Messages in this thread | | | From | Cody P Schafer <> | Subject | [PATCH v2 0/5] Add rbtree postorder iteration functions, runtime tests, and update zswap to use | Date | Mon, 29 Jul 2013 12:19:25 -0700 |
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Postorder iteration yields all of a node's children prior to yielding the node itself, and this particular implementation also avoids examining the leaf links in a node after that node has been yielded.
In what I expect will be its most common usage, postorder iteration allows the deletion of every node in an rbtree without modifying the rbtree nodes (no _requirement_ that they be nulled) while avoiding referencing child nodes after they have been "deleted" (most commonly, freed).
I have only updated zswap to use this functionality at this point, but numerous bits of code (most notably in the filesystem drivers) use a hand rolled postorder iteration that NULLs child links as it traverses the tree. Each of those instances could be replaced with this common implementation.
1 & 2 add rbtree postorder iteration functions. 3 adds testing of the iteration to the rbtree runtime tests 4 allows building the rbtree runtime tests as builtins 5 updates zswap.
-- since v1: - spacing - s/it's/its/ - remove now unused var in zswap code. - Reviewed-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cody P Schafer (5): rbtree: add postorder iteration functions rbtree: add rbtree_postorder_for_each_entry_safe() helper rbtree_test: add test for postorder iteration rbtree: allow tests to run as builtin mm/zswap: use postorder iteration when destroying rbtree
include/linux/rbtree.h | 22 ++++++++++++++++++++++ lib/Kconfig.debug | 2 +- lib/rbtree.c | 40 ++++++++++++++++++++++++++++++++++++++++ lib/rbtree_test.c | 12 ++++++++++++ mm/zswap.c | 16 ++-------------- 5 files changed, 77 insertions(+), 15 deletions(-)
-- 1.8.3.4
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