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| author | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-12-09 23:52:20 +0100 |
|---|---|---|
| committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2023-12-19 05:14:16 +0100 |
| commit | 40fc60e36c60ba85b2974e507b67df40c94e9578 (patch) | |
| tree | e2f1e5e645e1e1e38c8de4b45661058b410a8498 /kernel | |
| parent | tracing: Allow for max buffer data size trace_marker writes (diff) | |
| download | linux-40fc60e36c60ba85b2974e507b67df40c94e9578.tar.xz linux-40fc60e36c60ba85b2974e507b67df40c94e9578.zip | |
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')
| -rw-r--r-- | kernel/trace/trace.c | 6 | ||||
| -rw-r--r-- | kernel/trace/trace_seq.c | 3 |
2 files changed, 3 insertions, 6 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index dba1328e454b..0be30cccabb4 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3753,7 +3753,7 @@ static bool trace_safe_str(struct trace_iterator *iter, const char *str, /* OK if part of the temp seq buffer */ if ((addr >= (unsigned long)iter->tmp_seq.buffer) && - (addr < (unsigned long)iter->tmp_seq.buffer + PAGE_SIZE)) + (addr < (unsigned long)iter->tmp_seq.buffer + TRACE_SEQ_BUFFER_SIZE)) return true; /* Core rodata can not be freed */ @@ -6932,8 +6932,8 @@ waitagain: goto out; } - if (cnt >= PAGE_SIZE) - cnt = PAGE_SIZE - 1; + if (cnt >= TRACE_SEQ_BUFFER_SIZE) + cnt = TRACE_SEQ_BUFFER_SIZE - 1; /* reset all but tr, trace, and overruns */ trace_iterator_reset(iter); 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 |