On 08.10.24 14:57, Vlastimil Babka wrote:
On 10/8/24 13:52, Zi Yan wrote:
On 8 Oct 2024, at 4:26, David Hildenbrand wrote:
I remember we discussed that in the past and that we do *not* want to sprinkle these CONFIG_INIT_ON_ALLOC_DEFAULT_ON checks all over the kernel.
Ideally, we'd use GFP_ZERO and have the buddy just do that for us? There is the slight chance that we zero-out when we're not going to use the allocated folio, but ... that can happen either way even with the current code?
I agree that putting CONFIG_INIT_ON_ALLOC_DEFAULT_ON here is not ideal, but
Create some nice inline wrapper for the test and it will look less ugly? :)
folio_zero_user() uses vmf->address to improve cache performance by changing
subpage clearing order. See commit c79b57e462b5 ("mm: hugetlb: clear target
sub-page last when clearing huge page”). If we use GFP_ZERO, we lose this
optimization. To keep it, vmf->address will need to be passed to allocation
code. Maybe that is acceptable?
I'd rather not change the page allocation code for this...
Although I'm curious if that optimization from 2017 is still valuable :)
--
Cheers,
David / dhildenb
