similar to: [PATCH 1/2] vhost: simplify work flushing

Hi Jason, Overall patches look good. Just one doubt I have is below: > > We use spinlock to synchronize the work list now which may cause > unnecessary contentions. So this patch switch to use llist to remove > this contention. Pktgen tests shows about 5% improvement: > > Before: > ~1300000 pps > After: > ~1370000 pps > > Signed-off-by: Jason Wang <jasowang

Hi Jason, Overall patches look good. Just one doubt I have is below: > > We use spinlock to synchronize the work list now which may cause > unnecessary contentions. So this patch switch to use llist to remove > this contention. Pktgen tests shows about 5% improvement: > > Before: > ~1300000 pps > After: > ~1370000 pps > > Signed-off-by: Jason Wang <jasowang

We use spinlock to synchronize the work list now which may cause unnecessary contentions. So this patch switch to use llist to remove this contention. Pktgen tests shows about 5% improvement: Before: ~1300000 pps After: ~1370000 pps Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/vhost/vhost.c | 52 +++++++++++++++++++++++++-------------------------- drivers/vhost/vhost.h |

If userspace does VHOST_VSOCK_SET_GUEST_CID before VHOST_SET_OWNER we can race where: 1. thread0 calls vhost_transport_send_pkt -> vhost_work_queue 2. thread1 does VHOST_SET_OWNER which calls vhost_worker_create. 3. vhost_worker_create will set the dev->worker pointer before setting the worker->vtsk pointer. 4. thread0's vhost_work_queue will see the dev->worker pointer is set and

If userspace does VHOST_VSOCK_SET_GUEST_CID before VHOST_SET_OWNER we can race where: 1. thread0 calls vhost_transport_send_pkt -> vhost_work_queue 2. thread1 does VHOST_SET_OWNER which calls vhost_worker_create. 3. vhost_worker_create will set the dev->worker pointer before setting the worker->vtsk pointer. 4. thread0's vhost_work_queue will see the dev->worker pointer is set and

On 5/31/23 10:15 AM, Mike Christie wrote: >>> rcu would work for your case and for what Jason had requested. >> Yeah, so you already have some patches? >> >> Do you want to send it to solve this problem? >> > Yeah, I'll break them out and send them later today when I can retest > rebased patches. > Just one question. Do you core vhost developers

On Wed, May 31, 2023 at 11:27:12AM -0500, Mike Christie wrote: >On 5/31/23 10:15 AM, Mike Christie wrote: >>>> rcu would work for your case and for what Jason had requested. >>> Yeah, so you already have some patches? >>> >>> Do you want to send it to solve this problem? >>> >> Yeah, I'll break them out and send them later today when I

In the next patches each vq might have different workers so one could have work but others do not. For net, we only want to check specific vqs, so this adds a helper to check if a vq has work pending and converts vhost-net to use it. Signed-off-by: Mike Christie <michael.christie at oracle.com> --- drivers/vhost/net.c | 2 +- drivers/vhost/vhost.c | 6 +++--- drivers/vhost/vhost.h | 2 +-

The following patches were built over linux-next which contains various vhost patches in mst's tree and the vhost_task patchset in Christian Brauner's tree: git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git kernel.user_worker branch: https://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git/log/?h=kernel.user_worker The latter patchset handles the review comment

From: Razya Ladelsky <razya at il.ibm.com> Date: Thu, 31 Jul 2014 09:47:20 +0300 Subject: [PATCH] vhost: Add polling mode When vhost is waiting for buffers from the guest driver (e.g., more packets to send in vhost-net's transmit queue), it normally goes to sleep and waits for the guest to "kick" it. This kick involves a PIO in the guest, and therefore an exit (and possibly

From: Razya Ladelsky <razya at il.ibm.com> Date: Thu, 31 Jul 2014 09:47:20 +0300 Subject: [PATCH] vhost: Add polling mode When vhost is waiting for buffers from the guest driver (e.g., more packets to send in vhost-net's transmit queue), it normally goes to sleep and waits for the guest to "kick" it. This kick involves a PIO in the guest, and therefore an exit (and possibly

I saw WARN_ON(!list_empty(&dev->work_list)) trigger so our custom flush is not as airtight as need be. This patch switches to a simple atomic counter + srcu instead of the custom locked queue + flush implementation. This will slow down the setup ioctls, which should not matter - it's slow path anyway. We use the expedited flush to at least make sure it has a sane time bound. Works

I saw WARN_ON(!list_empty(&dev->work_list)) trigger so our custom flush is not as airtight as need be. This patch switches to a simple atomic counter + srcu instead of the custom locked queue + flush implementation. This will slow down the setup ioctls, which should not matter - it's slow path anyway. We use the expedited flush to at least make sure it has a sane time bound. Works

Move vhost.h to include/linux to allow vhost driver out-of-tree compilation. Currently, this cannot be done properly because the vhost header file is in driver/vhost. To distribute a new vhost driver before it is included in the kernel tree, we need to package it using kmod, dkms, ..., and to compile it out-of-tree using headers provided by the distribution's kernel development package.

Move vhost.h to include/linux to allow vhost driver out-of-tree compilation. Currently, this cannot be done properly because the vhost header file is in driver/vhost. To distribute a new vhost driver before it is included in the kernel tree, we need to package it using kmod, dkms, ..., and to compile it out-of-tree using headers provided by the distribution's kernel development package.

On Mon, May 06, 2013 at 08:10:03PM +0800, Asias He wrote: > On Mon, May 06, 2013 at 01:03:42PM +0300, Michael S. Tsirkin wrote: > > On Mon, May 06, 2013 at 04:38:21PM +0800, Asias He wrote: > > > Currently, vhost-net and vhost-scsi are sharing the vhost core code. > > > However, vhost-scsi shares the code by including the vhost.c file > > > directly. > >

On Mon, May 06, 2013 at 08:10:03PM +0800, Asias He wrote: > On Mon, May 06, 2013 at 01:03:42PM +0300, Michael S. Tsirkin wrote: > > On Mon, May 06, 2013 at 04:38:21PM +0800, Asias He wrote: > > > Currently, vhost-net and vhost-scsi are sharing the vhost core code. > > > However, vhost-scsi shares the code by including the vhost.c file > > > directly. > >

The patch (7235acdb1) changed the way of the work flushing in which the queued seq, done seq, and the flushing are not used anymore. Then remove them now. Fixes: 7235acdb1 ("vhost: simplify work flushing") Cc: Jason Wang <jasowang at redhat.com> Signed-off-by: Tonghao Zhang <xiangxia.m.yue at gmail.com> --- drivers/vhost/vhost.c | 1 - drivers/vhost/vhost.h | 4 ---- 2

Asias He (3): vhost: Remove vhost_enable_zcopy in vhost.h vhost: Move VHOST_NET_FEATURES to net.c vhost: Make vhost a separate module drivers/vhost/Kconfig | 8 ++++++++ drivers/vhost/Makefile | 3 ++- drivers/vhost/net.c | 6 ++++++ drivers/vhost/scsi.c | 1 - drivers/vhost/vhost.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++- drivers/vhost/vhost.h | 8 ++------ 6

Asias He (3): vhost: Remove vhost_enable_zcopy in vhost.h vhost: Move VHOST_NET_FEATURES to net.c vhost: Make vhost a separate module drivers/vhost/Kconfig | 8 ++++++++ drivers/vhost/Makefile | 3 ++- drivers/vhost/net.c | 6 ++++++ drivers/vhost/scsi.c | 1 - drivers/vhost/vhost.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++- drivers/vhost/vhost.h | 8 ++------ 6