* [Qemu-devel] [PATCH] virtio-balloon: Fix ballooning not working correctly when hotplug memory
@ 2014-09-15 12:29 zhanghailiang
2014-09-18 1:47 ` zhanghailiang
2014-09-19 13:09 ` Igor Mammedov
0 siblings, 2 replies; 5+ messages in thread
From: zhanghailiang @ 2014-09-15 12:29 UTC (permalink / raw)
To: qemu-devel
Cc: peter.maydell, zhanghailiang, mst, luonengjun, peter.huangpeng,
lcapitulino, imammedo
When do memory balloon, it references the ram_size as the real ram size of VM,
But here ram_size is not include the hotplugged memory, and the result will
be confused.
Steps to reproduce:
(1)Start VM: qemu -m size=1024,slots=4,maxmem=8G
(2)In VM: #free -m : 1024M
(3)qmp balloon 512M
(4)In VM: #free -m : 512M
(5)hotplug pc-dimm 1G
(6)In VM: #free -m : 1512M
(7)qmp balloon 256M
(8)In VM: #free -m :1256M
Here we add a new global variable 'vm_ram_size', it will stat
the VM's real ram size which include configured ram and hotplugged ram.
virtio-balloon will reference this parameter.
Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
---
hw/i386/pc.c | 1 +
hw/virtio/virtio-balloon.c | 10 +++++-----
include/exec/cpu-common.h | 1 +
vl.c | 3 +++
4 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index b6c9b61..817810b 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1606,6 +1606,7 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev,
memory_region_add_subregion(&pcms->hotplug_memory,
addr - pcms->hotplug_memory_base, mr);
vmstate_register_ram(mr, dev);
+ vm_ram_size += memory_region_size(mr);
hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
hhc->plug(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err);
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index 2c30b3d..205e1fe 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -292,7 +292,7 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
dev->actual = le32_to_cpu(config.actual);
if (dev->actual != oldactual) {
- qapi_event_send_balloon_change(ram_size -
+ qapi_event_send_balloon_change(vm_ram_size -
((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
&error_abort);
}
@@ -307,7 +307,7 @@ static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
{
VirtIOBalloon *dev = opaque;
- info->actual = ram_size - ((uint64_t) dev->actual <<
+ info->actual = vm_ram_size - ((uint64_t) dev->actual <<
VIRTIO_BALLOON_PFN_SHIFT);
}
@@ -316,11 +316,11 @@ static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
- if (target > ram_size) {
- target = ram_size;
+ if (target > vm_ram_size) {
+ target = vm_ram_size;
}
if (target) {
- dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
+ dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
virtio_notify_config(vdev);
}
}
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index e3ec4c8..f55db6a 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -46,6 +46,7 @@ typedef uintptr_t ram_addr_t;
#endif
extern ram_addr_t ram_size;
+extern ram_addr_t vm_ram_size;
/* memory API */
diff --git a/vl.c b/vl.c
index 9c9acf5..5d20d0c 100644
--- a/vl.c
+++ b/vl.c
@@ -132,6 +132,7 @@ DisplayType display_type = DT_DEFAULT;
static int display_remote;
const char* keyboard_layout = NULL;
ram_addr_t ram_size;
+ram_addr_t vm_ram_size; /* ram_size + hotplugged ram size */
const char *mem_path = NULL;
int mem_prealloc = 0; /* force preallocation of physical target memory */
int nb_nics;
@@ -3015,6 +3016,7 @@ int main(int argc, char **argv, char **envp)
machine_class = find_default_machine();
cpu_model = NULL;
ram_size = default_ram_size;
+ vm_ram_size = ram_size;
snapshot = 0;
cyls = heads = secs = 0;
translation = BIOS_ATA_TRANSLATION_AUTO;
@@ -3388,6 +3390,7 @@ int main(int argc, char **argv, char **envp)
"'%s' option\n", slots_str ? "maxmem" : "slots");
exit(EXIT_FAILURE);
}
+ vm_ram_size = ram_size;
break;
}
#ifdef CONFIG_TPM
--
1.7.12.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [PATCH] virtio-balloon: Fix ballooning not working correctly when hotplug memory
2014-09-15 12:29 [Qemu-devel] [PATCH] virtio-balloon: Fix ballooning not working correctly when hotplug memory zhanghailiang
@ 2014-09-18 1:47 ` zhanghailiang
2014-09-19 13:09 ` Igor Mammedov
1 sibling, 0 replies; 5+ messages in thread
From: zhanghailiang @ 2014-09-18 1:47 UTC (permalink / raw)
To: qemu-devel
Cc: peter.maydell, mst, luonengjun, peter.huangpeng, lcapitulino,
imammedo
Hi,
Ping...
