[libvirt] [PATCH] qemu: align the cur_balloon too if not explicitly specified by the user

[Peter Krempa]

On Thu, Dec 10, 2015 at 20:26:31 +0530, Shivaprasad G Bhat wrote:
> As of now, the cur_ballon is set to actual memory if not specified by the user.
> When the user specified memory is not aligned the cur_balloon alone ends up
> unaligned. For qemu in function qemuDomainAttachMemory(), the cur_balloon
> wouldn't add up to the actual memory as the cur_ballon was not aligned.
> So, there is need for explicit setmem post attach-device for such guests.
> 
> The decision as to whether to align the cur_balloon memory or not is
> not possible if we set it to actual memory by default in post-parse.
> Move the default cur_balloon assignment to their respective drivers during
> domain start wherever possible. For qemu align the cur_balloon too iow assign
> the aligned actual memory when not specified by the user.
> 
> Signed-off-by: Shivaprasad G Bhat <sbhat at linux.vnet.ibm.com>
> ---

Sorry for the delay. I was on christmas hollidays and I'm catching up
with stuff that nappened earlier.

>  src/conf/domain_conf.c     |    3 +--
>  src/libxl/libxl_conf.c     |    2 ++
>  src/lxc/lxc_process.c      |    3 +++
>  src/openvz/openvz_driver.c |   13 +++++++------
>  src/phyp/phyp_driver.c     |   10 +++-------
>  src/qemu/qemu_domain.c     |    3 +++
>  src/uml/uml_conf.c         |    3 +++
>  src/vbox/vbox_common.c     |    3 +++
>  src/vmx/vmx.c              |    3 +++
>  src/vz/vz_sdk.c            |    3 +++
>  src/xenconfig/xen_common.c |    3 +++
>  src/xenconfig/xen_sxpr.c   |    4 ++++
>  12 files changed, 38 insertions(+), 15 deletions(-)

So at first:

This breaks lxcconf2xmltest:
TEST: lxcconf2xmltest
      !.!!!!!!!!!!                             12  FAIL


> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 2f5c0ed..68338f4 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -3527,8 +3527,7 @@ virDomainDefPostParseMemory(virDomainDefPtr def,
>          return -1;
>      }
>  
> -    if (def->mem.cur_balloon > virDomainDefGetMemoryActual(def) ||
> -        def->mem.cur_balloon == 0)
> +    if (def->mem.cur_balloon > virDomainDefGetMemoryActual(def))
>          def->mem.cur_balloon = virDomainDefGetMemoryActual(def);

It probably would be better to add a bool that signalizes that this
field was not provided by the user (at the point where cur_balloon gets
parsed) and then just modify the qemu code when starting to override the
number.

>  
>      if ((def->mem.max_memory || def->mem.memory_slots) &&
> diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
> index 4eed5ca..6b6e764 100644
> --- a/src/libxl/libxl_conf.c
> +++ b/src/libxl/libxl_conf.c
> @@ -665,6 +665,8 @@ libxlMakeDomBuildInfo(virDomainDefPtr def,
>      }
>      b_info->sched_params.weight = 1000;
>      b_info->max_memkb = virDomainDefGetMemoryInitial(def);
> +    if (!def->mem.cur_balloon)
> +        def->mem.cur_balloon = virDomainDefGetMemoryInitial(def);

You then won't have to change any other driver, while making it work for
qemu. Additionally it will not break the lxc test.

>      b_info->target_memkb = def->mem.cur_balloon;
>      if (hvm) {
>          char bootorder[VIR_DOMAIN_BOOT_LAST + 1];
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