Messages in this thread | | | From | Miguel Ojeda <> | Date | Mon, 30 Apr 2018 12:35:25 +0200 | Subject | Re: DOS by unprivileged user |
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On Mon, Apr 30, 2018 at 12:00 PM, Ferry Toth <ftoth@telfort.nl> wrote: > Op woensdag 25 april 2018 16:54:59 CEST schreef Alan Cox: >> > > I think memory allocation and io waits can't be decoupled from >> > > scheduling as they are now. >> > >> > The scheduler is not decoupled from either, it is intimately involved >> > in both. However, none of the decision making smarts for either reside >> > in the scheduler, nor should they. >> >> It belongs in both. >> >> Classical Unix systems never had this problem because they respond to >> thrashing by ensuring that all processes consumed CPU and made some >> progress. Linux handles it by thrashing itself to dealth while BSD always >> handled it by moving from paging more towards swapping and behaving like >> a swap bound batch machine. >> >> Linux thrashes itself to death, the classic BSD algorithn instead throws >> fairness out of the window under extreme load to prevent it. It might take >> a few seconds but at least you will get your prompt back. >> >> Alan >> > I haven t tried BSD. > > But when I was young I allocated 10MB on a HP9000 (UX) with 1MB of RAM. People wanted to launch me out of the window (18th floor). > > I did not want to say Unix was better, only with so much emphasis on security I' m surprised how easy it is for a regular user to bring linux to on it s knees.
While it is true that things can be improved/tweaked for typical desktop/single user usage; this isn't really a security issue. For shared systems, there are a few ways to soft/hard limit resources: nice, *limit, cgroups, systemd limits, containers/VMs...
Cheers, Miguel
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