Is anyone concerned about this patch? Is this a bug?
Thanks,
zhanghailiang
On 2014/9/15 20:29, zhanghailiang wrote:
> When do memory balloon, it references the ram_size as the real ram size of VM,
> But here ram_size is not include the hotplugged memory, and the result will
> be confused.
>
> Steps to reproduce:
> (1)Start VM: qemu -m size=1024,slots=4,maxmem=8G
> (2)In VM: #free -m : 1024M
> (3)qmp balloon 512M
> (4)In VM: #free -m : 512M
> (5)hotplug pc-dimm 1G
> (6)In VM: #free -m : 1512M
> (7)qmp balloon 256M
> (8)In VM: #free -m :1256M
>
> Here we add a new global variable 'vm_ram_size', it will stat
> the VM's real ram size which include configured ram and hotplugged ram.
> virtio-balloon will reference this parameter.
>
> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
> ---
> hw/i386/pc.c | 1 +
> hw/virtio/virtio-balloon.c | 10 +++++-----
> include/exec/cpu-common.h | 1 +
> vl.c | 3 +++
> 4 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index b6c9b61..817810b 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1606,6 +1606,7 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev,
> memory_region_add_subregion(&pcms->hotplug_memory,
> addr - pcms->hotplug_memory_base, mr);
> vmstate_register_ram(mr, dev);
> + vm_ram_size += memory_region_size(mr);
>
> hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
> hhc->plug(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err);
> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> index 2c30b3d..205e1fe 100644
> --- a/hw/virtio/virtio-balloon.c
> +++ b/hw/virtio/virtio-balloon.c
> @@ -292,7 +292,7 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
> memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
> dev->actual = le32_to_cpu(config.actual);
> if (dev->actual != oldactual) {
> - qapi_event_send_balloon_change(ram_size -
> + qapi_event_send_balloon_change(vm_ram_size -
> ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
> &error_abort);
> }
> @@ -307,7 +307,7 @@ static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
> static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
> {
> VirtIOBalloon *dev = opaque;
> - info->actual = ram_size - ((uint64_t) dev->actual <<
> + info->actual = vm_ram_size - ((uint64_t) dev->actual <<
> VIRTIO_BALLOON_PFN_SHIFT);
> }
>
> @@ -316,11 +316,11 @@ static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
> VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
> VirtIODevice *vdev = VIRTIO_DEVICE(dev);
>
> - if (target > ram_size) {
> - target = ram_size;
> + if (target > vm_ram_size) {
> + target = vm_ram_size;
> }
> if (target) {
> - dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
> + dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
> virtio_notify_config(vdev);
> }
> }
> diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
> index e3ec4c8..f55db6a 100644
> --- a/include/exec/cpu-common.h
> +++ b/include/exec/cpu-common.h
> @@ -46,6 +46,7 @@ typedef uintptr_t ram_addr_t;
> #endif
>
> extern ram_addr_t ram_size;
> +extern ram_addr_t vm_ram_size;
>
> /* memory API */
>
> diff --git a/vl.c b/vl.c
> index 9c9acf5..5d20d0c 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -132,6 +132,7 @@ DisplayType display_type = DT_DEFAULT;
> static int display_remote;
> const char* keyboard_layout = NULL;
> ram_addr_t ram_size;
> +ram_addr_t vm_ram_size; /* ram_size + hotplugged ram size */
> const char *mem_path = NULL;
> int mem_prealloc = 0; /* force preallocation of physical target memory */
> int nb_nics;
> @@ -3015,6 +3016,7 @@ int main(int argc, char **argv, char **envp)
> machine_class = find_default_machine();
> cpu_model = NULL;
> ram_size = default_ram_size;
> + vm_ram_size = ram_size;
> snapshot = 0;
> cyls = heads = secs = 0;
