Attached is the memhog source code.
In test, I run two memhogs at same time with options " -t 2 -M 512 -R 30 -s 2 -K 100"
which means, 2threads, total alloc 512M memory, run 30times, sleep every 2 seconds between
rounds, and every malloc, malloc 100KB.
Also, in currently test, after VM starts with 512M memory, no memory is given back to VM.
Actually, we have three physical host to test the blue screen, quite strange is only on machine
hit the blue screen quite easily(your driver with/without low memory event hit the screen).
But on other two machine, everything goes fine. Even I recompile the host system, different result
still exists.
I also noticed the your post on ntdev, is it possible "ExAllocatePoolWithTag" failed, but in code
the return NULL is not fully checked?
More, what kind of logs your need, and does "check code" means
something like "
***STOP: 0x0000004D (0x00015742,0x00015742,0x00000000,0x00000000)
***STOP: 0x0000004D (0x0001583B,0x0001583B,0x00000000,0x00000000)
this the latest two crashes.
> Subject: Re: blue screen in windows balloon driver
> From: james.harper@xxxxxxxxxxxxxxxx
> Date: Tue, 1 Mar 2011 16:01:46 +1100
> To: tinnycloud@xxxxxxxxxxx
> CC: xen-devel@xxxxxxxxxxxxxxxxxxx
>
> Please send logs and bug check codes for any future crashes
>
> Can you also send me your memhog program?
>
> Sent from my iPhone
>
> On 01/03/2011, at 13:37, "MaoXiaoyun" <tinnycloud@xxxxxxxxxxx> wrote:
>
> > Thanks James.
> >
> > Well, what if the memory is balloon dow already?
> > In my test, the eat memory process(named memhog) is started after the server starts,
> > (that is all VMs have already ballooned down to 512M)
> > It looks like the "balloon down threads " is not working at that time.
> >
> > One more question is, if memhog eat process at very fast speed, will it consume the
> > NopagePool memor
y? (I am not whether NopagePool and Page Pool is seperate pool).
> > If so, if the memory is exhausted, some other places like"ExAllocatePoolWithTag(NonPagedPool,...)",
> > will gets no memory, and could it cause bluescreen?
> >
> > I will have the latest driver tested, thanks.
> >
> >
> > > Subject: RE: blue screen in windows balloon driver
> > > Date: Tue, 1 Mar 2011 10:45:52 +1100
> > > From: james.harper@xxxxxxxxxxxxxxxx
> > > To: tinnycloud@xxxxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxx
> > >
> > > I have just pushed a change to check the
> > > "\KernelObjects\LowMemoryCondition" event before allocating memory for
> > > ballooning, and waiting if the event is set. This may resolve the
> > > problems you are seeing.
> > >
> > > What I have seen is that initially the event gets set, but t
hen as
> > > Windows pages some active memory out the event gets cleared again and
> > > further ballooning down is possible. It may prevent you ballooning down
> > > quite as low as you could before, but if it stops windows crashing then
> > > I think it is good.
> > >
> > > James
> > >
> > > > -----Original Message-----
> > > > From: MaoXiaoyun [mailto:tinnycloud@xxxxxxxxxxx]
> > > > Sent: Monday, 28 February 2011 19:30
> > > > To: xen devel
> > > > Cc: James Harper
> > > > Subject: RE: blue screen in windows balloon driver
> > > >
> > > > Hi James:
> > > >
> > > > Unfortunately, We still hit the blue screen on the stress test.
> > > > (Start total 24 HVMS on a single 16core, 24G host,
> > > > each HVM owns 2G
Memory, start with memory=512M,
> > > > and inside two eating memory processes, each of which will each
> > > 1G
> > > > memory)
> > > >
> > > > As I go though the code, I noticed that all memory allocation
> > > relates to
> > > > "ExAllocatePoolWithTag(NonPagedPool,...)", which is from
> > > NonePaged Pool,
> > > > As I know, the NonePagePool memory is the memory could not be
> > > paged out,
> > > > and that is limited, and for the blue screen VMS, I also found
> > > the free
> > > > memory
> > > > is quite low, only about hundreds KB left.
