[lkml]   [2000]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: Overcomittable memory
    On 15 Mar 2000, Rask Ingemann Lambertsen wrote:

    > Den 13-Mar-00 14:14:19 skrev Khimenko Victor følgende om "Re: Overcomittable memory (Was: Linux 2.2.15pre12)":
    > > In <> Rask Ingemann Lambertsen
    > > ( wrote:
    > >> This doesn't mean that overcommit is a good idea. It just means that
    > >> fork()/exec() is not a good way of launching programs. Using overcommit to
    > >> cover up for fork()/exec() deficiencies is like redirecting compiler
    > >> warnings to /dev/null instead of fixing the code. The symptoms become less
    > >> visible but the problem remains. The problem could be solved by introducing
    > >> a new system call with the ability to start an external program as a new
    > >> process.
    > > And then we should start playing stupid games with file descriptors. And
    > > then you can not spawn simple process to communicate with extenal program
    > > over net. And my 20 apache processes will require 800MiB of virtual memory
    > > instead of 60MiB they are using now.
    > Where on Earth did you get those ideas from?

    Those 20 Apache processes each have 40Mb exclusively allocated to them.
    To honour that allocation without overcommit requires 20*40 = 800Mb of VM.

    > > Not every fork will end up with exec, you know.
    > I don't think anybody said they do. I surely didn't.

    The problem is, that fork() allocates memory - the same amount as the
    parent process has allocated. If you want to honour this without
    overcommit, you must disable COW - otherwise you've overcommitted your


    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:57    [W:0.020 / U:4.812 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site