On Wed, Oct 10, 2012 at 03:52:08PM +0800, Lai Jiangshan wrote:
> rculfstack is not really require RCU-only.
>
> 1) cds_lfs_push_rcu() don't need any lock, don't need RCU nor other locks.
>
> 2) cds_lfs_pop_rcu() don't only one of the following synchronization(not only
> RCU):
> A) use rcu_read_lock() to protect cds_lfs_pop_rcu() and use
> synchronize_rcu()
> or call_rcu() to free the popped node. (current comments said we
> need this
> synchronization, and thus we named this struct with rcu prefix.
> But actually,
> the followings are OK, and are more popular/friendly)
> B) use mutexs/locks to protect cds_lfs_pop_rcu(), we can free to
> free/modify the
> popped node any time, we don't need any synchronization when free
> them.
> C) only ONE thread can call cds_lfs_pop_rcu(). (multi-providers-single
> customer)
> D) others, like read-write locks.
>
> I consider B) and C) are more popular. In linux kernel,
> kernel/task_work.c uses a hybird ways of B) and C).
>
> I suggest to rename it, Or document B) and C) at least.
Good timing -- stacks and queues are next on my list for documentation. ;-)
Thanx, Paul
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