lkml.org 
[lkml]   [2010]   [Jun]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH] rbtree: undo augmented damage -v2
    From
    Date
    On Thu, 2010-06-03 at 09:13 +0200, Peter Zijlstra wrote:
    > On Wed, 2010-06-02 at 14:11 -0700, Suresh Siddha wrote:
    > > P SL
    > > / \ / \
    > > N S ---> N S
    > > / / \ / \
    > > C SL SR C SR
    > >
    > > If P needs to be removed, we need to re-augment S also in this case,
    > > right? It looks like we are not handling this case.
    >
    >
    > rb_augment_erase_begin(P) will return S if I read the code right, so
    > rb_augment_path(S) will the re-augment S, SL, N.

    To be more explicit: P has two children, so we select the next entry,
    SL, as its substitute. Since SL doesn't have a right child we select its
    parent, S.

    If SL were to represent a subtree with a right child, then we'd select
    that, lets call it SLR. SLR would then end up being a direct descendant
    of S, and hence rb_augment_path(SLR) would still pass S on its way up.




    \
     
     \ /
      Last update: 2010-06-03 09:51    [W:0.044 / U:31.704 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site