On Wed, Sep 09, 2020 at 03:29:41PM +0100, Christoph Hellwig wrote: > On Wed, Sep 09, 2020 at 10:05:18AM -0300, Jason Gunthorpe wrote: > > How to use? The VMAs can have mixed page sizes so the caller would > > have to somehow switch and call twice? Not sure this is faster. > > We can find out the page size based on the page. Right now it is > rather cumbersome, but one of willys pending series has a nicer helper > for that. Actually already merged. There's page_size() which went into 5.4, and is the one you'd want to use (also page_shift() and compound_nr()). The thp_* equivalents (merged in 5.9) compile away to nothing if you don't have CONFIG_TRANSPARENT_HUGEPAGE enabled, but since there are many ways of getting a compound page mapped into userspace, page_size() is the helper to use for VFIO.
