[PATCH tip 1/1] blktrace: the ftrace interface needs CONFIG_TRACING

From: Arnaldo Carvalho de Melo
Date: Mon Jan 26 2009 - 15:26:30 EST

Resend, the first time I forgot to add [PATCH tip 1/1].

Ingo, this fix that problem you reported me, where a .config didn't had

Impact: Fix Kconfig selection for blktrace

Also mention in the help text that blktrace now can be used using
the ftrace interface.

Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
Reported-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

diff --git a/block/Kconfig b/block/Kconfig
index 0cbb3b8..7cdaa1d 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -50,6 +50,8 @@ config BLK_DEV_IO_TRACE
select RELAY
select DEBUG_FS
+ select TRACING
Say Y here if you want to be able to trace the block layer actions
on a given queue. Tracing allows you to see any traffic happening
@@ -58,6 +60,12 @@ config BLK_DEV_IO_TRACE


+ Tracing also is possible using the ftrace interface, e.g.:
+ echo 1 > /sys/block/sda/sda1/trace/enable
+ echo blk > /sys/kernel/debug/tracing/current_tracer
+ cat /sys/kernel/debug/tracing/trace_pipe
If unsure, say N.

config BLK_DEV_BSG
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