[Crash-utility] [PATCH] Fix for "help -m" option to display correct hz value

[lijiang]

On Tue, Jan 11, 2022 at 12:12 PM HAGIO KAZUHITO(萩尾　一仁)
<k-hagio-ab at nec.com> wrote:
>
> Hi Lianbo,
>
> thanks for the fix.
>
> -----Original Message-----
> > Subject: [PATCH] Fix for "help -m" option to display correct hz value
>
> This is a fix for HZ calculation, not for "help -m" itself.
> Let me modify the subject like this:
>
>   [PATCH] Fix for HZ calculation on Linux 5.14 and later
>

Thank you for pointing out this issue, Kazu.
This looks better. I will merge it later(with the above changes).

Thanks.
Lianbo

> >
> > Kernel commit 3e9a99eba058 ("block/mq-deadline: Rename dd_init_queue()
> > and dd_exit_queue()") renamed dd_init_queue to dd_init_sched. Without
> > the patch, the 'help -m' may print incorrect hz value as follows:
> >
> > crash> help -m | grep hz
> >        hz: 1000    <---The correct hz value on ppc64le machine is 100.
> >          ^^^^
> >
> > Fixes: b93027ce5c75 ("Add alternate HZ calculation using write_expire")
> > Signed-off-by: Lianbo Jiang <lijiang at redhat.com>
>
> Otherwise, the looks good to me and tested ok.
>
> Acked-by: Kazuhito Hagio <k-hagio-ab at nec.com>
>
> Thanks,
> Kazu
>
> > ---
> >  task.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/task.c b/task.c
> > index bb6a5da8ad33..e24f06396a6c 100644
> > --- a/task.c
> > +++ b/task.c
> > @@ -440,6 +440,8 @@ task_init(void)
> >               }
> >       } else if ((symbol_exists("dd_init_queue") &&
> >           gdb_set_crash_scope(symbol_value("dd_init_queue"), "dd_init_queue")) ||
> > +         (symbol_exists("dd_init_sched") &&
> > +         gdb_set_crash_scope(symbol_value("dd_init_sched"), "dd_init_sched")) ||
> >           (symbol_exists("deadline_init_queue") &&
> >           gdb_set_crash_scope(symbol_value("deadline_init_queue"), "deadline_init_queue"))) {
> >               char buf[BUFSIZE];
> > --
> > 2.20.1
>