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: | Matthew Dillon (dil...@apollo.backplane.com) | |
| Date: | Jul 12, 2002 11:51:56 pm | |
| List: | org.freebsd.freebsd-hackers | |
:BTW, NetBSD's new UVM code has the ability to do this. Perhaps :it's worth looking in to how difficult it would really be in FreeBSD... : :To Unsubscribe: send mail to majo...@FreeBSD.org :with "unsubscribe freebsd-hackers" in the body of the message
Someone got it mostly working a year or two ago if I remember right but I don't know what happened to it finally.
Implementing swapoff is a bunch of grunt-work but not too hard in concept. Basically the work involved is this:
* Make a calculation to be sure that it is possible to turn off the swap device and not run the system out of VM. If it is not possible do not allow the swapoff.
* Allocate all the free bitmap bits related to the swap device you are trying to remove to prevent pageouts to the device you are removing.
* Flag the swap device being removed and then scan all OBJT_SWAP VM Objects looking for swap blocks associated with the device, and force a page-in of those blocks. The getpages code for the swap backing store would detect the flag and not clear the swap bitmap bits as it pages-in the data.
(Forcing a pagein may force pages to cycle back out to another swap device, so special treatment of the paged-in pages (like immediately placing it in the VM page cache instead of the active or inactive queues) is necessary to reduce load effects on the system.
* The swap device being removed can now be closed and the related swap device index marked free.
-Matt Matthew Dillon <dil...@backplane.com>
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