On 16.05.25 12:10, Pankaj Raghav wrote:
Introduce LARGE_ZERO_PAGE of size 2M as an alternative to ZERO_PAGE of size PAGE_SIZE. There are many places in the kernel where we need to zeroout larger chunks but the maximum segment we can zeroout at a time is limited by PAGE_SIZE. This is especially annoying in block devices and filesystems where we attach multiple ZERO_PAGEs to the bio in different bvecs. With multipage bvec support in block layer, it is much more efficient to send out larger zero pages as a part of single bvec. While there are other options such as huge_zero_page, they can fail based on the system memory pressure requiring a fallback to ZERO_PAGE[3].
Instead of adding another one, why not have a config option that will always allocate the huge zeropage, and never free it?
I mean, the whole thing about dynamically allocating/freeing it was for memory-constrained systems. For large systems, we just don't care.
-- Cheers, David / dhildenb
