30 messages in org.freebsd.freebsd-hackersRe: swapoff?| From | Sent On | Attachments |
|---|---|---|
| Sean Kelly | Jul 12, 2002 9:02 pm | |
| David Schultz | Jul 12, 2002 10:23 pm | |
| David Schultz | Jul 12, 2002 10:32 pm | |
| Matthew Dillon | Jul 12, 2002 11:51 pm | |
| David Schultz | Jul 13, 2002 12:18 am | |
| Matthew Dillon | Jul 13, 2002 12:27 am | |
| Peter Wemm | Jul 13, 2002 12:33 am | |
| Andrey Alekseyev | Jul 13, 2002 1:23 am | |
| Terry Lambert | Jul 13, 2002 3:17 am | |
| Jon Mini | Jul 13, 2002 3:44 am | |
| Terry Lambert | Jul 13, 2002 4:30 am | |
| David Schultz | Jul 13, 2002 4:57 am | |
| Terry Lambert | Jul 13, 2002 5:22 am | |
| Matthew Dillon | Jul 13, 2002 9:36 am | |
| David Schultz | Jul 13, 2002 2:00 pm | |
| Peter Wemm | Jul 13, 2002 3:39 pm | |
| David Schultz | Oct 7, 2002 8:38 am | |
| Matthew Dillon | Oct 7, 2002 4:46 pm | |
| Nate Lawson | Oct 7, 2002 9:47 pm | |
| David Schultz | Oct 8, 2002 4:35 am | |
| David Schultz | Oct 8, 2002 4:39 am | |
| Matthew Dillon | Oct 8, 2002 10:04 am | |
| Matthew Dillon | Oct 8, 2002 10:45 am | |
| David Schultz | Oct 11, 2002 6:01 am | |
| Matthew Dillon | Oct 11, 2002 11:14 am | |
| David Schultz | Oct 14, 2002 2:41 am | |
| Matthew Dillon | Oct 14, 2002 8:55 am | |
| David Schultz | Oct 15, 2002 12:10 am | |
| David Schultz | Oct 23, 2002 11:07 am | |
| Matthew Dillon | Oct 23, 2002 11:45 am |
| Subject: | Re: swapoff? | |
|---|---|---|
| From: | David Schultz (dsch...@uclink.Berkeley.EDU) | |
| Date: | Oct 23, 2002 11:07:55 am | |
| List: | org.freebsd.freebsd-hackers | |
Thus spake Matthew Dillon <dil...@apollo.backplane.com>:
:The concern was that there could be a race where the process is :swapped out again after I have swapped it back in but before I can :dirty its pages. (Perhaps I need to hold the process lock a bit :longer.) Under heavy swapping load, swapoff() is failing to find :a single page about one time out of ten, and I thought that might :be the cause.
Have you definitively tracked down the missing page? It ought to be fairly easy to do from a kernel core with a gdb macro.
No, I've tested it extensively, and I haven't been able to reproduce the problem since I updated my sources. (It was hard to reproduce beforehand.) I did two more runs with one swap device and two runs with two swap devices, and it worked even when the system was thrashing.
The latest patches are at
http://www.CSUA.Berkeley.EDU/~das/swapoff.patch4
Performance is now much better when there are multiple swap devices. Instead of effectively having to wait for each hash chain to become quiescent, swapoff now skips busy objects, then does a complete rescan if it missed anything. Only a few rescans are required, even with multiple active swap devices. A clustering optimization might still be worthwhile, but that can be done another day.
(Sorry for the delay in getting back to you. I've been too busy and sick for the last week to work on this.)
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