From: Juri Lelli <juri.lelli@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, walken@google.com,
dave@stgolabs.net, mingo@kernel.org, tglx@linutronix.de,
oleg@redhat.com, irogers@google.com, vincent.guittot@linaro.org
Subject: Re: [RFC][PATCH 1/7] rbtree: Add generic add and find helpers
Date: Thu, 30 Apr 2020 09:28:47 +0200 [thread overview]
Message-ID: <20200430072847.GA68379@localhost.localdomain> (raw)
In-Reply-To: <20200429153549.006661686@infradead.org>
Hi,
On 29/04/20 17:32, Peter Zijlstra wrote:
> 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_first(): find the first (leftmost) matching entry
> - rb_next_match(): continue from rb_find_first()
> - rb_for_each(): for loop with rb_find_first() / rb_next_match()
>
> Also make rb_add_cached() / rb_erase_cached() return true when
> leftmost.
>
> Inlining and constant propagation should see the compiler inline the
> whole thing, including the various compare functions.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> include/linux/rbtree.h | 127 +++++++++++++++++++++++++++++++++++++++++-
> tools/include/linux/rbtree.h | 129 ++++++++++++++++++++++++++++++++++++++++++-
> tools/objtool/elf.c | 63 ++-------------------
> 3 files changed, 257 insertions(+), 62 deletions(-)
>
> --- a/include/linux/rbtree.h
> +++ b/include/linux/rbtree.h
> @@ -141,12 +141,18 @@ static inline void rb_insert_color_cache
> rb_insert_color(node, &root->rb_root);
> }
>
> -static inline void rb_erase_cached(struct rb_node *node,
> +static inline bool rb_erase_cached(struct rb_node *node,
> struct rb_root_cached *root)
> {
> - if (root->rb_leftmost == node)
> + bool leftmost = false;
> +
> + if (root->rb_leftmost == node) {
> root->rb_leftmost = rb_next(node);
Think we need
if (root->rb_leftmost)
> + leftmost = true;
DEADLINE crashes w/o that.
> + }
> rb_erase(node, &root->rb_root);
> +
> + return leftmost;
> }
The rest looks good to me.
Thanks,
Juri
next prev parent reply other threads:[~2020-04-30 7:28 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-29 15:32 [RFC][PATCH 0/7] Generic RB-tree helpers Peter Zijlstra
2020-04-29 15:32 ` [RFC][PATCH 1/7] rbtree: Add generic add and find helpers Peter Zijlstra
2020-04-30 1:04 ` Michel Lespinasse
2020-04-30 8:46 ` Peter Zijlstra
2020-04-30 9:26 ` Peter Zijlstra
2020-04-30 7:28 ` Juri Lelli [this message]
2020-04-30 7:51 ` Michel Lespinasse
2020-04-30 8:07 ` Juri Lelli
2020-04-30 8:27 ` Peter Zijlstra
2020-04-29 15:33 ` [RFC][PATCH 2/7] rbtree, sched/fair: Use rb_add_cached() Peter Zijlstra
2020-04-29 15:33 ` [RFC][PATCH 3/7] rbtree, sched/deadline: " Peter Zijlstra
2020-04-29 15:33 ` [RFC][PATCH 4/7] rbtree, perf: Use new rbtree helpers Peter Zijlstra
2020-04-29 15:33 ` [RFC][PATCH 5/7] rbtree, uprobes: Use " Peter Zijlstra
2020-04-29 15:33 ` [RFC][PATCH 6/7] rbtree, rtmutex: Use rb_add_cached() Peter Zijlstra
2020-04-29 15:33 ` [RFC][PATCH 7/7] rbtree, timerqueue: " Peter Zijlstra
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