Re: [2.6.0-mm2] e100 driver hangs after period of moderate receive load

Re: [2.6.0-mm2] e100 driver hangs after period of moderate receive load

[Feldman, Scott]

On Wed, 31 Dec 2003, Lennert Buytenhek wrote:

> > Is NAPI enabled for this driver?  The interrupt behavior seems normal
> > for NAPI, but certainly the rest of the behavior does not...
> 
> Yes, NAPI was indeed enabled.
> 
> I 'went back' to 2.6.1-rc1 and that seems fine now.  Any patches you want
> me to try on top of 2.6.0-mm2?

Lennert, would you mind trying this patch to verify that problem is fixed?

The driver was indicating skbs to the stack before h/w was done with the 
DMA.  Not good.  That's what causes the corruption.  The stack free's the 
skb, and then h/w writes to it's data area.

-scott

-------------

--- net-drivers-2.5-exp/drivers/net/e100.c.orig	2004-01-09 16:41:42.000000000 -0800
+++ net-drivers-2.5-exp/drivers/net/e100.c	2004-01-09 16:44:59.000000000 -0800
@@ -143,7 +143,6 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/pci.h>
-#include <linux/list.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/mii.h>
@@ -273,11 +272,13 @@
 };
 
 enum scb_stat_ack {
+	stat_ack_not_ours    = 0x00,
 	stat_ack_sw_gen      = 0x04,
 	stat_ack_rnr         = 0x10,
 	stat_ack_cu_idle     = 0x20,
 	stat_ack_frame_rx    = 0x40,
 	stat_ack_cu_cmd_done = 0x80,
+	stat_ack_not_present = 0xFF,
 	stat_ack_rx = (stat_ack_sw_gen | stat_ack_rnr | stat_ack_frame_rx),
 	stat_ack_tx = (stat_ack_cu_idle | stat_ack_cu_cmd_done),
 };
@@ -367,11 +368,10 @@
 	u16 size;
 };
 
-struct rx_list {
-	struct list_head list;
+struct rx {
+	struct rx *next, *prev;
 	struct sk_buff *skb;
 	dma_addr_t dma_addr;
-	unsigned int length;
 };
 
 #if defined(__BIG_ENDIAN_BITFIELD)
@@ -492,11 +492,13 @@
 	u32 msg_enable				____cacheline_aligned;
 	struct net_device *netdev;
 	struct pci_dev *pdev;
-	
-	struct list_head rx_list_head		____cacheline_aligned;
-	struct rx_list *rx_list;
+
+	struct rx *rxs				____cacheline_aligned;
+	struct rx *rx_to_use;
+	struct rx *rx_to_clean;
 	struct rfd blank_rfd;
-	
+	int ru_running;
+
 	spinlock_t cb_lock			____cacheline_aligned;
 	spinlock_t cmd_lock;
 	struct csr *csr;
@@ -1350,57 +1352,46 @@
 
 static inline void e100_start_receiver(struct nic *nic)
 {
-	/* (Re)start RU if suspended or idle and RFA is fully allocated */
-	struct rx_list *curr =
-		list_entry(nic->rx_list_head.next, struct rx_list, list);
-	if(curr->skb) {
-		u8 status = readb(&nic->csr->scb.status);
-		if(unlikely((status & rus_mask) != rus_ready))
-			e100_exec_cmd(nic, ruc_start, curr->dma_addr);
+	/* (Re)start RU if suspended or idle and RFA is non-NULL */
+	if(!nic->ru_running && nic->rx_to_clean->skb) {
+		e100_exec_cmd(nic, ruc_start, nic->rx_to_clean->dma_addr);
+		nic->ru_running = 1;
 	}
 }
 
-static inline int e100_rx_alloc_skb(struct nic *nic, struct rx_list *curr)
+#define RFD_BUF_LEN (sizeof(struct rfd) + VLAN_ETH_FRAME_LEN)
+static inline int e100_rx_alloc_skb(struct nic *nic, struct rx *rx)
 {
 	unsigned int rx_offset = 2; /* u32 align protocol headers */
 
