linux-toradex.git/drivers/virtio/virtio_balloon.c, branch v3.2.51

virtio: Add module.h to drivers/virtio users.

2011-10-31T23:32:14+00:00

Up to now, the module.h header was as hard to keep out as
sunlight.  But we are cleaning that up.  Fix the virtio users
who simply expect module.h to be there in every C file.

Signed-off-by: Paul Gortmaker

virtio balloon: kill tell-host-first logic

2011-05-30T01:44:13+00:00

The virtio balloon driver has a VIRTIO_BALLOON_F_MUST_TELL_HOST
feature bit.  Whenever the bit is set, the guest kernel must
always tell the host before we free pages back to the allocator.
Without this feature, we might free a page (and have another
user touch it) while the hypervisor is unprepared for it.

But, if the bit is _not_ set, we are under no obligation to
reverse the order; we're under no obligation to do _anything_.
As of now, qemu-kvm defines the bit, but doesn't set it.

This patch makes the "tell host first" logic the only case.  This
should make everybody happy, and reduce the amount of untested or
untestable code in the kernel.

This _also_ means that we don't have to preserve a pfn list
after the pages are freed, which should let us get rid of some
temporary storage (vb->pfns) eventually.

Signed-off-by: Dave Hansen 
Signed-off-by: Rusty Russell

virtio_balloon: use virtqueue_xxx wrappers

2010-05-19T12:45:41+00:00

Switch virtio_balloon to new virtqueue_xxx wrappers.

Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Rusty Russell

virtio: Fix GFP flags passed from the virtio balloon driver

2010-04-22T14:34:05+00:00

The virtio balloon driver can dig into the reservation pools of the OS
to satisfy a balloon request.  This is not advisable and other balloon
drivers (drivers/xen/balloon.c) avoid this as well.

The patch also adds changes to avoid printing a warning if allocation
fails, since we retry after sometime anyway.

Signed-off-by: Balbir Singh 
Signed-off-by: Rusty Russell 
Cc: kvm 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32+00:00

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

virtio: fix balloon without VIRTIO_BALLOON_F_STATS_VQ

2010-02-24T03:52:17+00:00

When running under qemu-kvm-0.11.0:

	BUG: unable to handle kernel paging request at 56e58955
	...
	Process vballoon (pid: 1297, ti=c7976000 task=c70a6ca0 task.ti=c7
	...
	Call Trace:
	 [] ? balloon+0x1b3/0x440 [virtio_balloon]
	 [] ? schedule+0x327/0x9d0
	 [] ? balloon+0x0/0x440 [virtio_balloon]
	 [] ? kthread+0x74/0x80
	 [] ? kthread+0x0/0x80
	 [] ? kernel_thread_helper+0x6/0x30

need_stats_update should be zero-initialized.

Signed-off-by: Rusty Russell 
Acked-by: Adam Litke

virtio: Fix scheduling while atomic in virtio_balloon stats

2010-02-24T03:52:14+00:00

This is a fix for my earlier patch: "virtio: Add memory statistics reporting to
the balloon driver (V4)".

I discovered that all_vm_events() can sleep and therefore stats collection
cannot be done in interrupt context.  One solution is to handle the interrupt
by noting that stats need to be collected and waking the existing vballoon
kthread which will complete the work via stats_handle_request().  Rusty, is
this a saner way of doing business?

There is one issue that I would like a broader opinion on.  In stats_request, I
update vb->need_stats_update and then wake up the kthread.  The kthread uses
vb->need_stats_update as a condition variable.  Do I need a memory barrier
between the update and wake_up to ensure that my kthread sees the correct
value?  My testing suggests that it is not needed but I would like some
confirmation from the experts.

Signed-off-by: Adam Litke 
To: Rusty Russell 
Cc: Anthony Liguori 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Rusty Russell

virtio: Add memory statistics reporting to the balloon driver (V4)

2010-02-24T03:52:08+00:00

Changes since V3:
 - Do not do endian conversions as they will be done in the host
 - Report stats that reference a quantity of memory in bytes
 - Minor coding style updates

Changes since V2:
 - Increase stat field size to 64 bits
 - Report all sizes in kb (not pages)
 - Drop anon_pages stat and fix endianness conversion

Changes since V1:
 - Use a virtqueue instead of the device config space

When using ballooning to manage overcommitted memory on a host, a system for
guests to communicate their memory usage to the host can provide information
that will minimize the impact of ballooning on the guests.  The current method
employs a daemon running in each guest that communicates memory statistics to a
host daemon at a specified time interval.  The host daemon aggregates this
information and inflates and/or deflates balloons according to the level of
host memory pressure.  This approach is effective but overly complex since a
daemon must be installed inside each guest and coordinated to communicate with
the host.  A simpler approach is to collect memory statistics in the virtio
balloon driver and communicate them directly to the hypervisor.

This patch enables the guest-side support by adding stats collection and
reporting to the virtio balloon driver.

Signed-off-by: Adam Litke 
Cc: Anthony Liguori 
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Rusty Russell  (minor fixes)

virtio: fix section mismatch warnings

2010-01-16T20:15:39+00:00

Fix fixes the following warnings by renaming the driver structures to be
suffixed with _driver.

WARNING: drivers/virtio/virtio_balloon.o(.data+0x88): Section mismatch in reference from the variable virtio_balloon to the function .devexit.text:virtballoon_remove()

WARNING: drivers/char/hw_random/virtio-rng.o(.data+0x88): Section mismatch in reference from the variable virtio_rng to the function .devexit.text:virtrng_remove()

Signed-off-by: Jeff Mahoney 
Acked-by: Rusty Russell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

move virtballoon_remove to .devexit.text

2009-10-22T06:09:31+00:00

The function virtballoon_remove is used only wrapped by __devexit_p so
define it using __devexit.

Signed-off-by: Uwe Kleine-König 
Acked-by: Sam Ravnborg 
Acked-by: Michael S. Tsirkin 
Signed-off-by: Rusty Russell