Messages in this thread | | | Date | Mon, 4 Jun 2007 09:56:05 -0700 | From | Andrew Morton <> | Subject | Re: [patch 1/2] ufd v1 - unsequential O(1) fdmap core |
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On Mon, 4 Jun 2007 06:05:22 -0700 (PDT) Davide Libenzi <davidel@xmailserver.org> wrote:
> On Mon, 4 Jun 2007, Andrew Morton wrote: > > > a) Were IDR trees evaluated and if so, why were they rejected? > > > > b) it's a bit disappointing that this new allocator is only usable for > > one specific application. We have a *lot* of places in the kernel which > > want allocators of this type. Many of them are open-coded and crappy. > > Some use IDR trees. > > > > If we're going to go and add a complete new allocator, it would be > > good to position it as a library thing if poss. > > Thank you for pointing me to that, Andrew. I didn't know about it (IDR > trees). > It does not fit AFAICS. > Locking should be handled extarnally (the files > struct),
Yeah, that's already a problem in IDR and I'm hoping sometime someone will be inspired to redo it, move it to caller-provided locking.
> must be RCU friendly (proper barriers) since it's used in > lockless code,
Haven't looked at that.
> and must have flags associated to an allocation.
Don't understand that.
> And I'm > leaving out the O(1) part, that for something like this, is just silly not > to have it. This is really an array.
Having to walk down a tree in fget_light() would kinda suck.
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