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| author | Namhyung Kim <namhyung@kernel.org> | 2016-06-29 13:56:48 +0300 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2016-07-06 00:28:30 +0300 |
| commit | a4a551b8f1d4c4ebffd0f49dfef44df3128546f8 (patch) | |
| tree | f59e73d2d4265f88018dea61756793eb15797604 /kernel/trace/trace_entries.h | |
| parent | 7ad8fb61c4abf589596f0a4da34d987471481569 (diff) | |
| download | linux-a4a551b8f1d4c4ebffd0f49dfef44df3128546f8.tar.xz | |
ftrace: Reduce size of function graph entries
Currently ftrace_graph_ent{,_entry} and ftrace_graph_ret{,_entry} struct
can have padding bytes at the end due to alignment in 64-bit data type.
As these data are recorded so frequently, those paddings waste
non-negligible space. As the ring buffer maintains alignment properly
for each architecture, just to remove the extra padding using 'packed'
attribute.
ftrace_graph_ent_entry: 24 -> 20
ftrace_graph_ret_entry: 48 -> 44
Also I moved the 'overrun' field in struct ftrace_graph_ret to minimize
the padding in the middle.
Tested on x86_64 only.
Link: http://lkml.kernel.org/r/1467197808-13578-1-git-send-email-namhyung@kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_entries.h')
| -rw-r--r-- | kernel/trace/trace_entries.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h index ee7b94a4810a..5c30efcda5e6 100644 --- a/kernel/trace/trace_entries.h +++ b/kernel/trace/trace_entries.h @@ -72,7 +72,7 @@ FTRACE_ENTRY_REG(function, ftrace_entry, ); /* Function call entry */ -FTRACE_ENTRY(funcgraph_entry, ftrace_graph_ent_entry, +FTRACE_ENTRY_PACKED(funcgraph_entry, ftrace_graph_ent_entry, TRACE_GRAPH_ENT, @@ -88,7 +88,7 @@ FTRACE_ENTRY(funcgraph_entry, ftrace_graph_ent_entry, ); /* Function return entry */ -FTRACE_ENTRY(funcgraph_exit, ftrace_graph_ret_entry, +FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry, TRACE_GRAPH_RET, |