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| author | Eric Dumazet <edumazet@google.com> | 2025-07-02 07:12:30 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2025-07-08 13:00:24 +0200 |
| commit | 84a7d6797e6a03705e6b48c613fa424662049d87 (patch) | |
| tree | 7d75b61ad897920fc33aa63a7844fd0aa913cd00 /net | |
| parent | Merge branch 'net-mctp-add-support-for-gateway-routing' (diff) | |
| download | linux-84a7d6797e6a03705e6b48c613fa424662049d87.tar.gz linux-84a7d6797e6a03705e6b48c613fa424662049d87.zip | |
net/sched: acp_api: no longer acquire RTNL in tc_action_net_exit()
tc_action_net_exit() got an rtnl exclusion in commit
a159d3c4b829 ("net_sched: acquire RTNL in tc_action_net_exit()")
Since then, commit 16af6067392c ("net: sched: implement reference
counted action release") made this RTNL exclusion obsolete for
most cases.
Only tcf_action_offload_del() might still require it.
Move the rtnl locking into tcf_idrinfo_destroy() when
an offload action is found.
Most netns do not have actions, yet deleting them is adding a lot
of pressure on RTNL, which is for many the most contended mutex
in the kernel.
We are moving to a per-netns 'rtnl', so tc_action_net_exit()
will not be able to grab 'rtnl' a single time for a batch of netns.
Before the patch:
perf probe -a rtnl_lock
perf record -e probe:rtnl_lock -a /bin/bash -c 'unshare -n "/bin/true"; sleep 1'
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.305 MB perf.data (25 samples) ]
After the patch:
perf record -e probe:rtnl_lock -a /bin/bash -c 'unshare -n "/bin/true"; sleep 1'
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.304 MB perf.data (9 samples) ]
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Vlad Buslov <vladbu@nvidia.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Link: https://patch.msgid.link/20250702071230.1892674-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sched/act_api.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 057e20cef375..9e468e463467 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -933,18 +933,25 @@ void tcf_idrinfo_destroy(const struct tc_action_ops *ops, struct tcf_idrinfo *idrinfo) { struct idr *idr = &idrinfo->action_idr; + bool mutex_taken = false; struct tc_action *p; - int ret; unsigned long id = 1; unsigned long tmp; + int ret; idr_for_each_entry_ul(idr, p, tmp, id) { + if (tc_act_in_hw(p) && !mutex_taken) { + rtnl_lock(); + mutex_taken = true; + } ret = __tcf_idr_release(p, false, true); if (ret == ACT_P_DELETED) module_put(ops->owner); else if (ret < 0) return; } + if (mutex_taken) + rtnl_unlock(); idr_destroy(&idrinfo->action_idr); } EXPORT_SYMBOL(tcf_idrinfo_destroy); |