-	curr->dma_addr = 0;
-	curr->length = sizeof(struct rfd) + VLAN_ETH_FRAME_LEN;
-
-	if(!(curr->skb = dev_alloc_skb(curr->length + rx_offset)))
+	if(!(rx->skb = dev_alloc_skb(RFD_BUF_LEN + rx_offset)))
 		return -ENOMEM;
 
-	skb_reserve(curr->skb, rx_offset);
-	curr->skb->dev = nic->netdev;
-	curr->dma_addr = pci_map_single(nic->pdev, curr->skb->data,
-		curr->length, PCI_DMA_FROMDEVICE);
-
-	return 0;
-}
-
-static inline void e100_rx_rfa_add_tail(struct nic *nic, struct rx_list *curr)
-{
-	memcpy(curr->skb->data, &nic->blank_rfd, sizeof(struct rfd));
-	pci_dma_sync_single(nic->pdev, curr->dma_addr, 
-		sizeof(struct rfd), PCI_DMA_TODEVICE);
+	/* Align, init, and map the RFA. */
+	rx->skb->dev = nic->netdev;
+	skb_reserve(rx->skb, rx_offset);
+	memcpy(rx->skb->data, &nic->blank_rfd, sizeof(struct rfd));
+	rx->dma_addr = pci_map_single(nic->pdev, rx->skb->data,
+		RFD_BUF_LEN, PCI_DMA_FROMDEVICE);
 
-	if(likely(curr->list.prev != &nic->rx_list_head)) {
-		struct rx_list *prev = (struct rx_list *)curr->list.prev;
-		if(likely(prev->skb != NULL)) {
-			struct rfd *prev_rfd = (struct rfd *)prev->skb->data;
-			put_unaligned(cpu_to_le32(curr->dma_addr),
-				(u32 *)&prev_rfd->link);
-			prev_rfd->command = 0;
-			pci_dma_sync_single(nic->pdev, prev->dma_addr, 
-				sizeof(struct rfd), PCI_DMA_TODEVICE);
-		}
+	/* Link the RFD to end of RFA by linking previous RFD to
+	 * this one, and clearing EL bit of previous.  */
+	if(rx->prev->skb) {
+		struct rfd *prev_rfd = (struct rfd *)rx->prev->skb->data;
+		put_unaligned(cpu_to_le32(rx->dma_addr),
+			(u32 *)&prev_rfd->link);
+		prev_rfd->command &= ~cpu_to_le16(cb_el);
+		pci_dma_sync_single(nic->pdev, rx->prev->dma_addr,
+			sizeof(struct rfd), PCI_DMA_TODEVICE);
 	}
+
+	return 0;
 }
 
-static inline int e100_rx_indicate(struct nic *nic, struct rx_list *curr,
+static inline int e100_rx_indicate(struct nic *nic, struct rx *rx,
 	unsigned int *work_done, unsigned int work_to_do)
 {
-	struct sk_buff *skb = curr->skb;
+	struct sk_buff *skb = rx->skb;
 	struct rfd *rfd = (struct rfd *)skb->data;
 	u16 rfd_status, actual_size;
 
@@ -1408,7 +1399,7 @@
 		return -EAGAIN;
 
 	/* Need to sync before taking a peek at cb_complete bit */
-	pci_dma_sync_single(nic->pdev, curr->dma_addr,
+	pci_dma_sync_single(nic->pdev, rx->dma_addr,
 		sizeof(struct rfd), PCI_DMA_FROMDEVICE);
 	rfd_status = le16_to_cpu(rfd->status);
 
@@ -1420,15 +1411,15 @@
 
 	/* Get actual data size */
 	actual_size = le16_to_cpu(rfd->actual_size) & 0x3FFF;
-	if(unlikely(actual_size > curr->length - sizeof(struct rfd)))
-		actual_size = curr->length - sizeof(struct rfd);
+	if(unlikely(actual_size > RFD_BUF_LEN - sizeof(struct rfd)))
+		actual_size = RFD_BUF_LEN - sizeof(struct rfd);
 
