On Sun, 21 Apr 2019 11:45:06 -0700, Paul E. McKenney wrote:
> On Mon, Apr 22, 2019 at 12:25:00AM +0900, Akira Yokosawa wrote:
>> Hi Paul,
>>
>> The sentence shown below as a diff looks incomplete to me.
>> What is your intention here?
>
> Not that! Thank you for catching this!!! Please see below for an
> attempted fix. Thoughts?
>
> I have queued your four patches. My problems are (1) force of habit
> and (2) failing to remember that comment-only lines are discarded.
And please remember the option "keepcomment=yes" can change the
behavior. This reminds me that I need to update style guide.
> I am not all that happy with the #ifdef, but it beats the alternative.
> But what I did in this case was to just remove the fprintf() in favor
> of the BUG_ON(). ;-)
Yes, that sounds reasonable.
>
> Thanx, Paul
>
> ------------------------------------------------------------------------
>
> commit 72e774fda87eaead9637d887426b701ec229664d
> Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
> Date: Sun Apr 21 11:33:49 2019 -0700
>
> defer/hazptr: Fix broken statement of restart location constraints
>
> Reported-by: Akira Yokosawa <akiyks@xxxxxxxxx>
> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
>
> diff --git a/defer/hazptr.tex b/defer/hazptr.tex
> index 4b61d34d334c..b491c590ae2d 100644
> --- a/defer/hazptr.tex
> +++ b/defer/hazptr.tex
> @@ -239,9 +239,12 @@ Which is a very good thing, because B's successor is the now-freed
> element~C, which means that Thread~0's subsequent accesses might have
> resulted in arbitrarily horrible memory corruption, especially if the
> memory for element~C had since been re-allocated for some other purpose.
> -Therefore, statically allocated global variables), hazard-pointer
> -readers must typically restart the full traversal in the face of a
> -concurrent deletion.
> +Therefore, hazard-pointer readers must typically restart the full
> +traversal in the face of a concurrent deletion.
> +Often the restart must go back to some global (and thus immortal) pointer,
> +but it is sometimes possible to restart at some intermediate location
> +if that location is guaranteed to still be live, for example, due to
> +the current thread holding a lock, a reference count, etc.
Looks good to me!
Thanks, Akira
>
> \QuickQuiz{}
> Readers must ``typically'' restart?
>
