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From: Alan Maguire <alan.maguire@oracle.com>
To: ast@kernel.org, daniel@iogearbox.net, yhs@fb.com, andriin@fb.com,
	arnaldo.melo@gmail.com
Cc: kafai@fb.com, songliubraving@fb.com, john.fastabend@gmail.com,
	kpsingh@chromium.org, linux@rasmusvillemoes.dk, joe@perches.com,
	pmladek@suse.com, rostedt@goodmis.org,
	sergey.senozhatsky@gmail.com, andriy.shevchenko@linux.intel.com,
	corbet@lwn.net, bpf@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org
Subject: [PATCH v3 bpf-next 5/8] printk: initialize vmlinux BTF outside of printk in late_initcall()
Date: Tue, 23 Jun 2020 13:07:08 +0100	[thread overview]
Message-ID: <1592914031-31049-6-git-send-email-alan.maguire@oracle.com> (raw)
In-Reply-To: <1592914031-31049-1-git-send-email-alan.maguire@oracle.com>

vmlinux BTF initialization can take time so it's best to do that
outside of printk context; otherwise the first printk() using %pT
will trigger BTF initialization.

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
---
 lib/vsprintf.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index c0d209d..8ac136a 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -3628,3 +3628,15 @@ int sscanf(const char *buf, const char *fmt, ...)
 	return i;
 }
 EXPORT_SYMBOL(sscanf);
+
+/*
+ * Initialize vmlinux BTF as it may be used by printk()s and it's better
+ * to incur the cost of initialization outside of printk context.
+ */
+static int __init init_btf_vmlinux(void)
+{
+	(void) bpf_get_btf_vmlinux();
+
+	return 0;
+}
+late_initcall(init_btf_vmlinux);
-- 
1.8.3.1


  parent reply	other threads:[~2020-06-23 12:10 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-23 12:07 [PATCH v3 bpf-next 0/8] bpf, printk: add BTF-based type printing Alan Maguire
2020-06-23 12:07 ` [PATCH v3 bpf-next 1/8] bpf: provide function to get vmlinux BTF information Alan Maguire
2020-06-23 12:07 ` [PATCH v3 bpf-next 2/8] bpf: move to generic BTF show support, apply it to seq files/strings Alan Maguire
2020-06-23 12:07 ` [PATCH v3 bpf-next 3/8] checkpatch: add new BTF pointer format specifier Alan Maguire
2020-06-23 12:07 ` [PATCH v3 bpf-next 4/8] printk: add type-printing %pT format specifier which uses BTF Alan Maguire
2020-06-23 12:40   ` Andy Shevchenko
2020-06-23 13:11   ` Rasmus Villemoes
2020-06-26 10:15   ` Petr Mladek
2020-06-26 11:37     ` Alan Maguire
2020-06-29  9:43       ` Petr Mladek
2020-06-23 12:07 ` Alan Maguire [this message]
2020-06-23 12:07 ` [PATCH v3 bpf-next 6/8] printk: extend test_printf to test %pT BTF-based format specifier Alan Maguire
2020-06-23 13:02   ` Andy Shevchenko
2020-06-23 12:07 ` [PATCH v3 bpf-next 7/8] bpf: add support for %pT format specifier for bpf_trace_printk() helper Alan Maguire
2020-06-23 13:04   ` Andy Shevchenko
2020-06-23 12:07 ` [PATCH v3 bpf-next 8/8] bpf/selftests: add tests for %pT format specifier Alan Maguire
2020-06-23 18:16   ` Andrii Nakryiko
2020-06-30 11:31 ` [PATCH v3 bpf-next 0/8] bpf, printk: add BTF-based type printing Sergey Senozhatsky

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