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-rw-r--r--Documentation/dynamic-debug-howto.txt23
1 files changed, 8 insertions, 15 deletions
diff --git a/Documentation/dynamic-debug-howto.txt b/Documentation/dynamic-debug-howto.txt
index 378b5d1bf43..74e6c778267 100644
--- a/Documentation/dynamic-debug-howto.txt
+++ b/Documentation/dynamic-debug-howto.txt
@@ -12,7 +12,7 @@ dynamically enabled per-callsite.
Dynamic debug has even more useful features:
* Simple query language allows turning on and off debugging statements by
- matching any combination of:
+ matching any combination of 0 or 1 of:
- source filename
- function name
@@ -79,31 +79,24 @@ Command Language Reference
==========================
At the lexical level, a command comprises a sequence of words separated
-by whitespace characters. Note that newlines are treated as word
-separators and do *not* end a command or allow multiple commands to
-be done together. So these are all equivalent:
+by spaces or tabs. So these are all equivalent:
nullarbor:~ # echo -c 'file svcsock.c line 1603 +p' >
<debugfs>/dynamic_debug/control
nullarbor:~ # echo -c ' file svcsock.c line 1603 +p ' >
<debugfs>/dynamic_debug/control
-nullarbor:~ # echo -c 'file svcsock.c\nline 1603 +p' >
- <debugfs>/dynamic_debug/control
nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
<debugfs>/dynamic_debug/control
-Commands are bounded by a write() system call. If you want to do
-multiple commands you need to do a separate "echo" for each, like:
+Command submissions are bounded by a write() system call.
+Multiple commands can be written together, separated by ';' or '\n'.
-nullarbor:~ # echo 'file svcsock.c line 1603 +p' > /proc/dprintk ;\
-> echo 'file svcsock.c line 1563 +p' > /proc/dprintk
+ ~# echo "func pnpacpi_get_resources +p; func pnp_assign_mem +p" \
+ > <debugfs>/dynamic_debug/control
-or even like:
+If your query set is big, you can batch them too:
-nullarbor:~ # (
-> echo 'file svcsock.c line 1603 +p' ;\
-> echo 'file svcsock.c line 1563 +p' ;\
-> ) > /proc/dprintk
+ ~# cat query-batch-file > <debugfs>/dynamic_debug/control
At the syntactical level, a command comprises a sequence of match
specifications, followed by a flags change specification.