Please put back VM cleaning! - rkdk

Sjk posted quite a good reason for why cleaning virtual memory is not necessary. However, you seem to like that function. I'm now stuck at the decision on whether or not to put vm cleaning back in. Anyone have any suggestions? Thanks

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Friday, March 25 2005 @ 11:00 PM PST

swap file roulette - sjk

For the daring, here's something to try:

• Check available disk space on boot volume.
• Delete a swap file (using "rm -f").
• Check available disk space on boot volume.

My untested theory is that if the swap file you delete is still active then disk space will remain about the same as before the deletion since the filesystem won't reclaim the space until the swap file is closed (i.e. dynamic_pager quits). So, you don't immediately regain any disk space and have left the demand paging system in a undesirably vulnerable condition.

Now, what's happening if disk space does increase immediately after removing a swap file? My earlier post shows why, under normal conditions, there won't be any "leftover" swap files after restarting. Assuming that, the swap file must have been created by dynamic_pager during the current session but isn't holding it open (so disk space reappears). Yet dynamic_pager is capable of removing swap files on its own and manually removing them is trying to outguess dynamic_pager's algorithm for doing it. That's another potentially undesirable condition for the dynamic paging system.

If you notice an abnormally large number of swap files try logging out (without restarting), wait a bit, then do a console login and check how many swap files remain. I've done that numerous times since running 10.1 and noticed how the number of swap files can differ, even with only a minimal set of processes running. To me that indicates dynamic_pager will delete those it considers safe to delete, for reasons I don't fully understand (yet). And I have no reason to risk trouble by manually removing any others based on that lack of understanding. Again, I welcome anyone with deeper knowledge to help clarify this.

Anyway, if someone wants to play Russian roulette with dynamic_pager by manually removing swap files on their systems that's their business.

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Saturday, March 26 2005 @ 11:47 AM PST

swap file roulette - rkdk

Again, Thanks a lot. <br><br>

You've been really helpful in helping understand all this. I put virtual memory cleaning in the app because all the other "maintenance/cleaning" utilities had this feature, without thinking of the risks and the need for this. <br><br>

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Saturday, March 26 2005 @ 02:12 PM PST

swap file roulette - rkdk

Again, Thanks a lot.

You've been really helpful in helping understand all this. I put virtual memory cleaning in the app because all the other "maintenance/cleaning" utilities had this feature, without thinking of the risks and the need for this.

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Saturday, March 26 2005 @ 02:12 PM PST