kernel/linux.git/include/linux/rbtree.h, branch v6.19.11

rbtree: inline rb_last()

2025-11-27T22:24:30+00:00

This is a very small function, inlining it saves cpu cycles in TCP by reducing register pressure and removing call/ret overhead. It also reduces vmlinux text size by 122 bytes on a typical x86_64 build. Before: size vmlinux text data bss dec hex filename 34811781 22177365 5685248 62674394 3bc55da vmlinux After: size vmlinux text data bss dec hex filename 34811659 22177365 5685248 62674272 3bc5560 vmlinux [ojeda@kernel.org: fix rust build] Link: https://lkml.kernel.org/r/20251120085518.1463498-1-ojeda@kernel.org Link: https://lkml.kernel.org/r/20251114140646.3817319-3-edumazet@google.com Signed-off-by: Eric Dumazet Signed-off-by: Miguel Ojeda Reviewed-by: Kuan-Wei Chiu Cc: Jakub Kacinski Cc: Neal Cardwell Cc: Paolo Abeni Cc: Alice Ryhl Cc: Stehen Rothwell Signed-off-by: Andrew Morton

rbtree: inline rb_first()

2025-11-27T22:24:30+00:00

Patch series "rbree: inline rb_first() and rb_last()". Inline these two small helpers, heavily used in TCP and FQ packet scheduler, and in many other places. This reduces kernel text size, and brings an 1.5 % improvement on network TCP stress test. This patch (of 2): This is a very small function, inlining it saves cpu cycles by reducing register pressure and removing call/ret overhead. It also reduces vmlinux text size by 744 bytes on a typical x86_64 build. Before: size vmlinux text data bss dec hex filename 34812525 22177365 5685248 62675138 3bc58c2 vmlinux After: size vmlinux text data bss dec hex filename 34811781 22177365 5685248 62674394 3bc55da vmlinux [ojeda@kernel.org: fix rust build] Link: https://lkml.kernel.org/r/20251120085518.1463498-1-ojeda@kernel.org Link: https://lkml.kernel.org/r/20251114140646.3817319-1-edumazet@google.com Link: https://lkml.kernel.org/r/20251114140646.3817319-2-edumazet@google.com Signed-off-by: Eric Dumazet Signed-off-by: Miguel Ojeda Reviewed-by: Kuan-Wei Chiu Cc: Jakub Kacinski Cc: Neal Cardwell Cc: Paolo Abeni Cc: Alice Ryhl Cc: Stehen Rothwell Signed-off-by: Andrew Morton

rbtree: add rb_find_add_cached() to rbtree.h

2025-01-13T13:53:18+00:00

Adds rb_find_add_cached() as a helper function for use with red-black trees. Used in btrfs to reduce boilerplate code. And since it's a new helper, the cmp() function will require both parameter to be const rb_node pointers. Suggested-by: Josef Bacik Signed-off-by: Roger L. Beckermeyer III Acked-by: Peter Zijlstra (Intel) Reviewed-by: Qu Wenruo Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

rbtree: provide rb_find_rcu() / rb_find_add_rcu()

2024-09-05T14:56:15+00:00

Much like latch_tree, add two RCU methods for the regular RB-tree, which can be used in conjunction with a seqcount to provide lockless lookups. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: "Peter Zijlstra (Intel)" Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Oleg Nesterov Reviewed-by: "Masami Hiramatsu (Google)" Link: https://lore.kernel.org/r/20240903174603.3554182-7-andrii@kernel.org

include/linux/rbtree.h: replace kernel.h with the necessary inclusions

2022-06-17T02:58:20+00:00

When kernel.h is used in the headers it adds a lot into dependency hell, especially when there are circular dependencies are involved. Replace kernel.h inclusion with the list of what is really being used. Link: https://lkml.kernel.org/r/20220603171012.48880-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Cc: Matthew Wilcox Signed-off-by: Andrew Morton

rbtree: Split out the rbtree type definitions into

2021-08-17T15:36:48+00:00

So we have this header dependency problem on RT: - needs the definition of 'struct rb_root_cached'. - includes , which includes . That works nicely for non-RT enabled kernels, but on RT enabled kernels spinlocks are based on rtmutexes, which creates another circular header dependency, as will require . Split out the type definitions and move them into their own header file so the rtmutex header can include just those. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20210815211303.542123501@linutronix.de

rbtree, sched/deadline: Use rb_add_cached()

2021-02-17T13:07:44+00:00

Reduce rbtree boiler plate by using the new helpers. Make rb_add_cached() / rb_erase_cached() return a pointer to the leftmost node to aid in updating additional state. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Acked-by: Davidlohr Bueso

rbtree: Add generic add and find helpers

2021-02-17T13:07:31+00:00

I've always been bothered by the endless (fragile) boilerplate for rbtree, and I recently wrote some rbtree helpers for objtool and figured I should lift them into the kernel and use them more widely. Provide: partial-order; less() based: - rb_add(): add a new entry to the rbtree - rb_add_cached(): like rb_add(), but for a rb_root_cached total-order; cmp() based: - rb_find(): find an entry in an rbtree - rb_find_add(): find an entry, and add if not found - rb_find_first(): find the first (leftmost) matching entry - rb_next_match(): continue from rb_find_first() - rb_for_each(): iterate a sub-tree using the previous two Inlining and constant propagation should see the compiler inline the whole thing, including the various compare functions. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Michel Lespinasse Acked-by: Davidlohr Bueso

docs: Add rbtree documentation to the core-api

2020-04-21T16:29:19+00:00

This file is close enough to being in rst format that I didn't feel the need to alter it in any way. Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Michel Lespinasse Link: https://lore.kernel.org/r/20200401173343.17472-1-willy@infradead.org Signed-off-by: Jonathan Corbet

lib/rbtree: avoid generating code twice for the cached versions

2019-07-17T02:23:22+00:00

As was already noted in rbtree.h, the logic to cache rb_first (or rb_last) can easily be implemented externally to the core rbtree api. Change the implementation to do just that. Previously the update of rb_leftmost was wired deeper into the implmentation, but there were some disadvantages to that - mostly, lib/rbtree.c had separate instantiations for rb_insert_color() vs rb_insert_color_cached(), as well as rb_erase() vs rb_erase_cached(), which were doing exactly the same thing save for the rb_leftmost update at the start of either function. text data bss dec hex filename 5405 120 0 5525 1595 lib/rbtree.o-vanilla 3827 96 0 3923 f53 lib/rbtree.o-patch [dave@stgolabs.net: changelog addition] Link: http://lkml.kernel.org/r/20190628171416.by5gdizl3rcxk5h5@linux-r8p5 [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20190628045008.39926-1-walken@google.com Signed-off-by: Michel Lespinasse Acked-by: Davidlohr Bueso Acked-by: Peter Zijlstra (Intel) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds