Hi Dan:
You are right,
the HVM guest is kernel-2.6.18-164.el5.src.rpm, coming from ftp://ftp.redhat.com/pub/redhat/linux/enterprise/5Server/en/os/SRPMS/
Currently the
balloon driver is compiled from this kernel. (So I am afraid of if the driver
may out of date, and I plan to get new balloon.c from xenlinux and put it into
this kernel to compile a new xen-balloon.ko)
My xen is
4.0.0, again pvops kernel 2.6.31
Actually, I have
two problems, first is PoD “populate-on-demand memory” issue, and
second is xen panic(I will get more test and report on another reply)
I have
googled some and apply the patch from http://lists.xensource.com/archives/html/xen-devel/2010-07/msg01404.html,
but it doesn’t work for me.
-------------------------------------------------Domain Crash
Case---------------------------------------------
The
issue is easy to reproduce, I started one HVM with command line:
xm cr
hvm.linux.balloon maxmem=2048 memory=512
the guest works
well at first, but crashed as long as I logined into it throught VNC
the serial
output is:
blktap_sysfs_create:
adding attributes for dev ffff8801224df000
(XEN) p2m_pod_demand_populate: Out of populate-on-demand memory!
tot_pages 132088 pod_entries 9489
(XEN) domain_crash called from p2m.c:1127
(XEN) Domain 4 reported crashed by domain 0 on cpu#0:
(XEN) printk: 31 messages suppressed.
(XEN) grant_table.c:555:d0 Iomem mapping not permitted
ffffffffffffffff (domain 4)
blktap_sysfs_destroy
blktap_sysfs_create: adding attributes for dev ffff88012259ca00
-------------------------------------------------Xen Crash Case---------------------------------------------
In addition, if start guest like
m cr hvm.linux.balloon maxmem=2048 memory=400
blktap_sysfs_destroy
blktap_sysfs_create: adding attributes for dev ffff8801224df000
(XEN) p2m_pod_demand_populate: Out of populate-on-demand memory!
tot_pages 132088 pod_entries 9489
(XEN) domain_crash called from p2m.c:1127
(XEN) Domain 4 reported crashed by domain 0 on cpu#0:
(XEN) printk: 31 messages suppressed.
(XEN) grant_table.c:555:d0 Iomem mapping not permitted
ffffffffffffffff (domain 4)
blktap_sysfs_destroy
blktap_sysfs_create: adding attributes for dev ffff88012259ca00
blktap_sysfs_destroy
blktap_sysfs_create: adding attributes for dev ffff88012259c600
(XEN) Error: p2m lock held by p2m_change_type
(XEN) Xen BUG at p2m-ept.c:38
(XEN) ----[ Xen-4.0.0 x86_64 debug=n Not
tainted ]----
(XEN) CPU: 6
(XEN) RIP: e008:[<ffff82c4801df2aa>]
ept_pod_check_and_populate+0x13a/0x150
(XEN) RFLAGS: 0000000000010282 CONTEXT: hypervisor
(XEN) rax: 0000000000000000 rbx:
ffff83063fdc0000 rcx: 0000000000000092
(XEN) rdx: 000000000000000a rsi: 000000000000000a
rdi: ffff82c48021e844
(XEN) rbp: ffff83023fefff28 rsp:
ffff83023feffc18 r8: 0000000000000001
(XEN) r9: 0000000000000001 r10:
0000000000000000 r11: ffff82c4801318d0
(XEN) r12: ffff8302f5914ef8 r13:
0000000000000001 r14: 0000000000000000
(XEN) r15: 0000000000003bdf cr0:
0000000080050033 cr4: 00000000000026f0
(XEN) cr3: 000000063fc2e000 cr2: 00002ba99c046000
(XEN) ds: 0000 es: 0000 fs:
0000 gs: 0000 ss: 0000 cs: e008
(XEN) Xen stack trace from rsp=ffff83023feffc18:
(XEN) 0000000000000002 0000000000000000
0000000000000000 ffff83063fdc0000
(XEN) ffff8302f5914ef8 0000000000000001
ffff83023feffc70 ffff82c4801df46e
(XEN) 0000000000000000 ffff83023feffcc4
0000000000003bdf 00000000000001df
(XEN) ffff8302f5914000 ffff83063fdc0000
ffff83023fefff28 0000000000003bdf
(XEN) 0000000000000002 0000000000000001
0000000000000030 ffff82c4801bafe4
(XEN) ffff8302f89dc000 000000043fefff28
ffff83023fefff28 0000000000003bdf
(XEN) 00000000002f9223 0000000000000030
ffff83023fefff28 ffff82c48019bab1
(XEN) 0000000000000000 00000001bdc62000
0000000000000000 0000000000000182
(XEN) ffff8300bdc62000 ffff82c4801b3824
ffff83063fdc0348 07008300bdc62000
(XEN) ffff83023fe808d0 0000000000000040
000000063fc3601e 0000000000000000
(XEN) ffff83023fefff28 ffff82c480167d17
ffff82c4802509c0 0000000000000000
(XEN) 0000000003bdf000 000000000001c000
ffff83023feffdc8 0000000000000080
