Re: [PATCH v2 1/3] mm: vmalloc: Let user to control huge vmalloc default behavior

[Kefeng Wang]

On 2022/1/19 21:22, Matthew Wilcox wrote:
> On Wed, Jan 19, 2022 at 08:57:58PM +0800, Kefeng Wang wrote:
> > Only parts of our products wants this feature,  we add some interfaces which
> > only
> >
> > alloc hugevmalloc for them, eg,
> > vmap_hugepage/vmalloc_hugepage/remap_vmalloc_hugepage_range..
> >
> > for our products, but it's not the choice of most products, also add
> > nohugevmalloc
> >
> > for most products is expensive, so this is the reason for adding the patch.
> >
> > more config/cmdline are more flexible for test/products，
> But why do only some products want it?  What goes wrong if all products
> enable it?  Features should be auto-tuning, not relying on admins to
> understand them.

Because this feature will use more memory for vmalloc/vmap, that's why 
we add some explicit
interfaces as said above in our kernel to control the user.