[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 1/2] docs/rcu: Distinguish rcu_dereference and a
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] docs/rcu: Distinguish rcu_dereference and atomic_rcu_read |
Date: |
Tue, 18 Oct 2016 17:50:11 -0400 (EDT) |
----- Original Message -----
> From: "Pranith Kumar" <address@hidden>
> To: "Paolo Bonzini" <address@hidden>, "Sergey Fedorov" <address@hidden>, "Cao
> jin"
> <address@hidden>, "open list:All patches CC here" <address@hidden>
> Sent: Tuesday, October 18, 2016 4:56:19 PM
> Subject: [PATCH 1/2] docs/rcu: Distinguish rcu_dereference and atomic_rcu_read
>
> Signed-off-by: Pranith Kumar <address@hidden>
> ---
> docs/rcu.txt | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/docs/rcu.txt b/docs/rcu.txt
> index c84e7f4..c177dcb 100644
> --- a/docs/rcu.txt
> +++ b/docs/rcu.txt
> @@ -197,7 +197,9 @@ DIFFERENCES WITH LINUX
> critical section to become an updater.
>
> - atomic_rcu_read and atomic_rcu_set replace rcu_dereference and
> - rcu_assign_pointer. They take a _pointer_ to the variable being accessed.
> + rcu_assign_pointer. Note that although both atomic_rcu_read and
> + rcu_dereference take a _pointer_ to the variable being accessed,
> + atomic_rcu_read dereferences the pointer whereas rcu_dereference does not.
No, neither rcu_dereference nor rcu-assign_pointer take a pointer. You use
them like rcu_dereference(p) versus QEMU's atomic_rcu_read(&p).
Paolo
> - call_rcu is a macro that has an extra argument (the name of the first
> field in the struct, which must be a struct rcu_head), and expects the
> --
> 2.10.1
>
>