On Thu, Dec 17, 2020 at 11:00 PM Oscar Salvador <osalvador@xxxxxxx> wrote: > > On Thu, Dec 17, 2020 at 08:12:52PM +0800, Muchun Song wrote: > > In this case, for the 1GB HugeTLB page, we can save 4088 pages(There are > > 4096 pages for struct page structs, we reserve 2 pages for vmemmap and 8 > > pages for page tables. So we can save 4088 pages). This is a very substantial > > gain. On our server, run some SPDK/QEMU applications which will use 1024GB > > hugetlbpage. With this feature enabled, we can save ~16GB(1G hugepage)/~11GB > > (2MB hugepage, the worst case is 10GB while the best is 12GB) memory. > > Is the above really true? > We no longer need to allocate pagetables, so the savings go up to 4094, right? Yeah, you are right. I forget to update this. > > I will be off for a few days but I expect to get back to this and review the > missing bits when I am back. > Thanks. > -- > Oscar Salvador > SUSE L3 -- Yours, Muchun
