On Fri, Sep 28, 2018 at 04:17:34PM +0300, Ilya Maximets wrote:
> On 28.09.2018 15:13, Bruce Richardson wrote:
> > On Fri, Sep 28, 2018 at 01:40:25PM +0300, Ilya Maximets wrote:
> >> On 27.09.2018 11:28, Ilya Maximets wrote:
> >>> On 26.09.2018 10:26, Maxime Coquelin wrote:
> >>>> This patch opens a userfaultfd and sends it back to Qemu's
> >>>> VHOST_USER_POSTCOPY_ADVISE request.
> >>>>
> >>>> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> >>>> Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
> >>>> ---
> >>>> lib/librte_vhost/vhost.h | 2 ++
> >>>> lib/librte_vhost/vhost_user.c | 37 +++++++++++++++++++++++++++++++++++
> >>>> lib/librte_vhost/vhost_user.h | 3 ++-
> >>>> 3 files changed, 41 insertions(+), 1 deletion(-)
> >>>>
> >>>> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> >>>> index 25ffd7614..21722d8a8 100644
> >>>> --- a/lib/librte_vhost/vhost.h
> >>>> +++ b/lib/librte_vhost/vhost.h
> >>>> @@ -363,6 +363,8 @@ struct virtio_net {
> >>>> int slave_req_fd;
> >>>> rte_spinlock_t slave_req_lock;
> >>>>
> >>>> + int postcopy_ufd;
> >>>> +
> >>>> /*
> >>>> * Device id to identify a specific backend device.
> >>>> * It's set to -1 for the default software implementation.
> >>>> diff --git a/lib/librte_vhost/vhost_user.c
> >>>> b/lib/librte_vhost/vhost_user.c
> >>>> index a9b429598..bdfe2cac0 100644
> >>>> --- a/lib/librte_vhost/vhost_user.c
> >>>> +++ b/lib/librte_vhost/vhost_user.c
> >>>> @@ -24,9 +24,13 @@
> >>>> #include <stdlib.h>
> >>>> #include <string.h>
> >>>> #include <unistd.h>
> >>>> +#include <fcntl.h>
> >>>> +#include <linux/userfaultfd.h>
> >>>
> >>> Maybe we need compile time check for this header existence?
> >>> Otherwise, this will bump minimal kernel version for default linux build
> >>> to something like 4.3.
> >>
> >> We'll need a config option here (disabled by default) and guard all
> >> the postcopy related code.
> >> Meson build will be able to detect the header file and enable
> >> the config if possible. Like this:
> >>
> >> lib/librte_vhost/meson.build:
> >> if cc.has_header('linux/userfaultfd.h')
> >> dpdk_conf.set10('RTE_LIBRTE_VHOST_POSTCOPY', true)
> >
> > Are you sure you want 'set10' rather than 'set'. Set is probably easier
> > because it ensures no define on false, while set10 has a define of 0. This
> > has caught me out before.
> >
> > FYI, you can also avoid the if by putting the condition into the define:
> >
> > dpdk_conf.set('RTE_LIBRTE_VHOST_POSTCOPY', cc.has_header('...'))
>
> Sure, this variant looks better. Thanks for suggestions.
> I just copied my version from the similar code for 'RTE_HAS_LIBNUMA'.
>
Yes, looking at that code, it could do with a clean-up to shorten it too.
[It's true that nothing embarasses a programmer more than their own code 6
months layer :-)]
/Bruce
