Date:   Thu, 2 Feb 2023 10:06:40 -0800
From:   Jakub Kicinski <kuba@kernel.org>
To:     Qingfang DENG <dqfext@gmail.com>
Cc:     Jesper Dangaard Brouer <hawk@kernel.org>,
        Ilias Apalodimas <ilias.apalodimas@linaro.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Lorenzo Bianconi <lorenzo@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        John Fastabend <john.fastabend@gmail.com>,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] net: page_pool: use in_softirq() instead
Message-ID: <20230202100640.350fcd08@kernel.org>
In-Reply-To: <20230201220105.410fee4c@kernel.org>
References: <20230202024417.4477-1-dqfext@gmail.com>
        <20230201220105.410fee4c@kernel.org>
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On Wed, 1 Feb 2023 22:01:05 -0800 Jakub Kicinski wrote:
> On Thu,  2 Feb 2023 10:44:17 +0800 Qingfang DENG wrote:
> > From: Qingfang DENG <qingfang.deng@siflower.com.cn>
> > 
> > We use BH context only for synchronization, so we don't care if it's
> > actually serving softirq or not.
> > 
> > As a side node, in case of threaded NAPI, in_serving_softirq() will
> > return false because it's in process context with BH off, making
> > page_pool_recycle_in_cache() unreachable.  
> 
> LGTM, but I don't think this qualifies as a fix.
> It's just a missed optimization, right?

Well, nobody seems to have disagreed with me in 12h, so please drop the
Fixes tags and repost against net-next :)