From: "Ziyang Xuan (William)" <william.xuanziyang@huawei.com>
To: "Martinez, Ricardo" <ricardo.martinez@linux.intel.com>,
Sergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: "Devegowda, Chandrashekar" <chandrashekar.devegowda@intel.com>,
"Intel Corporation" <linuxwwan@intel.com>,
chiranjeevi.rapolu@linux.intel.com,
"Haijun Liu (刘海军)" <haijun.liu@mediatek.com>,
"M Chetan Kumar" <m.chetan.kumar@linux.intel.com>,
"Loic Poulain" <loic.poulain@linaro.org>,
"David Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
netdev@vger.kernel.org,
"open list" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net-next] net: wwan: t7xx: fix GFP_KERNEL usage in spin_lock context
Date: Tue, 17 May 2022 11:12:14 +0800 [thread overview]
Message-ID: <0d5e1262-8140-32d2-e589-d29d68ac49a4@huawei.com> (raw)
In-Reply-To: <0b90f4f6-6911-017b-6d37-50354003900e@linux.intel.com>
>
> On 5/16/2022 1:36 PM, Sergey Ryazanov wrote:
>> Hello Ziyang,
>>
>> On Sat, May 14, 2022 at 11:57 AM Ziyang Xuan
>> <william.xuanziyang@huawei.com> wrote:
>>> t7xx_cldma_clear_rxq() call t7xx_cldma_alloc_and_map_skb() in spin_lock
>>> context, But __dev_alloc_skb() in t7xx_cldma_alloc_and_map_skb() uses
>>> GFP_KERNEL, that will introduce scheduling factor in spin_lock context.
>>>
>>> Replace GFP_KERNEL with GFP_ATOMIC to fix it.
>> Would not it will be more reliable to just rework
>> t7xx_cldma_clear_rxq() to avoid calling t7xx_cldma_alloc_and_map_skb()
>> under the spin lock instead of doing each allocation with GFP_ATOMIC?
>> E.g. t7xx_cldma_gpd_rx_from_q() calls t7xx_cldma_alloc_and_map_skb()
>> avoiding any lock holding.
>
> t7xx_cldma_clear_rxq() is a helper for t7xx_cldma_clear_all_qs() which is only called by t7xx_cldma_exception() after stopping CLDMA, so it should be OK to remove the spin lock from t7xx_cldma_clear_rxq().
>
OK, I see. Thus we can remove spink_lock and annotate it.
>
> .
prev parent reply other threads:[~2022-05-17 3:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-14 9:14 [PATCH net-next] net: wwan: t7xx: fix GFP_KERNEL usage in spin_lock context Ziyang Xuan
2022-05-16 20:36 ` Sergey Ryazanov
2022-05-16 20:57 ` Martinez, Ricardo
2022-05-17 3:12 ` Ziyang Xuan (William) [this message]
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