Messages in this thread | | | Date | Sat, 28 Mar 1998 10:48:17 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: 2.1.91 swap performance: jerky. |
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On Sat, 28 Mar 1998, Gerard Roudier wrote: > > Without some very smart algorithm that selects pages to swap out, this > 128kB contiguous free area goal seems to me close to impossible without > trashing LOTS of really used pages.
No, it seems to be a very good goal, actually. I've had reports of this approach getting close to exact the behaviour we want: we don't actually want exactly 128kB free, we want something like 5-10% of memory free just in case...
I've also got a patch that maxes out at 25% free, just in case, to avoid the really bad (but unlikely) cases.
> What's the real need of contiguous memory?
DMA.
> Modules that need large physically contiguous memory chunks should be > loaded very early after system start-up.
Not necessarily. Think video capture etc, that definitely wants memory only when it is needed, but that we don't want to allocate memory for all the time (it can need quite a bit of memory)
Linus
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