From: Olaf Hering <olaf@aepfle.de>
To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
Subject: Re: [PATCH 00 of 24] xenpaging fixes for xen-unstable
Date: Tue, 4 Oct 2011 17:05:45 +0200 [thread overview]
Message-ID: <20111004150545.GA13277@aepfle.de> (raw)
In-Reply-To: <1317721869.21903.110.camel@zakaz.uk.xensource.com>
On Tue, Oct 04, Ian Campbell wrote:
> totmem is unfortunately not all that descriptive to an end user of what
> it does (which I think is a general problem we have with the memory
> related options).
>
> Currently the xl config file options are:
> memory = actual start of day RAM
> maxmem = max ram guest could balloon to (?)
>
> How does POD fit in? Is it just maxmem-memory for HVM domains? (not
> really relevant for this discussion, more for completeness).
>
> The associated command line options are:
> mem-set (runtime equivalent of memory?)
> mem-max (runtime equivalent of maxmem?)
>
> Hmm, I was hoping that enumerating the existing options would make the
> name and semantics of the paging option magically pop into my head, I
> was wrong :-(
>
> BTW tools/libxl/libxl_memory.txt should be patched by this series too,
> once we figure out what to call things.
>
> The phrase "actual memory" is used in that document -- perhaps that is
> suitable terminology for totmem?
The naming of the various numbers is confusing, so far I could not come
up with a better name than tot_pages.
"actual target" is close to what xenpaging leaves for the guest, the
amount of video ram has to be substracted.
I think the code in libxl, xenstore and in my changes is not 100%
consistent with the figure below. I have to wade through the individual
members again and check if the math is correct in all places.
Olaf
/* === Domain memory breakdown: HVM guests ==================================
+ +----------+ +
| | shadow | |
| +----------+ |
overhead | | extra | |
| | external | |
| +----------+ + |
| | extra | | |
| | internal | | |
+ +----------+ + | | footprint
| | video | | | |
| +----------+ + + + | | xen |
| | | | guest OS | | | actual | maximum |
| | guest | | real RAM | | | target | |
| | | | | | build | | |
| +----------+ + | | start + | |
static | | paging | | | | |
maximum | +----------+ | + + +
| | | |
| | | |
| | balloon | | build
| | | | maximum
| | | |
+ +----------+ +
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
libxl_domain_setmaxmem -> xen maximum
libxl_set_memory_target -> actual target
build maximum = RAM as seen inside the virtual machine
Increase/Decrease via memory hotplug of virtual hardware (?)
xl mem-max (?)
build start = RAM usable by the guest OS
guest OS sees balloon driver as memory hog (?)
Increase/Decrease via commands to the balloon driver
xl mem-set
real RAM = RAM allocated for the guest
Increase/Decrease via commands to paging daemon
xl mem-FOO
guest = real RAM
paging = virtual RAM / swap
balloon = will become real or virtual RAM after mem-set command
next prev parent reply other threads:[~2011-10-04 15:05 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-03 15:54 [PATCH 00 of 24] xenpaging fixes for xen-unstable Olaf Hering
2011-10-03 15:54 ` [PATCH 01 of 24] xenpaging: remove filename from comment Olaf Hering
2011-10-03 15:54 ` [PATCH 02 of 24] xenpaging: remove obsolete comment in resume path Olaf Hering
2011-10-03 15:54 ` [PATCH 03 of 24] xenpaging: use PERROR to print errno Olaf Hering
2011-10-04 16:19 ` George Dunlap
2011-10-04 17:19 ` Olaf Hering
2011-10-03 15:54 ` [PATCH 04 of 24] xenpaging: update xenpaging_init Olaf Hering
2011-10-03 15:54 ` [PATCH 05 of 24] xenpaging: remove xc_dominfo_t from paging_t Olaf Hering
2011-10-03 15:54 ` [PATCH 06 of 24] xenpaging: track the number of paged-out pages Olaf Hering
2011-10-03 15:54 ` [PATCH 07 of 24] xenpaging: move page add/resume loops into its own function Olaf Hering
2011-10-03 15:54 ` [PATCH 08 of 24] xenpaging: compare both token and path when checking for @releaseDomain event Olaf Hering
2011-10-03 15:54 ` [PATCH 09 of 24] xenpaging: improve mainloop exit handling Olaf Hering
2011-10-03 15:54 ` [PATCH 10 of 24] libxc: add bitmap_clear function Olaf Hering
2011-10-03 15:54 ` [PATCH 11 of 24] xenpaging: retry unpageable gfns Olaf Hering
2011-10-03 15:54 ` [PATCH 12 of 24] libxl: rename libxl__device_model_starting Olaf Hering
2011-10-03 15:54 ` [PATCH 13 of 24] libxl: rename dm_xenstore_record_pid to libxl_spawner_record_pid Olaf Hering
2011-10-03 15:54 ` [PATCH 14 of 24] libxl: add pid path to libxl__spawner_starting Olaf Hering
2011-10-04 8:23 ` Ian Campbell
2011-10-04 9:09 ` Olaf Hering
2011-10-03 15:54 ` [PATCH 15 of 24] libxl: add libxl__wait_for_offspring function Olaf Hering
2011-10-03 15:54 ` [PATCH 16 of 24] libxl: use libxl__wait_for_offspring for device model Olaf Hering
2011-10-03 15:54 ` [PATCH 17 of 24] libxl: add libxl__spawn_confirm_offspring_startup Olaf Hering
2011-10-25 15:31 ` Ian Jackson
2011-10-25 17:21 ` Olaf Hering
2011-10-25 17:53 ` Ian Jackson
2011-10-26 16:30 ` Olaf Hering
2011-10-27 10:34 ` Ian Jackson
2011-10-03 15:54 ` [PATCH 18 of 24] libxl: use libxl__spawn_confirm_offspring_startup for device model Olaf Hering
2011-10-03 15:54 ` [PATCH 19 of 24] xenpaging: install into LIBEXEC dir Olaf Hering
2011-10-03 15:54 ` [PATCH 20 of 24] xenpaging: add XEN_PAGING_DIR / libxl_xenpaging_dir_path() Olaf Hering
2011-10-03 15:54 ` [PATCH 21 of 24] xenpaging: use guests tot_pages as working target Olaf Hering
2011-10-03 15:54 ` [PATCH 22 of 24] xenpaging: watch the guests memory/target-tot_pages xenstore value Olaf Hering
2011-10-03 15:55 ` [PATCH 23 of 24] xenpaging: add cmdline interface for pager Olaf Hering
2011-10-03 15:55 ` [PATCH 24 of 24] xenpaging: libxl support Olaf Hering
2011-10-04 9:51 ` [PATCH 00 of 24] xenpaging fixes for xen-unstable Ian Campbell
2011-10-04 15:05 ` Olaf Hering [this message]
2011-10-04 15:08 ` Olaf Hering
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