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authorSteven Rostedt (Google) <rostedt@goodmis.org>2023-12-09 17:52:20 -0500
committerSteven Rostedt (Google) <rostedt@goodmis.org>2023-12-18 23:14:16 -0500
commit40fc60e36c60ba85b2974e507b67df40c94e9578 (patch)
treee2f1e5e645e1e1e38c8de4b45661058b410a8498 /kernel/trace/trace_seq.c
parent8ec90be7f15fac42992ea821be929d3b06cd0fd9 (diff)
trace_seq: Increase the buffer size to almost two pages
Now that trace_marker can hold more than 1KB string, and can write as much as the ring buffer can hold, the trace_seq is not big enough to hold writes: ~# a="1234567890" ~# cnt=4080 ~# s="" ~# while [ $cnt -gt 10 ]; do ~# s="${s}${a}" ~# cnt=$((cnt-10)) ~# done ~# echo $s > trace_marker ~# cat trace # tracer: nop # # entries-in-buffer/entries-written: 2/2 #P:8 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | <...>-860 [002] ..... 105.543465: tracing_mark_write[LINE TOO BIG] <...>-860 [002] ..... 105.543496: tracing_mark_write: 789012345678901234567890 By increasing the trace_seq buffer to almost two pages, it can now print out the first line. This also subtracts the rest of the trace_seq fields from the buffer, so that the entire trace_seq is now PAGE_SIZE aligned. Link: https://lore.kernel.org/linux-trace-kernel/20231209175220.19867af4@gandalf.local.home Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_seq.c')
-rw-r--r--kernel/trace/trace_seq.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c
index 7be97229ddf8..c158d65a8a88 100644
--- a/kernel/trace/trace_seq.c
+++ b/kernel/trace/trace_seq.c
@@ -13,9 +13,6 @@
* trace_seq_init() more than once to reset the trace_seq to start
* from scratch.
*
- * The buffer size is currently PAGE_SIZE, although it may become dynamic
- * in the future.
- *
* A write to the buffer will either succeed or fail. That is, unlike
* sprintf() there will not be a partial write (well it may write into
* the buffer but it wont update the pointers). This allows users to