Commit Graph

66 Commits

Author SHA1 Message Date
Denis V. Lunev 997e120843 virtio_balloon: do not change memory amount visible via /proc/meminfo
Balloon device is frequently used as a mean of cooperative memory control
in between guest and host to manage memory overcommitment. This is the
typical case for any hosting workload when KVM guest is provided for
end-user.

Though there is a problem in this setup. The end-user and hosting provider
have signed SLA agreement in which some amount of memory is guaranted for
the guest. The good thing is that this memory will be given to the guest
when the guest will really need it (f.e. with OOM in guest and with
VIRTIO_BALLOON_F_DEFLATE_ON_OOM configuration flag set). The bad thing
is that end-user does not know this.

Balloon by default reduce the amount of memory exposed to the end-user
each time when the page is stolen from guest or returned back by using
adjust_managed_page_count and thus /proc/meminfo shows reduced amount
of memory.

Fortunately the solution is simple, we should just avoid to call
adjust_managed_page_count with VIRTIO_BALLOON_F_DEFLATE_ON_OOM set.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-09-08 13:32:11 +03:00
Denis V. Lunev b4d3403732 virtio_ballon: change stub of release_pages_by_pfn
and rename it to release_pages_balloon. The function originally takes
arrays of pfns and now it takes pointer to struct virtio_ballon.
This change is necessary to conditionally call adjust_managed_page_count
in the next patch.

Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-09-08 13:31:51 +03:00
Michael S. Tsirkin df81b29c7b virtio_balloon: transitional interface
Virtio 1.0 doesn't include a modern balloon device.
But it's not a big change to support a transitional
balloon device: this has the advantage of supporting
existing drivers, transparently.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-04-15 12:41:09 +09:30
Michael S. Tsirkin 3d2a3774c1 virtio-balloon: do not call blocking ops when !TASK_RUNNING
virtio balloon has this code:
        wait_event_interruptible(vb->config_change,
                                 (diff = towards_target(vb)) != 0
                                 || vb->need_stats_update
                                 || kthread_should_stop()
                                 || freezing(current));

Which is a problem because towards_target() call might block after
wait_event_interruptible sets task state to TAST_INTERRUPTIBLE, causing
the task_struct::state collision typical of nesting of sleeping
primitives

See also http://lwn.net/Articles/628628/ or Thomas's
bug report
http://article.gmane.org/gmane.linux.kernel.virtualization/24846
for a fuller explanation.

To fix, rewrite using wait_woken.

Cc: stable@vger.kernel.org
Reported-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-03-10 11:56:15 +10:30
Michael S. Tsirkin 88660f7fb9 virtio_balloon: set DRIVER_OK before using device
virtio spec requires that all drivers set DRIVER_OK
before using devices. While balloon isn't yet
included in the virtio 1 spec, previous spec versions
also required this.

virtio balloon might violate this rule: probe calls
kthread_run before setting DRIVER_OK, which might run
immediately and cause balloon to inflate/deflate.

To fix, call virtio_device_ready before running the kthread.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
2015-03-10 11:48:28 +10:30
Michael S. Tsirkin 25e65e4efc virtio_balloon: coding style fixes
Most of our code has
struct foo {
}

Fix two instances where balloon is inconsistent.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-01-21 16:28:56 +10:30
Michael S. Tsirkin 2d9becc1e0 virtio/balloon: verify device has config space
Some devices might not implement config space access
(e.g. remoteproc used not to - before 3.9).
virtio/balloon needs config space access so make it
fail gracefully if not there.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-01-21 16:28:48 +10:30
Raushaniya Maksudova 5a10b7dbf9 virtio_balloon: free some memory from balloon on OOM
Excessive virtio_balloon inflation can cause invocation of OOM-killer,
when Linux is under severe memory pressure. Various mechanisms are
responsible for correct virtio_balloon memory management. Nevertheless
it is often the case that these control tools does not have enough time
to react on fast changing memory load. As a result OS runs out of memory
and invokes OOM-killer. The balancing of memory by use of the virtio
balloon should not cause the termination of processes while there are
pages in the balloon. Now there is no way for virtio balloon driver to
free some memory at the last moment before some process will be get
killed by OOM-killer.

