Re: [PATCH stable 4.6+] radix-tree: account nodes to memcg only if explicitly requested

From: Greg KH
Date: Wed Aug 03 2016 - 04:29:35 EST


On Wed, Aug 03, 2016 at 11:15:25AM +0300, Vladimir Davydov wrote:
> On Wed, Aug 03, 2016 at 05:51:39AM +0200, Greg KH wrote:
> > On Tue, Aug 02, 2016 at 03:45:34PM +0300, Vladimir Davydov wrote:
> > > Radix trees may be used not only for storing page cache pages, so
> > > unconditionally accounting radix tree nodes to the current memory cgroup
> > > is bad: if a radix tree node is used for storing data shared among
> > > different cgroups we risk pinning dead memory cgroups forever. So let's
> > > only account radix tree nodes if it was explicitly requested by passing
> > > __GFP_ACCOUNT to INIT_RADIX_TREE. Currently, we only want to account
> > > page cache entries, so mark mapping->page_tree so.
> > >
> > > Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
> > > Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> > > Acked-by: Michal Hocko <mhocko@xxxxxxxx>
> > > Cc: <stable@xxxxxxxxxxxxxxx> [4.6+]
> > > ---
> > > fs/inode.c | 2 +-
> > > lib/radix-tree.c | 14 ++++++++++----
> > > 2 files changed, 11 insertions(+), 5 deletions(-)
> >
> > Is this patch in Linus's tree already?
>
> Not yet, it should only be added to 4.8, so I shouldn't have sent this
> (didn't know how patches are submitted to stable). Please ignore.

Please read Documentation/stable_kernel_rules.txt, it should help answer
this question (hint, you almost got it right...)

thanks,

greg k-h