Messages in this thread |  | | | Date | Fri, 3 Jul 2009 10:54:48 -0700 | | Subject | Re: [PATCH 1/2] Adds a read-only "procs" file similar to "tasks" that shows only unique tgids | | From | Paul Menage <> |
On Fri, Jul 3, 2009 at 9:50 AM, Andrew Morton<akpm@linux-foundation.org> wrote: > > I think you're saying "for each pid N in the cgroup, set the Nth > element in an IDR tree".
Right.
> That would work. And it automatically gives > ordered traversal and dupe removal. > > I don't think IDRs permit in-order traversal, whereas radix-trees do > support this.
I thought that an IDR *was* a form of radix tree.
Looking at the IDR API it doesn't appear support the notion of "insert an entry with id N" anyway.
> Unfortunately radix-trees are presented as operating on > void* data, so one would need to do some typecasting when storing > BITS_PER_LONG-sized bitfields inside them.
That would mean adding something a bit like the IDA wrapper that converts IDR to deal with bitfields?
Is the benefit of avoiding a vmalloc() at all costs really worth the additional complexity, versus just doing:
if (size > 2 * PAGE_SIZE) { array = vmalloc(size); } else { array = kmalloc(size, GFP_KERNEL); } ?
That would only require vmalloc on cgroups with >2048 tasks, which is going to be pretty rare, and is way simpler.
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