This does not provide a security breach as balloon itself is running
inside guest OS and is working in the cooperation with the host. Thus
some improvements from guest side should be considered as normal.

To solve the problem, introduce a virtio_balloon callback which is
expected to be called from the oom notifier call chain in out_of_memory()
function. If virtio balloon could release some memory, it will make
the system to return and retry the allocation that forced the out of
memory killer to run.

Allocate virtio  feature bit for this: it is not set by default,
the the guest will not deflate virtio balloon on OOM without explicit
permission from host.

Signed-off-by: Raushaniya Maksudova <rmaksudova@parallels.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-11-11 17:09:58 +10:30
Raushaniya Maksudova 1fd9c67203 virtio_balloon: return the amount of freed memory from leak_balloon()
This value would be useful in the next patch to provide the amount of
the freed memory for OOM killer.

Signed-off-by: Raushaniya Maksudova <rmaksudova@parallels.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-11-11 17:09:57 +10:30
Linus Torvalds 0e6e58f941 One cc: stable commit, the rest are a series of minor cleanups which have
been sitting in MST's tree during my vacation.  I changed a function name
 and made one trivial change, then they spent two days in linux-next.
 
 Thanks,
 Rusty.
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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull virtio updates from Rusty Russell:
 "One cc: stable commit, the rest are a series of minor cleanups which
  have been sitting in MST's tree during my vacation.  I changed a
  function name and made one trivial change, then they spent two days in
  linux-next"

* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (25 commits)
  virtio-rng: refactor probe error handling
  virtio_scsi: drop scan callback
  virtio_balloon: enable VQs early on restore
  virtio_scsi: fix race on device removal
  virito_scsi: use freezable WQ for events
  virtio_net: enable VQs early on restore
  virtio_console: enable VQs early on restore
  virtio_scsi: enable VQs early on restore
  virtio_blk: enable VQs early on restore
  virtio_scsi: move kick event out from virtscsi_init
  virtio_net: fix use after free on allocation failure
  9p/trans_virtio: enable VQs early
  virtio_console: enable VQs early
  virtio_blk: enable VQs early
  virtio_net: enable VQs early
  virtio: add API to enable VQs early
  virtio_net: minor cleanup
  virtio-net: drop config_mutex
  virtio_net: drop config_enable
  virtio-blk: drop config_mutex
  ...
2014-10-18 10:25:09 -07:00
Michael S. Tsirkin 486d2e632c virtio_balloon: enable VQs early on restore
virtio spec requires drivers to set DRIVER_OK before using VQs.
This is set automatically after resume returns, virtio balloon
violated this rule by adding bufs, which causes the VQ to be used
directly within restore.

To fix, call virtio_device_ready before using VQ.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-10-15 10:25:13 +10:30
Konstantin Khlebnikov 09316c09dd mm/balloon_compaction: add vmstat counters and kpageflags bit
Always mark pages with PageBalloon even if balloon compaction is disabled
and expose this mark in /proc/kpageflags as KPF_BALLOON.

Also this patch adds three counters into /proc/vmstat: "balloon_inflate",
"balloon_deflate" and "balloon_migrate".  They accumulate balloon
activity.  Current size of balloon is (balloon_inflate - balloon_deflate)
pages.