> > > >
> > > > So, when memory overcommit, some of the VM will not got enough
> > > memory,
> > > > and if most of its Memory is occupied by eating memory process, then
> > >
; > ExAllocatePoolWithTag
> > > > will fail, thus caused "NO_PAGES_AVALIABLE" blue screen. Is this
> > > possible?
> > > >
> > > > Meanwhile, I will have your PVdriver tested to see if blue
> > > exists,
> > > > thanks.
> > > >
> > > >
> > > > >From: tinnycloud@xxxxxxxxxxx
> > > > >To: tinnycloud@xxxxxxxxxxx
> > > > >Subject: FW: blue screen in windows balloon driver
> > > > >Date: Mon, 28 Feb 2011 16:16:59 +0800
> > > > >
> > > > >
> > > > >Thanks for fixing the POD. It's is better make it earlier to avoid
> > > crash.
> > > > >
> > > > >The meminfo is written every 1 seconds into xenstore dir
> > > > /local/domain/did/memory/meminfo.
> > > > >And to avo
id to many writes, only the memory changes large than 5M,
> > > the
> > > > thread will do the write.
> > > > >
> > > > >As for userspace daemon, it is our first choice, but we found it
> > > xenstore
> > > > daemon in dom0 comsume
> > > > >many CPU(we test in linux only), so we decide to move it into driver.
> > > > >
> > > > >I've done merge my code with latest changeset 866, and do the stree
> > > test
> > > > later.
> > > > >
> > > > >many thanks.
> > > > >
> > > > >> Subject: RE: RE: blue screen in windows balloon driver
> > > > >> Date: Sun, 27 Feb 2011 22:25:28 +1100
> > > > >> From: james.harper@xxxxxxxxxxxxxxxx
> > > > >> To: tinnycloud@xxxxxxxxxxx; xen-devel@list
s.xensource.com
> > > > >> CC: george.dunlap@xxxxxxxxxxxxx
> > > > >>
> > > > >> > Thanks James.
> > > > >> >
> > > > >> > I think it is GPLPV. The driver is from
> > > > >> http://xenbits.xen.org/ext/win-
> > > > >> > pvdrivers.hg
> > > > >> > But, I have done some other things
> > > > >> >
> > > > >> > 1) Add pod support
> > > > >> > 2) enable a meminfo thread, periodically write VM meminfo into
> > > > >> xenstore
> > > > >> > We use info of Current Memory, Free memory, and Committed memory,
> > > > >> retrived
> > > > >> > through NativeAPI
> > > > >> > 3) our code is based from changeset 823, attached is the
diff of
> > > my
> > > > >> current
> > > > >> > code with changset of 853.
> > > > >> >
> > > > >> > Maybe I need add my code to 853, and test again.
> > > > >> > Thanks.
> > > > >> >
> > > > >>
> > > > >> As per other post, I have just committed some patches and PoD
> > > should now
> > > > >> be working properly. I can start a DomU with 4GB of maxmem but only
> > > > >> 128MB of populated memory without any problems. This now works
> > > because I
> > > > >> do the initial balloon down in DriverEntry, way before xenpci does
> > > > >> anything else. Before it would blow up in DriverEntry. I think I
> > > > >> determine the amount to initially balloon down
a little differently
> > > from
> > > > >> you too.
> > > > >>
> > > > >> It takes a while to balloon down the memory though... I think
> > > Windows
> > > > >> tends to delay large allocations or something, because ballooning
> > > up
> > > > >> again is pretty much instant.
> > > > >>
> > > > >> How often are you writing meminfo stuff into xenstore? Could you do
> > > that
> > > > >> in userspace (the interface to xenstore exists and seems to work
> > > well
> > > > >> although it's a little tedious)? You would then be able to just run
> > > it
> > > > >> as a service and not need to patch GPLPV.
> > > > >>
> > > > >> James
> > > > >
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