> translation = BIOS_ATA_TRANSLATION_AUTO;
> @@ -3388,6 +3390,7 @@ int main(int argc, char **argv, char **envp)
> "'%s' option\n", slots_str ? "maxmem" : "slots");
> exit(EXIT_FAILURE);
> }
> + vm_ram_size = ram_size;
> break;
> }
> #ifdef CONFIG_TPM
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [PATCH] virtio-balloon: Fix ballooning not working correctly when hotplug memory
2014-09-15 12:29 [Qemu-devel] [PATCH] virtio-balloon: Fix ballooning not working correctly when hotplug memory zhanghailiang
2014-09-18 1:47 ` zhanghailiang
@ 2014-09-19 13:09 ` Igor Mammedov
2014-09-22 3:36 ` zhanghailiang
1 sibling, 1 reply; 5+ messages in thread
From: Igor Mammedov @ 2014-09-19 13:09 UTC (permalink / raw)
To: zhanghailiang
Cc: peter.maydell, mst, qemu-devel, luonengjun, peter.huangpeng,
lcapitulino
On Mon, 15 Sep 2014 20:29:38 +0800
zhanghailiang <zhang.zhanghailiang@huawei.com> wrote:
> When do memory balloon, it references the ram_size as the real ram size of VM,
> But here ram_size is not include the hotplugged memory, and the result will
> be confused.
>
> Steps to reproduce:
> (1)Start VM: qemu -m size=1024,slots=4,maxmem=8G
> (2)In VM: #free -m : 1024M
> (3)qmp balloon 512M
> (4)In VM: #free -m : 512M
> (5)hotplug pc-dimm 1G
> (6)In VM: #free -m : 1512M
> (7)qmp balloon 256M
> (8)In VM: #free -m :1256M
>
> Here we add a new global variable 'vm_ram_size', it will stat
"qmp balloon" is not performance critical code and instead of a global
variable, size could be calculated each time by enumerating present memory devices.
> the VM's real ram size which include configured ram and hotplugged ram.
> virtio-balloon will reference this parameter.
I know it's not supported yet but what will happen with balloonig
if dimm device is removed without telling about it to balloon first?
I'm not sure if balloon and native memory hotplug should be integrated.
Native memory hotplug was intended as a replacement for ballooning
without its drawbacks albeit guest OS memory unplug support is in
its infancy stage yet.
>
> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
> ---
> hw/i386/pc.c | 1 +
> hw/virtio/virtio-balloon.c | 10 +++++-----
> include/exec/cpu-common.h | 1 +
> vl.c | 3 +++
> 4 files changed, 10 insertions(+), 5 deletions(-)
>
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index b6c9b61..817810b 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1606,6 +1606,7 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev,
> memory_region_add_subregion(&pcms->hotplug_memory,
> addr - pcms->hotplug_memory_base, mr);
> vmstate_register_ram(mr, dev);
> + vm_ram_size += memory_region_size(mr);
>
> hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
> hhc->plug(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err);
> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> index 2c30b3d..205e1fe 100644
> --- a/hw/virtio/virtio-balloon.c
> +++ b/hw/virtio/virtio-balloon.c
> @@ -292,7 +292,7 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
> memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
> dev->actual = le32_to_cpu(config.actual);
> if (dev->actual != oldactual) {
> - qapi_event_send_balloon_change(ram_size -
> + qapi_event_send_balloon_change(vm_ram_size -
> ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
> &error_abort);
> }
> @@ -307,7 +307,7 @@ static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
> static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
> {
> VirtIOBalloon *dev = opaque;
> - info->actual = ram_size - ((uint64_t) dev->actual <<
> + info->actual = vm_ram_size - ((uint64_t) dev->actual <<
> VIRTIO_BALLOON_PFN_SHIFT);
> }
>
> @@ -316,11 +316,11 @@ static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
> VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
> VirtIODevice *vdev = VIRTIO_DEVICE(dev);
>
> - if (target > ram_size) {
> - target = ram_size;
> + if (target > vm_ram_size) {
> + target = vm_ram_size;
> }
> if (target) {
> - dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
> + dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
> virtio_notify_config(vdev);
> }
> }
> diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
> index e3ec4c8..f55db6a 100644
> --- a/include/exec/cpu-common.h
> +++ b/include/exec/cpu-common.h
> @@ -46,6 +46,7 @@ typedef uintptr_t ram_addr_t;
> #endif
>
> extern ram_addr_t ram_size;
> +extern ram_addr_t vm_ram_size;
>
> /* memory API */
>
> diff --git a/vl.c b/vl.c
> index 9c9acf5..5d20d0c 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -132,6 +132,7 @@ DisplayType display_type = DT_DEFAULT;
> static int display_remote;
> const char* keyboard_layout = NULL;
> ram_addr_t ram_size;
> +ram_addr_t vm_ram_size; /* ram_size + hotplugged ram size */
> const char *mem_path = NULL;
> int mem_prealloc = 0; /* force preallocation of physical target memory */
> int nb_nics;
> @@ -3015,6 +3016,7 @@ int main(int argc, char **argv, char **envp)
> machine_class = find_default_machine();
> cpu_model = NULL;
> ram_size = default_ram_size;
> + vm_ram_size = ram_size;
> snapshot = 0;
> cyls = heads = secs = 0;
> translation = BIOS_ATA_TRANSLATION_AUTO;
> @@ -3388,6 +3390,7 @@ int main(int argc, char **argv, char **envp)
> "'%s' option\n", slots_str ? "maxmem" : "slots");
> exit(EXIT_FAILURE);
> }
> + vm_ram_size = ram_size;
> break;
> }
> #ifdef CONFIG_TPM
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [PATCH] virtio-balloon: Fix ballooning not working correctly when hotplug memory
2014-09-19 13:09 ` Igor Mammedov
@ 2014-09-22 3:36 ` zhanghailiang
2014-09-22 8:14 ` Igor Mammedov
0 siblings, 1 reply; 5+ messages in thread
From: zhanghailiang @ 2014-09-22 3:36 UTC (permalink / raw)
To: Igor Mammedov
Cc: peter.maydell, mst, qemu-devel, luonengjun, peter.huangpeng,
lcapitulino
Hi Igor,
Thanks for your reviewing...
> On Mon, 15 Sep 2014 20:29:38 +0800
> zhanghailiang <zhang.zhanghailiang@huawei.com> wrote:
>
>> When do memory balloon, it references the ram_size as the real ram size of VM,
>> But here ram_size is not include the hotplugged memory, and the result will
>> be confused.
>>
>> Steps to reproduce:
>> (1)Start VM: qemu -m size=1024,slots=4,maxmem=8G
>> (2)In VM: #free -m : 1024M
>> (3)qmp balloon 512M
>> (4)In VM: #free -m : 512M
>> (5)hotplug pc-dimm 1G
>> (6)In VM: #free -m : 1512M
>> (7)qmp balloon 256M
>> (8)In VM: #free -m :1256M
>>
>> Here we add a new global variable 'vm_ram_size', it will stat
> "qmp balloon" is not performance critical code and instead of a global
> variable, size could be calculated each time by enumerating present memory devices.
>
Good idea, in this way, we don't have to treat hotplug/unplug memory specially.
Will fix like that. Thanks.
>
>> the VM's real ram size which include configured ram and hotplugged ram.
>> virtio-balloon will reference this parameter.
> I know it's not supported yet but what will happen with balloonig
> if dimm device is removed without telling about it to balloon first?
>
Then, calculating the ram size will also be wrong and the result of balloon
will be confused too. 'size be calculated each time' you have suggested above will
solve this problem;)
> I'm not sure if balloon and native memory hotplug should be integrated.
> Native memory hotplug was intended as a replacement for ballooning
> without its drawbacks albeit guest OS memory unplug support is in
> its infancy stage yet.
>
IMHO memory hotplug/unplug can not replace the balloon completely,
Memory hotplug/unplug way may be a little stiff.
