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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v4 4/4] xl: Improve xl documentation in regards to guest memory management
Improve xl documentation in regards to guest memory management.
Some improvements are suggested by Ian Jackson and Konrad Rzeszutek Wilk.
Signed-off-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
---
docs/man/xl.conf.pod.5 | 15 +++++
docs/misc/libxl_memory.txt | 124 +++++++++++++++++++++----------------
docs/misc/xenstore-paths.markdown | 22 ++++---
tools/examples/xl.conf | 4 ++
4 files changed, 105 insertions(+), 60 deletions(-)
diff --git a/docs/man/xl.conf.pod.5 b/docs/man/xl.conf.pod.5
index 1229c8a..658b1eb 100644
--- a/docs/man/xl.conf.pod.5
+++ b/docs/man/xl.conf.pod.5
@@ -62,6 +62,21 @@ of memory given to domain 0 by default.
Default: C<"auto">
+=item B<mem_set_enforce_limit=BOOLEAN>
+
+If enabled, then C<xl mem-set> by default will set a memory allocation
+target and enforce the maximum memory allocation for each domain.
+If disabled, then C<xl mem-set> by default will set only a memory allocation
+target for each domain.
+
+The memory allocation target is a suggested amount of memory which
+should be allocated by a guest. It is nice when the guest follows this
+value but it may have its own idea about memory requirments. However,
+it could not allocate more memory than a ceiling known as the maximum
+memory allocation.
+
+Default: C<1>
+
=item B<run_hotplug_scripts=BOOLEAN>
If disabled hotplug scripts will be called from udev, as it used to
diff --git a/docs/misc/libxl_memory.txt b/docs/misc/libxl_memory.txt
index 253476d..b89214a 100644
--- a/docs/misc/libxl_memory.txt
+++ b/docs/misc/libxl_memory.txt
@@ -1,70 +1,90 @@
/* === Domain memory breakdown: HVM guests ==================================
-
- + +----------+ +
- | | shadow | |
- | +----------+ |
- overhead | | extra | |
- | | external | |
- | +----------+ + |
- | | extra | | |
- | | internal | | |
- + +----------+ + | | footprint
- | | video | | | |
- | +----------+ + + | | xen |
- | | | | | | actual | maximum |
- | | | | | | target | |
- | | guest | | | build | | |
- | | | | | start | | |
- static | | | | | | | |
- maximum | +----------+ | + + + +
- | | | |
- | | | |
- | | balloon | | build
- | | | | maximum
- | | | |
- + +----------+ +
-
-
+
+ + +----------+ +
+ | | shadow | |
+ | +----------+ |
+ overhead | | extra | |
+ | | external | |
+ | +----------+ + |
+ | | extra | | |
+ | | internal | | |
+ + +----------+ + + | |
footprint
+ | | video | | | | |
+ | +----------+ | + + | | xen |
+ | | | | | | | actual | maximum |
+ | | | | | | | target | |
+ | | guest | | | | build | | |
+ | | | | | | start | | |
+ | | | | | | | | |
+ | +----------+ | | + + + +
+ | | | | |
+ | | | | |
+ guest | | | | | build
+ maximum | | | | | maximum
+ | | balloon | | |
+ | | | | |
+ | | | | static |
+ | | | | maximum |
+ | | | | |
+ | +----------+ + +
+ | | |
+ | | memory |
+ | | hotplug |
+ | | |
+ + +----------+
+
+
extra internal = LIBXL_MAXMEM_CONSTANT
extra external = LIBXL_HVM_EXTRA_MEMORY
shadow = libxl_domain_build_info.shadow_memkb
static maximum = libxl_domain_build_info.max_memkb
video = libxl_domain_build_info.video_memkb
build start = libxl_domain_build_info.target_memkb
+ guest maximum = declared by a guest its maximum supported memory size
libxl_domain_setmaxmem -> xen maximum
- libxl_set_memory_target -> actual target
-
-
+ libxl_set_memory_target -> actual target & optionaly xen maximum
+
+
=== Domain memory breakdown: PV guests ==================================
-
-
- + +----------+ +
