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Re: [Qemu-devel] [PATCH v3 0/2] Introduce default ram size in MachineCla
Nikunj A Dadhania
Re: [Qemu-devel] [PATCH v3 0/2] Introduce default ram size in MachineClass
Thu, 05 Mar 2015 20:32:03 +0530
Notmuch/0.17+27~gae47d61 (http://notmuchmail.org) Emacs/24.3.1 (x86_64-redhat-linux-gnu)
Markus Armbruster <address@hidden> writes:
> Nikunj A Dadhania <address@hidden> writes:
>> Markus Armbruster <address@hidden> writes:
>>> Nikunj A Dadhania <address@hidden> writes:
>>>> Current DEFAULT_RAM_SIZE(128MB) enforced by QEMU would not work for
>>>> all machines. Introduce a default_ram_size as part of MachineClass.
>>>> The below patches has following behaviour:
>>>> 1) If the user does not provide "-m" option, machine's default ram
>>>> size will be picked.
>>>> 2) In case the user provides memory that is lesser than machine's
>>>> default ram size, we upscale the ram_size to machine's
>>>> default_ram_size. A warning is displayed for the change that qemu
>>>> has done.
>>> Please do not "improve" the user's explicit order that way. Either
>>> execute the order as is, or reject it as invalid.
>> If there is consensus for doing this, I can change the patches
>> Rejection is also change of behaviour. Because till now, a VM would
>> start with any memory size, even if it's less that 128MB
>> (default_ram_size). With rejection, all those VMs would fail booting
>> displaying the warning. Is this OK?
> I'd stick to "don't reject".
Agree, i have already sent v4 with those changes, as there were multiple
opinions against changing the behaviour.
> Yes, the failure mode is ugly. But protecting the user from it is
> also somewhat problematic, because we don't generally know how much
> RAM the actual guest requires, and it's an incompatible change. Seems
> not worth it.
> Back in 2012, we discussed rejecting RAM size less than 1MiB for PC
> machines, because SeaBIOS requires at least that much, and decided
> against it. See
> If you want to pursue "reject" anyway, please make sure to split this
> into two separate patches: one patch to make the default ram size
> machine-specific, and another patch to reject user requests for less.
[Qemu-devel] [PATCH v3 2/2] spapr: override default ram size 1GB, Nikunj A Dadhania, 2015/03/05
Re: [Qemu-devel] [PATCH v3 0/2] Introduce default ram size in MachineClass, Markus Armbruster, 2015/03/05
- Re: [Qemu-devel] [PATCH v3 1/2] machine: add default_ram_size to machine class, (continued)