| Message ID | 20240814220021.3208384-5-shakeel.butt@linux.dev (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | memcg: initiate deprecation of v1 features | expand |
On Wed, Aug 14, 2024 at 3:00 PM Shakeel Butt <shakeel.butt@linux.dev> wrote: > > The pressure_level in memcg v1 provides memory pressure notifications to > the user space. At the moment it provides notifications for three levels > of memory pressure i.e. low, medium and critical, which are defined > based on internal memory reclaim implementation details. More > specifically the ratio or scanned and reclaimed pages during a memory "ratio of" > reclaim. However this is not robust as there are workloads with mostly > unreclaimable user memory or kernel memory. > > For v2, the users can use PSI for memory pressure status of the system > or the cgroup. Let's start the deprecation process for pressure_level > and add warnings to gather the info on how the current users are using > this interface and how they can be used to PSI. > > Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: T.J. Mercier <tjmercier@google.com> > --- > Changes since v1: > - Fix build (T.J. Mercier) > > Documentation/admin-guide/cgroup-v1/memory.rst | 8 ++++++-- > mm/memcontrol-v1.c | 3 +++ > 2 files changed, 9 insertions(+), 2 deletions(-) > > diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst > index 0042206414c8..270501db9f4e 100644 > --- a/Documentation/admin-guide/cgroup-v1/memory.rst > +++ b/Documentation/admin-guide/cgroup-v1/memory.rst > @@ -86,6 +86,8 @@ Brief summary of control files. > used. > memory.force_empty trigger forced page reclaim > memory.pressure_level set memory pressure notifications > + This knob is deprecated and shouldn't be > + used. > memory.swappiness set/show swappiness parameter of vmscan > (See sysctl's vm.swappiness) > memory.move_charge_at_immigrate set/show controls of moving charges > @@ -898,8 +900,10 @@ At reading, current status of OOM is shown. > The number of processes belonging to this cgroup killed by any > kind of OOM killer. > > -11. Memory Pressure > -=================== > +11. Memory Pressure (DEPRECATED) > +================================ > + > +THIS IS DEPRECATED! > > The pressure level notifications can be used to monitor the memory > allocation cost; based on the pressure, applications can implement > diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c > index 334a02597d9a..52aecdae2c28 100644 > --- a/mm/memcontrol-v1.c > +++ b/mm/memcontrol-v1.c > @@ -1913,6 +1913,9 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, > event->register_event = mem_cgroup_oom_register_event; > event->unregister_event = mem_cgroup_oom_unregister_event; > } else if (!strcmp(name, "memory.pressure_level")) { > + pr_warn_once("pressure_level is deprecated and will be removed. " > + "Please report your usecase to linux-mm-@kvack.org " > + "if you depend on this functionality. \n"); > event->register_event = vmpressure_register_event; > event->unregister_event = vmpressure_unregister_event; > } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) { > -- > 2.43.5 >
diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index 0042206414c8..270501db9f4e 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -86,6 +86,8 @@ Brief summary of control files. used. memory.force_empty trigger forced page reclaim memory.pressure_level set memory pressure notifications + This knob is deprecated and shouldn't be + used. memory.swappiness set/show swappiness parameter of vmscan (See sysctl's vm.swappiness) memory.move_charge_at_immigrate set/show controls of moving charges @@ -898,8 +900,10 @@ At reading, current status of OOM is shown. The number of processes belonging to this cgroup killed by any kind of OOM killer. -11. Memory Pressure -=================== +11. Memory Pressure (DEPRECATED) +================================ + +THIS IS DEPRECATED! The pressure level notifications can be used to monitor the memory allocation cost; based on the pressure, applications can implement diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index 334a02597d9a..52aecdae2c28 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -1913,6 +1913,9 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, event->register_event = mem_cgroup_oom_register_event; event->unregister_event = mem_cgroup_oom_unregister_event; } else if (!strcmp(name, "memory.pressure_level")) { + pr_warn_once("pressure_level is deprecated and will be removed. " + "Please report your usecase to linux-mm-@kvack.org " + "if you depend on this functionality. \n"); event->register_event = vmpressure_register_event; event->unregister_event = vmpressure_unregister_event; } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
The pressure_level in memcg v1 provides memory pressure notifications to the user space. At the moment it provides notifications for three levels of memory pressure i.e. low, medium and critical, which are defined based on internal memory reclaim implementation details. More specifically the ratio or scanned and reclaimed pages during a memory reclaim. However this is not robust as there are workloads with mostly unreclaimable user memory or kernel memory. For v2, the users can use PSI for memory pressure status of the system or the cgroup. Let's start the deprecation process for pressure_level and add warnings to gather the info on how the current users are using this interface and how they can be used to PSI. Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> --- Changes since v1: - Fix build (T.J. Mercier) Documentation/admin-guide/cgroup-v1/memory.rst | 8 ++++++-- mm/memcontrol-v1.c | 3 +++ 2 files changed, 9 insertions(+), 2 deletions(-)