On Tue, 5 Apr 2016 17:55:39 -0700 (PDT) Hugh Dickins <hu...@google.com> wrote:
> > I ended up doing this: > > > > /* Checks for THP-specific high-order allocations */ > > if (!is_thp_allocation(gfp_mask, order)) > > migration_mode = MIGRATE_SYNC_LIGHT; > > > > /* > > * Checks for THP-specific high-order allocations and back off > > * if the the compaction backed off > > */ > > if (is_thp_allocation(gfp_mask) && compaction_withdrawn(compact_result)) > > goto nopage; > > You'll already have found that is_thp_allocation() needs the order too. > But then you had to drop a hunk out of his 10/11 also to fit with mine. > > What you've done may be just right, but I haven't had time to digest > Michal's changes yet (and not yet seen what happens to the PF_KTHREAD > distinction), so I think it will probably end up better if you take > his exactly as he tested and posted them, and drop my 30/31 and 31/31 > for now - I can resubmit them (or maybe drop 30 altogether) after I've > pondered and tested a little on top of Michal's. > > Huge tmpfs got along fine for many months without 30/31 and 31/31: 30 > is just for experimentation, and 31 to reduce the compaction stalls we > saw under some loads. Maybe I'll find that Michal's rework has changed > the balance there anyway, and something else or nothing at all needed. > > (The gfp_mask stuff was very confusing, and it's painful for me, how > ~__GFP_KSWAPD_RECLAIM gets used as a secret password to say "THP" and > how to angle compaction - or maybe it's all more straightforward now.) OK, thanks. I dropped huge-tmpfs-shmem_huge_gfpmask-and-shmem_recovery_gfpmask.patch and huge-tmpfs-no-kswapd-by-default-on-sync-allocations.patch and restored Michal's patches. > Many thanks for giving us both this quick exposure! I'll push all this into -next later today.
