process_durations() is not a hot path, but there is no good reason to iterate over and over the data already in 'buf'.
Using a seq_buf saves some useless strcat() and the need of a temp buffer. Data is written directly at the correct place. Signed-off-by: Christophe JAILLET <[email protected]> --- kernel/rcu/refscale.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c index 2c2648a3ad30..861485d865ec 100644 --- a/kernel/rcu/refscale.c +++ b/kernel/rcu/refscale.c @@ -28,6 +28,7 @@ #include <linux/rcupdate_trace.h> #include <linux/reboot.h> #include <linux/sched.h> +#include <linux/seq_buf.h> #include <linux/spinlock.h> #include <linux/smp.h> #include <linux/stat.h> @@ -890,31 +891,36 @@ static u64 process_durations(int n) { int i; struct reader_task *rt; - char buf1[64]; + struct seq_buf s; char *buf; u64 sum = 0; buf = kmalloc(800 + 64, GFP_KERNEL); if (!buf) return 0; - buf[0] = 0; + + seq_buf_init(&s, buf, 800 + 64); + sprintf(buf, "Experiment #%d (Format: <THREAD-NUM>:<Total loop time in ns>)", exp_idx); for (i = 0; i < n && !torture_must_stop(); i++) { rt = &(reader_tasks[i]); - sprintf(buf1, "%d: %llu\t", i, rt->last_duration_ns); if (i % 5 == 0) - strcat(buf, "\n"); - if (strlen(buf) >= 800) { + seq_buf_putc(&s, '\n'); + + if (seq_buf_used(&s) >= 800) { + seq_buf_terminate(&s); pr_alert("%s", buf); - buf[0] = 0; + seq_buf_clear(&s); } - strcat(buf, buf1); + + seq_buf_printf(&s, "%d: %llu\t", i, rt->last_duration_ns); sum += rt->last_duration_ns; } + seq_buf_terminate(&s); pr_alert("%s\n", buf); kfree(buf); -- 2.34.1
