All of lore.kernel.org
 help / color / mirror / Atom feed
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 V2 03/20] bpf/tracing: Remove redundant preempt_disable() in __bpf_trace_run()
Date: Thu, 20 Feb 2020 21:45:20 +0100	[thread overview]
Message-ID: <20200220204617.637603528@linutronix.de> (raw)
In-Reply-To: 20200220204517.863202864@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.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/trace/bpf_trace.c |    2 --
 1 file changed, 2 deletions(-)

--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1476,9 +1476,7 @@ static __always_inline
 void __bpf_trace_run(struct bpf_prog *prog, u64 *args)
 {
 	rcu_read_lock();
-	preempt_disable();
 	(void) BPF_PROG_RUN(prog, args);
-	preempt_enable();
 	rcu_read_unlock();
 }
 


  parent reply	other threads:[~2020-02-20 20:56 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-20 20:45 [patch V2 00/20] bpf: Make BPF and PREEMPT_RT co-exist Thomas Gleixner
2020-02-20 20:45 ` [patch V2 01/20] bpf: Enforce preallocation for all instrumentation programs Thomas Gleixner
2020-02-22  4:29   ` Alexei Starovoitov
2020-02-22  8:40     ` Thomas Gleixner
2020-02-23 22:40       ` Alexei Starovoitov
2020-02-22 16:44   ` kbuild test robot
2020-02-22 16:44     ` kbuild test robot
2020-02-20 20:45 ` [patch V2 02/20] bpf: Update locking comment in hashtab code Thomas Gleixner
2020-02-20 20:45 ` Thomas Gleixner [this message]
2020-02-20 20:45 ` [patch V2 04/20] perf/bpf: Remove preempt disable around BPF invocation Thomas Gleixner
2020-02-20 20:45 ` [patch V2 05/20] bpf: Remove recursion prevention from rcu free callback Thomas Gleixner
2020-02-20 20:45 ` [patch V2 06/20] bpf: Dont iterate over possible CPUs with interrupts disabled Thomas Gleixner
2020-02-20 20:45 ` [patch V2 07/20] bpf: Provide bpf_prog_run_pin_on_cpu() helper Thomas Gleixner
2020-02-20 20:45 ` [patch V2 08/20] bpf: Replace cant_sleep() with cant_migrate() Thomas Gleixner
2020-02-20 20:45 ` [patch V2 09/20] bpf: Use bpf_prog_run_pin_on_cpu() at simple call sites Thomas Gleixner
2020-02-20 20:45 ` [patch V2 10/20] trace/bpf: Use migrate disable in trace_call_bpf() Thomas Gleixner
2020-02-20 20:45 ` [patch V2 11/20] bpf/tests: Use migrate disable instead of preempt disable Thomas Gleixner
2020-02-20 20:45 ` [patch V2 12/20] bpf: Use migrate_disable/enabe() in trampoline code Thomas Gleixner
2020-02-20 20:45 ` [patch V2 13/20] bpf: Use migrate_disable/enable in array macros and cgroup/lirc code Thomas Gleixner
2020-02-20 20:45 ` [patch V2 14/20] bpf: Use migrate_disable() in hashtab code Thomas Gleixner
2020-02-20 20:45 ` [patch V2 15/20] bpf: Provide recursion prevention helpers Thomas Gleixner
2020-02-20 20:45 ` [patch V2 16/20] bpf: Replace open coded recursion prevention Thomas Gleixner
2020-02-20 20:45 ` [patch V2 17/20] bpf: Factor out hashtab bucket lock operations Thomas Gleixner
2020-02-20 20:45 ` [patch V2 18/20] bpf: Prepare hashtab locking for PREEMPT_RT Thomas Gleixner
2020-02-20 20:45 ` [patch V2 19/20] bpf, lpm: Make locking RT friendly Thomas Gleixner
2020-02-20 20:45 ` [patch V2 20/20] bpf/stackmap: Dont trylock mmap_sem with PREEMPT_RT and interrupts disabled Thomas Gleixner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200220204617.637603528@linutronix.de \
    --to=tglx@linutronix.de \
    --cc=ast@kernel.org \
    --cc=bigeasy@linutronix.de \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=davem@davemloft.net \
    --cc=juri.lelli@redhat.com \
    --cc=kuba@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mathieu.desnoyers@efficios.com \
    --cc=mingo@kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=peterz@infradead.org \
    --cc=rostedt@goodmis.org \
    --cc=vinicius.gomes@intel.com \
    --cc=williams@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.