Messages in this thread | | | From | David Laight <> | Subject | [PATCH 00/13] lib/generic-radix-tree: genradix bug fix and optimisations. | Date | Tue, 25 Aug 2020 14:52:34 +0000 |
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The genradix code is used by SCTP for accessing per-stream data. This means there are quite a lot of lookups but the code wasn't really optimised at all.
Patch 1 fixes a rather nasty bug that could cause all sorts of oddities including having a loop in a tree. Fortunately the only 2 users of the genradix code in the kernel source tree and neither can possibly hit the bug.
Patches 2 through 11 all reduce codepath. Especially for the common case (for both users) where all the data fits in one page.
Patch 12 inlines the common lookup function for 1 page trees. This also remove the '% constant' calcuation from the lookups. However it will increase code size (but not codepath) because of the number of callers.
Patch 13 removes part of the optimisation for 1 page tress under the assumption that the lookup will have been inlined. The code still works even if inlining didn't happen.
David Laight (13): 01/13: Fix potentially corrupt tree 02/13: Optimise out ilog2(variable). 03/13: Always use low 8 bits of 'root' for depth. 04/13: Optimise __genradix_ptr() 05/13: Optimise __genradix_ptr_alloc() 06/13: Rename gfp_mask to gfp to shorten lines. 07/13: Optimise __genradix_iter_peek() 08/13: Save number of bits to shift instead of tree level. 09/13: Check sizeof(_type) when defining a tree. 10/13: Simplify offset calculation: 11/13: Pass the root pointer to __genradix_ptr. 12/13: Inline genradix_ptr() for simple trees. 13/13: Simplify __genradix_ptr()
include/linux/generic-radix-tree.h | 54 ++++--- lib/generic-radix-tree.c | 224 ++++++++++++++++------------- 2 files changed, 162 insertions(+), 116 deletions(-)
-- 2.25.1
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