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Alexander Duyck c74042f3b3 ixgbe: Limit use of 2K buffers on architectures with 256B or larger cache lines
On architectures that have a cache line size larger than 64 Bytes we start
running into issues where the amount of headroom for the frame starts
shrinking.

The size of skb_shared_info on a system with a 64B L1 cache line size is
320.  This increases to 384 with a 128B cache line, and 512 with a 256B
cache line.

In addition the NET_SKB_PAD value increases as well consistent with the
cache line size.  As a result when we get to a 256B cache line as seen on
the s390 we end up 768 bytes used by padding and shared info leaving us
with only 1280 bytes to use for data storage.  On architectures such as
this we should default to using 3K Rx buffers out of a 8K page instead of
trying to do 1.5K buffers out of a 4K page.

To take all of this into account I have added one small check so that we
compare the max_frame to the amount of actual data we can store.  This was
already occurring for igb, but I had overlooked it for ixgbe as it doesn't
have strict limits for 82599 once we enable jumbo frames.  By adding this
check we will automatically enable 3K Rx buffers as soon as the maximum
frame size we can handle drops below the standard Ethernet MTU.

I also went through and fixed one small typo that I found where I had left
an IGB in a variable name due to a copy/paste error.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2017-03-02 18:03:39 -08:00
arch Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-02-28 11:50:53 -08:00
block lib/vsprintf.c: remove %Z support 2017-02-27 18:43:47 -08:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto crypto: change LZ4 modules to work with new LZ4 module version 2017-02-24 17:46:57 -08:00
Documentation This is a few small fixes to the main IPMI driver, make some 2017-02-28 21:06:30 -08:00
drivers ixgbe: Limit use of 2K buffers on architectures with 256B or larger cache lines 2017-03-02 18:03:39 -08:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs The nfsd update this round is mainly a lot of miscellaneous cleanups and 2017-02-28 15:39:09 -08:00
include This contains just the average.h change in order to get it 2017-03-02 14:39:17 -08:00
init Merge branch 'idr-4.11' of git://git.infradead.org/users/willy/linux-dax 2017-02-28 20:29:41 -08:00
ipc ipc/shm: Fix shmat mmap nil-page protection 2017-02-27 18:43:46 -08:00
kernel bpf: update the comment about the length of analysis 2017-03-01 14:56:50 -08:00
lib Merge branch 'idr-4.11' of git://git.infradead.org/users/willy/linux-dax 2017-02-28 20:29:41 -08:00
mm Merge branch 'idr-4.11' of git://git.infradead.org/users/willy/linux-dax 2017-02-28 20:29:41 -08:00
net This contains just the average.h change in order to get it 2017-03-02 14:39:17 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-02-22 10:15:09 -08:00
scripts checkpatch: warn when formats use %Z and suggest %z 2017-02-27 18:43:48 -08:00
security lib/vsprintf.c: remove %Z support 2017-02-27 18:43:47 -08:00
sound lib/vsprintf.c: remove %Z support 2017-02-27 18:43:47 -08:00
tools Merge branch 'idr-4.11' of git://git.infradead.org/users/willy/linux-dax 2017-02-28 20:29:41 -08:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt mm: add new mmget() helper 2017-02-27 18:43:48 -08:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap mailmap: add codeaurora.org names for nameless email commits 2017-01-10 18:31:55 -08:00
COPYING
CREDITS MAINTAINERS: Remove old e-mail address 2017-02-13 12:24:56 -05:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS MAINTAINERS: Orphan usb/net/hso driver 2017-03-01 09:50:58 -08:00
Makefile Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-02-28 10:15:59 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.