Messages in this thread |  | | Date | Thu, 4 Jul 1996 00:08:07 -0400 | From | "Theodore Y. Ts'o" <> | Subject | Re: PATCH: Ramdisk version 2.0.1 |
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From: greg@wind.rmcc.com (G.W. Wettstein) Date: Mon, 1 Jul 1996 12:39:22 CDT
I had a question on a related note. I find the new ramdisk code very useful but it has been unclear how to make the entity go away completely? It seems that the ramdisk gets swapped away but I have never been able to make its consumption of swap space go away.
If the ramdisk is compiled as a module, all of the blocks will be released when the module is unloaded.
You can also use the ioctl BLKFLSBUF to make the memory pages used by ramdisk go away. (Note that ramdisk doesn't use swap space; it uses kernel memory pages.) It's important to remember that BLKFLSBUF on normal disk devices causes the buffer cache for that device to be flushed, but they can always be reread in from the device. However, BLKFLSBUF on a ramdisk makes the data in the ram disk go away permanently.
We probably should have used a different ioctl, because these two meanings *are* different, and the results could be quite disastrous if a program were to call the ioctl expecting one behavior, and it got another. Fortunately, that ioctl isn't used often by most programs.
- Ted
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