On 2022/1/19 21:22, Matthew Wilcox wrote:

On Wed, Jan 19, 2022 at 08:57:58PM +0800, Kefeng Wang wrote:

quoted

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.