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authorFrederic Weisbecker <fweisbec@gmail.com>2008-11-16 06:02:06 +0100
committerIngo Molnar <mingo@elte.hu>2008-11-16 07:57:38 +0100
commite7d3737ea1b102030f44e96c97754101e41515f0 (patch)
tree44fdc3dea100d1fa639e6ba3cb1bfca2ab40e70b /kernel/trace/Kconfig
parentb01c746617da5e260803eb10ed64ca043e9a1241 (diff)
downloadop-kernel-dev-e7d3737ea1b102030f44e96c97754101e41515f0.zip
op-kernel-dev-e7d3737ea1b102030f44e96c97754101e41515f0.tar.gz
tracing/function-return-tracer: support for dynamic ftrace on function return tracer
This patch adds the support for dynamic tracing on the function return tracer. The whole difference with normal dynamic function tracing is that we don't need to hook on a particular callback. The only pro that we want is to nop or set dynamically the calls to ftrace_caller (which is ftrace_return_caller here). Some security checks ensure that we are not trying to launch dynamic tracing for return tracing while normal function tracing is already running. An example of trace with getnstimeofday set as a filter: ktime_get_ts+0x22/0x50 -> getnstimeofday (2283 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1396 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1825 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1426 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1464 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1524 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1382 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1434 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1464 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1502 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1404 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1397 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1051 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1314 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1344 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1163 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1390 ns) ktime_get_ts+0x22/0x50 -> getnstimeofday (1374 ns) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace/Kconfig')
-rw-r--r--kernel/trace/Kconfig1
1 files changed, 0 insertions, 1 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 9c89526..b8378fa 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -59,7 +59,6 @@ config FUNCTION_TRACER
config FUNCTION_RET_TRACER
bool "Kernel Function return Tracer"
- depends on !DYNAMIC_FTRACE
depends on HAVE_FUNCTION_RET_TRACER
depends on FUNCTION_TRACER
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