similar to: [PATCH v4 0/2] virtio_balloon: Fix restore and convert to workqueue

Workqueues have clean and rich API for all basic operations. The code is usually easier and better readable. It can be easily tuned for the given purpose. In many cases, it allows to avoid an extra kernel thread. It helps to stop the growing number of them. Also there will be less thread-specific hacks all over the kernel code. It forces making the task selfcontained. There is no longer an

Workqueues have clean and rich API for all basic operations. The code is usually easier and better readable. It can be easily tuned for the given purpose. In many cases, it allows to avoid an extra kernel thread. It helps to stop the growing number of them. Also there will be less thread-specific hacks all over the kernel code. It forces making the task selfcontained. There is no longer an

The previous version did not prevent updating the balloon when it was being removed. There was an idea to update the stats in a separate work and cancel it after the config reset. But this does not seem to work. The code for updating the stats communicates with the host. IMHO, it should not run after the reset (flushing buffers). Therefore I decided to use a boolean value and a spin lock (inspired

The previous version did not prevent updating the balloon when it was being removed. There was an idea to update the stats in a separate work and cancel it after the config reset. But this does not seem to work. The code for updating the stats communicates with the host. IMHO, it should not run after the reset (flushing buffers). Therefore I decided to use a boolean value and a spin lock (inspired

Workqueues have clean and rich API for all basic operations. The code is usually easier and better readable. It can be easily tuned for the given purpose. In many cases, it allows to avoid an extra kernel thread. It helps to stop the growing number of them. Also there will be less thread-specific hacks all over the kernel code. It forces making the task selfcontained. There is no longer an

Workqueues have clean and rich API for all basic operations. The code is usually easier and better readable. It can be easily tuned for the given purpose. In many cases, it allows to avoid an extra kernel thread. It helps to stop the growing number of them. Also there will be less thread-specific hacks all over the kernel code. It forces making the task selfcontained. There is no longer an

On Fri, Dec 04, 2015 at 02:37:50PM +0100, Petr Mladek wrote: > fill_balloon() and leak_balloon() manipulate only a limited number > of pages in one call. This is the reason why remove_common() calls > leak_balloon() in a while cycle. > > remove_common() is called also when the system is being frozen. > But fill_balloon() is called only once when the system is being >

On Fri, Dec 04, 2015 at 02:37:50PM +0100, Petr Mladek wrote: > fill_balloon() and leak_balloon() manipulate only a limited number > of pages in one call. This is the reason why remove_common() calls > leak_balloon() in a while cycle. > > remove_common() is called also when the system is being frozen. > But fill_balloon() is called only once when the system is being >

Peter Mladek reported that balloon might never refill completely after restore. This is because fill_balloon is only called once there. Calling fill_balloon repeatedly seems too aggressive, especially in light of the fact that it sleeps on failure: let's wake the config change handler and fill it asynchronously. Reported-by: Petr Mladek <pmladek at suse.com> Signed-off-by: Michael S.

Peter Mladek reported that balloon might never refill completely after restore. This is because fill_balloon is only called once there. Calling fill_balloon repeatedly seems too aggressive, especially in light of the fact that it sleeps on failure: let's wake the config change handler and fill it asynchronously. Reported-by: Petr Mladek <pmladek at suse.com> Signed-off-by: Michael S.

On Fri, Dec 04, 2015 at 02:37:51PM +0100, Petr Mladek wrote: > From: Petr Mladek <pmladek at suse.cz> > > This patch moves the deferred work from the "vballoon" kthread into a > system freezable workqueue. > > We do not need to maintain and run a dedicated kthread. Also the event > driven workqueues API makes the logic much easier. Especially, we do > not

On Fri, Dec 04, 2015 at 02:37:51PM +0100, Petr Mladek wrote: > From: Petr Mladek <pmladek at suse.cz> > > This patch moves the deferred work from the "vballoon" kthread into a > system freezable workqueue. > > We do not need to maintain and run a dedicated kthread. Also the event > driven workqueues API makes the logic much easier. Especially, we do > not

Workqueues have clean and rich API for all basic operations. The code is usually easier and better readable. It can be easily tuned for the given purpose. In many cases, it allows to avoid an extra kernel thread. It helps to stop the growing number of them. Also there will be less thread-specific hacks all over the kernel code. It forces making the task selfcontained. There is no longer an

Workqueues have clean and rich API for all basic operations. The code is usually easier and better readable. It can be easily tuned for the given purpose. In many cases, it allows to avoid an extra kernel thread. It helps to stop the growing number of them. Also there will be less thread-specific hacks all over the kernel code. It forces making the task selfcontained. There is no longer an

On Thu, Feb 26, 2015 at 06:08:49PM +0100, Peter Zijlstra wrote: > On Thu, Feb 26, 2015 at 09:30:31AM +0100, Michael S. Tsirkin wrote: > > On Thu, Feb 26, 2015 at 11:50:42AM +1030, Rusty Russell wrote: > > > Thomas Huth <thuth at linux.vnet.ibm.com> writes: > > > > Hi all, > > > > > > > > with the recent kernel 3.19, I get a kernel

On Thu, Feb 26, 2015 at 06:08:49PM +0100, Peter Zijlstra wrote: > On Thu, Feb 26, 2015 at 09:30:31AM +0100, Michael S. Tsirkin wrote: > > On Thu, Feb 26, 2015 at 11:50:42AM +1030, Rusty Russell wrote: > > > Thomas Huth <thuth at linux.vnet.ibm.com> writes: > > > > Hi all, > > > > > > > > with the recent kernel 3.19, I get a kernel

From: Petr Mladek <pmladek at suse.cz> This patch moves the deferred work from the "vballoon" kthread into a system freezable workqueue. We do not need to maintain and run a dedicated kthread. Also the event driven workqueues API makes the logic much easier. Especially, we do not longer need an own wait queue, wait function, and freeze point. The conversion is pretty

On Thu, Feb 26, 2015 at 11:50:42AM +1030, Rusty Russell wrote: > Thomas Huth <thuth at linux.vnet.ibm.com> writes: > > Hi all, > > > > with the recent kernel 3.19, I get a kernel warning when I start my > > KVM guest on s390 with virtio balloon enabled: > > The deeper problem is that virtio_ccw_get_config just silently fails on > OOM. > > Neither

On Thu, Feb 26, 2015 at 11:50:42AM +1030, Rusty Russell wrote: > Thomas Huth <thuth at linux.vnet.ibm.com> writes: > > Hi all, > > > > with the recent kernel 3.19, I get a kernel warning when I start my > > KVM guest on s390 with virtio balloon enabled: > > The deeper problem is that virtio_ccw_get_config just silently fails on > OOM. > > Neither

Memory fragmentation introduced by ballooning might reduce significantly the number of 2MB contiguous memory blocks that can be used within a guest, thus imposing performance penalties associated with the reduced number of transparent huge pages that could be used by the guest workload. This patch-set follows the main idea discussed at 2012 LSFMMS session: "Ballooning for transparent huge