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-rw-r--r--include/linux/trace_seq.h15
1 files changed, 12 insertions, 3 deletions
diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index 3691e0e76..1ef95c028 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -8,11 +8,20 @@
/*
* Trace sequences are used to allow a function to call several other functions
- * to create a string of data to use (up to a max of PAGE_SIZE).
+ * to create a string of data to use.
+ *
+ * Have the trace seq to be 8K which is typically PAGE_SIZE * 2 on
+ * most architectures. The TRACE_SEQ_BUFFER_SIZE (which is
+ * TRACE_SEQ_SIZE minus the other fields of trace_seq), is the
+ * max size the output of a trace event may be.
*/
+#define TRACE_SEQ_SIZE 8192
+#define TRACE_SEQ_BUFFER_SIZE (TRACE_SEQ_SIZE - \
+ (sizeof(struct seq_buf) + sizeof(size_t) + sizeof(int)))
+
struct trace_seq {
- char buffer[PAGE_SIZE];
+ char buffer[TRACE_SEQ_BUFFER_SIZE];
struct seq_buf seq;
size_t readpos;
int full;
@@ -21,7 +30,7 @@ struct trace_seq {
static inline void
trace_seq_init(struct trace_seq *s)
{
- seq_buf_init(&s->seq, s->buffer, PAGE_SIZE);
+ seq_buf_init(&s->seq, s->buffer, TRACE_SEQ_BUFFER_SIZE);
s->full = 0;
s->readpos = 0;
}