| Date | Thu, 8 Oct 2015 15:50:46 +0200 | Subject | Re: [PATCH 05/44] kdbus: Add comment on merging free pool slices | From | David Herrmann <> |
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Hi
On Thu, Oct 8, 2015 at 1:31 PM, Sergei Zviagintsev <sergei@s15v.net> wrote: > Add comment on why we remove the same slice from free slices tree and > then add it back again when merging the slice to be released with > previous free slice. > > Signed-off-by: Sergei Zviagintsev <sergei@s15v.net> > --- > ipc/kdbus/pool.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/ipc/kdbus/pool.c b/ipc/kdbus/pool.c > index 84afe96fbc22..c26ef963d8d1 100644 > --- a/ipc/kdbus/pool.c > +++ b/ipc/kdbus/pool.c > @@ -304,6 +304,12 @@ static void __kdbus_pool_slice_release(struct kdbus_pool_slice *slice) > s = list_entry(slice->entry.prev, > struct kdbus_pool_slice, entry); > if (s->free) { > + /* > + * As size of slice increases after merge and free > + * slices tree is ordered by slice size, we have to > + * remove the slice from free slices tree and then add > + * it again to keep the tree balanced. > + */
Mhh, isn't this obvious? "slices_free" is ordered by s->size, so a change of the key requires a re-insert. If you disagree, maybe keep it simple:
/* s->size changed, re-insert slice in rbtree */
Thanks David
> rb_erase(&s->rb_node, &pool->slices_free); > list_del(&slice->entry); > s->size += slice->size; > -- > 1.8.3.1 >
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