From: Eric Dumazet <eric.dumazet@gmail.com>
To: "Luis R. Rodriguez" <mcgrof@gmail.com>
Cc: Christian Lamparter <chunkeey@googlemail.com>,
greearb@candelatech.com, linux-wireless@vger.kernel.org,
ath9k-devel@venema.h4ckr.net
Subject: Re: [PATCH 1/3] ath9k: Decrease skb size to fit into one page.
Date: Fri, 07 Jan 2011 03:07:52 +0100 [thread overview]
Message-ID: <1294366072.2704.32.camel@edumazet-laptop> (raw)
In-Reply-To: <AANLkTinQ42y9Tu=Ugb92-R+56BP4U+cDBzd4tQQCES1W@mail.gmail.com>
Le jeudi 06 janvier 2011 à 17:57 -0800, Luis R. Rodriguez a écrit :
> On Thu, Jan 6, 2011 at 5:23 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> > Le vendredi 07 janvier 2011 à 02:04 +0100, Christian Lamparter a écrit :
> >> On Friday 07 January 2011 01:46:03 greearb@candelatech.com wrote:
> >> > From: Ben Greear <greearb@candelatech.com>
> >> >
> >> > Patch is from Eric Dumazet, as described here:
> >> > https://patchwork.kernel.org/patch/104271/
> >> >
> >> > Reported-by: Michael Guntsche <mike@it-loops.com>
> >> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> >> > Signed-off-by: Ben Greear <greearb@candelatech.com>
> >> > ---
> >> >
> >> > NOTE: This needs review by ath9k and/or other informed
> >> > people.
> >>
> >> Does the hardware support vector-i/o for rx (like for instance iwlagn)?
> >> Else, this change would break A-MSDU rx - which is a mandatory feature
> >> (although, not very popular) of 802.11n -
> >>
> >> See for example 802.11n-2009 9.7c:
> >>
> >> "Support for the reception of an A-MSDU, where [...], is mandatory for
> >> an HT STA"
> >>
> >> And 7.1.2 "The maximum frame body size is determined by the maximum
> >> MSDU size (2304 octets) OR the maximum A-MSDU (3839 or 7935 octets,
> >> depending upon the STA's capability), plus any overhead from security
> >> encapsulation.
> >
> > Then, only solution is to mark this broken, and perform a copy of each
> > received frame, to keep a order-1 buffer(s) allocated for hardware.
>
> -ENOTPOSSIBLE -- its an WFA requirement to RX AMSDU.
>
> > Its too easy to have memory allocation failures for high order pages and
> > freeze the card.
>
> Can't we us paged RX skbs, which mac80211 supports now?
>
> See 2f301227a1ede57504694e1f64839839f5737cac and friends.
>
Maybe you dont understand the point. A fix is needed for stable kernels.
paged RX skbs is probably a bit complex, even if copy/pasted from other
drivers.
If the hardware needs 8192 bytes (or 16384) buffers to perform its
operation, it should not give them back to linux, because there is no
guarantee it can allocate fresh ones for the next frames.
next prev parent reply other threads:[~2011-01-07 2:07 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-07 0:46 [PATCH 1/3] ath9k: Decrease skb size to fit into one page greearb
2011-01-07 0:46 ` [PATCH 2/3] ath9k: Re-start xmit logic in xmit watchdog timer greearb
2011-01-07 6:51 ` Vasanthakumar Thiagarajan
2011-01-07 7:16 ` Ben Greear
2011-01-07 15:11 ` [ath9k-devel] " Peter Stuge
2011-01-07 15:19 ` Ben Greear
2011-01-07 15:20 ` Vasanthakumar Thiagarajan
2011-01-07 0:46 ` [PATCH 3/3] ath9k: Keep track of stations for debugfs greearb
2011-01-07 2:30 ` [ath9k-devel] " Luis R. Rodriguez
2011-01-07 2:45 ` Ben Greear
2011-01-07 2:49 ` Luis R. Rodriguez
2011-01-07 3:17 ` Ben Greear
2011-01-07 15:36 ` Peter Stuge
2011-01-07 15:52 ` Ben Greear
2011-01-07 20:01 ` Luis R. Rodriguez
2011-01-07 20:25 ` Luis R. Rodriguez
2011-01-07 20:30 ` Luis R. Rodriguez
2011-01-07 19:46 ` Luis R. Rodriguez
2011-01-07 2:45 ` Felix Fietkau
2011-01-07 2:48 ` Ben Greear
2011-01-07 0:57 ` [ath9k-devel] [PATCH 1/3] ath9k: Decrease skb size to fit into one page Luis R. Rodriguez
2011-01-07 1:03 ` Ben Greear
2011-01-07 1:04 ` Christian Lamparter
2011-01-07 1:23 ` Eric Dumazet
2011-01-07 1:57 ` Luis R. Rodriguez
2011-01-07 2:07 ` Eric Dumazet [this message]
2011-01-07 2:13 ` Luis R. Rodriguez
2011-01-07 2:24 ` Eric Dumazet
2011-01-07 2:33 ` Eric Dumazet
2011-01-07 10:58 ` Johannes Berg
2011-01-07 18:34 ` Ben Greear
2011-01-07 20:09 ` [ath9k-devel] " Luis R. Rodriguez
2011-01-07 20:26 ` Eric Dumazet
2011-01-07 22:20 ` Ben Greear
2011-01-07 22:26 ` Eric Dumazet
2011-01-07 22:46 ` Ben Greear
2011-01-09 9:34 ` Johannes Berg
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1294366072.2704.32.camel@edumazet-laptop \
--to=eric.dumazet@gmail.com \
--cc=ath9k-devel@venema.h4ckr.net \
--cc=chunkeey@googlemail.com \
--cc=greearb@candelatech.com \
--cc=linux-wireless@vger.kernel.org \
--cc=mcgrof@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).