Re: [PATCH] mm/balloon_compaction: suppress allocation warnings

From: Nadav Amit
Date: Wed Aug 21 2019 - 12:34:51 EST

> On Aug 21, 2019, at 9:29 AM, David Hildenbrand <david@xxxxxxxxxx> wrote:
> On 21.08.19 18:23, Nadav Amit wrote:
>>> On Aug 21, 2019, at 9:05 AM, David Hildenbrand <david@xxxxxxxxxx> wrote:
>>> On 20.08.19 11:16, Nadav Amit wrote:
>>>> There is no reason to print warnings when balloon page allocation fails,
>>>> as they are expected and can be handled gracefully. Since VMware
>>>> balloon now uses balloon-compaction infrastructure, and suppressed these
>>>> warnings before, it is also beneficial to suppress these warnings to
>>>> keep the same behavior that the balloon had before.
>>> I am not sure if that's a good idea. The allocation warnings are usually
>>> the only trace of "the user/admin did something bad because he/she tried
>>> to inflate the balloon to an unsafe value". Believe me, I processed a
>>> couple of such bugreports related to virtio-balloon and the warning were
>>> very helpful for that.
>> Ok, so a message is needed, but does it have to be a generic frightening
>> warning?
>> How about using __GFP_NOWARN, and if allocation do something like:
>> pr_warn(âBalloon memory allocation failedâ);
>> Or even something more informative? This would surely be less intimidating
>> for common users.
> ratelimit would make sense :)
> And yes, this would certainly be nicer.

Thanks. I will post v2 of the patch.