From: Jakub Kicinski <kuba@kernel.org>
To: Alex Elder <elder@linaro.org>
Cc: davem@davemloft.net, bjorn.andersson@linaro.org,
evgreen@chromium.org, cpratapa@codeaurora.org,
subashab@codeaurora.org, elder@kernel.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 4/6] net: ipa: ensure hardware has power in ipa_start_xmit()
Date: Mon, 16 Aug 2021 07:15:43 -0700 [thread overview]
Message-ID: <20210816071543.39a44815@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <3a9e82cc-c09e-62e8-4671-8f16d4f6a35b@linaro.org>
On Fri, 13 Aug 2021 21:25:23 -0500 Alex Elder wrote:
> > This is racy, what if the pm work gets scheduled on another CPU and
> > calls wake right here (i.e. before you call netif_stop_queue())?
> > The queue may never get woken up?
>
> I haven't been seeing this happen but I think you may be right.
>
> I did think about this race, but I think I was relying on the
> PM work queue to somehow avoid the problem. I need to think
> about this again after a good night's sleep. I might need
> to add an atomic flag or something.
Maybe add a spin lock? Seems like the whole wake up path will be
expensive enough for a spin lock to be in the noise. You can always
add complexity later.
next prev parent reply other threads:[~2021-08-16 14:15 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-12 19:50 [PATCH net-next 0/6] net: ipa: last things before PM conversion Alex Elder
2021-08-12 19:50 ` [PATCH net-next 1/6] net: ipa: enable wakeup in ipa_power_setup() Alex Elder
2021-08-12 19:50 ` [PATCH net-next 2/6] net: ipa: distinguish system from runtime suspend Alex Elder
2021-08-12 19:50 ` [PATCH net-next 3/6] net: ipa: re-enable transmit in PM WQ context Alex Elder
2021-08-14 0:44 ` Jakub Kicinski
2021-08-14 2:32 ` Alex Elder
2021-08-12 19:50 ` [PATCH net-next 4/6] net: ipa: ensure hardware has power in ipa_start_xmit() Alex Elder
2021-08-14 0:46 ` Jakub Kicinski
2021-08-14 2:25 ` Alex Elder
2021-08-16 14:15 ` Jakub Kicinski [this message]
2021-08-16 14:20 ` Alex Elder
2021-08-16 17:56 ` Alex Elder
2021-08-16 20:19 ` Jakub Kicinski
2021-08-12 19:50 ` [PATCH net-next 5/6] net: ipa: don't stop TX on suspend Alex Elder
2021-08-12 19:50 ` [PATCH net-next 6/6] net: ipa: don't hold clock reference while netdev open Alex Elder
2021-08-14 13:20 ` [PATCH net-next 0/6] net: ipa: last things before PM conversion patchwork-bot+netdevbpf
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