Re: How to setup network connection for initramfs running in QEMU?

2017-05-25 Thread Pranay Srivastava 
Hi Douglas,

Do you've /etc/hosts ? Have you tried giving the loopback address in that
file?

Just check any /etc/hosts file from another distribution and hack on it to
at least have loopback address pinged. Then we'll try to fix machine to
machine ping. (Tun-tap? Not sure really.)




On 26-May-2017 8:34 AM, "Douglas Su"  wrote:

> Thanks to this mail list, I have already successfully set up a simple
> initramfs and booted it in QEMU with busybox tools.
>
> However, there is no network connection for the initramfs, that makes me
> hard to exchange files between qemu and the host.
>
> Command `ip link show` tells there exists only one 'lo' interface, and I
> can't ping 127.0.0.1 successfully.
>
> So how to boot initramfs in qemu with full network support?
>
> Best regards.
>
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How to setup network connection for initramfs running in QEMU?

2017-05-25 Thread Douglas Su 
Thanks to this mail list, I have already successfully set up a simple initramfs 
and booted it in QEMU with busybox tools.

However, there is no network connection for the initramfs, that makes me hard 
to exchange files between qemu and the host.

Command `ip link show` tells there exists only one 'lo' interface, and I can't 
ping 127.0.0.1 successfully.

So how to boot initramfs in qemu with full network support?

Best regards.
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Re: what is the current/ongoing state of userspace access to GPIO?

2017-05-25 Thread Robert P. J. Day 
On Thu, 25 May 2017, valdis.kletni...@vt.edu wrote:

> On Thu, 25 May 2017 15:20:06 -0400, "Robert P. J. Day" said:
> > On Thu, 25 May 2017, Greg KH wrote:
> >
> > > On Thu, May 25, 2017 at 03:02:24PM -0400, Robert P. J. Day wrote:
> > > >
> > > >   thoughts?
> > >
> > > Why not ask on the linux-gpio mailing list?
> >
> >   huh, i didn't even know there was such a thing.
>
> See http://vger.kernel.org for most of them.  Or look in MAINTAINERS:
>
> GPIO SUBSYSTEM
> M:  Linus Walleij 
> M:  Alexandre Courbot 
> L:  linux-g...@vger.kernel.org
>
> :)

  well, i'm pretty sure i can find it once i know what to look for.
:-)

rday

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Re: what is the current/ongoing state of userspace access to GPIO?

2017-05-25 Thread valdis . kletnieks 
On Thu, 25 May 2017 15:20:06 -0400, "Robert P. J. Day" said:
> On Thu, 25 May 2017, Greg KH wrote:
>
> > On Thu, May 25, 2017 at 03:02:24PM -0400, Robert P. J. Day wrote:
> > >
> > >   thoughts?
> >
> > Why not ask on the linux-gpio mailing list?
>
>   huh, i didn't even know there was such a thing.

See http://vger.kernel.org for most of them.  Or look in MAINTAINERS:

GPIO SUBSYSTEM
M:  Linus Walleij 
M:  Alexandre Courbot 
L:  linux-g...@vger.kernel.org

:)


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Re: what is the current/ongoing state of userspace access to GPIO?

2017-05-25 Thread Robert P. J. Day 
On Thu, 25 May 2017, Greg KH wrote:

> On Thu, May 25, 2017 at 03:02:24PM -0400, Robert P. J. Day wrote:
> >
> >   thoughts?
>
> Why not ask on the linux-gpio mailing list?

  huh, i didn't even know there was such a thing.

rday

-- 


Robert P. J. Day Ottawa, Ontario, CANADA
http://crashcourse.ca

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Re: what is the current/ongoing state of userspace access to GPIO?

2017-05-25 Thread Greg KH 
On Thu, May 25, 2017 at 03:02:24PM -0400, Robert P. J. Day wrote:
> 
>   thoughts?

Why not ask on the linux-gpio mailing list?

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Lock contention determination

2017-05-25 Thread Yiqun Chen 
Hi all
If I have a lockstat report showing that some lock has more waiting time
than holding time, can I assert that this lock is (one of) the performance
bottlenecks? Here performance bottleneck means we could optimize lock
usage, e.g. reduce the size of critical section etc.
If not, why?
Thanks beforehand

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Chen, Yiqun
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Re: what is the current/ongoing state of userspace access to GPIO?

