lkml.org 
[lkml]   [2005]   [Dec]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: Question on the current behaviour of malloc () on Linux
    On 12/22/05, linux-os (Dick Johnson) <linux-os@analogic.com> wrote:
    >
    > On Wed, 21 Dec 2005, Jie Zhang wrote:
    >
    > > Hi,
    > >
    > > I first asked this question on uClinux mailing list. My first question
    > > is <http://mailman.uclinux.org/pipermail/uclinux-dev/2005-December/036042.html>.
    > > Although I found this issue on uClinux, it's also can be demostrated
    > > on Linux. This is a small program:
    > >
    >
    > Another FAQ....
    >
    > > $> cat test2.c
    > > #include <stdio.h>
    > > #include <stdlib.h>
    > >
    > > int
    > > main ()
    > > {
    > > char *p;
    > > int i, j;
    > > for (i = 0;; i++)
    > > {
    > > p = (char *) malloc (8 * 1024 * 1024);
    > > if (p)
    > > for (j = 0; j < 8 * 1024 * 1024; j++)
    > > p[j] = 0x55;
    > > else
    > > {
    > > printf ("%d fail\n", i);
    > > break;
    > > }
    > > }
    > > return 0;
    > > }
    > >
    > > When I run it on my Linux notebook, it will be killed. I expect to see
    > > it prints out "fail".
    >
    > Your expectations are not based upon any logic, only wishes.
    >
    According to SuSv3, I think my expectation is completely based upon
    logic. Actually, overcommitting is based upon wishes I think. It
    wishes application not use all the memory it allocated.
    >
    >
    > To make your wishes come true execute:
    > echo "1" >/proc/sys/vm/overcommit_memory
    > ... as a super-user.
    >
    > That will make malloc() fail when there isn't any more virtual
    > memory.

    That's what I'm looking for. Thanks.

    Jie
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-12-22 08:23    [W:0.032 / U:0.232 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site