Re: Page alloc failures under network/disk IO load

From: Robert Hancock
Date: Thu Dec 04 2008 - 23:09:18 EST


Dan Noà wrote:
Francois Romieu wrote:
Dan Noà <dpn@xxxxxxxxxxxxx> :
[...]
I'm a bit confused because on another system (2.6.26.3) I never see
messages like this despite having the same amount of physical RAM in
each. The 2.6.26.3 system is also under more active use, and has more
userspace memory usage. On that system:
Does this system use the same network card ?

Nope, good point :) The system experiencing the allocation failures is
using an rtl8169 gigabit NIC (at 1gbps), the 2.6.26.3 system is on a
100M connection with a gigabit Broadcom BCM5721 / tg3.

02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd.
RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 01)

04:00.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5721
Gigabit Ethernet PCI Express (rev 11)

I can see how this could account for different behavior, although
presumably both drivers are calling __netdev_alloc_skb.

The Realtek driver is doing an order 1 allocation (an 8KB chunk). That is more likely to fail than an order 0. Are you using jumbo frames or higher than 1500 byte MTU on the network?

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