Messages in this thread | | | Date | Sun, 24 Jan 1999 16:27:51 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: MM deadlock [was: Re: arca-vm-8...] |
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On Sun, 24 Jan 1999, Alan Cox wrote: > > Being able to throw out page tables is something that is going to be needed > too. As far as I can see that does not mean complexity. The Linux VM is > very clean in its page handling, there is almost nothing in the page tables > that cannot be flushed or dumped to disk if need be.
There _is_ a major problem: being able to swap out page tables means that the thing that swaps them out _has_ to own the mm semaphore.
That's the right thing to do anyway, but it means, for example, that the _only_ process that can page stuff out would be kswapd.
Who knows? Maybe I should just bite the bullet and make that the rule, then we could forget about all the extra recursive semaphore crap too. And it has other advantages - it can speed up the page fault handler (which right now has to get the kernel lock for certain situations).
Once that is done, paging out page tables is not really a problem.
> There are real cases where grab large linear block is needed.
Nobody has so far shown a reasonable implementation where this would be possible.
Linus
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