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Subject: Re: [PATCH net-next v2] net: page_pool: optimize page pool page
 allocation in NUMA scenario
To:     Jesper Dangaard Brouer <jbrouer@redhat.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Guangbin Huang <huangguangbin2@huawei.com>
References: <20220629133305.15012-1-huangguangbin2@huawei.com>
 <20220630211534.6d1c32da@kernel.org>
 <728b4c15-8114-e253-5d45-a5610882f891@redhat.com>
CC:     <brouer@redhat.com>, <hawk@kernel.org>,
        <ilias.apalodimas@linaro.org>, <davem@davemloft.net>,
        <edumazet@google.com>, <pabeni@redhat.com>, <lorenzo@kernel.org>,
        <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <bpf@vger.kernel.org>, <lipeng321@huawei.com>,
        <chenhao288@hisilicon.com>
From:   "wangjie (L)" <wangjie125@huawei.com>
Message-ID: <5fbe43df-7469-f8af-97a2-ad5f20efa889@huawei.com>
Date:   Mon, 4 Jul 2022 09:14:00 +0800
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On 2022/7/1 15:56, Jesper Dangaard Brouer wrote:
>
> On 01/07/2022 06.15, Jakub Kicinski wrote:
>> On Wed, 29 Jun 2022 21:33:05 +0800 Guangbin Huang wrote:
>>> +#ifdef CONFIG_NUMA
>>> +    pref_nid = (pool->p.nid == NUMA_NO_NODE) ? numa_mem_id() :
>>> pool->p.nid;
>>> +#else
>>> +    /* Ignore pool->p.nid setting if !CONFIG_NUMA */
>>> +    pref_nid = NUMA_NO_NODE;
>>> +#endif
>>
>> Please factor this out to a helper, this is a copy of the code from
>> page_pool_refill_alloc_cache() and #ifdefs are a little yuck.
>>
>
> I would say simply use 'pool->p.nid' in the call to
> alloc_pages_bulk_array_node() and drop this optimization (that was
> copy-pasted from fast-path).
>
> The optimization avoids one reading from memory compile time depending
> on CONFIG_NUMA.  It is *not* worth doing in this code path which is even
> named "slow" (__page_pool_alloc_pages_slow).
>
> --Jesper
>
Simply use pool->p.nid looks simply and makes sense in both scenario. I 
will rewrite and test the patch in next version.
>
> .
>