2017-05-25 Thread Robert P. J. Day 
On Wed, 24 May 2017, Clemens Gruber wrote:

> Hi,
>
> On Wed, May 24, 2017 at 07:58:19AM -0400, Robert P. J. Day wrote:
> >
> >   ashamed to admit, i haven't been keeping up with this, so AIUI,
> > the GPIO sysfs interface is deprecated, replaced with character
> > device files (/dev/gpiochip*) to allow access to GPIO.
> >
> >   first, i find it curious that this is a move away from sysfs
> > access to using ioctl(), since i had always thought ioctls were
> > massively discouraged in new code. is there a document that goes
> > through the rationale for this change?
> >
> >   and i notice under Documentation/ABI/ that sysfs-gpio is listed
> > under "obsolete", while gpio-cdev is listed under "testing". this
> > seems inconsistent -- how can one be obsolete while the other be
> > categorized as testing? that just seems strange.
> >
> >   in any event, is the /dev/gpiochip* interface the recommended
> > interface now? thanks.
>
> Linus Walleij described the rationale in the first commit
> description. Have a look at 3c702e9987e2.
>
> Implementing it with netlink sockets would have made it much more
> complex, I suppose this is why they chose ioctl?
>
> By the way, I can recommend accessing the GPIO chardev with
> libgpiod: https://github.com/brgl/libgpiod
>
> This simplifies using it a lot! The tools are also quite nice.

  thanks, now a couple more (admittedly trivial) questions as i claw
my way through the current state of gpio. the doc file "gpio.txt"
explains that there are two different ways to access GPIO:

  - The descriptor-based interface is the preferred way to manipulate
GPIOs, and is described by all the files in this directory
excepted gpio-legacy.txt.

  - The legacy integer-based interface which is considered deprecated
(but still usable for compatibility reasons) is documented in
gpio-legacy.txt.

the above *seems* to suggest that one can use the newer, preferred
descriptor-based interface and bypass the "legacy" interface, but if i
look in drivers/gpio/Makefile, i see:

  obj-$(CONFIG_GPIOLIB)   += devres.o
  obj-$(CONFIG_GPIOLIB)   += gpiolib.o
  obj-$(CONFIG_GPIOLIB)   += gpiolib-legacy.o  <--- 
  obj-$(CONFIG_GPIOLIB)   += gpiolib-devprop.o

suggesting that if i select GPIOLIB, i get the legacy code compiled,
anyway. is that correct? it seems to disagree with the documentation,
unless that legacy source file is required no matter what, at which
point describing it as "legacy" seems misleading.

  thoughts?

rday

-- 


Robert P. J. Day Ottawa, Ontario, CANADA
http://crashcourse.ca

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Re: Multipath support?

2017-05-25 Thread Vasu M 
On Thu, May 25, 2017 at 12:05 AM, Vasu M  wrote:

> I would like to know from which version of Linux, ECMP is supported? I am
> trying to add a route with two next hops. Only one path gets added. And for
> the other path, the route says "RTNETLINK answers: File exists". I am not
> able to understand what's going on. The route prefix is not pointing to
> ecmp because metric is not given for static routes? How can I test
> multipath for a prefix that goes over 2 links?
>
> I tried "echo 7 > /proc/sys/kernel/printk" and dmesg but I don't see
> anything related to route add events. Just wondering how I should approach
> this problem.
>
> I am running the following versions on two devices running ONL.
>
> *Linux localhost 3.16.43-OpenNetworkLinux #1 SMP Thu May 11 18:37:48 UTC
> 2017 x86_64 GNU/Linux*
> I tried the following :-
>
> root@localhost:~# route -n
>
> Kernel IP routing table
>
> Destination Gateway Genmask Flags Metric RefUse
> Iface
>
> 0.0.0.0 192.168.100.1   0.0.0.0 UG0  00 ma1
>
> 10.10.10.0  0.0.0.0 255.255.255.0   U 0  00
> fpPort2
>
> 20.20.20.0  0.0.0.0 255.255.255.0   U 0  00
> fpPort13
>
> 192.168.100.0   0.0.0.0 255.255.255.0   U 0  00 ma1
>
> root@localhost:~# arp -a
>
> ? *(20.20.20.2) at 00:a0:c9:00:00:01 [ether] on fpPort13 *
>
> ? (192.168.100.100) at f0:7f:06:1d:56:ff [ether] on ma1
>
> ? (192.168.100.1) at 18:b1:69:33:88:a4 [ether] on ma1
>
> ? (192.168.100.52) at cc:37:ab:7c:ca:16 [ether] on ma1
>
> ? (192.168.100.3) at c8:1f:66:f6:ea:07 [ether] on ma1
>
> ? *(10.10.10.2) at 00:a0:c9:00:00:01 [ether] on fpPort2*
>
>
> ip route add 100.100.100.0/24  via 10.10.10.2
>
> root@localhost:~# route -n
>
> Kernel IP routing table
>
> Destination Gateway Genmask Flags Metric RefUse
> Iface
>
> 0.0.0.0 192.168.100.1   0.0.0.0 UG0  00 ma1
>
> 10.10.10.0  0.0.0.0 255.255.255.0   U 0  00
> fpPort2
>
> 20.20.20.0  0.0.0.0 255.255.255.0   U 0  00
> fpPort13
>
> 100.100.100.0   10.10.10.2  255.255.255.0   UG0  00
> fpPort2
>
> 192.168.100.0   0.0.0.0 255.255.255.0   U 0  00 ma1
>
> root@localhost:~# ip route add 100.100.100.0/24  via 20.20.20.2
>
> *RTNETLINK answers: File exists*
>


Figured "ip route append" is used to add ECMP. I am, however, seeing some
ECMP paths getting added to the rt table which seems to be a bug although
the behavior is not consistent.
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Multipath support?

2017-05-25 Thread Vasu M 
I would like to know from which version of Linux, ECMP is supported? I am
trying to add a route with two next hops. Only one path gets added. And for
the other path, the route says "RTNETLINK answers: File exists". I am not
able to understand what's going on. The route prefix is not pointing to
ecmp because metric is not given for static routes? How can I test
multipath for a prefix that goes over 2 links?

I tried "echo 7 > /proc/sys/kernel/printk" and dmesg but I don't see
anything related to route add events. Just wondering how I should approach
this problem.

I am running the following versions on two devices running ONL.

*Linux localhost 3.16.43-OpenNetworkLinux #1 SMP Thu May 11 18:37:48 UTC
2017 x86_64 GNU/Linux*
I tried the following :-

root@localhost:~# route -n

Kernel IP routing table

Destination Gateway Genmask Flags Metric RefUse
Iface

0.0.0.0 192.168.100.1   0.0.0.0 UG0  00 ma1

10.10.10.0  0.0.0.0 255.255.255.0   U 0  00
fpPort2

20.20.20.0  0.0.0.0 255.255.255.0   U 0  00
fpPort13

192.168.100.0   0.0.0.0 255.255.255.0   U 0  00 ma1

root@localhost:~# arp -a

? *(20.20.20.2) at 00:a0:c9:00:00:01 [ether] on fpPort13 *

? (192.168.100.100) at f0:7f:06:1d:56:ff [ether] on ma1

? (192.168.100.1) at 18:b1:69:33:88:a4 [ether] on ma1

? (192.168.100.52) at cc:37:ab:7c:ca:16 [ether] on ma1

? (192.168.100.3) at c8:1f:66:f6:ea:07 [ether] on ma1

? *(10.10.10.2) at 00:a0:c9:00:00:01 [ether] on fpPort2*


ip route add 100.100.100.0/24  via 10.10.10.2

root@localhost:~# route -n

Kernel IP routing table

Destination Gateway Genmask Flags Metric RefUse
Iface

0.0.0.0 192.168.100.1   0.0.0.0 UG0  00 ma1

10.10.10.0  0.0.0.0 255.255.255.0   U 0  00
fpPort2

20.20.20.0  0.0.0.0 255.255.255.0   U 0  00
fpPort13

100.100.100.0   10.10.10.2  255.255.255.0   UG0  00
fpPort2

192.168.100.0   0.0.0.0 255.255.255.0   U 0  00 ma1

root@localhost:~# ip route add 100.100.100.0/24  via 20.20.20.2

*RTNETLINK answers: File exists*
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