All generic balloon code now gathered under option CONFIG_MEMORY_BALLOON.
It should be selected by ballooning driver which wants use this feature.
Currently virtio-balloon is the only user.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:01 -04:00
Konstantin Khlebnikov 9d1ba80564 mm/balloon_compaction: remove balloon mapping and flag AS_BALLOON_MAP
Now ballooned pages are detected using PageBalloon().  Fake mapping is no
longer required.  This patch links ballooned pages to balloon device using
field page->private instead of page->mapping.  Also this patch embeds
balloon_dev_info directly into struct virtio_balloon.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:01 -04:00
Konstantin Khlebnikov d6d86c0a7f mm/balloon_compaction: redesign ballooned pages management
Sasha Levin reported KASAN splash inside isolate_migratepages_range().
Problem is in the function __is_movable_balloon_page() which tests
AS_BALLOON_MAP in page->mapping->flags.  This function has no protection
against anonymous pages.  As result it tried to check address space flags
inside struct anon_vma.

Further investigation shows more problems in current implementation:

* Special branch in __unmap_and_move() never works:
  balloon_page_movable() checks page flags and page_count.  In
  __unmap_and_move() page is locked, reference counter is elevated, thus
  balloon_page_movable() always fails.  As a result execution goes to the
  normal migration path.  virtballoon_migratepage() returns
  MIGRATEPAGE_BALLOON_SUCCESS instead of MIGRATEPAGE_SUCCESS,
  move_to_new_page() thinks this is an error code and assigns
  newpage->mapping to NULL.  Newly migrated page lose connectivity with
  balloon an all ability for further migration.

* lru_lock erroneously required in isolate_migratepages_range() for
  isolation ballooned page.  This function releases lru_lock periodically,
  this makes migration mostly impossible for some pages.

* balloon_page_dequeue have a tight race with balloon_page_isolate:
  balloon_page_isolate could be executed in parallel with dequeue between
  picking page from list and locking page_lock.  Race is rare because they
  use trylock_page() for locking.

This patch fixes all of them.

Instead of fake mapping with special flag this patch uses special state of
page->_mapcount: PAGE_BALLOON_MAPCOUNT_VALUE = -256.  Buddy allocator uses
PAGE_BUDDY_MAPCOUNT_VALUE = -128 for similar purpose.  Storing mark
directly in struct page makes everything safer and easier.

PagePrivate is used to mark pages present in page list (i.e.  not
isolated, like PageLRU for normal pages).  It replaces special rules for
reference counter and makes balloon migration similar to migration of
normal pages.  This flag is protected by page_lock together with link to
the balloon device.

Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Link: http://lkml.kernel.org/p/53E6CEAA.9020105@oracle.com
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: <stable@vger.kernel.org>	[3.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:26:01 -04:00
Rusty Russell 4951cc9083 virtio_balloon: don't crash if virtqueue is broken.
A bad implementation of virtio might cause us to mark the virtqueue
broken: we'll dev_err() in that case, and the device is useless, but
let's not BUG().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-03-13 11:27:56 +10:30
Rusty Russell 1f74ef0f2d virtio_balloon: don't softlockup on huge balloon changes.
When adding or removing 100G from a balloon:

    BUG: soft lockup - CPU#0 stuck for 22s! [vballoon:367]

We have a wait_event_interruptible(), but the condition is always true
(more ballooning to do) so we don't ever sleep.  We also have a
wait_event() for the host to ack, but that is also always true as QEMU
is synchronous for balloon operations.

Reported-by: Gopesh Kumar Chaudhary <gopchaud@in.ibm.com>
Cc: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-03-13 11:27:55 +10:30
Linus Torvalds 93b05cba8e A few simple fixes. Quiet cycle.
Cheers,
 Rusty.
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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull virtio update from Rusty Russell:
 "A few simple fixes.  Quiet cycle"

* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  drivers: virtio: Mark function virtballoon_migratepage() as static in virtio_balloon.c
  virtio-scsi: Fix hotcpu_notifier use-after-free with virtscsi_freeze
  virtio: pci: remove unnecessary pci_set_drvdata()
2014-01-22 22:24:35 -08:00
Rashika Kheria 05c54de8c8 drivers: virtio: Mark function virtballoon_migratepage() as static in virtio_balloon.c
Mark the function virtballoon_migratepage() as static in
virtio_balloon.c because it is not used outside this file.