 	/* Get data */
-	pci_dma_sync_single(nic->pdev, curr->dma_addr,
+	pci_dma_sync_single(nic->pdev, rx->dma_addr,
 		sizeof(struct rfd) + actual_size,
 		PCI_DMA_FROMDEVICE);
-	pci_unmap_single(nic->pdev, curr->dma_addr,
-		curr->length, PCI_DMA_FROMDEVICE);
+	pci_unmap_single(nic->pdev, rx->dma_addr,
+		RFD_BUF_LEN, PCI_DMA_FROMDEVICE);
 
 	/* Pull off the RFD and put the actual data (minus eth hdr) */
 	skb_reserve(skb, sizeof(struct rfd));
@@ -1452,37 +1443,26 @@
 			(*work_done)++;
 	}
 
-	curr->length = 0;
-	curr->dma_addr = 0;
-	curr->skb = NULL;
-	
+	rx->skb = NULL;
+
 	return 0;
 }
 
 static inline void e100_rx_clean(struct nic *nic, unsigned int *work_done,
 	unsigned int work_to_do)
 {
-	struct list_head *list, *tmp;
-	struct rx_list *curr;
+	struct rx *rx;
 
 	/* Indicate newly arrived packets */
-	list_for_each(list, &nic->rx_list_head) {
-		curr = list_entry(list, struct rx_list, list);
-		if(likely(curr->skb != NULL))
-			if(e100_rx_indicate(nic, curr, work_done, work_to_do))
-				break;
+	for(rx = nic->rx_to_clean; rx->skb; rx = nic->rx_to_clean = rx->next) {
+		if(e100_rx_indicate(nic, rx, work_done, work_to_do))
+			break; /* No more to clean */
 	}
 
 	/* Alloc new skbs to refill list */
-	list_for_each_safe(list, tmp, &nic->rx_list_head) {
-		curr = list_entry(list, struct rx_list, list);
-		if(unlikely(curr->skb != NULL))
-			break; /* List is full, done */
-		if(unlikely(e100_rx_alloc_skb(nic, curr)))
+	for(rx = nic->rx_to_use; !rx->skb; rx = nic->rx_to_use = rx->next) {
+		if(unlikely(e100_rx_alloc_skb(nic, rx)))
 			break; /* Better luck next time (see watchdog) */
-		list_del(&curr->list);
-		list_add_tail(&curr->list, &nic->rx_list_head);
-		e100_rx_rfa_add_tail(nic, curr);
 	}
 
 	e100_start_receiver(nic);
@@ -1490,44 +1470,47 @@
 
 static void e100_rx_clean_list(struct nic *nic)
 {
-	struct list_head *list;
-	
-	if(!nic->rx_list)
-		return;
+	struct rx *rx;
+	unsigned int i, count = nic->params.rfds.count;
 
-	list_for_each(list, &nic->rx_list_head) {
-		struct rx_list *curr = list_entry(list, 
-			struct rx_list, list);
-		if(curr->skb) {
-			pci_unmap_single(nic->pdev, curr->dma_addr,
-				curr->length, PCI_DMA_FROMDEVICE);
-			dev_kfree_skb(curr->skb);
+	if(nic->rxs) {
+		for(rx = nic->rxs, i = 0; i < count; rx++, i++) {
+			if(rx->skb) {
+				pci_unmap_single(nic->pdev, rx->dma_addr,
+					RFD_BUF_LEN, PCI_DMA_FROMDEVICE);
+				dev_kfree_skb(rx->skb);
+			}
 		}
+		kfree(nic->rxs);
+		nic->rxs = NULL;
 	}
 
-	kfree(nic->rx_list);
-	nic->rx_list = NULL;
+	nic->rx_to_use = nic->rx_to_clean = NULL;
+	nic->ru_running = 0;
 }
 
 static int e100_rx_alloc_list(struct nic *nic)
 {
-	struct rx_list *curr;
+	struct rx *rx;
 	unsigned int i, count = nic->params.rfds.count;
-	
-	INIT_LIST_HEAD(&nic->rx_list_head);
 
-	if(!(nic->rx_list = kmalloc(sizeof(struct rx_list)*count, GFP_ATOMIC)))
+	nic->rx_to_use = nic->rx_to_clean = NULL;
+
+	if(!(nic->rxs = kmalloc(sizeof(struct rx) * count, GFP_ATOMIC)))
 		return -ENOMEM;
+	memset(nic->rxs, 0, sizeof(struct rx) * count);
 
-	for(curr = nic->rx_list, i = 0; i < count; curr++, i++) {
-		if(e100_rx_alloc_skb(nic, curr)) {
+	for(rx = nic->rxs, i = 0; i < count; rx++, i++) {
+		rx->next = (i + 1 < count) ? rx + 1 : nic->rxs;
+		rx->prev = (i == 0) ? nic->rxs + count - 1 : rx - 1;
+		if(e100_rx_alloc_skb(nic, rx)) {
 			e100_rx_clean_list(nic);
 			return -ENOMEM;
 		}
-		list_add_tail(&curr->list, &nic->rx_list_head);
-		e100_rx_rfa_add_tail(nic, curr);
 	}
-	
+
+	nic->rx_to_use = nic->rx_to_clean = nic->rxs;
+
 	return 0;
 }
 
@@ -1539,13 +1522,16 @@
 
 	DPRINTK(INTR, DEBUG, "stat_ack = 0x%02X\n", stat_ack);
 
-	if(stat_ack == 0x00 ||	/* Not our interrupt */
-	   stat_ack == 0xFF)	/* Hardware is ejected (cardbus, hotswap)  */
+	if(stat_ack == stat_ack_not_ours ||	/* Not our interrupt */
+	   stat_ack == stat_ack_not_present)	/* Hardware is ejected */
 		return IRQ_NONE;
 
-	/* Ack interrupts */
+	/* Ack interrupt(s) */
 	writeb(stat_ack, &nic->csr->scb.stat_ack);
-	e100_write_flush(nic);
+
+	/* We hit Receive No Resource (RNR); restart RU after cleaning */
+	if(stat_ack & stat_ack_rnr)
+		nic->ru_running = 0;
 
 #ifdef CONFIG_E100_NAPI
 	e100_disable_irq(nic);
@@ -1664,7 +1650,7 @@
 
 static void e100_down(struct nic *nic)
 {
-	e100_disable_irq(nic);
+	e100_hw_reset(nic);
 	free_irq(nic->pdev->irq, nic->netdev);
 	del_timer_sync(&nic->watchdog);
 	netif_carrier_off(nic->netdev);
@@ -1687,7 +1673,6 @@
 {
 	int err;
 	struct sk_buff *skb;
-	struct rx_list *rx;
 
 	/* Use driver resources to perform internal MAC or PHY
 	 * loopback test.  A single packet is prepared and transmitted
@@ -1724,8 +1709,8 @@
 	set_current_state(TASK_UNINTERRUPTIBLE);
 	schedule_timeout(HZ / 100 + 1);
 
-	rx = list_entry(nic->rx_list_head.next, struct rx_list, list);
-	if(memcmp(rx->skb->data + sizeof(struct rfd), skb->data, ETH_DATA_LEN))
+	if(memcmp(nic->rx_to_clean->skb->data + sizeof(struct rfd),
+	   skb->data, ETH_DATA_LEN))
        		err = -EAGAIN;
 
 err_loopback_none:

Re: [2.6.0-mm2] e100 driver hangs after period of moderate receive load

[Lennert Buytenhek]

On Fri, Jan 09, 2004 at 05:17:40PM -0800, Feldman, Scott wrote:

> > > Is NAPI enabled for this driver?? The interrupt behavior seems normal
> > > for NAPI, but certainly the rest of the behavior does not...
> > 
> > Yes, NAPI was indeed enabled.
> > 
> > I 'went back' to 2.6.1-rc1 and that seems fine now.? Any patches you want
> > me to try on top of 2.6.0-mm2?
> 
> Lennert, would you mind trying this patch to verify that problem is fixed?
> 
> The driver was indicating skbs to the stack before h/w was done with the 
> DMA.  Not good.  That's what causes the corruption.  The stack free's the 
> skb, and then h/w writes to it's data area.

AFAICS, didn't help, I still get the slab corruption.  Anything else you
want me to try?  Do you want me to send the klogd output I get now?


