Mailinglist Archive: opensuse (946 mails)

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Re: [opensuse] Leap 42.3
On 13/09/17 05:10 PM, Aaron Digulla wrote:

What is the search and/or insert or compression algorithm? Is there some
hash
which might also be expanded for faster lookup in the nearly full situation?
The process list is already dynamic.  It's a security feature:
https://en.wikipedia.org/wiki/Fork_bomb

In a nutshell: This is to prevent your computer from locking up because
someone made a mistake (program endlessly creates processes in a loop)
or a denial of service attack (creating processes to bring the
performance to a crawl).

Yes, I'm quite aware of a fork bomb; it is not something new.
Applying a per-user process limit as opposed to merely the system wide process
limit is likely adequate.

Having for each user on a heavily multi-user system Patrick's 4K per user
setting nearly filled by Chrome -- or are we really talking about THREADS rather
than complete processes?[1] --leads to a pretty big main proc table. Or are
they indexed on a per-user basis as well.

The research I can find googling around on kernel hashing seems a bit out of
date and it general. I've seem mention that it is is

- a linear table
- a linked list
- a hash-indexed "table" but format of the "table" unspecified.

Please not, I'm not commenting on the data structure itself, only on its access
methods, creation, destruction.


One thing I do realise: with a VM kernel, tables can be resized. Grab a new
page set, copy into the larger space giving the table a new upper limit, reset
pointers, release old page set.

Whether you SHOULD is quite another matter. The circumstances that force you to
do this might be a problem that is in need of a solution first and foremost.




[1] I understand that for Chrome is it actually processes, but other
applications seem to spawn threads, which look remarkably like processes to some
process-listing tools. I run htop or "ps -eLf" and find firefox has 54 threads,
thunderbird has 91.

--
A: Yes.
> Q: Are you sure?
>> A: Because it reverses the logical flow of conversation.
>>> Q: Why is top posting frowned upon?


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