This eliminates the following warning in virtio_balloon.c:
drivers/virtio/virtio_balloon.c:372:5: warning: no previous prototype for ‘virtballoon_migratepage’ [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-01-16 10:22:28 +10:30
Luiz Capitulino 3459f11a8b virtio_balloon: update_balloon_size(): update correct field
According to the virtio spec, the device configuration field
that should be updated after an inflation or deflation
operation is the 'actual' field, not the 'num_pages' one.

Commit 855e0c5288 swapped them
in update_balloon_size(). Fix it.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Fixes: 855e0c5288
2013-12-05 13:12:39 +10:30
Rusty Russell 855e0c5288 virtio: use size-based config accessors.
This lets the transport do endian conversion if necessary, and insulates
the drivers from the difference.

Most drivers can use the simple helpers virtio_cread() and virtio_cwrite().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-10-17 10:55:37 +10:30
Aaron Lu 8910700039 virtio: pm: use CONFIG_PM_SLEEP instead of CONFIG_PM
The freeze and restore functions defined in virtio drivers are used
for suspend and hibernate, so CONFIG_PM_SLEEP is more appropriate than
CONFIG_PM. This patch replace all CONFIG_PM with CONFIG_PM_SLEEP for
virtio drivers that implement freeze and restore callbacks.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-09-23 15:45:58 +09:30
Linus Torvalds 5f12972171 No real surprises.
Thanks,
 Rusty.
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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull virtio updates from Rusty Russell:
 "No real surprises"

* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  MAINTAINERS: add tools/virtio/ under virtio
  tools/virtio: move module license stub to module.h
  virtio: include asm/barrier explicitly
  virtio: VIRTIO_F_ANY_LAYOUT feature
  lguest: fix example launcher compilation for broken glibc headers.
  virtio-net: fix the race between channels setting and refill
  tools/lguest: real barriers.
  tools/lguest: fix missing rmb().
  virtio_balloon: leak_balloon(): only tell host if we got pages deflated
  virtio-pci: fix leaks of msix_affinity_masks
  Fix comment typo "CONFIG_PAE"
2013-07-10 14:50:58 -07:00
Jiang Liu 3dcc0571cd mm: correctly update zone->managed_pages
Enhance adjust_managed_page_count() to adjust totalhigh_pages for
highmem pages.  And change code which directly adjusts totalram_pages to
use adjust_managed_page_count() because it adjusts totalram_pages,
totalhigh_pages and zone->managed_pages altogether in a safe way.

Remove inc_totalhigh_pages() and dec_totalhigh_pages() from xen/balloon
driver bacause adjust_managed_page_count() has already adjusted
totalhigh_pages.

This patch also fixes two bugs:

1) enhances virtio_balloon driver to adjust totalhigh_pages when
   reserve/unreserve pages.
2) enhance memory_hotplug.c to adjust totalhigh_pages when hot-removing
   memory.

We still need to deal with modifications of totalram_pages in file
arch/powerpc/platforms/pseries/cmm.c, but need help from PPC experts.

[akpm@linux-foundation.org: remove ifdef, per Wanpeng Li, virtio_balloon.c cleanup, per Sergei]
[akpm@linux-foundation.org: export adjust_managed_page_count() to modules, for drivers/virtio/virtio_balloon.c]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <sworddragon2@aol.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:07:33 -07:00
Luiz Capitulino 8c6bab4f38 virtio_balloon: leak_balloon(): only tell host if we got pages deflated
balloon_page_dequeue() can return NULL.  If it does for the first page
being freed then leak_balloon() will create a scatter list with len=0.
Which in turn seems to generate an invalid virtio request.

I didn't get this in practice, I found it by code review.  On the other
hand, such an invalid virtio request will cause errors in QEMU and
fill_balloon() also performs the same check implemented by this commit.

