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Michal Privoznik ea576ee543 qemuProcessHook: Call virNuma*() only when needed
https://bugzilla.redhat.com/show_bug.cgi?id=1198645

Once upon a time, there was a little domain. And the domain was pinned
onto a NUMA node and hasn't fully allocated its memory:

  <memory unit='KiB'>2355200</memory>
  <currentMemory unit='KiB'>1048576</currentMemory>

  <numatune>
    <memory mode='strict' nodeset='0'/>
  </numatune>

Oh little me, said the domain, what will I do with so little memory.
If I only had a few megabytes more. But the old admin noticed the
whimpering, barely audible to untrained human ear. And good admin he
was, he gave the domain yet more memory. But the old NUMA topology
witch forbade to allocate more memory on the node zero. So he
decided to allocate it on a different node:

virsh # numatune little_domain --nodeset 0-1

virsh # setmem little_domain 2355200

The little domain was happy. For a while. Until bad, sharp teeth
shaped creature came. Every process in the system was afraid of him.
The OOM Killer they called him. Oh no, he's after the little domain.
There's no escape.

Do you kids know why? Because when the little domain was born, her
father, Libvirt, called numa_set_membind(). So even if the admin
allowed her to allocate memory from other nodes in the cgroups, the
membind() forbid it.

So what's the lesson? Libvirt should rely on cgroups, whenever
possible and use numa_set_membind() as the last ditch effort.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2015-04-08 11:54:31 +02:00
.gnulib@106a3866d0 maint: update to latest gnulib 2015-03-26 09:41:55 -06:00
build-aux bracket-spacing: Add syntax-check for unnecessary curly brackets 2014-11-14 17:13:36 +01:00
daemon Do not include cpu_map.h in libvirtd.c 2015-04-02 10:27:56 +02:00
docs interface: allow multiple IPv4 addresses in interface XML 2015-04-06 13:27:15 -04:00
examples Fix common misspellings 2015-03-23 09:01:30 +01:00
gnulib maint: fix date in local gnulib patch 2015-01-05 16:44:10 +00:00
include qemu: lifecycle: make agent-mode shutdown and reboot timeout 2015-04-02 11:08:48 +02:00
m4 rpm-build: use pkg-config to detect wireshark presence 2015-03-16 22:58:54 +01:00
po Release of libvirt-1.2.14 2015-04-02 15:48:08 +08:00
src qemuProcessHook: Call virNuma*() only when needed 2015-04-08 11:54:31 +02:00
tests vircgroup: Introduce virCgroupControllerAvailable 2015-04-08 11:54:24 +02:00
tools virsh: Improve change-media success message 2015-04-06 16:32:31 -04:00
.ctags maint: Make ctags work out of the box 2013-07-18 08:47:21 +02:00
.dir-locals.el build: avoid tabs that failed syntax-check 2012-09-06 09:43:46 -06:00
.gitignore Revert "src/xenconfig: Xen-xl parser" 2015-01-12 10:15:13 -07:00
.gitmodules make .gnulib a submodule 2009-07-08 16:17:51 +02:00
.mailmap maint: update .mailmap for recent contributions 2015-03-20 06:17:55 -06:00
AUTHORS.in AUTHORS: add myself to commiters list 2015-03-16 09:30:02 +01:00
autobuild.sh Disable libvirtd by default when building on Win32 2014-04-29 11:30:32 +01:00
autogen.sh maint: improve usage of autogen's --no-git 2015-02-06 11:35:29 -07:00
bootstrap maint: update to latest gnulib 2015-03-26 09:41:55 -06:00
bootstrap.conf Revert "bootstrap.conf: add check for flex" 2015-01-12 10:14:30 -07:00
cfg.mk tests: nodeinfo: Test F21 aarch64 on APM mustang 2015-03-31 14:38:41 -06:00
ChangeLog-old Fix typos in src/* 2014-04-21 16:49:08 -06:00
config-post.h build: fix build of virt-login-shell on systems with older gnutls 2013-10-22 09:41:50 -06:00
configure.ac Bump version to 1.2.15 for new dev cycle 2015-04-02 10:10:21 +02:00
COPYING maint: follow recommended practice for using LGPL 2013-05-20 14:15:21 -06:00
COPYING.LESSER maint: follow recommended practice for using LGPL 2013-05-20 14:15:21 -06:00
HACKING docs: Fix missing curly braces 2014-12-10 11:21:31 +01:00
libvirt-lxc.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt-qemu.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt.pc.in Add pkg-config files for libvirt-qemu & libvirt-lxc 2014-06-23 16:17:27 +01:00
libvirt.spec.in Release of libvirt-1.2.14 2015-04-02 15:48:08 +08:00
Makefile.am examples: Introduce domtop 2014-07-18 16:39:54 +02:00
Makefile.nonreentrant maint: use LGPL correctly 2013-05-20 14:03:48 -06:00
mingw-libvirt.spec.in Move virConnect related APIs out of libvirt.h.in 2014-10-24 17:23:51 +01:00
README Correct typos in the documentation (Atsushi SAKAI) 2008-01-24 10:15:13 +00:00
README-hacking docs: update README-hacking 2014-05-06 16:20:24 -06:00
run.in Add PKG_CONFIG_PATH to run.in script. 2014-06-26 14:32:35 +01:00
TODO Update todo list file to point at bugzilla/website 2010-10-13 16:45:26 +01:00

         LibVirt : simple API for virtualization

  Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.

Daniel Veillard <veillard@redhat.com>