--L

Re: [2.6.0-mm2] e100 driver hangs after period of moderate receive load

[Lennert Buytenhek]

On Wed, Dec 31, 2003 at 07:34:46AM -0500, Jeff Garzik wrote:

> Well, the two are vastly different, since -mm2 includes a complete 
> rewrite of e100.
> 
> Does disabling NAPI in -mm2 change anything?

Disabling NAPI makes the slab corruption harder to trigger, but
it still occurs.


--L

RE: [2.6.0-mm2] e100 driver hangs after period of moderate receive load

[Feldman, Scott]

Lennert Buytenhek wrote:
> Make sure you have slab debugging enabled to see if you also 
> get the slab corruption messages, and then hit the machine 
> with anything above 50000 packets per second.  pktgen from a 
> different machine on the same subnet works nicely for that.  
> I doubt that downloading a Red Hat iso would give you a load 
> anywhere near that.
> 
> Oh, do you have an SMP box?  This was on a 2-way (4-way HT) 
> SMP box.  Not sure if that matters here.
> 
> I'm just about to try 2.6.0-mm2 without NAPI.

Ok, I've repro'd this (w/ and w/o NAPI, but w/o is much harder).  I
wasted a bunch of time having both page alloc debugging and slab
debugging on.  Seems one masks the other.  (Jeff warned me!)  In any
case, what I know so far is the problem happens when HW runs out of Rx
resources, and SW tries to resume the receiver after supplying new
resources.  Somehow HW is scribbling on resources already given back to
the OS.  It's something about the list management in this new e100.
eepro100 and legacy e100 work fine.  Investigation continuing...

-scott

Re: [2.6.0-mm2] e100 driver hangs after period of moderate receive load

[Lennert Buytenhek]

On Wed, Dec 31, 2003 at 09:21:56PM -0500, Thomas Molina wrote:

> [hangs on e100 under moderate receive load]
> > > Yes, NAPI was indeed enabled.
> > > 
> > > I 'went back' to 2.6.1-rc1 and that seems fine now.  Any patches you want
> > > me to try on top of 2.6.0-mm2?
> > 
> > Well, the two are vastly different, since -mm2 includes a complete 
> > rewrite of e100.
> > 
> > Does disabling NAPI in -mm2 change anything?
> 
> I have one of these beasts so I decided to test it after seeing this 
> message.  2.6.0-mm2 NAPI enabled and I am not seeing any of the symptoms 
> described here.  My test consists of downloading an iso from RedHat's ftp 
> site.  I'm not sure that is generating the kind of traffic you are talking 
> about, but I'm open to suggestions on what test to run trying to duplicate 
> what is being reported.

Make sure you have slab debugging enabled to see if you also get the slab
corruption messages, and then hit the machine with anything above 50000
packets per second.  pktgen from a different machine on the same subnet
works nicely for that.  I doubt that downloading a Red Hat iso would give
you a load anywhere near that.

Oh, do you have an SMP box?  This was on a 2-way (4-way HT) SMP box.  Not
sure if that matters here.

I'm just about to try 2.6.0-mm2 without NAPI.


--L

Re: [2.6.0-mm2] e100 driver hangs after period of moderate receive load

[Thomas Molina]

On Wed, 31 Dec 2003, Jeff Garzik wrote:

> Lennert Buytenhek wrote:
> > On Wed, Dec 31, 2003 at 07:11:10AM -0500, Jeff Garzik wrote:
> > 
> > 
> >>>After banging on an e100 card for about ten minutes with a ~60kpps stream,
> >>>the interface stops receiving packets.  Interrupts come in once every few
> >>>seconds (from /proc/interrupts), but no packets are received anymore at 
> >>>all.
> >>>Lots of slab corruption messages in the syslog that were generated during
> >>>that packet stream (see other email I sent.)  Stopping the packet stream
> >>>still leaves the interface unusable.  'ifconfig eth1 down ; ifconfig eth1 
> >>>up'
> >>>seems to fix things.
> >>
> >>Is NAPI enabled for this driver?  The interrupt behavior seems normal 
> >>for NAPI, but certainly the rest of the behavior does not...
> > 
> > 
> > Yes, NAPI was indeed enabled.
> > 
> > I 'went back' to 2.6.1-rc1 and that seems fine now.  Any patches you want
> > me to try on top of 2.6.0-mm2?
> 
> 
> Well, the two are vastly different, since -mm2 includes a complete 
> rewrite of e100.
> 
> Does disabling NAPI in -mm2 change anything?

