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authorTao Ma <boyu.mt@taobao.com>2011-01-18 21:51:44 -0500
committerJens Axboe <jaxboe@fusionio.com>2011-01-19 10:25:02 -0500
commit490da40d82b31c0562d3f5edb37810f492ca1c34 (patch)
tree6a5c05af9171044aa95b603ceb8346883139ca56 /kernel
parentc56eb8fb6dccb83d9fe62fd4dc00c834de9bc470 (diff)
blktrace: Don't output messages if NOTIFY isn't set.
Now if we enable blktrace, cfq has too many messages output to the trace buffer. It is fine if we don't specify any action mask. But if I do like this: blktrace /dev/sdb -a issue -a complete -o - | blkparse -i - I only want to see 'D' and 'C', while with the following command dd if=/mnt/ocfs2/test of=/dev/null bs=4k count=1 iflag=direct I will get(with a 2.6.37 vanilla kernel): 8,16 0 0 0.000000000 0 m N cfq3805 alloced 8,16 0 0 0.000004126 0 m N cfq3805 insert_request 8,16 0 0 0.000004884 0 m N cfq3805 add_to_rr 8,16 0 0 0.000008417 0 m N cfq workload slice:300 8,16 0 0 0.000009557 0 m N cfq3805 set_active wl_prio:0 wl_type:2 8,16 0 0 0.000010640 0 m N cfq3805 fifo= (null) 8,16 0 0 0.000011193 0 m N cfq3805 dispatch_insert 8,16 0 0 0.000012221 0 m N cfq3805 dispatched a request 8,16 0 0 0.000012802 0 m N cfq3805 activate rq, drv=1 8,16 0 1 0.000013181 3805 D R 114759 + 8 [dd] 8,16 0 2 0.000164244 0 C R 114759 + 8 [0] 8,16 0 0 0.000167997 0 m N cfq3805 complete rqnoidle 0 8,16 0 0 0.000168782 0 m N cfq3805 set_slice=100 8,16 0 0 0.000169874 0 m N cfq3805 arm_idle: 8 group_idle: 0 8,16 0 0 0.000170189 0 m N cfq schedule dispatch 8,16 0 0 0.000397938 0 m N cfq3805 slice expired t=0 8,16 0 0 0.000399763 0 m N cfq3805 sl_used=1 disp=1 charge=1 iops=0 sect=8 8,16 0 0 0.000400227 0 m N cfq3805 del_from_rr 8,16 0 0 0.000400882 0 m N cfq3805 put_queue See, there are 19 lines while I only need 2. I don't think it is appropriate for a user. So this patch will disable any messages if the BLK_TC_NOTIFY isn't set. Now the output for the same command will look like: 8,16 0 1 0.000000000 4908 D R 114759 + 8 [dd] 8,16 0 2 0.000146827 0 C R 114759 + 8 [0] Yes, it is what I want to see. Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/blktrace.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 153562d0b93c..d95721f33702 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -138,6 +138,13 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
138 !blk_tracer_enabled)) 138 !blk_tracer_enabled))
139 return; 139 return;
140 140
141 /*
142 * If the BLK_TC_NOTIFY action mask isn't set, don't send any note
143 * message to the trace.
144 */
145 if (!(bt->act_mask & BLK_TC_NOTIFY))
146 return;
147
141 local_irq_save(flags); 148 local_irq_save(flags);
142 buf = per_cpu_ptr(bt->msg_data, smp_processor_id()); 149 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
143 va_start(args, fmt); 150 va_start(args, fmt);