Messages in this thread | | | Date | Fri, 29 Sep 2000 11:39:18 -0300 (BRST) | From | Rik van Riel <> | Subject | Re: [patch] vmfixes-2.4.0-test9-B2 - fixing deadlocks |
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On Thu, 28 Sep 2000, Andrea Arcangeli wrote: > On Thu, Sep 28, 2000 at 08:16:32AM -0300, Rik van Riel wrote: > > Andrea, I have the strong impression that your idea of > > memory balancing is based on the idea that the OS should > > out-smart the application instead of looking at the usage > > pattern of the pages in memory. > > Not sure what you mean with out-smart. > > My only point is that the OS actually can only swapout such shm. > If that SHM is not supposed to be swapped out and if the OS I/O > cache have more aging then the shm cache, then the OS should > tell the DBMS that it's time to shrink some shm page by freeing > it.
OK, good to see that we agree on the fact that we should age and swapout all pages equally agressively.
> > of the pages in question, instead of making presumptions > > based on what kind of cache the page is in. > > For the mapped pages we never make presumptions. We always check > the accessed bit and that's the most reliable info to know if > the page is been accessed recently (set from the cpu accesse > through the pte not only during page faults or cache hits). > With the current design pages mapped multiple times will be > overaged a bit but this can't be fixed until we make a page->pte > reverse lookup...
Indeed.
regards,
Rik -- "What you're running that piece of shit Gnome?!?!" -- Miguel de Icaza, UKUUG 2000
http://www.conectiva.com/ http://www.surriel.com/
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