Example:
VM's memroy :1G
hotplugged one pc-dimm mem :1G
Now we want to limit the VM's ram size of guest OS to 1512M.
I don't know if we can unplugging a pc-dimm which has a different size to
its original size (hot add stage)? Here is 512M.
If it supports, what about limit ram size to 1100M?;) There seems to
be a minimal size limit for memory hotplug...(If i'm wrong, please let me know;))
Maybe in actual usage scenario we will use them together.
So i think we'd better to fix it.
Thanks,
zhanghailiang
>>
>> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
>> ---
>> hw/i386/pc.c | 1 +
>> hw/virtio/virtio-balloon.c | 10 +++++-----
>> include/exec/cpu-common.h | 1 +
>> vl.c | 3 +++
>> 4 files changed, 10 insertions(+), 5 deletions(-)
>>
>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
>> index b6c9b61..817810b 100644
>> --- a/hw/i386/pc.c
>> +++ b/hw/i386/pc.c
>> @@ -1606,6 +1606,7 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev,
>> memory_region_add_subregion(&pcms->hotplug_memory,
>> addr - pcms->hotplug_memory_base, mr);
>> vmstate_register_ram(mr, dev);
>> + vm_ram_size += memory_region_size(mr);
>>
>> hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
>> hhc->plug(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err);
>> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
>> index 2c30b3d..205e1fe 100644
>> --- a/hw/virtio/virtio-balloon.c
>> +++ b/hw/virtio/virtio-balloon.c
>> @@ -292,7 +292,7 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
>> memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
>> dev->actual = le32_to_cpu(config.actual);
>> if (dev->actual != oldactual) {
>> - qapi_event_send_balloon_change(ram_size -
>> + qapi_event_send_balloon_change(vm_ram_size -
>> ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
>> &error_abort);
>> }
>> @@ -307,7 +307,7 @@ static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
>> static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
>> {
>> VirtIOBalloon *dev = opaque;
>> - info->actual = ram_size - ((uint64_t) dev->actual <<
>> + info->actual = vm_ram_size - ((uint64_t) dev->actual <<
>> VIRTIO_BALLOON_PFN_SHIFT);
>> }
>>
>> @@ -316,11 +316,11 @@ static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
>> VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
>> VirtIODevice *vdev = VIRTIO_DEVICE(dev);
>>
>> - if (target > ram_size) {
>> - target = ram_size;
>> + if (target > vm_ram_size) {
>> + target = vm_ram_size;
>> }
>> if (target) {
>> - dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
>> + dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
>> virtio_notify_config(vdev);
>> }
>> }
>> diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
>> index e3ec4c8..f55db6a 100644
>> --- a/include/exec/cpu-common.h
>> +++ b/include/exec/cpu-common.h
>> @@ -46,6 +46,7 @@ typedef uintptr_t ram_addr_t;
>> #endif
>>
>> extern ram_addr_t ram_size;
>> +extern ram_addr_t vm_ram_size;
>>
>> /* memory API */
>>
>> diff --git a/vl.c b/vl.c
>> index 9c9acf5..5d20d0c 100644
>> --- a/vl.c
>> +++ b/vl.c
>> @@ -132,6 +132,7 @@ DisplayType display_type = DT_DEFAULT;
>> static int display_remote;
>> const char* keyboard_layout = NULL;
>> ram_addr_t ram_size;
>> +ram_addr_t vm_ram_size; /* ram_size + hotplugged ram size */
>> const char *mem_path = NULL;
>> int mem_prealloc = 0; /* force preallocation of physical target memory */
>> int nb_nics;
>> @@ -3015,6 +3016,7 @@ int main(int argc, char **argv, char **envp)
>> machine_class = find_default_machine();
>> cpu_model = NULL;
>> ram_size = default_ram_size;
>> + vm_ram_size = ram_size;
>> snapshot = 0;
>> cyls = heads = secs = 0;
>> translation = BIOS_ATA_TRANSLATION_AUTO;
>> @@ -3388,6 +3390,7 @@ int main(int argc, char **argv, char **envp)
>> "'%s' option\n", slots_str ? "maxmem" : "slots");
>> exit(EXIT_FAILURE);
>> }
>> + vm_ram_size = ram_size;
>> break;
>> }
>> #ifdef CONFIG_TPM
>
>
> .
