On 12/8/20 5:28 PM, Joao Martins wrote: > Introduce a new flag, MEMHP_REUSE_VMEMMAP, which signals that that > struct pages are onlined with a given alignment, and should reuse the > tail pages vmemmap areas. On that circunstamce we reuse the PFN backing > only the tail pages subsections, while letting the head page PFN remain > different. This presumes that the backing page structs are compound > pages, such as the case for compound pagemaps (i.e. ZONE_DEVICE with > PGMAP_COMPOUND set) > > On 2M compound pagemaps, it lets us save 6 pages out of the 8 necessary > PFNs necessary to describe the subsection's 32K struct pages we are > onlining. On a 1G compound pagemap it let us save 4096 pages. > > Sections are 128M (or bigger/smaller), and such when initializing a > compound memory map where we are initializing compound struct pages, we > need to preserve the tail page to be reused across the rest of the areas > for pagesizes which bigger than a section. > > Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx> Sigh, ignore this one. I mistakenly had stashed an old version of this patch, and wrongly send it up. Joao