- overhead | | extra | |
- | | external | |
- | +----------+ + |
- | | extra | | |
- | | internal | | |
- + +----------+ + + + | | footprint
- | | | | | | | xen |
- | | | | | | actual | maximum |
- | | guest | | | build | target | |
- | | | | | start | | |
- static | | | | | | | |
- maximum | +----------+ | + + + +
- | | | |
- | | | |
- | | balloon | | build
- | | | | maximum
- | | | |
- + +----------+ +
-
+
+
+ + +----------+ +
+ overhead | | extra | |
+ | | external | |
+ | +----------+ + |
+ | | extra | | |
+ | | internal | | |
+ + +----------+ + + + + | |
footprint
+ | | | | | | | | xen |
+ | | | | | | | actual | maximum |
+ | | guest | | | | build | target | |
+ | | | | | | start | | |
+ | | | | | | | | |
+ | +----------+ | | + + + +
+ | | | | |
+ | | | | |
+ | | | | | build
+ guest | | | | | maximum
+ maximum | | balloon | | |
+ | | | | |
+ | | | | static |
+ | | | | maximum |
+ | | | | |
+ | +----------+ + +
+ | | |
+ | | memory |
+ | | hotplug |
+ | | |
+ + +----------+
+
extra internal = LIBXL_MAXMEM_CONSTANT
extra external = LIBXL_PV_EXTRA_MEMORY
static maximum = libxl_domain_build_info.max_memkb
build start = libxl_domain_build_info.target_memkb
+ guest maximum = declared by a guest its maximum supported memory size
libxl_domain_setmaxmem -> xen maximum
- libxl_set_memory_target -> actual target
+ libxl_set_memory_target -> actual target & optionaly xen maximum
========================================================================= */
diff --git a/docs/misc/xenstore-paths.markdown
b/docs/misc/xenstore-paths.markdown
index 535830e..1ac2159 100644
--- a/docs/misc/xenstore-paths.markdown
+++ b/docs/misc/xenstore-paths.markdown
@@ -124,18 +124,24 @@ This protocol is not currently well documented.
#### ~/memory/static-max = MEMKB []
-Specifies a static maximum amount memory which this domain should
-expect to be given. In the absence of in-guest memory hotplug support
-this set on domain boot and is usually the maximum amount of RAM which
-a guest can make use of. See [docs/misc/libxl_memory.txt][LIBXLMEM]
-for a description of how memory is accounted for in toolstacks using
-the libxl library.
+Specifies a static maximum amount of memory which this domain
+should expect to be given. It is usually the maximum amount
+of RAM which a guest can make use of. This value is set on the
+domain boot. If ~/memory/guest-max is set then static maximum
+is ignored by libxl. See [docs/misc/libxl_memory.txt][LIBXLMEM]
+for a description of how the memory is accounted for in toolstacks
+using the libxl library.
+
+#### ~/memory/guest-max = ""|MEMKB [w]
+
+Declared by a guest its maximum supported memory size. Valid if numeric.
#### ~/memory/target = MEMKB []
The current balloon target for the domain. The balloon driver within
-the guest is expected to make every effort to every effort use no more
-than this amount of RAM.
+the guest is expected to make every effort to use no more than this
+amount of RAM. Guests whose actual allocation exceeds the target may
+experience memory allocation failures.
#### ~/memory/videoram = MEMKB [HVM,INTERNAL]
diff --git a/tools/examples/xl.conf b/tools/examples/xl.conf
index 9402c3f..9dbb1be 100644
--- a/tools/examples/xl.conf
+++ b/tools/examples/xl.conf
@@ -5,6 +5,10 @@
# starts with all the host's memory.
#autoballoon="auto"
+# xl mem-set by default will set a memory allocation target and enforce
+# the maximum memory allocation for each domain
+#mem_set_enforce_limit=1
+
# full path of the lockfile used by xl during domain creation
#lockfile="/var/lock/xl"
--
1.7.10.4
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