How to avoid or reduce GFP_ATOMIC allocation failed

[Greg KH]

On Fri, Mar 08, 2019 at 01:37:26PM +0800, wuzhouhui wrote:
> Hi,
> 
> I check kernel code and found that GFP_ATOMIC allocation will
> use emergency pool and maybe failed if emergency pool is not
> enough. And GFP_ATOMIC doesn't trigger reclaim (because of
> ATOMIC) even if there are a lot of page caches. So my question
> is how to avoid or reduce GFP_ATOMIC allocation failed if there
> are enough reclaimable memory? Is there some kernel parameters
> can be configured?

Have you seen the ATOMIC pools be used up and not able to be reclaimed
in real-world usages?  If so, I'm sure the mm developers would love to
hear from you about this as I really do not think that is a situation
that can happen easily, if at all.

And no, I do not think there are any such parameters, the kernel should
be self-tuning for things like this.

thanks,

greg k-h