From: Andrew Morton <akpm@linux-foundation.org>
To: Michel Lespinasse <walken@google.com>
Cc: riel@redhat.com, peterz@infradead.org, daniel.santos@pobox.com,
aarcange@redhat.com, dwmw2@infradead.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, torvalds@linux-foundation.org
Subject: Re: [PATCH v3 2/9] rbtree: add __rb_change_child() helper function
Date: Mon, 20 Aug 2012 15:17:10 -0700 [thread overview]
Message-ID: <20120820151710.eeed9bcf.akpm@linux-foundation.org> (raw)
In-Reply-To: <1345500331-10546-3-git-send-email-walken@google.com>
On Mon, 20 Aug 2012 15:05:24 -0700
Michel Lespinasse <walken@google.com> wrote:
> Add __rb_change_child() as an inline helper function to replace code that
> would otherwise be duplicated 4 times in the source.
>
> No changes to binary size or speed.
>
> ...
>
> --- a/lib/rbtree.c
> +++ b/lib/rbtree.c
> @@ -66,6 +66,19 @@ static inline struct rb_node *rb_red_parent(struct rb_node *red)
> return (struct rb_node *)red->__rb_parent_color;
> }
>
> +static inline void
> +__rb_change_child(struct rb_node *old, struct rb_node *new,
> + struct rb_node *parent, struct rb_root *root)
> +{
> + if (parent) {
> + if (parent->rb_left == old)
> + parent->rb_left = new;
> + else
> + parent->rb_right = new;
> + } else
> + root->rb_node = new;
> +}
I'm inclined to agree with Peter here - "inline" is now a vague,
pathetic and useless thing. The problem is that the reader just
doesn't *know* whether or not the writer really wanted it to be
inlined.
If we have carefully made a decision to inline a function, we should
(now) use __always_inline.
If we have carefully made a decision to not inline a function, we
should use noinline.
If we don't care, we should omit all such markings.
This leaves no place for "inline"?
Marking it noinline shrinks the text by 60-odd bytes. Given the number
of args, my gut feel is that this will be slower, despite the cache
benefit. But that might be wrong.
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next prev parent reply other threads:[~2012-08-20 22:17 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-20 22:05 [PATCH v3 0/9] faster augmented rbtree interface Michel Lespinasse
2012-08-20 22:05 ` [PATCH v3 1/9] rbtree test: fix sparse warning about 64-bit constant Michel Lespinasse
2012-08-20 22:05 ` [PATCH v3 2/9] rbtree: add __rb_change_child() helper function Michel Lespinasse
2012-08-20 22:17 ` Andrew Morton [this message]
2012-08-23 12:05 ` Jan Engelhardt
2012-08-23 13:08 ` David Woodhouse
2012-09-26 22:34 ` Daniel Santos
2012-09-26 22:43 ` Andrew Morton
2012-08-20 22:05 ` [PATCH v3 3/9] rbtree: place easiest case first in rb_erase() Michel Lespinasse
2012-08-20 22:28 ` Andrew Morton
2012-08-20 22:05 ` [PATCH v3 4/9] rbtree: handle 1-child recoloring in rb_erase() instead of rb_erase_color() Michel Lespinasse
2012-08-20 22:05 ` [PATCH v3 5/9] rbtree: low level optimizations in rb_erase() Michel Lespinasse
2012-08-20 22:05 ` [PATCH v3 6/9] rbtree: augmented rbtree test Michel Lespinasse
2012-08-20 22:05 ` [PATCH v3 7/9] rbtree: faster augmented rbtree manipulation Michel Lespinasse
2012-08-20 22:05 ` [PATCH v3 8/9] rbtree: remove prior augmented rbtree implementation Michel Lespinasse
2012-08-20 22:05 ` [PATCH v3 9/9] rbtree: add RB_DECLARE_CALLBACKS() macro Michel Lespinasse
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