Messages in this thread | | | Date | Thu, 16 Jan 2020 16:22:14 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH v4] drivers/base/memory.c: cache blocks in radix tree to accelerate lookup |
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On Wed 15-01-20 20:09:48, David Hildenbrand wrote: > On 09.01.20 22:25, Scott Cheloha wrote: > > Searching for a particular memory block by id is an O(n) operation > > because each memory block's underlying device is kept in an unsorted > > linked list on the subsystem bus. > > > > We can cut the lookup cost to O(log n) if we cache the memory blocks in > > a radix tree. With a radix tree cache in place both memory subsystem > > initialization and memory hotplug run palpably faster on systems with a > > large number of memory blocks. > > > > Signed-off-by: Scott Cheloha <cheloha@linux.ibm.com> > > Acked-by: David Hildenbrand <david@redhat.com> > > Acked-by: Nathan Lynch <nathanl@linux.ibm.com> > > Acked-by: Michal Hocko <mhocko@suse.com> > > Soooo, > > I just learned that radix trees are nowadays only a wrapper for xarray > (for quite a while already!), and that the xarray interface shall be > used in new code.
Good point. I somehow didn't realize this would add more work for a later code refactoring. The mapping should be pretty straightforward.
Thanks for noticing!
-- Michal Hocko SUSE Labs
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