Re: [RFC][PATCH] Put size in array to get rid of barriers in grow_ary()

[Hugh Dickins]

On Tue, 7 Sep 2004, Paul E. McKenney wrote:
> 
> The grow_ary() code has a number of explicit memory barriers, as does
> ipc_lock().  This patch gets rid of the need for some of these by
> placing the array size in the same block of memory containing the
> array itself, so that the array and the size cannot possibly get out
> of sync.  Also uses rcu_assign_pointer() to get rid of the remaining
> smp_wmb().

But Paul, if you keep removing all these examples of memory barriers,
how can I be expected to learn how to use them properly?

Seriously, good, yes, the fewer "mb"s the better.
I could always educate myself from the older source.

> Untested, therefore probably broken.

Agreed ;)

> Thoughts?

Wouldn't it be a little nicer to start ipc_ids off pointing to a
const ipc_id_ary of size 0, to avoid the various entries == NULL
tests you had to add?

Hugh

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