From: Lino Sanfilippo <lsanfil@marvell.com>
To: Pavel Machek <pavel@ucw.cz>, Lino Sanfilippo <LinoSanfilippo@gmx.de>
Cc: Giuseppe CAVALLARO <peppe.cavallaro@st.com>,
<alexandre.torgue@st.com>, David Miller <davem@davemloft.net>,
<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] Re: Re: stmmac ethernet in kernel 4.9-rc6: coalescing related pauses.
Date: Wed, 7 Dec 2016 14:18:19 +0100 [thread overview]
Message-ID: <c9169edc-3144-fab1-d176-7a8b9b3e4366@marvell.com> (raw)
In-Reply-To: <20161207123140.GA8785@amd>
Hi,
On 07.12.2016 13:31, Pavel Machek wrote:
> On Fri 2016-12-02 15:05:21, Lino Sanfilippo wrote:
>> Hi,
>>
>>
>>>
>>> There's nothing that protect stmmac_poll() from running concurently
>>> with stmmac_dma_interrupt(), right?
>>>
>>
>> could it be that there is also another issue concerned locking?:
>> The tx completion handler takes the xmit_lock in case that the
>> netif_queue is stopped. This is AFAICS unnecessary, since both
>> xmit and completion handler are already synchronized by the private
>> tx lock. But it is IMHO also dangerous:
>>
>> In the xmit handler we have the locking order
>> 1. xmit_lock
>> 2. private tx lock
>>
>> while in the completion handler its the reverse:
>>
>> 1. private tx lock
>> 2. xmit lock.
>>
>> Do I miss something?
>
> No, it seems you are right. Something like this?
>
> Hmm. And can priv->tx_lock be removed, as we already rely on
> netif_tx_lock?
>
David wanted indeed the private lock to be removed completely. See
this thread.
https://marc.info/?l=linux-netdev&m=148072001900620&w=2
If you can wait a bit, I already have patches prepared to fix this issue in both
drivers. I want to send them as soon as I am at home (a few hours).
Regards,
Lino
next prev parent reply other threads:[~2016-12-07 13:19 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-23 10:51 stmmac ethernet in kernel 4.4: coalescing related pauses? Pavel Machek
2016-11-24 8:55 ` stmmac ethernet in kernel 4.9-rc6: coalescing related pauses Pavel Machek
2016-11-24 10:29 ` Pavel Machek
2016-11-24 10:36 ` Pavel Machek
2016-11-24 10:46 ` [PATCH] stmmac ethernet: unify locking Pavel Machek
2016-11-24 11:05 ` [PATCH] stmmac ethernet: remove cut & paste code Pavel Machek
2016-11-24 20:05 ` Joe Perches
2016-11-24 21:44 ` Pavel Machek
2016-11-24 22:27 ` Joe Perches
2016-11-28 11:50 ` Pavel Machek
2016-11-28 14:24 ` Joe Perches
2016-11-28 14:35 ` Pavel Machek
2016-11-28 16:03 ` Joe Perches
2016-11-24 16:04 ` stmmac ethernet in kernel 4.9-rc6: coalescing related pauses David Miller
2016-11-24 21:25 ` Pavel Machek
2016-12-02 8:24 ` Giuseppe CAVALLARO
2016-12-02 8:41 ` Giuseppe CAVALLARO
2016-12-02 8:45 ` Pavel Machek
2016-12-02 9:43 ` Giuseppe CAVALLARO
2016-12-02 12:32 ` Pavel Machek
2016-12-02 13:51 ` Giuseppe CAVALLARO
2016-12-02 14:26 ` Alexandre Torgue
2016-12-02 15:19 ` Giuseppe CAVALLARO
2016-12-05 12:14 ` Pavel Machek
2016-12-05 12:01 ` Pavel Machek
2016-12-05 10:15 ` Pavel Machek
2016-12-05 11:40 ` Lino Sanfilippo
2016-12-05 22:02 ` Pavel Machek
2016-12-05 22:37 ` Lino Sanfilippo
2016-12-05 22:40 ` Pavel Machek
2016-12-05 22:54 ` Lino Sanfilippo
2016-12-05 23:11 ` Lino Sanfilippo
2016-12-02 14:05 ` Aw: " Lino Sanfilippo
2016-12-07 12:31 ` [RFC] " Pavel Machek
2016-12-07 13:18 ` Lino Sanfilippo [this message]
2016-12-05 11:56 ` Pavel Machek
2016-11-28 11:55 ` [PATCH] stmmac: fix comments, make debug output consistent Pavel Machek
2016-11-30 0:53 ` David Miller
2016-11-28 12:13 ` stmmac ethernet in kernel 4.9-rc6: coalescing related pauses Pavel Machek
2016-11-28 12:17 ` [PATCH] stmmac: reduce code duplication getting basic descriptors Pavel Machek
2016-11-28 15:25 ` kbuild test robot
2016-12-02 14:09 ` Alexandre Torgue
2016-11-30 11:44 ` [PATCH] stmmac: simplify flag assignment Pavel Machek
2016-12-01 20:23 ` David Miller
2016-12-01 22:48 ` stmmac: turn coalescing / NAPI off in stmmac Pavel Machek
2016-12-02 8:39 ` Giuseppe CAVALLARO
2016-12-02 10:42 ` Pavel Machek
2016-12-02 15:31 ` Giuseppe CAVALLARO
2016-12-05 11:45 ` Pavel Machek
2016-12-02 8:27 ` [PATCH] stmmac: simplify flag assignment Giuseppe CAVALLARO
2016-12-01 10:32 ` [PATCH] stmmac: cleanup documenation, make it match reality Pavel Machek
2016-12-03 20:07 ` David Miller
2016-12-05 12:27 ` [PATCH] stmmac: disable tx coalescing Pavel Machek
2016-12-11 19:07 ` Pavel Machek
2016-12-11 19:31 ` David Miller
2016-12-11 19:57 ` Pavel Machek
2016-11-28 13:07 ` stmmac ethernet in kernel 4.4: coalescing related pauses? Lino Sanfilippo
2016-11-28 14:54 ` David Miller
2016-11-28 15:31 ` Eric Dumazet
2016-11-28 15:57 ` Lino Sanfilippo
2016-11-28 16:30 ` David Miller
2016-11-28 17:01 ` Lino Sanfilippo
2016-11-30 10:28 ` Pavel Machek
2016-11-28 15:33 ` Lino Sanfilippo
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