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* virtio_balloon: prevent uninitialized variable useArnd Bergmann2017-03-281-0/+2
| | | | | | | | | | | | | | | | | | | | The latest gcc-7.0.1 snapshot reports a new warning: virtio/virtio_balloon.c: In function 'update_balloon_stats': virtio/virtio_balloon.c:258:26: error: 'events[2]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:260:26: error: 'events[3]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:261:56: error: 'events[18]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:262:56: error: 'events[17]' is used uninitialized in this function [-Werror=uninitialized] This seems absolutely right, so we should add an extra check to prevent copying uninitialized stack data into the statistics. >From all I can tell, this has been broken since the statistics code was originally added in 2.6.34. Fixes: 9564e138b1f6 ("virtio: Add memory statistics reporting to the balloon driver (V4)") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ladi Prosek <lprosek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio-balloon: use actual number of stats for stats queue buffersLadi Prosek2017-03-281-7/+10
| | | | | | | | | | | | | | | | The virtio balloon driver contained a not-so-obvious invariant that update_balloon_stats has to update exactly VIRTIO_BALLOON_S_NR counters in order to send valid stats to the host. This commit fixes it by having update_balloon_stats return the actual number of counters, and its callers use it when pushing buffers to the stats virtqueue. Note that it is still out of spec to change the number of counters at run-time. "Driver MUST supply the same subset of statistics in all buffers submitted to the statsq." Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ladi Prosek <lprosek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio_balloon: init 1st buffer in stats vqLadi Prosek2017-03-281-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | When init_vqs runs, virtio_balloon.stats is either uninitialized or contains stale values. The host updates its state with garbage data because it has no way of knowing that this is just a marker buffer used for signaling. This patch updates the stats before pushing the initial buffer. Alternative fixes: * Push an empty buffer in init_vqs. Not easily done with the current virtio implementation and violates the spec "Driver MUST supply the same subset of statistics in all buffers submitted to the statsq". * Push a buffer with invalid tags in init_vqs. Violates the same spec clause, plus "invalid tag" is not really defined. Note: the spec says: When using the legacy interface, the device SHOULD ignore all values in the first buffer in the statsq supplied by the driver after device initialization. Note: Historically, drivers supplied an uninitialized buffer in the first buffer. Unfortunately QEMU does not seem to implement the recommendation even for the legacy interface. Cc: stable@vger.kernel.org Signed-off-by: Ladi Prosek <lprosek@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* Merge branch 'WIP.sched-core-for-linus' of ↵Linus Torvalds2017-03-031-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull sched.h split-up from Ingo Molnar: "The point of these changes is to significantly reduce the <linux/sched.h> header footprint, to speed up the kernel build and to have a cleaner header structure. After these changes the new <linux/sched.h>'s typical preprocessed size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K lines), which is around 40% faster to build on typical configs. Not much changed from the last version (-v2) posted three weeks ago: I eliminated quirks, backmerged fixes plus I rebased it to an upstream SHA1 from yesterday that includes most changes queued up in -next plus all sched.h changes that were pending from Andrew. I've re-tested the series both on x86 and on cross-arch defconfigs, and did a bisectability test at a number of random points. I tried to test as many build configurations as possible, but some build breakage is probably still left - but it should be mostly limited to architectures that have no cross-compiler binaries available on kernel.org, and non-default configurations" * 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits) sched/headers: Clean up <linux/sched.h> sched/headers: Remove #ifdefs from <linux/sched.h> sched/headers: Remove the <linux/topology.h> include from <linux/sched.h> sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h> sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h> sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h> sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h> sched/headers: Remove <linux/sched.h> from <linux/sched/init.h> sched/core: Remove unused prefetch_stack() sched/headers: Remove <linux/rculist.h> from <linux/sched.h> sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h> sched/headers: Remove <linux/signal.h> from <linux/sched.h> sched/headers: Remove <linux/rwsem.h> from <linux/sched.h> sched/headers: Remove the runqueue_is_locked() prototype sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h> sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h> sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h> sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h> sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h> ...
