[libvirt] [PATCH 1/8] Revert "qemu: Forbid <memoryBacking><locked> without <memtune><hard_limit>"

Luiz Capitulino lcapitulino at redhat.com
Fri Mar 24 17:36:00 UTC 2017


On Thu, 23 Mar 2017 19:16:40 +0100
Andrea Bolognani <abologna at redhat.com> wrote:

> This reverts commit c2e60ad0e5124482942164e5fec088157f5e716a.
> 
> Turns out this check is excessively strict: there are ways
> other than <memtune><hard_limit> to raise the memory locking
> limit for QEMU processes, one prominent example being
> tweaking /etc/security/limits.conf.

Actually, it seems that limits.conf doesn't work with libvirt
as mentioned by Daniel in another thread. I didn't know this
myself btw.

This makes this series even more important because only through
libvirt we can set this limit to infinity.

> 
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1431793
> ---
>  src/qemu/qemu_domain.c                           | 10 ----------
>  tests/qemuxml2argvdata/qemuxml2argv-mlock-on.xml |  3 ---
>  2 files changed, 13 deletions(-)
> 
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index c239a06..8fa43f2 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -2919,16 +2919,6 @@ qemuDomainDefValidate(const virDomainDef *def,
>          }
>      }
>  
> -    /* Memory locking can only work properly if the memory locking limit
> -     * for the QEMU process has been raised appropriately: the default one
> -     * is extrememly low, so there's no way the guest will fit in there */
> -    if (def->mem.locked && !virMemoryLimitIsSet(def->mem.hard_limit)) {
> -        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
> -                       _("Setting <memoryBacking><locked> requires "
> -                         "<memtune><hard_limit> to be set as well"));
> -        goto cleanup;
> -    }
> -
>      if (qemuDomainDefValidateVideo(def) < 0)
>          goto cleanup;
>  
> diff --git a/tests/qemuxml2argvdata/qemuxml2argv-mlock-on.xml b/tests/qemuxml2argvdata/qemuxml2argv-mlock-on.xml
> index 2046663..20a5eaa 100644
> --- a/tests/qemuxml2argvdata/qemuxml2argv-mlock-on.xml
> +++ b/tests/qemuxml2argvdata/qemuxml2argv-mlock-on.xml
> @@ -3,9 +3,6 @@
>    <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
>    <memory unit='KiB'>219136</memory>
>    <currentMemory unit='KiB'>219136</currentMemory>
> -  <memtune>
> -    <hard_limit unit='KiB'>256000</hard_limit>
> -  </memtune>
>    <memoryBacking>
>      <locked/>
>    </memoryBacking>




More information about the libvir-list mailing list