[Crash-utility] [PATCH] Add alternate HZ calculation using write_expire
Linux 4.8 and later kernels that contain kernel commit 9a7f38c42c2b
("cfq-iosched: Convert from jiffies to nanoseconds") changed the
definition of cfq_slice_async, and it cannot be used to calculate
the HZ value.
Add alternate HZ calculation using write_expire, which depends on
CONFIG_MQ_IOSCHED_DEADLINE or CONFIG_IOSCHED_DEADLINE.
Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com>
---
task.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/task.c b/task.c
index ce2b55f430e0..36cf259e5d7b 100644
--- a/task.c
+++ b/task.c
@@ -432,6 +432,29 @@ task_init(void)
"cfq_slice_async exists: setting hz to %d\n",
machdep->hz);
}
+ } else if ((symbol_exists("dd_init_queue") &&
+ gdb_set_crash_scope(symbol_value("dd_init_queue"),
"dd_init_queue")) ||
+ (symbol_exists("deadline_init_queue") &&
+ gdb_set_crash_scope(symbol_value("deadline_init_queue"),
"deadline_init_queue"))) {
+ char buf[BUFSIZE];
+ uint write_expire = 0;
+
+ open_tmpfile();
+ sprintf(buf, "printf \"%%d\", write_expire");
+ if (gdb_pass_through(buf, pc->tmpfile, GNU_RETURN_ON_ERROR)) {
+ rewind(pc->tmpfile);
+ if (fgets(buf, BUFSIZE, pc->tmpfile))
+ sscanf(buf, "%d", &write_expire);
+ }
+ close_tmpfile();
+
+ if (write_expire) {
+ machdep->hz = write_expire / 5;
+ if (CRASHDEBUG(2))
+ fprintf(fp, "write_expire exists: setting hz to %d\n",
+ machdep->hz);
+ }
+ gdb_set_crash_scope(0, NULL);
}
if (VALID_MEMBER(runqueue_arrays))
--
2.18.4