This bug was introduced in e2250429.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org # 3.9
2013-07-02 15:42:03 +09:30
Rusty Russell 92549abc6a virtio_balloon: use simplified virtqueue accessors.
We never add buffers with input and output parts, so use the new accessors.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-03-20 15:45:06 +10:30
Rusty Russell b2a17029c2 virtio: use module_virtio_driver.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-02-13 17:00:37 +10:30
Greg Kroah-Hartman 8590dbc79a Drivers: virtio: remove __dev* attributes.
CONFIG_HOTPLUG is going away as an option.  As a result, the __dev*
markings need to be removed.

This change removes the use of __devinit, __devexit_p, and __devexit
from these drivers.

Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.

Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-03 15:57:01 -08:00
Linus Torvalds b7dfde956d Some nice cleanups, and even a patch my wife did as a "live" demo for
Latinoware 2012.
 
 There's a slightly non-trivial merge in virtio-net, as we cleaned up the
 virtio add_buf interface while DaveM accepted the mq virtio-net patches.
 
 You can see my solution in my pending-rebases branch, if that helps, but I
 know you love merging:
 
 https://git.kernel.org/?p=linux/kernel/git/rusty/linux.git;a=commit;h=12e4e64fa66a4c812e4855de32abdb4d819526fe
 
 Cheers,
 Rusty.
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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull virtio update from Rusty Russell:
 "Some nice cleanups, and even a patch my wife did as a "live" demo for
  Latinoware 2012.

  There's a slightly non-trivial merge in virtio-net, as we cleaned up
  the virtio add_buf interface while DaveM accepted the mq virtio-net
  patches."

* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (27 commits)
  virtio_console: Add support for remoteproc serial
  virtio_console: Merge struct buffer_token into struct port_buffer
  virtio: add drv_to_virtio to make code clearly
  virtio: use dev_to_virtio wrapper in virtio
  virtio-mmio: Fix irq parsing in command line parameter
  virtio_console: Free buffers from out-queue upon close
  virtio: Convert dev_printk(KERN_<LEVEL> to dev_<level>(
  virtio_console: Use kmalloc instead of kzalloc
  virtio_console: Free buffer if splice fails
  virtio: tools: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: scsi: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: rpmsg: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: net: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: console: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: make virtqueue_add_buf() returning 0 on success, not capacity.
  virtio: console: don't rely on virtqueue_add_buf() returning capacity.
  virtio_net: don't rely on virtqueue_add_buf() returning capacity.
  virtio-net: remove unused skb_vnet_hdr->num_sg field
  virtio-net: correct capacity math on ring full
  virtio: move queue_index and num_free fields into core struct virtqueue.
  ...
2012-12-20 08:37:05 -08:00
Joe Perches 800ba5eabf virtio: Convert dev_printk(KERN_<LEVEL> to dev_<level>(
dev_<level> calls take less code than dev_printk(KERN_<LEVEL>
and reducing object size is good.
Convert if (printk_ratelimit()) dev_printk to dev_<level>_ratelimited.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-12-18 15:20:40 +10:30
Rafael Aquini e22504296d virtio_balloon: introduce migration primitives to balloon pages
Memory fragmentation introduced by ballooning might reduce significantly
the number of 2MB contiguous memory blocks that can be used within a guest,
thus imposing performance penalties associated with the reduced number of
transparent huge pages that could be used by the guest workload.

Besides making balloon pages movable at allocation time and introducing
the necessary primitives to perform balloon page migration/compaction,
this patch also introduces the following locking scheme, in order to
enhance the syncronization methods for accessing elements of struct
virtio_balloon, thus providing protection against concurrent access
introduced by parallel memory migration threads.

 - balloon_lock (mutex) : synchronizes the access demand to elements of
                          struct virtio_balloon and its queue operations;

[yongjun_wei@trendmicro.com.cn: fix missing unlock on error in fill_balloon()]
[akpm@linux-foundation.org: avoid having multiple return points in fill_balloon()]
[akpm@linux-foundation.org: fix printk warning]Signed-off-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-11 17:22:27 -08:00
Michael S. Tsirkin 9c378abc5c virtio-balloon: fix add/get API use
Since ee7cd8981e 'virtio: expose added
descriptors immediately.', in virtio balloon virtqueue_get_buf might
now run concurrently with virtqueue_kick.  I audited both and this
seems safe in practice but this is not guaranteed by the API.
Additionally, a spurious interrupt might in theory make
virtqueue_get_buf run in parallel with virtqueue_add_buf, which is
racy.

