Re: Break 2.4 VM in five easy steps

Mike Galbraith
2001-06-07T15:39:41Z

On Thu, 7 Jun 2001, Bulent Abali wrote:

> I happened to saw this one with debugger attached serial port.
> The system was alive. I think I was watching the free page count and
> it was decreasing very slowly may be couple pages per second. Bigger
> the swap usage longer it takes to do swapoff. For example, if I had
> 1GB in the swap space then it would take may be an half hour to shutdown...

I took a ~300ms ktrace snapshot of the no IO spot with 2.4.4.ikd..

% TOTAL TOTAL USECS AVG/CALL NCALLS
0.0693% 208.54 0.40 517 c012d4b9 __free_pages
0.0755% 227.34 1.01 224 c012cb67 __free_pages_ok
...
34.7195% 104515.15 0.95 110049 c012de73 unuse_vma
53.3435% 160578.37 303.55 529 c012dd38 __swap_free
Total entries: 131051 Total usecs: 301026.93 Idle: 0.00%

Andrew Morton could be right about that loop not being wonderful.

-Mike