On Wed, 1 Sep 2021, Yang Shi wrote: > On Wed, Sep 1, 2021 at 3:26 AM Vlastimil Babka <vbabka@xxxxxxx> wrote: > > On 9/1/21 05:46, Yang Shi wrote: > > > On Tue, Aug 31, 2021 at 4:38 PM Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> wrote: > > >> On Mon, Aug 30, 2021 at 11:49:43AM -0700, Yang Shi wrote: > > >> > Gently ping... > > >> > > > >> > Does this patch make sense? BTW, I have a couple of other khugepaged > > >> > related patches in my queue. I plan to send them with this patch > > >> > together. It would be great to hear some feedback before resending > > >> > this one. > > >> > > >> I don't really care for !NUMA optimization. I believe that most of setups > > >> that benefit from THP has NUMA enabled compile time. > > > > > > Agreed. > > > > > >> > > >> But if you wanna to go this path, make an effort to cleanup other > > >> artifacts for the !NUMA optimization: the ifdef has to be gone and all > > >> callers of these helpers has to be revisited. There's more opportunities to > > >> cleanup. Like it is very odd that khugepaged_prealloc_page() frees the > > >> page. > > > > > > Yes, they are gone in this patch. The only remaining for !NUMA is > > > khugepaged_find_target_node() which just returns 0. > > > > As Kirill pointed out, there's also khugepaged_prealloc_page() where the > > only remaining variant does actually no preallocation, just freeing of an > > unused page and some kind of "sleep after first alloc fail, break after > > second alloc fail" logic. > > This could now be moved to khugepaged_do_scan() loop itself and maybe it > > will be easier to follow. > > Aha, I see. Misunderstood him. I'm supposed that you mean move into > khugepaged_scan_mm_slot(). It may not be possible, but I'd always imagined that a cleanup of this kind would get rid of all those "struct page **hpage" artifacts. Hugh