| * sched/headers: Prepare to remove the <linux/magic.h> include from ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | <linux/sched/task_stack.h> Update files that depend on the magic.h inclusion. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds2017-03-021-1/+2
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull vhost updates from Michael Tsirkin: "virtio, vhost: optimizations, fixes Looks like a quiet cycle for vhost/virtio, just a couple of minor tweaks. Most notable is automatic interrupt affinity for blk and scsi. Hopefully other devices are not far behind" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: virtio-console: avoid DMA from stack vhost: introduce O(1) vq metadata cache virtio_scsi: use virtio IRQ affinity virtio_blk: use virtio IRQ affinity blk-mq: provide a default queue mapping for virtio device virtio: provide a method to get the IRQ affinity mask for a virtqueue virtio: allow drivers to request IRQ affinity when creating VQs virtio_pci: simplify MSI-X setup virtio_pci: don't duplicate the msix_enable flag in struct pci_dev virtio_pci: use shared interrupts for virtqueues virtio_pci: remove struct virtio_pci_vq_info vhost: try avoiding avail index access when getting descriptor virtio_mmio: expose header to userspace
| * virtio: allow drivers to request IRQ affinity when creating VQsChristoph Hellwig2017-02-271-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a struct irq_affinity pointer to the find_vqs methods, which if set is used to tell the PCI layer to create the MSI-X vectors for our I/O virtqueues with the proper affinity from the start. Compared to after the fact affinity hints this gives us an instantly working setup and allows to allocate the irq descritors node-local and avoid interconnect traffic. Last but not least this will allow blk-mq queues are created based on the interrupt affinity for storage drivers. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* | mm balloon: umount balloon_mnt when removing vb deviceYisheng Xie2017-02-241-0/+4
|/ | | | | | | | | | | | | | | | | | | | | | | With CONFIG_BALLOON_COMPACTION=y the kernel will mount balloon_mnt for balloon page migration when we probe a virtio_balloon device. However we do not unmount it when removing the device. Fix this. Fixes: b1123ea6d3b3 ("mm: balloon: use general non-lru movable page feature") Link: http://lkml.kernel.org/r/1486531318-35189-1-git-send-email-xieyisheng1@huawei.com Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Rafael Aquini <aquini@redhat.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Gioh Kim <gi-oh.kim@profitbricks.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* virtio: update balloon size in balloon "probe"Konstantin Neumoin2016-10-311-0/+2
| | | | | | | | | | | | | | | | | | | The following commit 'fad7b7b27b6a (virtio_balloon: Use a workqueue instead of "vballoon" kthread)' has added a regression. Original code with kthread starts the thread inside probe and checks the necessity to update balloon inside the thread immediately. Nowadays the code behaves differently. Work is queued only on the first command from the host after the negotiation. Thus there is a window especially at the guest startup or the module reloading when the balloon size is not updated until the notification from the host. This patch adds balloon size check at the end of the probe to match original behaviour. Signed-off-by: Konstantin Neumoin <kneumoin@virtuozzo.com> Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds2016-08-061-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull virtio/vhost updates from Michael Tsirkin: - new vsock device support in host and guest - platform IOMMU support in host and guest, including compatibility quirks for legacy systems. - misc fixes and cleanups. * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: VSOCK: Use kvfree() vhost: split out vringh Kconfig vhost: detect 32 bit integer wrap around vhost: new device IOTLB API vhost: drop vringh dependency vhost: convert pre sorted vhost memory array to interval tree vhost: introduce vhost memory accessors VSOCK: Add Makefile and Kconfig VSOCK: Introduce vhost_vsock.ko VSOCK: Introduce virtio_transport.ko VSOCK: Introduce virtio_vsock_common.ko VSOCK: defer sock removal to transports VSOCK: transport-specific vsock_transport functions vhost: drop vringh dependency vop: pull in vhost Kconfig virtio: new feature to detect IOMMU device quirk balloon: check the number of available pages in leak balloon vhost: lockless enqueuing vhost: simplify work flushing
| * balloon: check the number of available pages in leak balloonKonstantin Neumoin2016-08-011-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The balloon has a special mechanism that is subscribed to the oom notification which leads to deflation for a fixed number of pages. The number is always fixed even when the balloon is fully deflated. But leak_balloon did not expect that the pages to deflate will be more than taken, and raise a "BUG" in balloon_page_dequeue when page list will be empty. So, the simplest solution would be to check that the number of releases pages is less or equal to the number taken pages. Cc: stable@vger.kernel.org Signed-off-by: Konstantin Neumoin <kneumoin@virtuozzo.com> 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>
