From owner-freebsd-net@FreeBSD.ORG Fri Feb 11 19:53:57 2011 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DF6731065679 for ; Fri, 11 Feb 2011 19:53:57 +0000 (UTC) (envelope-from fodillemlinkarim@gmail.com) Received: from mail-pw0-f54.google.com (mail-pw0-f54.google.com [209.85.160.54]) by mx1.freebsd.org (Postfix) with ESMTP id A92908FC0A for ; Fri, 11 Feb 2011 19:53:57 +0000 (UTC) Received: by pwi10 with SMTP id 10so649695pwi.13 for ; Fri, 11 Feb 2011 11:53:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=uIPVg2CGnO2Pptk63Irf1RsVDrKlOEmZ6UuZFdJ0qe8=; b=auQcy2zFzW1rIt3a9hahIrkoWPDKdf5GBGwsVlutaQqKa4DPs3mpY5FplYPRvzl6rP Z1sD24e48O1ehQ8knLd+Kr1vbSbJ+aK1LwAGeJqWeB6Ger+IqIxxIaCwcISlHNokhD24 7uQh7cblgowEspNiQeP6JWfNFMyhi886l4PXw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=HvqsBdXai5MHIrJWoikEKrVIDGCRjGRnguj67QWT8ETRVVfPkgxQgIqAxcPiXY8VCz LOtFdXi1lS3yqh+80Y5Xw178k9YdWv8racbyOVkvtbp6JcjrzJo9Z4nug28LK1s1expq hSQLRZtuRk/oWGNCR1ilaInfe/H/spBgZZRPo= MIME-Version: 1.0 Received: by 10.142.142.5 with SMTP id p5mr666222wfd.257.1297454037111; Fri, 11 Feb 2011 11:53:57 -0800 (PST) Received: by 10.142.246.3 with HTTP; Fri, 11 Feb 2011 11:53:57 -0800 (PST) In-Reply-To: <12838373-FE96-443E-8979-AF5408705BF0@freebsd.org> References: <12838373-FE96-443E-8979-AF5408705BF0@freebsd.org> Date: Fri, 11 Feb 2011 14:53:57 -0500 Message-ID: From: Karim Fodil-Lemelin To: Jack Vogel Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-net@freebsd.org Subject: Re: igb driver RX (was TX) hangs when out of mbuf clusters X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Feb 2011 19:53:58 -0000 Hi, I see a commit was made in current (r218530 | jfv | 2011-02-10 20:00:26 -0500 (Thu, 10 Feb 2011)). Is that commit done to address this issue? And if so Is there any MFC planned for 7.4 for this? Thanks, Karim. 2011/2/9 Michael Tuexen > On Feb 9, 2011, at 6:35 PM, Jack Vogel wrote: > > > OK, but the question is why does the ring get totally consumed this way, > the > > ring has 1024 descriptors, it seems unintuitive that that whole quantity > can be > > used without some being recharged. Do you see the system mbuf pool being > > depleted at the same time? > That was the test case I created: I set up a server accepting connections > but not reading anything. So the driver passes the mbufs to the transport > stack and they are not consumed. Then the problem occurs. Then I kill the > server. Now there are mbufs available again, but the driver doesn't know. > > I had the impression that these were the circumstances in which the problem > showed up (mbuf allocations failing). > > > > Since you can reproduce it, do me a favor, in rxeof, change the > processed > > value from 8 to 4 and then 1, effectively call refresh every descriptor, > see if > > that eliminates the issue. > I will do. Need to see if I can do it remotely, since I'm not in my lab > right now. Can do it tomorrow for sure. > > But I do not think that this solves the problem, since I did the things > very slowly and you call it at least when you are leaving rxeof. > > Best regards > Michael > > > > Thanks for your help, > > > > Jack > > > > > > On Wed, Feb 9, 2011 at 2:36 AM, Michael Tuexen > wrote: > > Hi Jack, > > > > I could recreate the problem. When the problem occurs, we see > > > > rx_nxt_check = n > > rx_nxt_refresh = n + 1 > > > > (This was also reported in a mail from Karim) > > > > This means that the *whole* receive ring has no buffers anymore. This can > > occur if, for some amount of time, no clusters are available. > > > > Now outside of the driver, at some point of time, clusters are freed. > > I don't think that igb_refresh_mbufs() gets called, since it only gets > > called from igb_rxeof(), which gets called when a packet has been > received, > > which can not happen since the receive ring is empty. So how can the > driver > > know? I have no idea. Maybe we can periodically check for such an event > > and call igb_refresh_mbufs(). > > > > Does this make sense to you? > > > > Best regards > > Michael > > > > > > On Feb 9, 2011, at 8:32 AM, Jack Vogel wrote: > > > > > Hmmm, well