From a144ff09bc52ef3f3684ed23eadc9c7c0e57b3aa Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Tue, 17 Jun 2008 10:47:08 +0200 Subject: xen: Avoid allocations causing swap activity on the resume path Avoid allocations causing swap activity on the resume path by preventing the allocations from doing IO and allowing them to access the emergency pools. These paths are used when a frontend device is trying to connect to its backend driver over Xenbus. These reconnections are triggered on demand by IO, so by definition there is already IO underway, and further IO would naturally deadlock. On resume, this path is triggered when the running system tries to continue using its devices. If it cannot then the resume will fail; to try to avoid this we let it dip into the emergency pools. [ linux-2.6.18-xen changesets e8b49cfbdac, fdb998e79aba ] Signed-off-by: Ian Campbell Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Jens Axboe --- drivers/net/xen-netfront.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/net/xen-netfront.c') diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index d26f69b0184f..ef671d1a3bf0 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -1324,7 +1324,7 @@ static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info) goto fail; } - txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_KERNEL); + txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH); if (!txs) { err = -ENOMEM; xenbus_dev_fatal(dev, err, "allocating tx ring page"); @@ -1340,7 +1340,7 @@ static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info) } info->tx_ring_ref = err; - rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_KERNEL); + rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH); if (!rxs) { err = -ENOMEM; xenbus_dev_fatal(dev, err, "allocating rx ring page"); -- cgit v1.2.3 From 1ffb40b8ecdf314edd88dc5550d6bcbebf29970b Mon Sep 17 00:00:00 2001 From: Isaku Yamahata Date: Tue, 8 Jul 2008 15:06:31 -0700 Subject: xen-netfront: fix xennet_release_tx_bufs() After restore on ia64 xen domain, kernel panics as follows. This patch fixes it. union skb_entry assumes sizeof(link->skb, pointer) == sizeof(list->link, unsigned). However this isn't true on ia64. So make link type unsigned long. And introduced two accesor. kernel unaligned access to 0xe0000000000000bd, ip=0xa0000001004c2ca0 xenwatch[14]: error during unaligned kernel access -1 [1] Modules linked in: Pid: 14, CPU 0, comm: xenwatch psr : 0000101008422010 ifs : 8000000000000307 ip : [] Not tainted (2.6.26-rc4xen-ia64-dirty) ip is at dev_kfree_skb_irq+0x20/0x1a0 unat: 0000000000000000 pfs : 400000000000040b rsc : 0000000000000007 rnat: 0000000000000000 bsps: 0000000000000000 pr : 000000000000a941 ldrs: 0000000000000000 ccv : 0000000000000000 fpsr: 0009804c8a70433f csd : 0000000000000000 ssd : 0000000000000000 b0 : a0000001003efb70 b6 : a000000100070e40 b7 : a000000100070e40 f6 : 1003e000000fcb75352b1 f7 : 1003e000000000014ff97 f8 : 1003e00fcb74fc3454d80 f9 : 1003e0000000080000000 f10 : 1003e0000000000001431 f11 : 1003e0000000000989680 r1 : a000000100bfcf80 r2 : e0000000000000bd r3 : 000000000000308c r8 : 0000000000000000 r9 : e00000000fc31310 r10 : a000000100a13b28 r11 : 0000000000000000 r12 : e00000000fd0fdf0 r13 : e00000000fd08000 r14 : 0000000000000000 r15 : e00000000fcc8000 r16 : 0000000000000009 r17 : e000010000104000 r18 : e000010000104000 r19 : a000000100a13b40 r20 : a0000001009c23f0 r21 : a0000001009fd4d0 r22 : 0000000000004000 r23 : 0000000000000000 r24 : fffffffffff04c10 r25 : 0000000000000002 r26 : 0000000000000000 r27 : 0000000000000000 r28 : e00000000fd08bd4 r29 : a0000001007570b8 r30 : a0000001009e5500 r31 : a0000001009e54a0 Call Trace: [] show_stack+0x40/0xa0 sp=e00000000fd0f670 bsp=e00000000fd08f68 [] show_regs+0x9a0/0x9e0 sp=e00000000fd0f840 bsp=e00000000fd08f10 [] die+0x260/0x3a0 sp=e00000000fd0f840 bsp=e00000000fd08ec8 [] die_if_kernel+0x50/0x80 sp=e00000000fd0f840 bsp=e00000000fd08e98 [] ia64_handle_unaligned+0x2ea0/0x2fc0 sp=e00000000fd0f840 bsp=e00000000fd08df0 [] ia64_prepare_handle_unaligned+0x30/0x60 sp=e00000000fd0fa10 bsp=e00000000fd08df0 [] paravirt_leave_kernel+0x0/0x40 sp=e00000000fd0fc20 bsp=e00000000fd08df0 [] dev_kfree_skb_irq+0x20/0x1a0 sp=e00000000fd0fdf0 bsp=e00000000fd08db8 [] xennet_release_tx_bufs+0xd0/0x120 sp=e00000000fd0fdf0 bsp=e00000000fd08d78 [] backend_changed+0xc40/0xf80 sp=e00000000fd0fdf0 bsp=e00000000fd08d08 [] otherend_changed+0x190/0x1c0 sp=e00000000fd0fe00 bsp=e00000000fd08cc8 [] xenwatch_thread+0x310/0x3c0 sp=e00000000fd0fe00 bsp=e00000000fd08ca0 [] kthread+0xe0/0x160 sp=e00000000fd0fe30 bsp=e00000000fd08c68 [] kernel_thread_helper+0x30/0x60 sp=e00000000fd0fe30 bsp=e00000000fd08c40 [] start_kernel_thread+0x20/0x40 sp=e00000000fd0fe30 bsp=e00000000fd08c40 Kernel panic - not syncing: Aiee, killing interrupt handler! Signed-off-by: Isaku Yamahata Cc: Stephen Tweedie Cc: Eduardo Habkost Cc: Mark McLoughlin Signed-off-by: Ingo Molnar --- drivers/net/xen-netfront.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) (limited to 'drivers/net/xen-netfront.c') diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index ef671d1a3bf0..902bbe788215 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -92,7 +92,7 @@ struct netfront_info { */ union skb_entry { struct sk_buff *skb; - unsigned link; + unsigned long link; } tx_skbs[NET_TX_RING_SIZE]; grant_ref_t gref_tx_head; grant_ref_t grant_tx_ref[NET_TX_RING_SIZE]; @@ -125,6 +125,17 @@ struct netfront_rx_info { struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1]; }; +static void skb_entry_set_link(union skb_entry *list, unsigned short id) +{ + list->link = id; +} + +static int skb_entry_is_link(const union skb_entry *list) +{ + BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link)); + return ((unsigned long)list->skb < PAGE_OFFSET); +} + /* * Access macros for acquiring freeing slots in tx_skbs[]. */ @@ -132,7 +143,7 @@ struct netfront_rx_info { static void add_id_to_freelist(unsigned *head, union skb_entry *list, unsigned short id) { - list[id].link = *head; + skb_entry_set_link(&list[id], *head); *head = id; } @@ -993,7 +1004,7 @@ static void xennet_release_tx_bufs(struct netfront_info *np) for (i = 0; i < NET_TX_RING_SIZE; i++) { /* Skip over entries which are actually freelist references */ - if ((unsigned long)np->tx_skbs[i].skb < PAGE_OFFSET) + if (skb_entry_is_link(&np->tx_skbs[i])) continue; skb = np->tx_skbs[i].skb; @@ -1123,7 +1134,7 @@ static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev /* Initialise tx_skbs as a free chain containing every entry. */ np->tx_skb_freelist = 0; for (i = 0; i < NET_TX_RING_SIZE; i++) { - np->tx_skbs[i].link = i+1; + skb_entry_set_link(&np->tx_skbs[i], i+1); np->grant_tx_ref[i] = GRANT_INVALID_REF; } -- cgit v1.2.3