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* [LSF/MM/BPF TOPIC] The Maple Tree
@ 2022-02-01 15:06 Liam Howlett
  2022-02-20 17:10 ` Chaitanya Kulkarni
  0 siblings, 1 reply; 3+ messages in thread
From: Liam Howlett @ 2022-02-01 15:06 UTC (permalink / raw
  To: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org,
	linux-fsdevel@vger.kernel.org

Over the years, the tracking of VMAs has slowly gathered more refinement
with added complexity.  Currently each MM has a linked list, a tree, and
a cache to track a list of ranges. The current patch set adding the
maple tree replaces all three of these data structures and is just as
fast or faster - even without modifying the locking.  As more of the MM
code is optimized to use the tree, the locking can be extracted and the
RCU benefits will begin to show.

The maple tree is a RCU safe range based B-tree.  Many of the rules of a
B-tree are kept such as each leaf being at the same height and being
self-balancing.  There are also fundamental differences such as how to
handle an insert operation that may cause one entry to become three or
several entries to disappear all together.

I'd like to discuss how to use the maple tree efficiently in complicated
scenarios such as those arising in the vma_adjust() scenarios. Also on
the table is the possibility of a range-based b-tree for the file
systems as it would seem to work well for file based scenarios.  If
people are interested, I can also dive into how the internals of the
tree operate.


Thank you,
Liam

^ permalink raw reply	[flat|nested] 3+ messages in thread
* [LSF/MM/BPF TOPIC] The Maple Tree
@ 2021-06-01 22:30 Liam Howlett
  0 siblings, 0 replies; 3+ messages in thread
From: Liam Howlett @ 2021-06-01 22:30 UTC (permalink / raw
  To: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org,
	linux-fsdevel@vger.kernel.org

Over the years, the tracking of VMAs has slowly gathered more refinement
with added complexity.  Currently each MM has a linked list, a tree, and
a cache to track a list of ranges. The current patch set adding the
maple tree replaces all three of these data structures and is just as
fast or faster - even without modifying the locking.  As more of the MM
code is optimized to use the tree, the locking can be extracted and the
RCU benefits will begin to show.

The maple tree is a RCU safe range based B-tree.  Many of the rules of a
B-tree are kept such as each leaf being at the same height and being
self-balancing.  There are also fundamental differences such as how to
handle an insert operation that may cause one entry to become three or
several entries to disappear all together.

I'd like to discuss how to use the maple tree efficiently in complicated
scenarios such as those arising in the vma_adjust() scenarios. Also on
the table is the possibility of a range-based b-tree for the file
systems as it would seem to work well for file based scenarios.  If
people are interested, I can also dive into how the internals of the
tree operate.


Thank you,
Liam

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2022-02-20 17:11 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2022-02-01 15:06 [LSF/MM/BPF TOPIC] The Maple Tree Liam Howlett
2022-02-20 17:10 ` Chaitanya Kulkarni
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2021-06-01 22:30 Liam Howlett

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