Re: [PATCH] Warn if we run out of swap space

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

> On Wed, 27 May 2009, KAMEZAWA Hiroyuki wrote:
> 
> > >  3 files changed, 17 insertions(+)
> > >
> > > Index: linux-2.6/mm/swapfile.c
> > > ===================================================================
> > > --- linux-2.6.orig/mm/swapfile.c	2009-05-22 14:03:37.000000000 -0500
> > > +++ linux-2.6/mm/swapfile.c	2009-05-26 09:11:52.000000000 -0500
> > > @@ -374,6 +374,8 @@ no_page:
> > >  	return 0;
> > >  }
> > >
> > > +int out_of_swap_message_printed = 0;
> > > +
> > >  swp_entry_t get_swap_page(void)
> > >  {
> > >  	struct swap_info_struct *si;
> > > @@ -410,6 +412,11 @@ swp_entry_t get_swap_page(void)
> > >  	}
> > >
> > >  	nr_swap_pages++;
> > > +	if (!out_of_swap_message_printed) {
> > > +		out_of_swap_message_printed = 1;
> > > +		printk(KERN_WARNING "All of swap is in use. Some pages "
> > > +			"cannot be swapped out.\n");
> > > +	}
> > >  noswap:
> > >  	spin_unlock(&swap_lock);
> > BTW, hmm
> >
> > Isn't this should be
> > ==
> > noswap:
> > 	if (total_swap_pages && !out_of_swap_message_printed) {
> > 		....
> > 	}
> 
> Look at the beginning of get_swap_page():
> 
>    spin_lock(&swap_lock);
>         if (nr_swap_pages <= 0)
>                 goto noswap;
>         nr_swap_pages--;
> 
> I placed the printk intentionally before the noswap label.

I tested your patch. but it never output warning messages although swap full.

thanks.



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