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39 lines
1.6 KiB
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39 lines
1.6 KiB
Plaintext
swapinfo
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========
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Swapinfo is designed to provide some information to the user about the
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state of the swap space on the system. I've written it based on a
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brief (!) perusal of the VM code in 386BSD. I could be pretty confused
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about how it all fits together, and perhaps this is totally bogus.
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It seems to work for me, though.
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How it works:
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During startup, the system traverses the list of configured swap partitions,
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and determines the size of the various partitions. As each new partition
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is added for swapping (via swapon), the free space on that disk is added
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to a linked list of free space. Adjacent areas are coalesced to form
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larger areas. The swapping algorithm seems to take the first free section
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that it finds [?].
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Swapinfo reads in the list of configured swap partitions from the /dev/kmem,
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to determine the size of the partitions. It then traverses the list
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of free space, figuring up how much is still available and how much
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has therefore been used. Things get a little hairy in that the swap space
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is divided amongst the configured swap partitions so that the first
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4096 blocks of swap go on the first swap partition, the second 4096 on
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the second swap partition, and so on. This works out to be a fairly
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simple bit of code, though.
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More caveats:
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This works on my system. Your milage may vary. Since I'm reading /dev/kmem
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to follow a linked list, the program could easily get lost looking for
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some free space if anything got changed between reads of /dev/kmem.
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If you get occasional inconsistant results, ignore 'em.
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Feel free to send bug reports, flames, etc., to:
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Kevin Lahey
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kml@rokkaku.atl.ga.us
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