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KFunc bpf_get_root_mem_cgroup

v7.0

Returns a pointer to the root memory cGroup.

Definition

The function has KF_ACQUIRE semantics, even though the root memory cGroup is never destroyed after being created and doesn't require reference counting. And it's perfectly safe to pass it to bpf_put_mem_cgroup.

Returns

A pointer to the root memory cGroup.

Signature

struct mem_cgroup *bpf_get_root_mem_cgroup()

Note

This kfunc returns a pointer to a refcounted object. The verifier will then ensure that the pointer to the object is eventually released using a release kfunc, or transferred to a map using a referenced kptr (by invoking bpf_kptr_xchg). If not, the verifier fails the loading of the BPF program until no lingering references remain in all possible explored states of the program.

Note

The pointer returned by the kfunc may be NULL. Hence, it forces the user to do a NULL check on the pointer returned from the kfunc before making use of it (dereferencing or passing to another helper).

Usage

Docs could be improved

This part of the docs is incomplete, contributions are very welcome

Program types

The following program types can make use of this kfunc:

Example

Docs could be improved

This part of the docs is incomplete, contributions are very welcome