lkml.org 
[lkml]   [2004]   [Apr]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [Lhms-devel] Re: [patch 0/3] memory hotplug prototype
    --On Wednesday, April 07, 2004 11:59:53 -0700 Mike Kravetz <kravetz@us.ibm.com> wrote:

    > On Wed, Apr 07, 2004 at 11:12:55AM -0700, Martin J. Bligh wrote:
    >> > This is an updated version of memory hotplug prototype patch, which I
    >> > have posted here several times.
    >>
    >> I really, really suggest you take a look at Dave McCracken's work, which
    >> he posted as "Basic nonlinear for x86" recently. It's going to be much
    >> much easier to use this abstraction than creating 1000s of zones ...
    >>
    >
    > I agree. However, one could argue that taking a zone offline is 'easier'
    > than taking a 'section' offline: at least right now. Note that I said
    > easier NOT better. Currently a section represents a subset of one or more
    > zones. Ideally, these sections represent units that can be added or
    > removed. IIRC these sections only define a range of physical memory.
    > To determine if it is possible to take a section offline, one needs to
    > dig into the zone(s) that the section may be associated with. We'll
    > have to do things like:
    > - Stop allocations of pages associated with the section.
    > - Grab all 'free pages' associated with the section.
    > - Try to reclaim/free all pages associated with the section.
    > - Work on this until all pages in the section are not in use (or free).
    > - OR give up if we know we will not succeed.
    >
    > My claim of zones being easier to work with today is due to the
    > fact that zones contain much of the data/infrastructure to make
    > these types of operations easy. For example, in IWAMOTO's code a
    > node/zone can be take offline when 'z->present_pages == z->free_pages'.

    I really think the level of difference in difficultly here is trivial.
    The hard bit is freeing the pages, not measuring them. I would suspect
    altering the swap path to just not "free" the pages, but put them into
    a pool for hotplug is fairly easy.

    M.

    -
    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: 2005-03-22 14:02    [W:5.242 / U:0.668 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site