Re: [PATCH -v3 3/4] lib, Make gen_pool memory allocator lockless

From: Huang Ying
Date: Thu Apr 14 2011 - 20:24:48 EST

On 04/14/2011 05:07 AM, Mathieu Desnoyers wrote:
> * Huang Ying (ying.huang@xxxxxxxxx) wrote:
> [...]
>> + * rcu_read_lock and rcu_read_unlock is not used int gen_pool_alloc,
>> + * gen_pool_free, gen_pool_avail and gen_pool_size etc, because chunks
>> + * are only added into pool, not deleted from pool unless the pool
>> + * itself is destroyed. If chunk will be deleted from pool,
>> + * rcu_read_lock and rcu_read_unlock should be uses in these
>> + * functions.
> So how do you protect between pool destruction and adding chunks into
> the pool ?

Because the pool itself will be freed when destruction, we need some
mechanism outside of pool. For example, if gen_pool_add() is called via
device file IOCTL, we must un-register the device file first, and
destroy the pool after the last reference to device has gone.

Best Regards,
Huang Ying
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