On Fri, Sep 15, 2017 at 09:01:00AM +0200, Michal Hocko wrote: > On Thu 14-09-17 15:00:11, jglisse@xxxxxxxxxx wrote: > > From: Jérôme Glisse <jglisse@xxxxxxxxxx> > > > > Fix for 4.14, zone device page always have an elevated refcount > > of one and thus page count sanity check in uncharge_page() is > > inappropriate for them. > > > > Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx> > > Reported-by: Evgeny Baskakov <ebaskakov@xxxxxxxxxx> > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > Cc: Johannes Weiner <hannes@xxxxxxxxxxx> > > Cc: Michal Hocko <mhocko@xxxxxxxxxx> > > Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> > > Acked-by: Michal Hocko <mhocko@xxxxxxxx> > > Side note. Wouldn't it be better to re-organize the check a bit? It is > true that this is VM_BUG so it is not usually compiled in but when it > preferably checks for unlikely cases first while the ref count will be > 0 in the prevailing cases. So can we have > VM_BUG_ON_PAGE(page_count(page) && !is_zone_device_page(page) && > !PageHWPoison(page), page); > > I would simply fold this nano optimization into the patch as you are > touching it already. Not sure it is worth a separate commit. I am traveling sorry for late answer. This nano optimization make sense Andrew do you want me to respin or should we leave it be ? I don't mind either way. Cheers, Jérôme -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
