On Wed, 22 Jun 2016, Joonsoo Kim wrote: > > Well, http://marc.info/?l=linux-mm&m=146654572331344 fixes an issue that > > persists at least as far back as 3.11 whereas we can scan entire 256GB+ > > zones needlessly each time compaction_alloc() is called, and that function > > can be called multiple times for a single page isolated for migration in > > the case of -EAGAIN. It's been measured that compaction_alloc() can take > > 15-20% of cpu cycles while faulting thp on very large machines back in the > > 3.11 kernel. I would suggest that this is an important fix that needs to > > be included and perhaps backported to stable. > > Agreed. > > > > > I don't know the relative importance the reducing the size of page_owner > > patchset. It appears that the link you provided is a refreshed series of > > a patchset that is already in -mm? If so, I think the old set should be > > reverted, and whatever dependencies it has, and then a third version of > > http://marc.info/?l=linux-mm&m=146654572331344 merged. I can propose that > > for inclusion in this release cycle if folks agree that it's warranted. > > > > The alternative seems to be to rebase your refreshed series on top of -mm > > with the fix. > > I think that page_owner patch is less important. Andrew, could you > revert whole series? I will refresh series on top of -mm with the > David's fix. >
Ok, I'm not exactly sure what the result will look like, so I'll propose a version of http://marc.info/?l=linux-mm&m=146654572331344 against Linus's tree and suggest it be backported to stable. I think it should go into this release cycle as well, but I'll wait for you or Vlastimil to ack it and see if you agree.
