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authorLinus Torvalds <torvalds@linux-foundation.org>2022-08-03 19:45:08 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-08-03 19:45:08 +0300
commitb6bb70f9ab80a11161252bf217993d2c40ea5eb2 (patch)
treeca1d2669919d6b335dc6c28aa04cd089e5fa274f /include
parente2b542100719a93f8cdf6d90185410d38a57a4c1 (diff)
parent265792d0dede9259f0ca56bb3efcc23eceee7d01 (diff)
downloadlinux-b6bb70f9ab80a11161252bf217993d2c40ea5eb2.tar.xz
Merge tag 'cgroup-for-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo: "Several core optimizations: - threadgroup_rwsem write locking is skipped when configuring controllers in empty subtrees. Combined with CLONE_INTO_CGROUP, this allows the common static usage pattern to not grab threadgroup_rwsem at all (glibc still doesn't seem ready for CLONE_INTO_CGROUP unfortunately). - threadgroup_rwsem used to be put into non-percpu mode by default due to latency concerns in specific use cases. There's no reason for everyone else to pay for it. Make the behavior optional. - psi no longer allocates memory when disabled. ... along with some code cleanups" * tag 'cgroup-for-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Skip subtree root in cgroup_update_dfl_csses() cgroup: remove "no" prefixed mount options cgroup: Make !percpu threadgroup_rwsem operations optional cgroup: Add "no" prefixed mount options cgroup: Elide write-locking threadgroup_rwsem when updating csses on an empty subtree cgroup.c: remove redundant check for mixable cgroup in cgroup_migrate_vet_dst cgroup.c: add helper __cset_cgroup_from_root to cleanup duplicated codes psi: dont alloc memory for psi by default
Diffstat (limited to 'include')
-rw-r--r--include/linux/cgroup-defs.h21
-rw-r--r--include/linux/cgroup.h2
2 files changed, 18 insertions, 5 deletions
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 187b54a9567e..4bcf56b3491c 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -89,19 +89,32 @@ enum {
CGRP_ROOT_NS_DELEGATE = (1 << 3),
/*
+ * Reduce latencies on dynamic cgroup modifications such as task
+ * migrations and controller on/offs by disabling percpu operation on
+ * cgroup_threadgroup_rwsem. This makes hot path operations such as
+ * forks and exits into the slow path and more expensive.
+ *
+ * The static usage pattern of creating a cgroup, enabling controllers,
+ * and then seeding it with CLONE_INTO_CGROUP doesn't require write
+ * locking cgroup_threadgroup_rwsem and thus doesn't benefit from
+ * favordynmod.
+ */
+ CGRP_ROOT_FAVOR_DYNMODS = (1 << 4),
+
+ /*
* Enable cpuset controller in v1 cgroup to use v2 behavior.
*/
- CGRP_ROOT_CPUSET_V2_MODE = (1 << 4),
+ CGRP_ROOT_CPUSET_V2_MODE = (1 << 16),
/*
* Enable legacy local memory.events.
*/
- CGRP_ROOT_MEMORY_LOCAL_EVENTS = (1 << 5),
+ CGRP_ROOT_MEMORY_LOCAL_EVENTS = (1 << 17),
/*
* Enable recursive subtree protection
*/
- CGRP_ROOT_MEMORY_RECURSIVE_PROT = (1 << 6),
+ CGRP_ROOT_MEMORY_RECURSIVE_PROT = (1 << 18),
};
/* cftype->flags */
@@ -480,7 +493,7 @@ struct cgroup {
struct work_struct release_agent_work;
/* used to track pressure stalls */
- struct psi_group psi;
+ struct psi_group *psi;
/* used to store eBPF programs */
struct cgroup_bpf bpf;
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 0d1ada8968d7..ed53bfe7c46c 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -674,7 +674,7 @@ static inline void pr_cont_cgroup_path(struct cgroup *cgrp)
static inline struct psi_group *cgroup_psi(struct cgroup *cgrp)
{
- return &cgrp->psi;
+ return cgrp->psi;
}
bool cgroup_psi_enabled(void);