Actually, the daemon is involved in compacting swap. We add and subtract swap files based on total available free space in the swap files. When we decide to remove a swap file, there may still be contents in it. If there are, the dynamic_pager daemon's thread is the one used to bring those contents back into memory and out to its new home on another swap file. But it never leaves the kernel while doing this (but it is unavailable to respond to additional swap file need/excess notifications while doing it). --Jim On Feb 9, 2004, at 12:53 PM, Mike Smith wrote: dynamic_pager just creates/deletes the swapfiles. It's not involved in the I/O path, nor does it actually compact swap. = Mike On Feb 8, 2004, at 3:44 PM, Brian Tabone wrote: I was digging through the darwin kernel lists, and did some cursory searches on developer.apple.com, but I didn't find the answer. My question is , does the kernel turn to dynamic_pager every time it swaps pages in and out, or does dynamic_pager simply manage the swap file(s) and grow/shrink them based on usage by the kernel? The reason I ask is that it would seem a large performance penalty to have to context switch out to a user-space daemon for every page in/out request. Not only would you be contesting with page swaps, but you would further be slowed down by expensive context switching from kernel to user space. Thanks in advance, -Brian T _______________________________________________ darwin-kernel mailing list | darwin-kernel@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored. _______________________________________________ darwin-kernel mailing list | darwin-kernel@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored. _______________________________________________ darwin-kernel mailing list | darwin-kernel@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.