lkml.org 
[lkml]   [2008]   [May]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 08 of 11] anon-vma-rwsem


    On Wed, 7 May 2008, Christoph Lameter wrote:
    >
    > > (That said, we're not running out of vm flags yet, and if we were, we
    > > could just add another word. We're already wasting that space right now on
    > > 64-bit by calling it "unsigned long").
    >
    > We sure have enough flags.

    Oh, btw, I was wrong - we wouldn't want to mark the vma's (they are
    unique), we need to mark the address spaces/anonvma's. So the flag would
    need to be in the "struct anon_vma" (and struct address_space), not in the
    vma itself. My bad. So the flag wouldn't be one of the VM_xyzzy flags, and
    would require adding a new field to "struct anon_vma()"

    And related to that brain-fart of mine, that obviously also means that
    yes, the locking has to be stronger than "mm->mmap_sem" held for writing,
    so yeah, it would have be a separate global spinlock (or perhaps a
    blocking lock if you have some reason to protect anything else with this
    too).

    Linus


    \
     
     \ /
      Last update: 2008-05-08 03:45    [W:4.508 / U:0.288 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site