From: "Michael S. Tsirkin" <mst@redhat.com> To: linux-kernel@vger.kernel.org Cc: Rusty Russell <rusty@rustcorp.com.au>, Carsten Otte <cotte@de.ibm.com>, Christian Borntraeger <borntraeger@de.ibm.com>, linux390@de.ibm.com, Martin Schwidefsky <schwidefsky@de.ibm.com>, Heiko Carstens <heiko.carstens@de.ibm.com>, Shirley Ma <xma@us.ibm.com>, lguest@lists.ozlabs.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, Krishna Kumar <krkumar2@in.ibm.com>, Tom Lendacky <tahm@linux.vnet.ibm.com>, steved@us.ibm.com, habanero@linux.vnet.ibm.com Subject: [PATCH 07/18] virtio ring: inline function to check for events Date: Wed, 4 May 2011 23:51:29 +0300 [thread overview] Message-ID: <cc4596a5ecdbf8dd37b5567a36667e3841f18ca3.1304541919.git.mst@redhat.com> (raw) In-Reply-To: <cover.1304541918.git.mst@redhat.com> With the new used_event and avail_event and features, both host and guest need similar logic to check whether events are enabled, so it helps to put the common code in the header. Note that Xen has similar logic for notification hold-off in include/xen/interface/io/ring.h with req_event and req_prod corresponding to event_idx + 1 and new_idx respectively. +1 comes from the fact that req_event and req_prod in Xen start at 1, while event index in virtio starts at 0. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- include/linux/virtio_ring.h | 14 ++++++++++++++ 1 files changed, 14 insertions(+), 0 deletions(-) diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h index f791772..2a3b0ea 100644 --- a/include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -124,6 +124,20 @@ static inline unsigned vring_size(unsigned int num, unsigned long align) + sizeof(__u16) * 3 + sizeof(struct vring_used_elem) * num; } +/* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX */ +/* Assuming a given event_idx value from the other size, if + * we have just incremented index from old to new_idx, + * should we trigger an event? */ +static inline int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old) +{ + /* Note: Xen has similar logic for notification hold-off + * in include/xen/interface/io/ring.h with req_event and req_prod + * corresponding to event_idx + 1 and new_idx respectively. + * Note also that req_event and req_prod in Xen start at 1, + * event indexes in virtio start at 0. */ + return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old); +} + #ifdef __KERNEL__ #include <linux/irqreturn.h> struct virtio_device; -- 1.7.5.53.gc233e
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au>, Carsten Otte <cotte@de.ibm.com>, Christian Borntraeger <borntraeger@de.ibm.com>, linux390@de.ibm.com, Martin Schwidefsky <schwidefsky@de.ibm.com>, Heiko Carstens <heiko.carstens@de.ibm.com>, Shirley Ma <xma@us.ibm.com>, lguest@lists.ozlabs.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, Krishna Kumar <krkumar2@in.ibm.com>, Tom Lendacky <tahm@linux.vnet.ibm.com>, steved@us.ibm.com, habanero@linux.vnet.ibm.com Subject: [PATCH 07/18] virtio ring: inline function to check for events Date: Wed, 4 May 2011 23:51:29 +0300 [thread overview] Message-ID: <cc4596a5ecdbf8dd37b5567a36667e3841f18ca3.1304541919.git.mst@redhat.com> (raw) In-Reply-To: <cover.1304541918.git.mst@redhat.com> With the new used_event and avail_event and features, both host and guest need similar logic to check whether events are enabled, so it helps to put the common code in the header. Note that Xen has similar logic for notification hold-off in include/xen/interface/io/ring.h with req_event and req_prod corresponding to event_idx + 1 and new_idx respectively. +1 comes from the fact that req_event and req_prod in Xen start at 1, while event index in virtio starts at 0. