From: Alan Maguire <alan.maguire@oracle.com>
To: ast@kernel.org, daniel@iogearbox.net
Cc: kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com,
john.fastabend@gmail.com, kpsingh@chromium.org,
rostedt@goodmis.org, linux-doc@vger.kernel.org, corbet@lwn.net,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org,
Alan Maguire <alan.maguire@oracle.com>
Subject: [PATCH bpf] bpf: doc: remove references to warning message when using bpf_trace_printk()
Date: Fri, 7 Aug 2020 12:50:29 +0100 [thread overview]
Message-ID: <1596801029-32395-1-git-send-email-alan.maguire@oracle.com> (raw)
The BPF helper bpf_trace_printk() no longer uses trace_printk();
it is now triggers a dedicated trace event. Hence the described
warning is no longer present, so remove the discussion of it as
it may confuse people.
Fixes: ac5a72ea5c89 ("bpf: Use dedicated bpf_trace_printk event instead of trace_printk()")
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
---
Documentation/bpf/bpf_design_QA.rst | 11 -----------
1 file changed, 11 deletions(-)
diff --git a/Documentation/bpf/bpf_design_QA.rst b/Documentation/bpf/bpf_design_QA.rst
index 12a246f..2df7b06 100644
--- a/Documentation/bpf/bpf_design_QA.rst
+++ b/Documentation/bpf/bpf_design_QA.rst
@@ -246,17 +246,6 @@ program is loaded the kernel will print warning message, so
this helper is only useful for experiments and prototypes.
Tracing BPF programs are root only.
-Q: bpf_trace_printk() helper warning
-------------------------------------
-Q: When bpf_trace_printk() helper is used the kernel prints nasty
-warning message. Why is that?
-
-A: This is done to nudge program authors into better interfaces when
-programs need to pass data to user space. Like bpf_perf_event_output()
-can be used to efficiently stream data via perf ring buffer.
-BPF maps can be used for asynchronous data sharing between kernel
-and user space. bpf_trace_printk() should only be used for debugging.
-
Q: New functionality via kernel modules?
----------------------------------------
Q: Can BPF functionality such as new program or map types, new
--
1.8.3.1
next reply other threads:[~2020-08-07 11:51 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-07 11:50 Alan Maguire [this message]
2020-08-07 17:01 ` [PATCH bpf] bpf: doc: remove references to warning message when using bpf_trace_printk() Daniel Borkmann
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