Messages in this thread |  | | Date | Tue, 26 Sep 2000 16:05:54 +0200 | From | Andrea Arcangeli <> | Subject | Re: [patch] vmfixes-2.4.0-test9-B2 - fixing deadlocks |
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On Tue, Sep 26, 2000 at 08:54:23AM +0200, Christoph Rohland wrote: > "Stephen C. Tweedie" <sct@redhat.com> writes: > > > Hi, > > > > On Mon, Sep 25, 2000 at 09:32:42PM +0200, Andrea Arcangeli wrote: > > > > > Having shrink_mmap that browse the mapped page cache is useless > > > as having shrink_mmap browsing kernel memory and anonymous pages > > > as it does in 2.2.x as far I can tell. It's an algorithm > > > complexity problem and it will waste lots of CPU. > > > > It's a compromise between CPU cost and Getting It Right. Ignoring the > > mmap is not a good solution either. > > > > > Now think this simple real life example. A 2G RAM machine running > > > an executable image of 1.5G, 300M in shm and 200M in cache. > > Hey that's ridiculous: 1.5G executable image and 300M shm? Take it > vice-versa and you are approaching real life.
Could you tell me what's wrong in having an app with a 1.5G mapped executable (or a tiny executable but with a 1.5G shared/private file mapping if you prefer), 300M of shm (or 300M of anonymous memory if you prefer) and 200M as filesystem cache?
The application have a misc I/O load that in some part will run out of the working set, what's wrong with this?
What's ridiculous? Please elaborate.
To emulate that workload we only need to mmap(1.5G, MAP_PRIVATE or MAP_SHARED), fault into it, and run bonnie.
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