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- include/linux/virtio_ring.h | 14 ++++++++++++++ 1 files changed, 14 insertions(+), 0 deletions(-) diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h index f791772..2a3b0ea 100644 --- a/include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -124,6 +124,20 @@ static inline unsigned vring_size(unsigned int num, unsigned long align) + sizeof(__u16) * 3 + sizeof(struct vring_used_elem) * num; } +/* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX */ +/* Assuming a given event_idx value from the other size, if + * we have just incremented index from old to new_idx, + * should we trigger an event? */ +static inline int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old) +{ + /* Note: Xen has similar logic for notification hold-off + * in include/xen/interface/io/ring.h with req_event and req_prod + * corresponding to event_idx + 1 and new_idx respectively. + * Note also that req_event and req_prod in Xen start at 1, + * event indexes in virtio start at 0. */ + return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old); +} + #ifdef __KERNEL__ #include <linux/irqreturn.h> struct virtio_device; -- 1.7.5.53.gc233e
next prev parent reply other threads:[~2011-05-04 20:52 UTC|newest] Thread overview: 144+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-05-04 20:50 [PATCH 00/18] virtio and vhost-net performance enhancements Michael S. Tsirkin 2011-05-04 20:50 ` Michael S. Tsirkin 2011-05-04 20:50 ` [PATCH 01/18] virtio: 64 bit features Michael S. Tsirkin 2011-05-04 20:50 ` Michael S. Tsirkin 2011-05-04 20:50 ` Michael S. Tsirkin 2011-05-04 20:50 ` [PATCH 02/18] virtio_test: update for " Michael S. Tsirkin 2011-05-04 20:50 ` Michael S. Tsirkin 2011-05-04 20:50 ` Michael S. Tsirkin 2011-05-04 20:50 ` [PATCH 03/18] vhost: fix " Michael S. Tsirkin 2011-05-04 20:50 ` Michael S. Tsirkin 2011-05-04 20:50 ` Michael S. Tsirkin 2011-05-04 20:51 ` [PATCH 04/18] virtio: don't delay avail index update Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-04 20:51 ` [PATCH 05/18] virtio: used event index interface Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-04 21:56 ` Tom Lendacky 2011-05-04 21:56 ` Tom Lendacky 2011-05-05 9:38 ` Michael S. Tsirkin 2011-05-05 9:38 ` Michael S. Tsirkin 2011-05-04 20:51 ` [PATCH 06/18] virtio_ring: avail " Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-09 4:13 ` Rusty Russell 2011-05-09 4:13 ` Rusty Russell 2011-05-09 4:13 ` Rusty Russell 2011-05-15 12:47 ` Michael S. Tsirkin 2011-05-15 12:47 ` Michael S. Tsirkin 2011-05-15 12:47 ` Michael S. Tsirkin 2011-05-16 6:23 ` Rusty Russell 2011-05-16 6:23 ` Rusty Russell 2011-05-16 6:23 ` Rusty Russell 2011-05-17 6:00 ` Michael S. Tsirkin 2011-05-17 6:00 ` Michael S. Tsirkin 2011-05-17 6:00 ` Michael S. Tsirkin 2011-05-18 0:08 ` Rusty Russell 2011-05-18 0:08 ` Rusty Russell 2011-05-18 0:08 ` Rusty Russell 2011-05-04 20:51 ` [PATCH 07/18] virtio ring: inline function to check for events Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin [this message] 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-05 8:34 ` Stefan Hajnoczi 2011-05-05 8:56 ` Michael S. Tsirkin 2011-05-05 8:56 ` Michael S. Tsirkin 2011-05-05 8:34 ` Stefan Hajnoczi 2011-05-04 20:51 ` [PATCH 08/18] virtio_ring: support for used_event idx feature Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-09 4:17 ` Rusty Russell 2011-05-09 4:17 ` Rusty Russell 2011-05-09 4:17 ` Rusty Russell 2011-05-15 12:47 ` Michael S. Tsirkin 2011-05-15 12:47 ` Michael S. Tsirkin 2011-05-15 12:47 ` Michael S. Tsirkin 2011-05-04 20:51 ` [PATCH 09/18] virtio: use