I have one of these beasts so I decided to test it after seeing this 
message.  2.6.0-mm2 NAPI enabled and I am not seeing any of the symptoms 
described here.  My test consists of downloading an iso from RedHat's ftp 
site.  I'm not sure that is generating the kind of traffic you are talking 
about, but I'm open to suggestions on what test to run trying to duplicate 
what is being reported.

Re: [2.6.0-mm2] e100 driver hangs after period of moderate receive load

[Jeff Garzik]

Lennert Buytenhek wrote:
> On Wed, Dec 31, 2003 at 07:11:10AM -0500, Jeff Garzik wrote:
> 
> 
>>>After banging on an e100 card for about ten minutes with a ~60kpps stream,
>>>the interface stops receiving packets.  Interrupts come in once every few
>>>seconds (from /proc/interrupts), but no packets are received anymore at 
>>>all.
>>>Lots of slab corruption messages in the syslog that were generated during
>>>that packet stream (see other email I sent.)  Stopping the packet stream
>>>still leaves the interface unusable.  'ifconfig eth1 down ; ifconfig eth1 
>>>up'
>>>seems to fix things.
>>
>>Is NAPI enabled for this driver?  The interrupt behavior seems normal 
>>for NAPI, but certainly the rest of the behavior does not...
> 
> 
> Yes, NAPI was indeed enabled.
> 
> I 'went back' to 2.6.1-rc1 and that seems fine now.  Any patches you want
> me to try on top of 2.6.0-mm2?


Well, the two are vastly different, since -mm2 includes a complete 
rewrite of e100.

Does disabling NAPI in -mm2 change anything?

	Jeff

Re: [2.6.0-mm2] e100 driver hangs after period of moderate receive load

[Lennert Buytenhek]

On Wed, Dec 31, 2003 at 07:11:10AM -0500, Jeff Garzik wrote:

> >After banging on an e100 card for about ten minutes with a ~60kpps stream,
> >the interface stops receiving packets.  Interrupts come in once every few
> >seconds (from /proc/interrupts), but no packets are received anymore at 
> >all.
> >Lots of slab corruption messages in the syslog that were generated during
> >that packet stream (see other email I sent.)  Stopping the packet stream
> >still leaves the interface unusable.  'ifconfig eth1 down ; ifconfig eth1 
> >up'
> >seems to fix things.
> 
> Is NAPI enabled for this driver?  The interrupt behavior seems normal 
> for NAPI, but certainly the rest of the behavior does not...

Yes, NAPI was indeed enabled.

I 'went back' to 2.6.1-rc1 and that seems fine now.  Any patches you want
me to try on top of 2.6.0-mm2?


--L

Re: [2.6.0-mm2] e100 driver hangs after period of moderate receive load

[Jeff Garzik]

Lennert Buytenhek wrote:
> Hi,
> 
> After banging on an e100 card for about ten minutes with a ~60kpps stream,
> the interface stops receiving packets.  Interrupts come in once every few
> seconds (from /proc/interrupts), but no packets are received anymore at all.
> Lots of slab corruption messages in the syslog that were generated during
> that packet stream (see other email I sent.)  Stopping the packet stream
> still leaves the interface unusable.  'ifconfig eth1 down ; ifconfig eth1 up'
> seems to fix things.


Is NAPI enabled for this driver?  The interrupt behavior seems normal 
for NAPI, but certainly the rest of the behavior does not...

	Jeff

[2.6.0-mm2] e100 driver hangs after period of moderate receive load

[Lennert Buytenhek]

Hi,

After banging on an e100 card for about ten minutes with a ~60kpps stream,
the interface stops receiving packets.  Interrupts come in once every few
seconds (from /proc/interrupts), but no packets are received anymore at all.
Lots of slab corruption messages in the syslog that were generated during
that packet stream (see other email I sent.)  Stopping the packet stream
still leaves the interface unusable.  'ifconfig eth1 down ; ifconfig eth1 up'
seems to fix things.

Clues?


thanks,
Lennert