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [Qemu-devel] [PATCH] virtio-balloon: Fix ballooning not working correctly when hotplug memory
2014-09-22 3:36 ` zhanghailiang
@ 2014-09-22 8:14 ` Igor Mammedov
0 siblings, 0 replies; 5+ messages in thread
From: Igor Mammedov @ 2014-09-22 8:14 UTC (permalink / raw)
To: zhanghailiang
Cc: peter.maydell, mst, qemu-devel, luonengjun, peter.huangpeng,
lcapitulino
On Mon, 22 Sep 2014 11:36:35 +0800
zhanghailiang <zhang.zhanghailiang@huawei.com> wrote:
> Hi Igor,
>
> Thanks for your reviewing...
>
> > On Mon, 15 Sep 2014 20:29:38 +0800
> > zhanghailiang <zhang.zhanghailiang@huawei.com> wrote:
> >
> >> When do memory balloon, it references the ram_size as the real ram size of VM,
> >> But here ram_size is not include the hotplugged memory, and the result will
> >> be confused.
> >>
> >> Steps to reproduce:
> >> (1)Start VM: qemu -m size=1024,slots=4,maxmem=8G
> >> (2)In VM: #free -m : 1024M
> >> (3)qmp balloon 512M
> >> (4)In VM: #free -m : 512M
> >> (5)hotplug pc-dimm 1G
> >> (6)In VM: #free -m : 1512M
> >> (7)qmp balloon 256M
> >> (8)In VM: #free -m :1256M
> >>
> >> Here we add a new global variable 'vm_ram_size', it will stat
> > "qmp balloon" is not performance critical code and instead of a global
> > variable, size could be calculated each time by enumerating present memory devices.
> >
>
> Good idea, in this way, we don't have to treat hotplug/unplug memory specially.
> Will fix like that. Thanks.
>
> >
> >> the VM's real ram size which include configured ram and hotplugged ram.
> >> virtio-balloon will reference this parameter.
> > I know it's not supported yet but what will happen with balloonig
> > if dimm device is removed without telling about it to balloon first?
> >
>
> Then, calculating the ram size will also be wrong and the result of balloon
> will be confused too. 'size be calculated each time' you have suggested above will
> solve this problem;)
>
> > I'm not sure if balloon and native memory hotplug should be integrated.
> > Native memory hotplug was intended as a replacement for ballooning
> > without its drawbacks albeit guest OS memory unplug support is in
> > its infancy stage yet.
> >
>
> IMHO memory hotplug/unplug can not replace the balloon completely,
> Memory hotplug/unplug way may be a little stiff.
>
> Example:
> VM's memroy :1G
> hotplugged one pc-dimm mem :1G
>
> Now we want to limit the VM's ram size of guest OS to 1512M.
> I don't know if we can unplugging a pc-dimm which has a different size to
> its original size (hot add stage)? Here is 512M.
> If it supports, what about limit ram size to 1100M?;) There seems to
> be a minimal size limit for memory hotplug...(If i'm wrong, please let me know;))
>
> Maybe in actual usage scenario we will use them together.
> So i think we'd better to fix it.
Yep, mem hotplug is a coarse-grained method of control and requires some planning
when plugging/unplugging memory.
I'm not oposed to ballooning, just make sure that guests that have
a ballooning driver will still work as expected when memory plugged/unplugged.
