netdev - Re: [net-next PATCH v3 1/1] page_pool: do not release pool until inflight == 0.

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Date:   Thu, 14 Nov 2019 17:24:42 -0800
From:   "Jonathan Lemon" <jonathan.lemon@...il.com>
To:     "Jesper Dangaard Brouer" <brouer@...hat.com>
Cc:     davem@...emloft.net, netdev@...r.kernel.org,
        ilias.apalodimas@...aro.org, kernel-team@...com
Subject: Re: [net-next PATCH v3 1/1] page_pool: do not release pool until
 inflight == 0.

On 14 Nov 2019, at 14:17, Jesper Dangaard Brouer wrote:

> On Thu, 14 Nov 2019 14:13:00 -0800
> Jonathan Lemon <jonathan.lemon@...il.com> wrote:
>
>> The page pool keeps track of the number of pages in flight, and
>> it isn't safe to remove the pool until all pages are returned.
>>
>> Disallow removing the pool until all pages are back, so the pool
>> is always available for page producers.
>>
>> Make the page pool responsible for its own delayed destruction
>> instead of relying on XDP, so the page pool can be used without
>> the xdp memory model.
>>
>> When all pages are returned, free the pool and notify xdp if the
>> pool is registered with the xdp memory system.  Have the callback
>> perform a table walk since some drivers (cpsw) may share the pool
>> among multiple xdp_rxq_info.
>>
>> Note that the increment of pages_state_release_cnt may result in
>> inflight == 0, resulting in the pool being released.
>>
>> Fixes: d956a048cd3f ("xdp: force mem allocator removal and periodic 
>> warning")
>> Signed-off-by: Jonathan Lemon <jonathan.lemon@...il.com>
>> ---
>
> Acked-by: Jesper Dangaard Brouer <brouer@...hat.com>

Thanks, Jesper!
-- 
Jonathan