linux-toradex.git/drivers/hv/hv_balloon.c, branch v3.10.12 Linux kernel for Apalis and Colibri modules Drivers: hv: balloon: Do not post pressure status if interrupted 2013-08-04T08:50:58+00:00 K. Y. Srinivasan kys@microsoft.com 2013-07-15T05:38:12+00:00 e39992ecaa7230126f96285a19493a9883294fdf commit c5e2254f8d63a6654149aa32ac5f2b7dd66a976d upstream. When we are posting pressure status, we may get interrupted and handle the un-balloon operation. In this case just don't post the status as we know the pressure status is stale. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c5e2254f8d63a6654149aa32ac5f2b7dd66a976d upstream.

When we are posting pressure status, we may get interrupted and handle
the un-balloon operation. In this case just don't post the status as we
know the pressure status is stale.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers: hv: balloon: Fix a bug in the hot-add code 2013-08-04T08:50:58+00:00 K. Y. Srinivasan kys@microsoft.com 2013-07-15T05:38:11+00:00 7b7295e5a040abf574110c14de67e6b463a1d921 commit ed07ec93e83ec471d365ce084e43ad90fd205903 upstream. As we hot-add 128 MB chunks of memory, we wait to ensure that the memory is onlined before attempting to hot-add the next chunk. If the udev rule for memory hot-add is not executed within the allowed time, we would rollback the state and abort further hot-add. Since the hot-add has succeeded and the only failure is that the memory is not onlined within the allowed time, we should not be rolling back the state. Fix this bug. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit ed07ec93e83ec471d365ce084e43ad90fd205903 upstream.

As we hot-add 128 MB chunks of memory, we wait to ensure that the memory
is onlined before attempting to hot-add the next chunk. If the udev rule for
memory hot-add is not executed within the allowed time, we would rollback the
state and abort further hot-add. Since the hot-add has succeeded and the only
failure is that the memory is not onlined within the allowed time, we should not
be rolling back the state. Fix this bug.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers: hv: Notify the host of permanent hot-add failures 2013-03-29T16:03:21+00:00 K. Y. Srinivasan kys@microsoft.com 2013-03-18T20:51:38+00:00 7f4f2302a11173d0ef84bbab4b887b9b50c31dc6 If memory hot-add fails with the error -EEXIST, then this is a permanent failure. Notify the host of this information, so the host will not attempt hot-add again. If the failure were a transient failure, host will attempt a hot-add after some delay. In this version of the patch, I have added some additional comments to clarify how the host treats different failure conditions. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
If memory hot-add fails with the error -EEXIST, then this is a permanent
failure. Notify the host of this information, so the host will not attempt
hot-add again. If the failure were a transient failure, host will attempt
a hot-add after some delay.

In this version of the patch, I have added some additional comments
to clarify how the host treats different failure conditions.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers: hv: balloon: Support 2M page allocations for ballooning 2013-03-29T16:03:21+00:00 K. Y. Srinivasan kys@microsoft.com 2013-03-18T20:51:37+00:00 f766dc1ea576fcdfbf2bc5638757ddbdacfb5a69 On Hyper-V it will be very efficient to use 2M allocations in the guest as this makes the ballooning protocol with the host that much more efficient. Hyper-V uses page ranges (start pfn : number of pages) to specify memory being moved around and with 2M pages this encoding can be very efficient. However, when memory is returned to the guest, the host does not guarantee any granularity. To deal with this issue, split the page soon after a successful 2M allocation so that this memory can potentially be freed as 4K pages. If 2M allocations fail, we revert to 4K allocations. In this version of the patch, based on the feedback from Michal Hocko <mhocko@suse.cz>, I have added some additional commentary to the patch description. Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
On Hyper-V it will be very efficient to use 2M allocations in the guest as this
makes the ballooning protocol with the host that much more efficient. Hyper-V
uses page ranges (start pfn : number of pages) to specify memory being moved
around and with 2M pages this encoding can be very efficient. However, when
memory is returned to the guest, the host does not guarantee any granularity.
To deal with this issue, split the page soon after a successful 2M allocation
so that this memory can potentially be freed as 4K pages.

If 2M allocations fail, we revert to 4K allocations.

In this version of the patch, based on the feedback from Michal Hocko
<mhocko@suse.cz>, I have added some additional commentary to the patch
description.

Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers: hv: balloon: Permit Linux to specify hot-add alignment requirements 2013-03-29T15:53:12+00:00 K. Y. Srinivasan kys@microsoft.com 2013-03-29T14:36:11+00:00 647965a268fd876781dd9899185482682bf42f6a Some Windows hosts permit the guest to specify memory hot-add alignment requirements (if any). Linux currently requires a 128MB alignment on memory segments that can be hot-added. Specify this alignment requirement to the host. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Some Windows hosts permit the guest to specify memory hot-add alignment
requirements (if any). Linux currently requires a 128MB alignment on memory
segments that can be hot-added. Specify this alignment requirement to the
host.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers: hv: balloon: make local functions static 2013-03-25T20:31:24+00:00 Wei Yongjun yongjun_wei@trendmicro.com.cn 2013-03-20T15:25:59+00:00 a6025a2a861845447adeb7a11c3043039959d3a1 local functions that could be static. Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
local functions that could be static.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers: hv: balloon: Implement hot-add functionality 2013-03-15T19:11:51+00:00 K. Y. Srinivasan kys@microsoft.com 2013-03-15T19:25:43+00:00 1cac8cd4d146b60a7c70d778b5be928281b3b551 Implement the memory hot-add functionality. With this, Linux guests can fully participate in the Dynamic Memory protocol implemented in the Windows hosts. In this version of the patch, based Olaf Herring's feedback, I have gotten rid of the module level dependency on MEMORY_HOTPLUG. Instead the code within the driver that depends on MEMORY_HOTPLUG has the appropriate compilation switches. This would allow this driver to support pure ballooning in cases where the kernel does not support memory hotplug. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Implement the memory hot-add functionality. With this, Linux guests can fully
participate in the Dynamic Memory protocol implemented in the Windows hosts.

In this version of the patch, based Olaf Herring's feedback, I have gotten
rid of the module level dependency on MEMORY_HOTPLUG. Instead the code within
the driver that depends on MEMORY_HOTPLUG has the appropriate compilation
switches. This would allow this driver to support pure ballooning in cases
where the kernel does not support memory hotplug.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers: hv: balloon: Make the balloon driver not unloadable 2013-03-15T19:11:50+00:00 K. Y. Srinivasan kys@microsoft.com 2013-03-15T19:25:42+00:00 0cf40a3e661b09c0dda795a77ccc0402c3153859 The balloon driver is stateful. For instance, it needs to keep track of pages that have been ballooned out to properly post pressure reports. This state cannot be re-constructed if the driver were to be unloaded and subsequently loaded. Furthermore, as we support memory hot-add as part of this driver, this driver becomes even more stateful and this state cannot be re-created. Make the balloon driver unloadable to deal with this issue. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
The balloon driver is stateful. For instance, it needs to keep track of pages
that have been ballooned out to properly post pressure reports. This state cannot
be re-constructed if the driver were to be unloaded and subsequently loaded.
Furthermore, as we support memory hot-add as part of this driver, this driver becomes
even more stateful and this state cannot be re-created. Make the balloon driver
unloadable to deal with this issue.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers: hv: balloon: Execute hot-add code in a separate context 2013-03-15T19:11:50+00:00 K. Y. Srinivasan kys@microsoft.com 2013-03-15T19:25:41+00:00 c51af826cf062af3c49a99a05a33236d93c57e72 Execute the hot-add operation in a separate work context. This allows us to decouple the pressure reporting activity from the "hot-add" activity. Testing has shown that this makes the guest more responsive to hot add requests. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Execute the hot-add operation in a separate work context.
This allows us to decouple the pressure reporting activity from the
"hot-add" activity. Testing has shown that this makes the guest more
responsive to hot add requests.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Drivers: hv: balloon: Execute balloon inflation in a separate context 2013-03-15T19:11:50+00:00 K. Y. Srinivasan kys@microsoft.com 2013-03-15T19:25:40+00:00 6571b2dab4eb6c7061160490db984dbc01e5626d Execute the balloon inflation operation in a separate work context. This allows us to decouple the pressure reporting activity from the ballooning activity. Testing has shown that this decoupling makes the guest more reponsive. Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Execute the balloon inflation operation in a separate work context.
This allows us to decouple the pressure reporting activity from the
ballooning activity. Testing has shown that this decoupling makes the
guest more reponsive.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>