Re: [PATCH] mm: mempool: Factor out mempool_refill()

[Zhi Wang]

Hi Johannes:
    Thanks for the reply. In the end of the mempool_resize(), it will 
call the mempool_refill() to do the rest of the work. So this is not one 
of the "no-caller" case. If you insist this is a "no-caller" case, 
perhaps I should change it to a "static" function without exposing a new 
interface?

Personally I think mempool_refill() should be one of the typical 
interfaces in an implementation of a mempool. Currently the mempool will 
not grow only if pool->min_nr > new_min_nr.

So when user wants to refill the mempool immediately, not resize a 
mempool, in the current implementation, it has to do 2x 
mempool_resize(). First one is mempool_resize(pool->min_nr - 1), second 
one is mempool_resize(new_min_nr). So the refill action would truly 
happen. This is ugly and not convenient.

On 12/16/15 05:26, Johannes Weiner wrote:
> On Mon, Dec 14, 2015 at 11:09:43AM +0000, Wang, Zhi A wrote:
> > This patch factors out mempool_refill() from mempool_resize(). It's reasonable
> > that the mempool user wants to refill the pool immdiately when it has chance
> > e.g. inside a sleepible context, so that next time in the IRQ context the pool
> > would have much more available elements to allocate.
> >
> > After the refactor, mempool_refill() can also executes with mempool_resize()
> > /mempool_alloc/mempool_free() or another mempool_refill().
> >
> > Signed-off-by: Zhi Wang <zhi.a.wang@xxxxxxxxx>
>
> Who is going to call that function? Adding a new interace usually
> comes with a user, or as part of a series that adds users.
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