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Juergen Gross a5d5f328b0 xen: allocate page for shared info page from low memory
In a HVM guest the kernel allocates the page for mapping the shared
info structure via extend_brk() today. This will lead to a drop of
performance as the underlying EPT entry will have to be split up into
4kB entries as the single shared info page is located in hypervisor
memory.

The issue has been detected by using the libmicro munmap test:
unmapping 8kB of memory was faster by nearly a factor of two when no
pv interfaces were active in the HVM guest.

So instead of taking a page from memory which might be mapped via
large EPT entries use a page which is already mapped via a 4kB EPT
entry: we can take a page from the first 1MB of memory as the video
memory at 640kB disallows using larger EPT entries.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
2017-06-25 13:11:27 +02:00
arch xen: allocate page for shared info page from low memory 2017-06-25 13:11:27 +02:00
block block: Avoid that blk_exit_rl() triggers a use-after-free 2017-06-01 13:07:55 -06:00
certs scripts/spelling.txt: add "intialise(d)" pattern and fix typo instances 2017-05-08 17:15:13 -07:00
crypto crypto: skcipher - Add missing API setkey checks 2017-05-18 13:04:05 +08:00
Documentation xen: add sysfs node for hypervisor build id 2017-06-15 08:50:37 +02:00
drivers xen: avoid deadlock in xenbus driver 2017-06-25 13:11:22 +02:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs fs/ufs: Set UFS default maximum bytes per file 2017-06-04 16:33:54 -07:00
include xen: sync include/xen/interface/version.h 2017-06-15 08:50:34 +02:00
init Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-10 10:30:46 -07:00
ipc mm: introduce kv[mz]alloc helpers 2017-05-08 17:15:12 -07:00
kernel Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching 2017-06-02 08:59:17 -07:00
lib test_bpf: Add a couple of tests for BPF_JSGE. 2017-05-25 14:37:56 -04:00
mm mm: consider memblock reservations for deferred memory initialization sizing 2017-06-02 15:07:38 -07:00
net NFS client bugfixes for Linux 4.12 2017-06-04 11:56:53 -07:00
samples samples/bpf: run cleanup routines when receiving SIGTERM 2017-05-11 21:43:30 -04:00
scripts scripts/gdb: make lx-dmesg command work (reliably) 2017-06-02 15:07:38 -07:00
security Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-05-09 09:12:53 -07:00
sound sound fixes for 4.12-rc4 2017-06-02 09:40:47 -07:00
tools powerpc fixes for 4.12 #4 2017-05-27 09:28:34 -07:00
usr initramfs: fix disabling of initramfs (and its compression) 2017-06-02 15:07:37 -07:00
virt KVM: arm/arm64: Hold slots_lock when unregistering kvm io bus devices 2017-05-18 11:18:16 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING [PATCH] update FSF address in COPYING 2005-09-10 10:06:29 -07:00
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig kbuild: migrate all arch to the kconfig mainmenu upgrade 2010-09-19 22:54:11 -04:00
MAINTAINERS xen: add sysfs node for guest type 2017-06-15 08:50:32 +02:00
Makefile Linux 4.12-rc4 2017-06-04 16:47:43 -07:00
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.