(XEN) ffff82c480250dd0 0000000000003bdf
00ff82c480250080 ffff82c480250dc0
(XEN) ffff82c480250080 ffff82c480250dc0
0000000000004040 0000000000000000
(XEN) 0000000000004040 0000000000000040
ffff82c4801447da 0000000000000080
(XEN) ffff83023fefff28 0000000000000092
ffff82c4801a7f6c 00000000000000fc
(XEN) 0000000000000092 0000000000000006
ffff8300bdc63760 0000000000000006
(XEN) ffff82c48025c100 ffff82c480250100
ffff82c480250100 0000000000000292
(XEN) ffff8300bdc637f0 00000249b30f6a00
0000000000000292 ffff82c4801a9383
(XEN) 00000000000000ef ffff8300bdc62000
ffff8300bdc62000 ffff8300bdc637e8
(XEN) Xen call trace:
(XEN) [<ffff82c4801df2aa>]
ept_pod_check_and_populate+0x13a/0x150
(XEN) [<ffff82c4801df46e>]
ept_get_entry+0x1ae/0x1c0
(XEN) [<ffff82c4801bafe4>]
p2m_change_type+0x144/0x1b0
(XEN) [<ffff82c48019bab1>]
hvm_hap_nested_page_fault+0x121/0x190
(XEN) [<ffff82c4801b3824>]
vmx_vmexit_handler+0x304/0x1a90
(XEN) [<ffff82c480167d17>]
__smp_call_function_interrupt+0x57/0x90
(XEN) [<ffff82c4801447da>]
__find_next_bit+0x6a/0x70
(XEN) [<ffff82c4801a7f6c>]
vpic_get_highest_priority_irq+0x2c/0xa0
(XEN) [<ffff82c4801a9383>]
pt_update_irq+0x33/0x1e0
(XEN) [<ffff82c4801a6042>]
vlapic_has_pending_irq+0x42/0x70
(XEN) [<ffff82c4801a0c88>]
hvm_vcpu_has_pending_irq+0x88/0xa0
(XEN) [<ffff82c4801b263b>]
vmx_vmenter_helper+0x5b/0x150
(XEN) [<ffff82c4801ada63>]
vmx_asm_do_vmentry+0x0/0xdd
(XEN)
(XEN)
(XEN) ****************************************
(XEN) Panic on CPU 6:
(XEN) Xen BUG at p2m-ept.c:38
(XEN) ****************************************
(XEN)
(XEN) Manual reset required ('noreboot' specified)
---------------------------------------Works configuration--------------------------------------------------
And if starts guest like
xm cr hvm.linux.balloon maxmem=1024 memory=512
the guest can be successfully logon through VNC
Any idea on
what happens?
PoD is new to
me, I will try to know more, thanks.
From: Dan Magenheimer [mailto:dan.magenheimer@xxxxxxxxxx]
Date: 2010.11.28 10:36
sent: tinnycloud; xen devel
cc: george.dunlap@xxxxxxxxxxxxx
subject: RE: Xen balloon driver discuss
Am I understanding correctly that you are running each
linux-2.6.18 as HVM (not PV)? I didn’t think that the linux-2.6.18
balloon driver worked at all in an HVM guest.
You also didn’t say what version of Xen you are
using. If you are running xen-unstable, you should also provide the
changeset number.
In any case, any load of HVM guests should never crash Xen
itself, but if you are running HVM guests, I probably can’t help much as
I almost never run HVM guests.
From: cloudroot [mailto:cloudroot@xxxxxxxx]
Sent: Friday, November 26, 2010 11:55 PM
To: tinnycloud; Dan Magenheimer; xen devel
Cc: george.dunlap@xxxxxxxxxxxxx
Subject: re: Xen balloon driver discuss
Hi Dan:
I have set the
benchmark to test balloon driver, but unfortunately the Xen crashed on memory
Panic.
Before I attach
the details output from serial port(which takes time on next run), I am afraid
of I might miss something on test environment.
My dom0 kernel
is 2.6.31, pvops.
Well
currently there is no driver/xen/balloon.c on this kernel source tree, so
I build the xen-balloon.ko, Xen-platform-pci.ko form
linux-2.6.18.x86_64,
and installed in Dom U, which is redhat 5.4.
What I did is
put a C program in the each Dom U(total 24 HVM), the program will allocate the
memory and fill it with random string repeatly.
And in dom0, a
phthon monitor will collect the meminfo from xenstore and calculate the target
to balloon from Committed_AS.
The
panic happens when the program is running in just one Dom.
I am writing to
ask whether my balloon driver is out of date, or where can I get the latest
source code,
I’ve
googled a lot, but still have a lot of confusion on those source tree.
Many thanks.
From: tinnycloud [mailto:tinnycloud@xxxxxxxxxxx]
Date: 2010.11.23 22:58
TO: 'Dan Magenheimer'; 'xen devel'
CC: 'george.dunlap@xxxxxxxxxxxxx'
Subject: re: Xen balloon driver discuss
HI Dan:
Appreciate for your
presentation in summarizing the memory overcommit, really vivid and in great
help.
