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From: Francois Romieu <romieu@fr.zoreil.com>
To: "Keller, Jacob E" <jacob.e.keller@intel.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"Duyck, Alexander H" <alexander.h.duyck@intel.com>,
	Hyong-Youb Kim <hykim@myri.com>,
	Dmitry Kravkov <dmitry@broadcom.com>,
	Amir Vadai <amirv@mellanox.com>,
	Eliezer Tamir <eliezer.tamir@linux.intel.com>
Subject: Re: [PATCH net RFC 2/2] ixgbe: fix sleep bug caused by napi_disable inside local_bh_disable()d context
Date: Thu, 19 Sep 2013 23:32:54 +0200	[thread overview]
Message-ID: <20130919213254.GC31672@electric-eye.fr.zoreil.com> (raw)
In-Reply-To: <02874ECE860811409154E81DA85FBB58565F1520@ORSMSX104.amr.corp.intel.com>

Keller, Jacob E <jacob.e.keller@intel.com> :
[...]
> I know that we need local_bh_disable around the qv_lock_napi code because
> it uses spin_lock instead of spin_lock_bh. I believe the reason we need bh
> disabled around the entire context is so that the small window between
> failed calls to qv_lock_napi don't get interrupted and continue to have
> busy_poll lock the q_vector over and over.

Thanks for explaining the intent. I'll do my homework.

> I have to move the local_bh_disable in order to put napi_disable outside
> of the call since napi_disable could sleep, causing a scheduling while
> atomic BUG.

I am in violent agreement with this part.

--
Ueimor

  reply	other threads:[~2013-09-19 21:33 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-18 20:19 [PATCH net RFC 0/2] net: BUG napi_disable sleep while atomic Jacob Keller
2013-09-18 20:20 ` [PATCH net RFC 1/2] netdevice: add might_sleep() call to napi_disable Jacob Keller
2013-10-08 12:39   ` Amir Vadai
2013-09-18 20:20 ` [PATCH net RFC 2/2] ixgbe: fix sleep bug caused by napi_disable inside local_bh_disable()d context Jacob Keller
2013-09-18 23:09   ` Francois Romieu
2013-09-18 23:24     ` Keller, Jacob E
2013-09-19 21:32       ` Francois Romieu [this message]
2013-09-19 22:28         ` Keller, Jacob E
2013-10-01 12:11           ` Yuval Mintz
2013-10-01 20:05             ` Keller, Jacob E
2013-10-01 20:08             ` Keller, Jacob E
  -- strict thread matches above, loose matches on Subject: below --
2013-09-17  0:59 [PATCH net RFC 0/2] Series short description Jacob Keller
2013-09-17  0:59 ` [PATCH net RFC 2/2] ixgbe: fix sleep bug caused by napi_disable inside local_bh_disable()d context Jacob Keller

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