>
> Thanks,
> zhanghailiang
>
> >>
> >> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
> >> ---
> >> hw/i386/pc.c | 1 +
> >> hw/virtio/virtio-balloon.c | 10 +++++-----
> >> include/exec/cpu-common.h | 1 +
> >> vl.c | 3 +++
> >> 4 files changed, 10 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> >> index b6c9b61..817810b 100644
> >> --- a/hw/i386/pc.c
> >> +++ b/hw/i386/pc.c
> >> @@ -1606,6 +1606,7 @@ static void pc_dimm_plug(HotplugHandler *hotplug_dev,
> >> memory_region_add_subregion(&pcms->hotplug_memory,
> >> addr - pcms->hotplug_memory_base, mr);
> >> vmstate_register_ram(mr, dev);
> >> + vm_ram_size += memory_region_size(mr);
> >>
> >> hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
> >> hhc->plug(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err);
> >> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> >> index 2c30b3d..205e1fe 100644
> >> --- a/hw/virtio/virtio-balloon.c
> >> +++ b/hw/virtio/virtio-balloon.c
> >> @@ -292,7 +292,7 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
> >> memcpy(&config, config_data, sizeof(struct virtio_balloon_config));
> >> dev->actual = le32_to_cpu(config.actual);
> >> if (dev->actual != oldactual) {
> >> - qapi_event_send_balloon_change(ram_size -
> >> + qapi_event_send_balloon_change(vm_ram_size -
> >> ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PFN_SHIFT),
> >> &error_abort);
> >> }
> >> @@ -307,7 +307,7 @@ static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
> >> static void virtio_balloon_stat(void *opaque, BalloonInfo *info)
> >> {
> >> VirtIOBalloon *dev = opaque;
> >> - info->actual = ram_size - ((uint64_t) dev->actual <<
> >> + info->actual = vm_ram_size - ((uint64_t) dev->actual <<
> >> VIRTIO_BALLOON_PFN_SHIFT);
> >> }
> >>
> >> @@ -316,11 +316,11 @@ static void virtio_balloon_to_target(void *opaque, ram_addr_t target)
> >> VirtIOBalloon *dev = VIRTIO_BALLOON(opaque);
> >> VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> >>
> >> - if (target > ram_size) {
> >> - target = ram_size;
> >> + if (target > vm_ram_size) {
> >> + target = vm_ram_size;
> >> }
> >> if (target) {
> >> - dev->num_pages = (ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
> >> + dev->num_pages = (vm_ram_size - target) >> VIRTIO_BALLOON_PFN_SHIFT;
> >> virtio_notify_config(vdev);
> >> }
> >> }
> >> diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
> >> index e3ec4c8..f55db6a 100644
> >> --- a/include/exec/cpu-common.h
> >> +++ b/include/exec/cpu-common.h
> >> @@ -46,6 +46,7 @@ typedef uintptr_t ram_addr_t;
> >> #endif
> >>
> >> extern ram_addr_t ram_size;
> >> +extern ram_addr_t vm_ram_size;
> >>
> >> /* memory API */
> >>
> >> diff --git a/vl.c b/vl.c
> >> index 9c9acf5..5d20d0c 100644
> >> --- a/vl.c
> >> +++ b/vl.c
> >> @@ -132,6 +132,7 @@ DisplayType display_type = DT_DEFAULT;
> >> static int display_remote;
> >> const char* keyboard_layout = NULL;
> >> ram_addr_t ram_size;
> >> +ram_addr_t vm_ram_size; /* ram_size + hotplugged ram size */
> >> const char *mem_path = NULL;
> >> int mem_prealloc = 0; /* force preallocation of physical target memory */
> >> int nb_nics;
> >> @@ -3015,6 +3016,7 @@ int main(int argc, char **argv, char **envp)
> >> machine_class = find_default_machine();
> >> cpu_model = NULL;
> >> ram_size = default_ram_size;
> >> + vm_ram_size = ram_size;
> >> snapshot = 0;
> >> cyls = heads = secs = 0;
> >> translation = BIOS_ATA_TRANSLATION_AUTO;
> >> @@ -3388,6 +3390,7 @@ int main(int argc, char **argv, char **envp)
> >> "'%s' option\n", slots_str ? "maxmem" : "slots");
> >> exit(EXIT_FAILURE);
> >> }
> >> + vm_ram_size = ram_size;
> >> break;
> >> }
> >> #ifdef CONFIG_TPM
> >
> >
> > .
> >
>
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2014-09-22 8:36 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2014-09-15 12:29 [Qemu-devel] [PATCH] virtio-balloon: Fix ballooning not working correctly when hotplug memory zhanghailiang
2014-09-18 1:47 ` zhanghailiang
2014-09-19 13:09 ` Igor Mammedov
2014-09-22 3:36 ` zhanghailiang
2014-09-22 8:14 ` Igor Mammedov
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