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| author | Hou Tao <houtao1@huawei.com> | 2022-10-14 13:39:45 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2022-10-18 19:27:02 +0200 |
| commit | d39d1445d37747032e2b26732fed6fe25161cd36 (patch) | |
| tree | c7d7ca9a9cd280148fea567c5d7036076c574b48 /kernel/bpf | |
| parent | bpf: Use rcu_trace_implies_rcu_gp() in bpf memory allocator (diff) | |
| download | linux-d39d1445d37747032e2b26732fed6fe25161cd36.tar.xz linux-d39d1445d37747032e2b26732fed6fe25161cd36.zip | |
bpf: Use rcu_trace_implies_rcu_gp() in local storage map
Local storage map is accessible for both sleepable and non-sleepable bpf
program, and its memory is freed by using both call_rcu_tasks_trace() and
kfree_rcu() to wait for both RCU-tasks-trace grace period and RCU grace
period to pass.
With the introduction of rcu_trace_implies_rcu_gp(), both
bpf_selem_free_rcu() and bpf_local_storage_free_rcu() can check whether
or not a normal RCU grace period has also passed after a RCU-tasks-trace
grace period has passed. If it is true, it is safe to call kfree()
directly.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20221014113946.965131-4-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/bpf_local_storage.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index 802fc15b0d73..9dc6de1cf185 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -88,8 +88,14 @@ void bpf_local_storage_free_rcu(struct rcu_head *rcu) { struct bpf_local_storage *local_storage; + /* If RCU Tasks Trace grace period implies RCU grace period, do + * kfree(), else do kfree_rcu(). + */ local_storage = container_of(rcu, struct bpf_local_storage, rcu); - kfree_rcu(local_storage, rcu); + if (rcu_trace_implies_rcu_gp()) + kfree(local_storage); + else + kfree_rcu(local_storage, rcu); } static void bpf_selem_free_rcu(struct rcu_head *rcu) @@ -97,7 +103,10 @@ static void bpf_selem_free_rcu(struct rcu_head *rcu) struct bpf_local_storage_elem *selem; selem = container_of(rcu, struct bpf_local_storage_elem, rcu); - kfree_rcu(selem, rcu); + if (rcu_trace_implies_rcu_gp()) + kfree(selem); + else + kfree_rcu(selem, rcu); } /* local_storage->lock must be held and selem->local_storage == local_storage. |