Re: [PATCH] vmscan: add task name to warn_scan_unevictable() messages

From: Minchan Kim
Date: Wed Nov 23 2011 - 01:41:18 EST


On Tue, Nov 22, 2011 at 10:32:45PM -0800, David Rientjes wrote:
> On Wed, 23 Nov 2011, Minchan Kim wrote:
>
> > > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > > index a1893c0..29d163e 100644
> > > --- a/mm/vmscan.c
> > > +++ b/mm/vmscan.c
> > > @@ -3448,9 +3448,10 @@ void scan_mapping_unevictable_pages(struct address_space *mapping)
> > > static void warn_scan_unevictable_pages(void)
> > > {
> > > printk_once(KERN_WARNING
> > > - "The scan_unevictable_pages sysctl/node-interface has been "
> > > + "%s: The scan_unevictable_pages sysctl/node-interface has been "
> > > "disabled for lack of a legitimate use case. If you have "
> > > - "one, please send an email to linux-mm@xxxxxxxxxx\n");
> > > + "one, please send an email to linux-mm@xxxxxxxxxx\n",
> > > + current->comm);
> > > }
> >
> > Just nitpick:
> > How about using WARN_ONCE instead of custom warning?
> > It can show more exact call path as well as comm.
> > I guess it's more noticible to users.
> > Anyway, either is okay to me.
> >
>
> When I used WARN_ONCE() to notify users that /proc/pid/oom_adj was
> deprecated, people complained that it triggered userspace log parsers
> thinking that there's a serious problem and it adds a taint flag so it got
> reverted. I'd recommend keeping it printk_once().

printk_once is better in case of not serious WARNING
once I listen your opinion.

Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx>

--
Kind regards,
Minchan Kim
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