7 +757,7 @@ static int vgic_its_alloc_ite(struct its_device *device, > ite->collection = collection; > ite->lpi = lpi_id; > > - list_add_tail(&ite->ite_list, &device->itt_head); > + ite_list_insert_sorted(&device->itt_head, ite); > *itep = ite; > return 0; > } > @@ -835,6 +850,22 @@ static void vgic_its_unmap_device(struct kvm *kvm, struct its_device *device) > kfree(device); > } > > +static void device_list_insert_sorted(struct list_head *h, > + struct its_device *dev) > +{ > + struct list_head *pos = h->next; > + u32 id = dev->device_id; > + > + while (pos != h) { > + struct its_device *iter = > + list_entry(pos, struct its_device, dev_list); > + if (id < iter->device_id) > + break; > + pos = pos->next; > + } > + list_add_tail(&dev->dev_list, pos); > +} > + > /* Must be called with its_lock mutex held */ > static int vgic_its_alloc_device(struct vgic_its *its, > struct its_device **devp, > @@ -852,7 +883,8 @@ static int vgic_its_alloc_device(struct vgic_its *its, > device->nb_eventid_bits = nb_eventid_bits; > INIT_LIST_HEAD(&device->itt_head); > > - list_add_tail(&device->dev_list, &its->device_list); > + device_list_insert_sorted(&its->device_list, device); > + > *devp = device; > > return 0; What is the actual gain for sorting the list at runtime, vs sorting it at save time? A save/restore operation is a very rare event compared to the normal use of the ITS, so I'd rather put the overhead on the rarest event if possible. Thanks, M.
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index 2a1ccbf..7364b7d 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -726,6 +726,21 @@ static void vgic_its_free_collection(struct vgic_its *its, u32 coll_id) kfree(collection); } +static void ite_list_insert_sorted(struct list_head *h, struct its_ite *ite) +{ + struct list_head *pos = h->next; + u32 id = ite->event_id; + + while (pos != h) { + struct its_ite *iter = + list_entry(pos, struct its_ite, ite_list); + if (id < iter->event_id) + break; + pos = pos->next; + } + list_add_tail(&ite->ite_list, pos); +} + /* Must be called with its_lock mutex held */ static int vgic_its_alloc_ite(struct its_device *device, struct its_ite **itep, @@ -742,7 +757,7 @@ static int vgic_its_alloc_ite(struct its_device *device, ite->collection = collection; ite->lpi = lpi_id; - list_add_tail(&ite->ite_list, &device->itt_head); + ite_list_insert_sorted(&device->itt_head, ite); *itep = ite; return 0; } @@ -835,6 +850,22 @@ static void vgic_its_unmap_device(struct kvm *kvm, struct its_device *device) kfree(device); } +static void device_list_insert_sorted(struct list_head *h, + struct its_device *dev) +{ + struct list_head *pos = h->next; + u32 id = dev->device_id; + + while (pos != h) { + struct its_device *iter = + list_entry(pos, struct its_device, dev_list); + if (id < iter->device_id) + break; + pos = pos->next; + } + list_add_tail(&dev->dev_list, pos); +} + /* Must be called with its_lock mutex held */ static int vgic_its_alloc_device(struct vgic_its *its, struct its_device **devp, @@ -852,7 +883,8 @@ static int vgic_its_alloc_device(struct vgic_its *its, device->nb_eventid_bits = nb_eventid_bits; INIT_LIST_HEAD(&device->itt_head); - list_add_tail(&device->dev_list, &its->device_list); + device_list_insert_sorted(&its->device_list, device); + *devp = device; return 0;