On Wed, Apr 22, 2026 at 05:20:27PM -0400, Michael S. Tsirkin wrote: > On Wed, Apr 22, 2026 at 03:47:07PM -0400, Gregory Price wrote: > > > > __alloc_user_pages(..., gfp_t gfp, user_addr) > > With a wrapper approach, looks like we'd need something like > __GFP_SKIP_ZERO so post_alloc_hook doesn't zero sequentially, then the > wrapper re-zeros with folio_zero_user(). But then the wrapper needs to > know whether the page was pre-zeroed (PG_zeroed), which is cleared by > post_alloc_hook before return. So the information doesn't survive to > the wrapper. >
I was thinking more that internally you already have that information you need to know to skip the zeroing - and so the wrapper can just pass __GFP_ZERO and post_alloc_hook() would do the right thing regardless Then on the way out, the new wrapper would take care of cacheline piece. However, i explored this a bit - and while it saves some churn on the interface, it adds two paths into the buddy - and that increase in surface might not be worth it. So I see the tradeoff here. The churn is probably worth it. ~Gregory
