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    SubjectRe: upcoming kerneloops.org item: get_page_from_freelist

    > > This is not a new concept. oom has never been "immediately kill".
    >
    > Well, it has been immediate for a long time. A couple of reasons which
    > I can recall:
    >
    > - A page-allocating process will oom-kill another process in the
    > expectation that the killing will free up some memory. If the
    > oom-killed process remains stuck in the page allocator, that doesn't
    > work.
    >
    > - The oom-killed process might be holding locks (typically fs locks).
    > This can cause an arbitrary number of other processes to be blocked.
    > So to get the system unstuck we need the oom-killed process to
    > immediately exit the page allocator, to handle the NULL return and to
    > drop those locks.
    >
    > There may be other reasons - it was all a long time ago, and I've never
    > personally hacked on the oom-killer much and I never get oom-killed.
    > But given the amount of development work which goes on in there, some
    > people must be getting massacred.
    >
    >
    > A long time ago, the Suse kernel shipped with a largely (or
    > completely?) disabled oom-killer. It removed the
    > retry-small-allocations-for-ever logic and simply returned NULL to the
    > caller. I never really understood what problem/thinking led Andrea to
    > do that.

    I guess he was trying to get huge 32bit highmem machines to work... On
    such systems, kmalloc failures will eventually get you...
    Pavel
    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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