On 04/20/18 10:20, Roman Gushchin wrote: > > Hi, Randy! > > An updated version below. > > Thanks! OK, looks good now. Thanks. FWIW: Reviewed-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> # for Documentation/ only. > ------------------------------------------------------------ > > > From 2225fa0b3400431dd803f206b20a9344f0dfcd0a Mon Sep 17 00:00:00 2001 > From: Roman Gushchin <guro@xxxxxx> > Date: Fri, 20 Apr 2018 15:24:44 +0100 > Subject: [PATCH 1/2] mm: introduce memory.min > > Memory controller implements the memory.low best-effort memory > protection mechanism, which works perfectly in many cases and > allows protecting working sets of important workloads from > sudden reclaim. > > But it's semantics has a significant limitation: it works > only until there is a supply of reclaimable memory. > This makes it pretty useless against any sort of slow memory > leaks or memory usage increases. This is especially true > for swapless systems. If swap is enabled, memory soft protection > effectively postpones problems, allowing a leaking application > to fill all swap area, which makes no sense. > The only effective way to guarantee the memory protection > in this case is to invoke the OOM killer. > > This patch introduces the memory.min interface for cgroup v2 > memory controller. It works very similarly to memory.low > (sharing the same hierarchical behavior), except that it's > not disabled if there is no more reclaimable memory in the system. > > Signed-off-by: Roman Gushchin <guro@xxxxxx> > Cc: Johannes Weiner <hannes@xxxxxxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxx> > Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> > Cc: Tejun Heo <tj@xxxxxxxxxx> > --- > Documentation/cgroup-v2.txt | 24 ++++++++++- > include/linux/memcontrol.h | 15 ++++++- > include/linux/page_counter.h | 11 ++++- > mm/memcontrol.c | 99 ++++++++++++++++++++++++++++++++++++-------- > mm/page_counter.c | 63 ++++++++++++++++++++-------- > mm/vmscan.c | 19 ++++++++- > 6 files changed, 191 insertions(+), 40 deletions(-) > > diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt > index 657fe1769c75..a413118b9c29 100644 > --- a/Documentation/cgroup-v2.txt > +++ b/Documentation/cgroup-v2.txt > @@ -1002,6 +1002,26 @@ PAGE_SIZE multiple when read back. > The total amount of memory currently being used by the cgroup > and its descendants. > > + memory.min > + A read-write single value file which exists on non-root > + cgroups. The default is "0". > + > + Hard memory protection. If the memory usage of a cgroup > + is within its effective min boundary, the cgroup's memory > + won't be reclaimed under any conditions. If there is no > + unprotected reclaimable memory available, OOM killer > + is invoked. > + > + Effective low boundary is limited by memory.min values of > + all ancestor cgroups. If there is memory.min overcommitment > + (child cgroup or cgroups are requiring more protected memory > + than parent will allow), then each child cgroup will get > + the part of parent's protection proportional to its > + actual memory usage below memory.min. > + > + Putting more memory than generally available under this > + protection is discouraged and may lead to constant OOMs. > + > memory.low > A read-write single value file which exists on non-root > cgroups. The default is "0". > @@ -1013,9 +1033,9 @@ PAGE_SIZE multiple when read back. > > Effective low boundary is limited by memory.low values of > all ancestor cgroups. If there is memory.low overcommitment > - (child cgroup or cgroups are requiring more protected memory, > + (child cgroup or cgroups are requiring more protected memory > than parent will allow), then each child cgroup will get > - the part of parent's protection proportional to the its > + the part of parent's protection proportional to its > actual memory usage below memory.low. > > Putting more memory than generally available under this -- ~Randy
