lkml.org 
[lkml]   [2018]   [Jan]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2] kdb: use ktime_get_mono_fast_ns() instead of ktime_get_ts()
On Mon, Jan 29, 2018 at 10:22:51AM +0800, Baolin Wang wrote:
> The kdb code will print the monotonic time by ktime_get_ts(), but
> the ktime_get_ts() will be protected by a sequence lock, that will
> introduce one deadlock risk if the lock was already held in the
> context from which we entered the debugger.
>
> Thus we can use the ktime_get_mono_fast_ns() to get the monotonic
> time, which is NMI safe access to clock monotonic. Moreover we can
> remove the 'struct timespec', which is not y2038 safe.
>
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>


> ---
> Changes since v1:
> - Use ktime_get_mono_fast_ns() instead of ktime_get_seconds().
> ---
> kernel/debug/kdb/kdb_main.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
> index 69e70f4..bf1d0e0 100644
> --- a/kernel/debug/kdb/kdb_main.c
> +++ b/kernel/debug/kdb/kdb_main.c
> @@ -2486,10 +2486,10 @@ static int kdb_kill(int argc, const char **argv)
> */
> static void kdb_sysinfo(struct sysinfo *val)
> {
> - struct timespec uptime;
> - ktime_get_ts(&uptime);
> + u64 uptime = ktime_get_mono_fast_ns();
> +
> memset(val, 0, sizeof(*val));
> - val->uptime = uptime.tv_sec;
> + val->uptime = div_u64(uptime, NSEC_PER_SEC);
> val->loads[0] = avenrun[0];
> val->loads[1] = avenrun[1];
> val->loads[2] = avenrun[2];
> --
> 1.7.9.5
>

\
 
 \ /
  Last update: 2018-01-30 10:49    [W:0.112 / U:0.284 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site