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

From: Vladimir Davydov
Date: Wed Aug 03 2016 - 06:56:26 EST


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.

>
> confused,

Sorry for the noise.