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From: Johannes Berg <johannes@sipsolutions.net>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Marc MERLIN <marc@merlins.org>,
	David Miller <davem@davemloft.net>,
	Larry.Finger@lwfinger.net, bhutchings@solarflare.com,
	linux-wireless@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: 3.7.8/amd64 full interrupt hangs due to iwlwifi under big nfs copies out
Date: Wed, 20 Feb 2013 19:16:23 +0100	[thread overview]
Message-ID: <1361384183.8579.1.camel@jlt4.sipsolutions.net> (raw)
In-Reply-To: <1361381096.19353.195.camel@edumazet-glaptop> (sfid-20130220_182502_483935_369E6954)

On Wed, 2013-02-20 at 09:24 -0800, Eric Dumazet wrote:
> On Wed, 2013-02-20 at 18:01 +0100, Johannes Berg wrote:
> 
> > FWIW, I think just using order-0 pages and turning 8k A-MSDUs off by
> > default makes more sense, A-MSDU is rarely used to begin with ...
> > 
> 
> My suggested patch makes sure that if someone needs 8k A-MSDU, iwlwifi
> still works correctly.

True, but if we don't advertise 8k A-MSDU then they won't be used, and
it'll still work correctly, just not be able to receive such large
A-MSDUs. Linux can't even transmit _any_ A-MSDUs, and many (most?) APs
don't either.

> > Also, if we copy larger frames here, we should also take into account
> > the (variable) 802.11 header length to avoid copying into a position
> > where the IP header ends up being unaligned.
> 
> But the current code already has this problem (if its a problem at all,
> as on x86 NET_IP_ALIGN is 0)

Yes and no. The current code doesn't pull in much data, not even the IP
header, so worst case it copies 14 bytes (ethernet header) in mac80211
to obtain alignment. By pulling in everything here, it later has to copy
everything again later to obtain alignment.

johannes

  reply	other threads:[~2013-02-20 18:16 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-29 16:38 3.2.8/amd64 full interrupt hangs and deadlocks under big network copies (page allocation failure) Marc MERLIN
     [not found] ` <20120311183244.GA14001@merlins.org>
     [not found]   ` <20120329053111.GD24933@merlins.org>
     [not found]     ` <20120329163800.GH24933-xnduUnryOU1AfugRpC6u6w@public.gmane.org>
     [not found]       ` <20120329053111.GD24933-xnduUnryOU1AfugRpC6u6w@public.gmane.org>
2012-03-29 16:41         ` Marc MERLIN
2012-03-29 18:09 ` Ben Hutchings
     [not found]   ` <1333044575.2656.1.camel-/LGg1Z1CJKReKY3V0RtoKmatzQS1i7+A3tAM5lWOD0I@public.gmane.org>
2012-03-29 21:19     ` Marc MERLIN
2012-04-09 17:20   ` Marc MERLIN
2012-04-09 18:12     ` David Miller
     [not found]       ` <20120409.141241.1216091936509309354.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2012-04-09 18:36         ` Marc MERLIN
2012-04-09 18:37           ` David Miller
2012-04-09 18:58             ` Larry Finger
2012-04-09 19:11               ` Eric Dumazet
2012-04-09 19:34                 ` David Miller
     [not found]                   ` <20120409.153452.1284163346306246866.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2012-04-09 19:46                     ` Marc MERLIN
2012-04-10  3:56                   ` Eric Dumazet
2012-04-10  5:11                     ` Marc MERLIN
2012-04-10  6:11                       ` Eric Dumazet
2012-04-11  5:27                         ` Marc MERLIN
     [not found]                           ` <20120411052733.GA17352-xnduUnryOU1AfugRpC6u6w@public.gmane.org>
2012-04-11  5:43                             ` Eric Dumazet
2012-04-11  6:30                               ` [PATCH] tcp: avoid order-1 allocations on wifi and tx path Eric Dumazet
2012-04-11  7:38                                 ` Eric Dumazet
2012-04-11 14:12                                   ` David Miller
2012-04-11 14:11                                 ` David Miller
2012-04-11  6:08                           ` [PATCH] net: allow pskb_expand_head() to get maximum tailroom Eric Dumazet
2012-04-11 14:11                             ` David Miller
2012-07-15 21:59                           ` 3.4.4/amd64 full interrupt hangs under big nfs copies Marc MERLIN
2012-07-16  6:18                             ` Eric Dumazet
2012-07-16 15:18                               ` Marc MERLIN
2012-07-16 16:21                                 ` Eric Dumazet
2012-07-16 17:17                                   ` Marc MERLIN
2013-02-19  4:05                                   ` 3.7.8/amd64 full interrupt hangs due to iwlwifi under big nfs copies out Marc MERLIN
2013-02-19  5:17                                     ` Eric Dumazet
2013-02-19  5:26                                       ` Marc MERLIN
2013-02-19 10:03                                       ` Johannes Berg
2013-02-19 16:18                                         ` Marc MERLIN
2013-02-19 16:36                                           ` Eric Dumazet
2013-02-19 16:21                                         ` Eric Dumazet
2013-02-20  9:12                                           ` Johannes Berg
2013-02-20  9:15                                             ` Johannes Berg
2013-02-20 15:11                                               ` Eric Dumazet
2013-02-20 16:20                                                 ` Johannes Berg
     [not found]                                                   ` <1361377243.8629.34.camel-8Nb76shvtaUJvtFkdXX2HixXY32XiHfO@public.gmane.org>
2013-02-20 16:55                                                     ` Eric Dumazet
2013-02-20 16:59                                                       ` Johannes Berg
2013-02-20 17:39                                                         ` Eric Dumazet
2013-02-20 17:01                                                       ` Johannes Berg
2013-02-20 17:24                                                         ` Eric Dumazet
2013-02-20 18:16                                                           ` Johannes Berg [this message]
2013-02-20 19:17                                                             ` Eric Dumazet
2013-02-20 19:58                                                               ` Johannes Berg
2013-02-20 20:14                                                                 ` Eric Dumazet
2013-02-20 20:27                                                                   ` Johannes Berg
2013-02-20 20:09                                                 ` Johannes Berg
2013-02-23  6:14                                               ` Marc MERLIN
2013-02-26 20:54                                                 ` Johannes Berg
     [not found]                                                   ` <1361912099.8440.21.camel-8Nb76shvtaUJvtFkdXX2HixXY32XiHfO@public.gmane.org>
2013-06-18 16:52                                                     ` Eric Dumazet
2013-06-18 17:04                                                       ` Johannes Berg
2013-06-19 13:09                                                         ` Stanislaw Gruszka

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