Revision 42b5212fee4f57907e9415b18fe19c13e65574bc authored by David Vrabel on 02 February 2015, 16:57:51 UTC, committed by David S. Miller on 03 February 2015, 03:39:04 UTC
After commit e9d8b2c2968499c1f96563e6522c56958d5a1d0d (xen-netback:
disable rogue vif in kthread context), a fatal (protocol) error would
leave the guest Rx thread spinning, wasting CPU time.  Commit
ecf08d2dbb96d5a4b4bcc53a39e8d29cc8fef02e (xen-netback: reintroduce
guest Rx stall detection) made this even worse by removing a
cond_resched() from this path.

Since a fatal error is non-recoverable, just allow the guest Rx thread
to exit.  This requires taking additional refs to the task so the
thread exiting early is handled safely.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reported-by: Julien Grall <julien.grall@linaro.org>
Tested-by: Julien Grall <julien.grall@linaro.org>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 5a2e87b
Raw File
mono.txt
               Mono(tm) Binary Kernel Support for Linux
               -----------------------------------------

To configure Linux to automatically execute Mono-based .NET binaries
(in the form of .exe files) without the need to use the mono CLR
wrapper, you can use the BINFMT_MISC kernel support.

This will allow you to execute Mono-based .NET binaries just like any
other program after you have done the following:

1) You MUST FIRST install the Mono CLR support, either by downloading
   a binary package, a source tarball or by installing from CVS. Binary
   packages for several distributions can be found at:

	http://go-mono.com/download.html

   Instructions for compiling Mono can be found at:

	http://www.go-mono.com/compiling.html

   Once the Mono CLR support has been installed, just check that
   /usr/bin/mono (which could be located elsewhere, for example
   /usr/local/bin/mono) is working.

2) You have to compile BINFMT_MISC either as a module or into
   the kernel (CONFIG_BINFMT_MISC) and set it up properly.
   If you choose to compile it as a module, you will have
   to insert it manually with modprobe/insmod, as kmod
   cannot be easily supported with binfmt_misc. 
   Read the file 'binfmt_misc.txt' in this directory to know
   more about the configuration process.

3) Add the following entries to /etc/rc.local or similar script
   to be run at system startup:

# Insert BINFMT_MISC module into the kernel
if [ ! -e /proc/sys/fs/binfmt_misc/register ]; then
        /sbin/modprobe binfmt_misc
	# Some distributions, like Fedora Core, perform
	# the following command automatically when the
	# binfmt_misc module is loaded into the kernel
	# or during normal boot up (systemd-based systems).
	# Thus, it is possible that the following line
	# is not needed at all.
	mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
fi

# Register support for .NET CLR binaries
if [ -e /proc/sys/fs/binfmt_misc/register ]; then
	# Replace /usr/bin/mono with the correct pathname to
	# the Mono CLR runtime (usually /usr/local/bin/mono
	# when compiling from sources or CVS).
        echo ':CLR:M::MZ::/usr/bin/mono:' > /proc/sys/fs/binfmt_misc/register
else
        echo "No binfmt_misc support"
        exit 1
fi

4) Check that .exe binaries can be ran without the need of a
   wrapper script, simply by launching the .exe file directly
   from a command prompt, for example:

	/usr/bin/xsd.exe

   NOTE: If this fails with a permission denied error, check
         that the .exe file has execute permissions.
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