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| author |   Michal Koutný <mkoutny@suse.com> | 2025-03-11 13:36:25 +0100 |
|---|---|---|
| committer |   Tejun Heo <tj@kernel.org> | 2025-03-11 09:22:54 -1000 |
| commit | fd4fd0a869e969a97753986b107729d4bb56525b (patch) | |
| tree | 9be6538bfcebc131f2bcb7b8c7a88b1824a230e7 | |
| parent | RFC cgroup/cpuset-v1: Add deprecation messages to sched_relax_domain_level (diff) | |
| download | wireguard-linux-fd4fd0a869e969a97753986b107729d4bb56525b.tar.xz wireguard-linux-fd4fd0a869e969a97753986b107729d4bb56525b.zip | |
mm: Add transformation message for per-memcg swappiness
The concept of per-memcg swappiness has never landed well in memcg for
cgroup v2. Add a message to users who use it on v1 hierarchy.
Decreased swappiness transforms to memory.swap.max=0 whereas
increased swappiness transforms into active memory.reclaim operation.
Link: https://lore.kernel.org/r/1577252208-32419-1-git-send-email-teawater@gmail.com/
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | Documentation/admin-guide/cgroup-v1/memory.rst | 1 | ||||
| -rw-r--r-- | mm/memcontrol-v1.c | 6 |
2 files changed, 5 insertions, 2 deletions
diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index 286d16fc22eb..02b8206a3594 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -90,6 +90,7 @@ Brief summary of control files. used. memory.swappiness set/show swappiness parameter of vmscan (See sysctl's vm.swappiness) + Per memcg knob does not exist in cgroup v2. memory.move_charge_at_immigrate This knob is deprecated. memory.oom_control set/show oom controls. This knob is deprecated and shouldn't be diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index a071fa43d479..93291c0e6eac 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -1855,9 +1855,11 @@ static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css, if (val > MAX_SWAPPINESS) return -EINVAL; - if (!mem_cgroup_is_root(memcg)) + if (!mem_cgroup_is_root(memcg)) { + pr_info_once("Per memcg swappiness does not exist in cgroup v2. " + "See memory.reclaim or memory.swap.max there\n ") WRITE_ONCE(memcg->swappiness, val); - else + } else WRITE_ONCE(vm_swappiness, val); return 0; |