avail_event index Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-04 21:58 ` Tom Lendacky 2011-05-04 21:58 ` Tom Lendacky 2011-05-05 9:34 ` Michael S. Tsirkin 2011-05-05 9:34 ` Michael S. Tsirkin 2011-05-09 4:33 ` Rusty Russell 2011-05-09 4:33 ` Rusty Russell 2011-05-09 4:33 ` Rusty Russell 2011-05-15 13:55 ` Michael S. Tsirkin 2011-05-15 13:55 ` Michael S. Tsirkin 2011-05-15 13:55 ` Michael S. Tsirkin 2011-05-16 7:12 ` Rusty Russell 2011-05-16 7:12 ` Rusty Russell 2011-05-16 7:12 ` Rusty Russell 2011-05-17 6:10 ` Michael S. Tsirkin 2011-05-17 6:10 ` Michael S. Tsirkin 2011-05-18 0:19 ` Rusty Russell 2011-05-18 0:19 ` Rusty Russell 2011-05-18 0:19 ` Rusty Russell 2011-05-18 5:43 ` Michael S. Tsirkin 2011-05-18 5:43 ` Michael S. Tsirkin 2011-05-18 5:43 ` Michael S. Tsirkin 2011-05-19 7:27 ` Michael S. Tsirkin 2011-05-19 7:27 ` Michael S. Tsirkin 2011-05-19 7:27 ` Michael S. Tsirkin 2011-05-17 6:10 ` Michael S. Tsirkin 2011-05-17 16:23 ` Tom Lendacky 2011-05-17 16:23 ` Tom Lendacky 2011-05-04 20:51 ` [PATCH 10/18] vhost: utilize used_event index Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-04 20:51 ` Michael S. Tsirkin 2011-05-04 20:52 ` [PATCH 11/18] vhost: support avail_event idx Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-04 20:52 ` [PATCH 12/18] virtio_test: support used_event index Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-04 20:52 ` [PATCH 13/18] virtio_test: avail_event index support Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-04 20:52 ` [PATCH 14/18] virtio: add api for delayed callbacks Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-09 5:57 ` Rusty Russell 2011-05-09 5:57 ` Rusty Russell 2011-05-09 5:57 ` Rusty Russell 2011-05-15 12:48 ` Michael S. Tsirkin 2011-05-15 12:48 ` Michael S. Tsirkin 2011-05-15 12:48 ` Michael S. Tsirkin 2011-05-16 7:13 ` Rusty Russell 2011-05-16 7:13 ` Rusty Russell 2011-05-16 7:13 ` Rusty Russell 2011-05-19 7:24 ` Michael S. Tsirkin 2011-05-19 7:24 ` Michael S. Tsirkin 2011-05-20 7:43 ` Rusty Russell 2011-05-20 7:43 ` Rusty Russell 2011-05-20 7:43 ` Rusty Russell 2011-05-19 7:24 ` Michael S. Tsirkin 2011-05-04 20:52 ` [PATCH 15/18] virtio_net: delay TX callbacks Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-04 20:52 ` [PATCH 16/18] virtio_ring: Add capacity check API Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-04 20:52 ` Michael S. Tsirkin 2011-05-04 20:53 ` [PATCH 17/18] virtio_net: fix TX capacity checks using new API Michael S. Tsirkin 2011-05-04 20:53 ` Michael S. Tsirkin 2011-05-04 20:53 ` Michael S. Tsirkin 2011-05-04 20:53 ` [PATCH 18/18] virtio_net: limit xmit polling Michael S. Tsirkin 2011-05-04 20:53 ` Michael S. Tsirkin 2011-05-04 20:53 ` Michael S. Tsirkin 2011-05-05 15:07 ` [PATCH 0/3] virtio and vhost-net performance enhancements Michael S. Tsirkin 2011-05-05 15:07 ` Michael S. Tsirkin 2011-05-05 15:08 ` [PATCH 1/3] virtio: fix avail event support Michael S. Tsirkin 2011-05-05 15:08 ` Michael S. Tsirkin 2011-05-05 15:08 ` Michael S. Tsirkin 2011-05-05 15:08 ` [PATCH 2/3] virtio_ring: check used_event offset Michael S. Tsirkin 2011-05-05 15:08 ` Michael S. Tsirkin 2011-05-05 15:08 ` Michael S. Tsirkin 2011-05-05 15:08 ` [PATCH 3/3] virtio_ring: need_event api comment fix Michael S. Tsirkin 2011-05-05 15:08 ` Michael S. Tsirkin 2011-05-05 15:08 ` Michael S. Tsirkin 2011-05-09 5:59 ` Rusty Russell 2011-05-09 5:59 ` Rusty Russell 2011-05-09 5:59 ` Rusty Russell 2011-05-05 15:07 ` [PATCH 0/3] virtio and vhost-net performance enhancements Michael S. Tsirkin 2011-05-11 17:10 ` [PATCH 00/18] " Krishna Kumar2 2011-05-11 17:10 ` Krishna Kumar2
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