From: Thomas Gleixner <tglx@linutronix•de>
To: LKML <linux-kernel@vger•kernel.org>
Cc: David Miller <davem@davemloft•net>,
bpf@vger•kernel.org, netdev@vger•kernel.org,
Alexei Starovoitov <ast@kernel•org>,
Daniel Borkmann <daniel@iogearbox•net>,
Sebastian Sewior <bigeasy@linutronix•de>,
Peter Zijlstra <peterz@infradead•org>,
Clark Williams <williams@redhat•com>,
Steven Rostedt <rostedt@goodmis•org>,
Juri Lelli <juri.lelli@redhat•com>,
Ingo Molnar <mingo@kernel•org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios•com>,
Vinicius Costa Gomes <vinicius.gomes@intel•com>,
Jakub Kicinski <kuba@kernel•org>
Subject: [patch V3 04/22] bpf/tracing: Remove redundant preempt_disable() in __bpf_trace_run()
Date: Mon, 24 Feb 2020 15:01:35 +0100 [thread overview]
Message-ID: <20200224145642.847220186@linutronix.de> (raw)
In-Reply-To: 20200224140131.461979697@linutronix.de
__bpf_trace_run() disables preemption around the BPF_PROG_RUN() invocation.
This is redundant because __bpf_trace_run() is invoked from a trace point
via __DO_TRACE() which already disables preemption _before_ invoking any of
the functions which are attached to a trace point.
Remove it and add a cant_sleep() check.
Signed-off-by: Thomas Gleixner <tglx@linutronix•de>
---
V3: Add a cant_sleep() check.
---
kernel/trace/bpf_trace.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1516,10 +1516,9 @@ void bpf_put_raw_tracepoint(struct bpf_r
static __always_inline
void __bpf_trace_run(struct bpf_prog *prog, u64 *args)
{
+ cant_sleep();
rcu_read_lock();
- preempt_disable();
(void) BPF_PROG_RUN(prog, args);
- preempt_enable();
rcu_read_unlock();
}
next prev parent reply other threads:[~2020-02-24 15:03 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-24 14:01 [patch V3 00/22] bpf: Make BPF and PREEMPT_RT co-exist Thomas Gleixner
2020-02-24 14:01 ` [patch V3 01/22] bpf: Tighten the requirements for preallocated hash maps Thomas Gleixner
2020-02-24 14:01 ` [patch V3 02/22] bpf: Enforce preallocation for instrumentation programs on RT Thomas Gleixner
2020-02-24 14:01 ` [patch V3 03/22] bpf: Update locking comment in hashtab code Thomas Gleixner
2020-02-24 14:01 ` Thomas Gleixner [this message]
2020-02-24 14:01 ` [patch V3 05/22] bpf/trace: Remove EXPORT from trace_call_bpf() Thomas Gleixner
2020-02-24 18:16 ` Alexei Starovoitov
2020-02-24 14:01 ` [patch V3 06/22] bpf/trace: Remove redundant preempt_disable " Thomas Gleixner
2020-02-24 19:40 ` Alexei Starovoitov
2020-02-24 20:42 ` Thomas Gleixner
2020-02-25 0:33 ` Alexei Starovoitov
2020-02-25 12:36 ` Thomas Gleixner
2020-02-24 14:01 ` [patch V3 07/22] perf/bpf: Remove preempt disable around BPF invocation Thomas Gleixner
2020-02-24 14:01 ` [patch V3 08/22] bpf: Remove recursion prevention from rcu free callback Thomas Gleixner
2020-02-24 14:01 ` [patch V3 09/22] bpf: Dont iterate over possible CPUs with interrupts disabled Thomas Gleixner
2020-02-24 14:01 ` [patch V3 10/22] bpf: Provide bpf_prog_run_pin_on_cpu() helper Thomas Gleixner
2020-02-24 18:14 ` Thomas Gleixner
2020-02-24 18:41 ` [patch V4 " Thomas Gleixner
2020-02-24 14:01 ` [patch V3 11/22] bpf: Replace cant_sleep() with cant_migrate() Thomas Gleixner
2020-02-24 14:01 ` [patch V3 12/22] bpf: Use bpf_prog_run_pin_on_cpu() at simple call sites Thomas Gleixner
2020-02-24 14:01 ` [patch V3 13/22] bpf/tests: Use migrate disable instead of preempt disable Thomas Gleixner
2020-02-24 14:01 ` [patch V3 14/22] bpf: Use migrate_disable/enabe() in trampoline code Thomas Gleixner
2020-02-24 14:01 ` [patch V3 15/22] bpf: Use migrate_disable/enable in array macros and cgroup/lirc code Thomas Gleixner
2020-02-24 14:01 ` [patch V3 16/22] bpf: Provide recursion prevention helpers Thomas Gleixner
2020-02-24 14:01 ` [patch V3 17/22] bpf: Use recursion prevention helpers in hashtab code Thomas Gleixner
2020-02-24 14:01 ` [patch V3 18/22] bpf: Replace open coded recursion prevention in sys_bpf() Thomas Gleixner
2020-02-24 14:01 ` [patch V3 19/22] bpf: Factor out hashtab bucket lock operations Thomas Gleixner
2020-02-24 14:01 ` [patch V3 20/22] bpf: Prepare hashtab locking for PREEMPT_RT Thomas Gleixner
2020-02-24 14:01 ` [patch V3 21/22] bpf, lpm: Make locking RT friendly Thomas Gleixner
2020-02-24 14:01 ` [patch V3 22/22] bpf/stackmap: Dont trylock mmap_sem with PREEMPT_RT and interrupts disabled Thomas Gleixner
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