Well, I guess
recently days the strategy in my mind will fall into the solution Set C in pdf.
The tmem
solution your worked out for memory overcommit is both efficient and effective.
I guess I will
have a try on Linux Guest.
The real
situation I have is most of the running VMs on host are windows. So I had to
come up those policies to balance the memory.
Although
policies are all workload dependent. Good news is host workload is
configurable, and not very heavy
So I
will try to figure out some favorable policy. The policies referred in pdf are
good start for me.
Today, instead
of trying to implement “/proc/meminfo” with shared pages, I hacked
the balloon driver to have another
workqueue
periodically write meminfo into xenstore through xenbus, which solve the
problem of xenstrore high CPU
utilization
problem.
Later I will
try to google more on how Citrix does.
Thanks for your
help, or do you have any better idea for windows guest?
Sent: Dan Magenheimer
[mailto:dan.magenheimer@xxxxxxxxxx]
Date: 2010.11.23 1:47
To: MaoXiaoyun; xen devel
CC: george.dunlap@xxxxxxxxxxxxx
Subject: RE: Xen balloon driver discuss
Xenstore IS slow and you could improve xenballoond performance
by only sending the single CommittedAS value from xenballoond in domU to dom0
instead of all of /proc/meminfo. But you are making an assumption
that getting memory utilization information from domU to dom0 FASTER (e.g. with
a shared page) will provide better ballooning results. I have not found
this to be the case, which is what led to my investigation into
self-ballooning, which led to Transcendent Memory. See the 2010 Xen
Summit for more information.
In your last paragraph below “Regards balloon
strategy”, the problem is it is not easy to define “enough
memory” and “shortage of memory” within any guest and almost
impossible to define it and effectively load balance across many guests.
See my Linux Plumber’s Conference presentation (with complete speaker
notes) here:
http://oss.oracle.com/projects/tmem/dist/documentation/presentations/MemMgmtVirtEnv-LPC2010-Final.pdf
http://oss.oracle.com/projects/tmem/dist/documentation/presentations/MemMgmtVirtEnv-LPC2010-SpkNotes.pdf
From: MaoXiaoyun [mailto:tinnycloud@xxxxxxxxxxx]
Sent: Sunday, November 21, 2010 9:33 PM
To: xen devel
Cc: Dan Magenheimer; george.dunlap@xxxxxxxxxxxxx
Subject: RE: Xen balloon driver discuss
Since currently /cpu/meminfo is sent to domain 0 via xenstore,
which in
my opinoin is slow.
What I want
to do is: there is a shared page between domU and dom0,
and domU periodically
update the meminfo into the page, while on the other side dom0 retrive the
updated data for
caculating the
target, which is used by guest for balloning.
The problem I met is, currently
I don't know how to implement a shared page between
dom0 and domU.
Would it like dom 0 alloc a unbound event and wait guest to connect,
and transfer date through
grant table?
Or someone has more efficient
way?
many thanks.
> From: tinnycloud@xxxxxxxxxxx
> To: xen-devel@xxxxxxxxxxxxxxxxxxx
> CC: dan.magenheimer@xxxxxxxxxx; George.Dunlap@xxxxxxxxxxxxx
> Subject: Xen balloon driver discuss
> Date: Sun, 21 Nov 2010 14:26:01 +0800
>
> Hi:
> Greeting first.
>
> I was trying to run about 24 HVMS (currently only Linux, later will
> involve Windows) on one physical server with 24GB memory, 16CPUs.
> Each VM is configured with 2GB memory, and I reserved 8GB memory for
> dom0.
> For safety reason, only domain U's memory is allowed to balloon.
>
> Inside domain U, I used xenballooned provide by xensource,
> periodically write /proc/meminfo into xenstore in dom
> 0(/local/domain/did/memory/meminfo).
> And in domain 0, I wrote a python script to read the meminfo, like
> xen provided strategy, use Committed_AS to calculate the domain U balloon
> target.
> The time interval is ! 1 seconds.
>
> Inside each VM, I setup a apache server for test. Well, I'd
> like to say the result is not so good.
> It appears that too much read/write on xenstore, when I give some of
> the stress(by using ab) to guest domains,
> the CPU usage of xenstore is up to 100%. Thus the monitor running in
> dom0 also response quite slowly.
> Also, in ab test, the Committed_AS grows very fast, reach to maxmem
> in short time, but in fact the only a small amount
> of memory guest really need, so I guess there should be some more to
> be taken into consideration for ballooning.
>
> For xenstore issue, I first plan to wrote a C program inside domain
> U to replace xenballoond to see whether the situation
> will be refined. If not, how about set up event channel directly for
> domU and dom0, would it be faster?
>
> Regards balloon strategy, I would do like this, when there ! are
> enough memory , just fulfill the guest balloon request, and when shortage
> of memory, distribute memory evenly on the guests those request
> inflation.
>
> Does anyone have better suggestion, thanks in advance.
>
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