so much for that theory :) > > > > > > Jack > > > > > > > > > On Tue, Feb 8, 2011 at 4:06 PM, Karim Fodil-Lemelin < > fodillemlinkarim@gmail.com> wrote: > > > > > > > > > 2011/2/8 Jack Vogel > > > > > > > > > I have been following this, and thinking about it. I still am working > from a theoretical > > > standpoint, but based on a patch I got quite a long time back and never > quite groked, > > > I believe now that I might have a solution. > > > > > > The original PR and patch was kern/150516 from Beezar Liu, I was never > quite comfortable > > > with the code changes, nor convinced that it was a real issue and not a > misunderstanding. > > > However I think now that this very report might be behind what we are > seeing today. I have > > > a slightly different approach to solving it, of course it remains to be > seen if it handles it > > > properly. > > > > > > Please try the patch I've attached, I'm open to further correction or > polishing of the > > > changes. And thanks to Beezar for his original report and changes, this > is not for em, > > > but if this eliminates the problem its clearly needed in all drivers. > > > > > > Jack > > > > > > > > > Hi Jack, > > > > > > Thanks for your help. I tried your patch and it didn't work so I added > a couple of printf to see if the added code was getting hit: > > > > > > --- a/freebsd/sys/dev/e1000/if_igb.c > > > --More--(byte 1253)+++ b/freebsd/sys/dev/e1000/if_igb.c > > > @@ -612,7 +612,7 @@ igb_attach(device_t dev) > > > device_get_nameunit(dev)); > > > > > > INIT_DEBUGOUT("igb_attach: end"); > > > - > > > + printf("this driver has a patch from Jack Vogel\n"); > > > return (0); > > > > > > err_late: > > > @@ -4131,6 +4131,7 @@ igb_rxeof(struct igb_queue *que, int count, int > *done) > > > struct mbuf *sendmp, *mh, *mp; > > > struct igb_rx_buf *rxbuf; > > > u16 hlen, plen, hdr, vtag; > > > + int commit; > > > bool eop = FALSE; > > > > > > cur = &rxr->rx_base[i]; > > > @@ -4255,10 +4256,23 @@ next_desc: > > > bus_dmamap_sync(rxr->rxdma.dma_tag, rxr->rxdma.dma_map, > > > BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE); > > > > > > + commit = i; /* capture the old index */ > > > + > > > /* Advance our pointers to the next descriptor. */ > > > if (++i == adapter->num_rx_desc) > > > i = 0; > > > /* > > > + ** Sanity test for ring full, if this > > > + ** happens we need to refresh immediately > > > + ** or refresh may deadlock. > > > + */ > > > + if (i == rxr->next_to_refresh) { > > > + igb_refresh_mbufs(rxr, commit); > > > + printf("igb_refresh_mbufs called with commit > %d\n", commit); > > > + processed = 0; > > > + } > > > + > > > + /* > > > ** Send to the stack or LRO > > > */ > > > if (sendmp != NULL) { > > > > > > Here is the results: > > > > > > # dmesg | grep Vogel > > > this driver has a patch from Jack Vogel > > > this driver has a patch from Jack Vogel > > > > > > # netstat -m > > > 60453/52707/113160 mbufs in use (current/cache/total) > > > 48416/51584/100000/100000 mbuf clusters in use > (current/cache/total/max) > > > 2894/690 mbuf+clusters out of packet secondary zone in use > (current/cache) > > > 11946/854/12800/12800 4k (page size) jumbo clusters in use > (current/cache/total/max) > > > 0/0/0/6400 9k jumbo clusters in use (current/cache/total/max) > > > 0/0/0/3200 16k jumbo clusters in use (current/cache/total/max) > > > 164834K/119760K/284595K bytes allocated to network > (current/cache/total) > > > 0/339/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters) > > > 0/0/0 requests for jumbo clusters denied (4k/9k/16k) > > > 0/4/6656 sfbufs in use (current/peak/max) > > > 0 requests for sfbufs denied > > > 0 requests for sfbufs delayed > > > 0 requests for I/O initiated by sendfile > > > 0 calls to protocol drain routines > > > # dmesg | grep commit > > > > > > At this point RX has hung. > > > > > > Somehow the check (i == rxr->next_to_refresh) is never true in this > case. Also, I did read kern/150516 and couldn't wrap my head around the > patch for the em driver that Beezar Liu suggested. > > > > > > Regards, > > > > > > Karim. > > > > > > > > > > > >