lkml.org 
[lkml]   [2010]   [Mar]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: Memory management woes - order 1 allocation failures
    On Tue, Mar 02, 2010 at 07:11:10PM +0000, Mel Gorman wrote:
    > On Tue, Mar 02, 2010 at 06:34:51PM +0000, Alan Cox wrote:
    > > > For reasons that are not particularly clear to me, tty_buffer_alloc() is
    > > > called far more frequently in 2.6.33 than in 2.6.24. I instrumented the
    > > > function to print out the size of the buffers allocated, booted under
    > > > qemu and would just "cat /bin/ls" to see what buffers were allocated.
    > > > 2.6.33 allocates loads, including high-order allocations. 2.6.24
    > > > appeared to allocate once and keep silent.
    > >
    > > The pty layer is using them now and didn't before. That will massively
    > > distort your numhers.
    > >
    >
    > That makes perfect sense. It explains why only one allocation showed up
    > because it must belong to the tty attached to the serial console.
    >
    > Thanks Alan.
    >
    > > > While there have been snags recently with respect to high-order
    > > > allocation failures in recent kernels, this might be one of the cases
    > > > where it's due to subsystems requesting high-order allocations more.
    > >
    > > The pty code certainly triggered more such allocations. I've sent Greg
    > > patches to make the tty buffering layer allocate sensible sizes as it
    > > doesn't need multiple page allocations in the first place.
    > >
    >
    > Greg, what's the story with these patches?

    They are in -next and will go to Linus later on today for .34.

    thanks,

    greg k-h


    \
     
     \ /
      Last update: 2010-03-02 20:33    [W:0.028 / U:0.112 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site