While we might try to protect against spurious callbacks it's
easier to fix the driver: balloon seems to be the only one
(mis)using the API like this, so let's just fix balloon.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed unused var)
2012-07-09 09:07:22 +09:30
Amit Shah c877bab507 virtio: balloon: separate out common code between remove and freeze functions
The remove and freeze functions have a lot of shared code; put it into a
common function that gets called by both.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-05-22 12:16:11 +09:30
Amit Shah c45b4166d9 virtio: balloon: drop restore_common()
restore_common() was used when there were different thaw and freeze PM
callbacks implemented.  We removed thaw in commit
f38f8387cb.

restore_common() can be removed and virtballoon_restore() can itself do
the restore ops.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-05-22 12:16:11 +09:30
Amit Shah b8ae0eb320 virtio: balloon: let host know of updated balloon size before module removal
When the balloon module is removed, we deflate the balloon, reclaiming
all the pages that were given to the host.  However, we don't update the
config values for the new balloon size, resulting in the host showing
outdated balloon values.

The size update is done after each leak and fill operation, only the
module removal case was left out.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-05-17 12:14:34 +03:00
Michael S. Tsirkin 3ccc9372ed virtio_balloon: fix handling of PAGE_SIZE != 4k
As reported by David Gibson, current code handles PAGE_SIZE != 4k
completely wrong which can lead to guest memory corruption errors:

- page_to_balloon_pfn is wrong: e.g. on system with 64K page size
 it gives the same pfn value for 16 different pages.

- we also need to convert back to linux pfns when we free.

- for each linux page we need to tell host about multiple balloon
  pages, but code only adds one pfn to the array.

This patch fixes all that, tested with a 64k ppc64 kernel.

Reported-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-04-15 11:51:06 +03:00
David Gibson 1a87228f5f virtio_balloon: Fix endian bug
Although virtio config space fields are usually in guest-native endian,
the spec for the virtio balloon device explicitly states that both fields
in its config space are little-endian.

However, the current virtio_balloon driver does not have a suitable endian
swap for the 'num_pages' field, although it does have one for the 'actual'
field.  This patch corrects the bug, adding sparse annotation while we're
at it.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-04-15 11:51:05 +03:00
Amit Shah f38f8387cb virtio: drop thaw PM operation
The thaw operation was used by the balloon driver, but after the last
commit there's no reason to have separate thaw and restore callbacks.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
2012-03-31 08:09:50 +05:30
Amit Shah e47d854e57 virtio: balloon: Allow stats update after restore from S4
There's no reason stats update after restore can't work.  If a host
requested for stats, and before servicing the request, the guest entered
S4, upon restore, the stats request can still be processed and sent off
to the host.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
2012-03-31 08:09:50 +05:30
Amit Shah 4eb05d562e virtio: balloon: leak / fill balloon across S4
commit e562966dba added support for S4 to
the balloon driver.  The freeze function did nothing to free the pages,
since reclaiming the pages from the host to immediately give them back
(if S4 was successful) seemed wasteful.  Also, if S4 wasn't successful,
the guest would have to re-fill the balloon.  On restore, the pages were
supposed to be marked freed and the free page counters were incremented
to reflect the balloon was totally deflated.

However, this wasn't done right.  The pages that were earlier taken away
from the guest during a balloon inflation operation were just shown as
used pages after a successful restore from S4.  Just a fancy way of
leaking lots of memory.

