lkml.org 
[lkml]   [2012]   [Nov]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRE: [PATCH 1/2] mm: Export vm_committed_as
    Date


    > -----Original Message-----
    > From: David Rientjes [mailto:rientjes@google.com]
    > Sent: Monday, November 05, 2012 5:33 PM
    > To: KY Srinivasan
    > Cc: Andrew Morton; Greg KH; olaf@aepfle.de; linux-kernel@vger.kernel.org;
    > andi@firstfloor.org; apw@canonical.com; devel@linuxdriverproject.org; linux-
    > mm@kvack.org; Hiroyuki Kamezawa; Michal Hocko; Johannes Weiner; Ying Han
    > Subject: RE: [PATCH 1/2] mm: Export vm_committed_as
    >
    > On Mon, 5 Nov 2012, KY Srinivasan wrote:
    >
    > > The Hyper-V host has a policy engine for managing available physical memory
    > across
    > > competing virtual machines. This policy decision is based on a number of
    > parameters
    > > including the memory pressure reported by the guest. Currently, the pressure
    > calculation is
    > > based on the memory commitment made by the guest. From what I can tell,
    > the ratio of
    > > currently allocated physical memory to the current memory commitment made
    > by the guest
    > > (vm_committed_as) is used as one of the parameters in making the memory
    > balancing decision on
    > > the host. This is what Windows guests report to the host. So, I need some
    > measure of memory
    > > commitments made by the Linux guest. This is the reason I want export
    > vm_committed_as.
    > >
    >
    > I don't think you should export the symbol itself to modules but rather a
    > helper function that returns s64 that just wraps
    > percpu_counter_read_positive() which your driver could use instead.
    >
    > (And why percpu_counter_read_positive() returns a signed type is a
    > mystery.)

    Yes, this makes sense. I just want to access (read) this metric. Andrew, if you are willing to
    take this patch, I could send one.

    Regards,

    K. Y




    \
     
     \ /
      Last update: 2012-11-08 23:21    [W:2.304 / U:0.032 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site