Instead of trying that, just leak the balloon on freeze and fill it on
restore/thaw paths.  This works properly now.  The optimisation to not
leak can be added later on after a bit of refactoring of the code.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-03-01 09:28:41 +10:30
Amit Shah e562966dba virtio: balloon: Add freeze, restore handlers to support S4
Handling balloon hibernate / restore is tricky.  If the balloon was
inflated before going into the hibernation state, upon resume, the host
will not have any memory of that.  Any pages that were passed on to the
host earlier would most likely be invalid, and the host will have to
re-balloon to the previous value to get in the pre-hibernate state.

So the only sane thing for the guest to do here is to discard all the
pages that were put in the balloon.  When to discard the pages is the
next question.

One solution is to deflate the balloon just before writing the image to
the disk (in the freeze() PM callback).  However, asking for pages from
the host just to discard them immediately after seems wasteful of
resources.  Hence, it makes sense to do this by just fudging our
counters soon after wakeup.  This means we don't deflate the balloon
before sleep, and also don't put unnecessary pressure on the host.

This also helps in the thaw case: if the freeze fails for whatever
reason, the balloon should continue to remain in the inflated state.
This was tested by issuing 'swapoff -a' and trying to go into the S4
state.  That fails, and the balloon stays inflated, as expected.  Both
the host and the guest are happy.

Finally, in the restore() callback, we empty the list of pages that were
previously given off to the host, add the appropriate number of pages to
the totalram_pages counter, reset the num_pages counter to 0, and
all is fine.

As a last step, delete the vqs on the freeze callback to prepare for
hibernation, and re-create them in the restore and thaw callbacks to
resume normal operation.

The kthread doesn't race with any operations here, since it's frozen
before the freeze() call and is thawed after the thaw() and restore()
callbacks, so we're safe with that.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:47 +10:30
Amit Shah be91c33dd1 virtio: balloon: Move vq initialization into separate function
The probe and PM restore functions will share this code.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:46 +10:30
Rusty Russell f96fde41f7 virtio: rename virtqueue_add_buf_gfp to virtqueue_add_buf
Remove wrapper functions. This makes the allocation type explicit in
all callers; I used GPF_KERNEL where it seemed obvious, left it at
GFP_ATOMIC otherwise.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2012-01-12 15:44:42 +10:30
Sasha Levin 1e214a5c1a virtio-balloon: Trivial cleanups
Trivial changes to remove forgotten junk, format comments, and correct names.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:42 +10:30
Paul Gortmaker b5a2c4f199 virtio: Add module.h to drivers/virtio users.
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 <paul.gortmaker@windriver.com>
2011-10-31 19:32:14 -04:00
Dave Hansen bf50e69f63 virtio balloon: kill tell-host-first logic
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 <dave@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-30 11:14:13 +09:30
Michael S. Tsirkin 946cfe0e05 virtio_balloon: use virtqueue_xxx wrappers
Switch virtio_balloon to new virtqueue_xxx wrappers.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-05-19 22:15:41 +09:30
Balbir Singh 61fb06cc8e virtio: Fix GFP flags passed from the virtio balloon driver
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 <balbir@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: kvm <kvm@vger.kernel.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-22 07:34:05 -07:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
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 <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Rusty Russell 169c246a30 virtio: fix balloon without VIRTIO_BALLOON_F_STATS_VQ
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:
	 [<c88253a3>] ? balloon+0x1b3/0x440 [virtio_balloon]
	 [<c041c2d7>] ? schedule+0x327/0x9d0
	 [<c88251f0>] ? balloon+0x0/0x440 [virtio_balloon]
	 [<c014a2d4>] ? kthread+0x74/0x80
	 [<c014a260>] ? kthread+0x0/0x80
	 [<c0103b36>] ? kernel_thread_helper+0x6/0x30

need_stats_update should be zero-initialized.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Adam Litke <agl@us.ibm.com>
2010-02-24 14:22:17 +10:30
Adam Litke 1f34c71afe virtio: Fix scheduling while atomic in virtio_balloon stats
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 <agl@us.ibm.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Anthony Liguori <aliguori@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-02-24 14:22:14 +10:30