* | mm: fix build warnings in <linux/compaction.h>Minchan Kim2016-07-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Randy reported below build error. > In file included from ../include/linux/balloon_compaction.h:48:0, > from ../mm/balloon_compaction.c:11: > ../include/linux/compaction.h:237:51: warning: 'struct node' declared inside parameter list [enabled by default] > static inline int compaction_register_node(struct node *node) > ../include/linux/compaction.h:237:51: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default] > ../include/linux/compaction.h:242:54: warning: 'struct node' declared inside parameter list [enabled by default] > static inline void compaction_unregister_node(struct node *node) > It was caused by non-lru page migration which needs compaction.h but compaction.h doesn't include any header to be standalone. I think proper header for non-lru page migration is migrate.h rather than compaction.h because migrate.h has already headers needed to work non-lru page migration indirectly like isolate_mode_t, migrate_mode MIGRATEPAGE_SUCCESS. [akpm@linux-foundation.org: revert mm-balloon-use-general-non-lru-movable-page-feature-fix.patch temp fix] Link: http://lkml.kernel.org/r/20160610003304.GE29779@bbox Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Randy Dunlap <rdunlap@infradead.org> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Gioh Kim <gi-oh.kim@profitbricks.com> Cc: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: balloon: use general non-lru movable page featureMinchan Kim2016-07-261-6/+48
|/ | | | | | | | | | | | | | | | | | | | | Now, VM has a feature to migrate non-lru movable pages so balloon doesn't need custom migration hooks in migrate.c and compaction.c. Instead, this patch implements the page->mapping->a_ops-> {isolate|migrate|putback} functions. With that, we could remove hooks for ballooning in general migration functions and make balloon compaction simple. [akpm@linux-foundation.org: compaction.h requires that the includer first include node.h] Link: http://lkml.kernel.org/r/1464736881-24886-4-git-send-email-minchan@kernel.org Signed-off-by: Gioh Kim <gi-oh.kim@profitbricks.com> Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Rafael Aquini <aquini@redhat.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* virtio_balloon: fix PFN format for virtio-1Michael S. Tsirkin2016-05-221-8/+12
| | | | | | | | | | Everything should be LE when using virtio-1, but the linux balloon driver does not seem to care about that. Reported-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Cornelia Huck <cornelia.huck@de.ibm.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
* Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds2016-03-201-61/+61
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull virtio/vhost updates from Michael Tsirkin: "New features, performance improvements, cleanups: - basic polling support for vhost - rework virtio to optionally use DMA API, fixing it on Xen - balloon stats gained a new entry - using the new napi_alloc_skb speeds up virtio net - virtio blk stats can now be read while another VCPU is busy inflating or deflating the balloon plus misc cleanups in various places" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: virtio_net: replace netdev_alloc_skb_ip_align() with napi_alloc_skb() vhost_net: basic polling support vhost: introduce vhost_vq_avail_empty() vhost: introduce vhost_has_work() virtio_balloon: Allow to resize and update the balloon stats in parallel virtio_balloon: Use a workqueue instead of "vballoon" kthread virtio/s390: size of SET_IND payload virtio/s390: use dev_to_virtio vhost: rename vhost_init_used() vhost: rename cross-endian helpers virtio_blk: VIRTIO_BLK_F_WCE->VIRTIO_BLK_F_FLUSH vring: Use the DMA API on Xen virtio_pci: Use the DMA API if enabled virtio_mmio: Use the DMA API if enabled virtio: Add improved queue allocation API virtio_ring: Support DMA APIs vring: Introduce vring_use_dma_api() s390/dma: Allow per device dma ops alpha/dma: use common noop dma ops dma: Provide simple noop dma ops
| * virtio_balloon: Allow to resize and update the balloon stats in parallelPetr Mladek2016-03-111-15/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The virtio balloon statistics are not updated when the balloon is being resized. But it seems that both tasks could be done in parallel. stats_handle_request() updates the statistics in the balloon structure and then communicates with the host. update_balloon_stats() calls all_vm_events() that just reads some per-CPU variables. The values might change during and after the call but it is expected and happens even without this patch. update_balloon_stats() also calls si_meminfo(). It is a bit more complex function. It too just reads some variables and looks lock-less safe. In each case, it seems to be called lock-less on several similar locations, e.g. from post_status() in dm_thread_func(), or from vmballoon_send_get_target(). The communication with the host is done via a separate virtqueue, see vb->stats_vq vs. vb->inflate_vq and vb->deflate_vq. Therefore it could be used in parallel with fill_balloon() and leak_balloon(). This patch splits the existing work into two pieces. One is for updating the balloon stats. The other is for resizing of the balloon. It seems that they can be proceed in parallel without any extra locking. Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| * virtio_balloon: Use a workqueue instead of "vballoon" kthreadPetr Mladek2016-03-111-57/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch moves the deferred work from the "vballoon" kthread into a system freezable workqueue. We do not need to maintain and run a dedicated kthread. Also the event driven workqueues API makes the logic much easier. Especially, we do not longer need an own wait queue, wait function, and freeze point. The conversion is pretty straightforward. One cycle of the main loop is put into a work. The work is queued instead of waking the kthread. fill_balloon() and leak_balloon() have a limit for the amount of modified pages. The work re-queues itself when necessary. For this, we make fill_balloon() to return the number of really modified pages. Note that leak_balloon() already did this. virtballoon_restore() queues the work only when really needed. The only complication is that we need to prevent queuing the work when the balloon is being removed. It was easier before because the kthread simply removed itself from the wait queue. We need an extra boolean and spin lock now. My initial idea was to use a dedicated workqueue. Michael S. Tsirkin suggested using a system one. Tejun Heo confirmed that the system workqueue has a pretty high concurrency level (256) by default. Therefore we need not be afraid of too long blocking. Signed-off-by: Petr Mladek <pmladek@suse.cz> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* | virtio_balloon: export 'available' memory to balloon statisticsIgor Redko2016-03-171-0/+6
|/ | | | | | | | | | | | | | | Add a new field, VIRTIO_BALLOON_S_AVAIL, to virtio_balloon memory statistics protocol, corresponding to 'Available' in /proc/meminfo. It indicates to the hypervisor how big the balloon can be inflated without pushing the guest system to swap. Signed-off-by: Igor Redko <redkoi@virtuozzo.com> Signed-off-by: Denis V. Lunev <den@openvz.org> Reviewed-by: Roman Kagan <rkagan@virtuozzo.com> Cc: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* virtio: make find_vqs() checkpatch.pl-friendlyStefan Hajnoczi2016-01-121-1/+1
| | | | | | | | | | | | | | | | | | | checkpatch.pl wants arrays of strings declared as follows: static const char * const names[] = { "vq-1", "vq-2", "vq-3" }; Currently the find_vqs() function takes a const char *names[] argument so passing checkpatch.pl's const char * const names[] results in a compiler error due to losing the second const. This patch adjusts the find_vqs() prototype and updates all virtio transports. This makes it possible for virtio_balloon.c, virtio_input.c, virtgpu_kms.c, and virtio_rpmsg_bus.c to use the checkpatch.pl-friendly type. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
* virtio_balloon: fix race by fill and leakMinchan Kim2016-01-121-1/+1
| | | | | | | | | | | | | | | | | | | During my compaction-related stuff, I encountered a bug with ballooning. With repeated inflating and deflating cycle, guest memory( ie, cat /proc/meminfo | grep MemTotal) is decreased and couldn't be recovered. The reason is balloon_lock doesn't cover release_pages_balloon so struct virtio_balloon fields could be overwritten by race of fill_balloon(e,g, vb->*pfns could be critical). This patch fixes it in my test. Cc: <stable@vger.kernel.org> Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
* virtio_balloon: do not change memory amount visible via /proc/meminfoDenis V. Lunev2015-09-081-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* virtio_ballon: change stub of release_pages_by_pfnDenis V. Lunev2015-09-081-4/+4
| | | | | | | | | | | 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>
* virtio_balloon: transitional interfaceMichael S. Tsirkin2015-04-151-6/+15
| | | | | | | | | | | 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>
* virtio-balloon: do not call blocking ops when !TASK_RUNNINGMichael S. Tsirkin2015-03-101-5/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* virtio_balloon: set DRIVER_OK before using deviceMichael S. Tsirkin2015-03-101-0/+2
| | | | | | | | | | | | | | | | | 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
* virtio_balloon: coding style fixesMichael S. Tsirkin2015-01-211-2/+1
| | | | | | | | | | | 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>
* virtio/balloon: verify device has config spaceMichael S. Tsirkin2015-01-211-0/+6
| | | | | | | | | | 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>
* virtio_balloon: free some memory from balloon on OOMRaushaniya Maksudova2014-11-111-0/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* virtio_balloon: return the amount of freed memory from leak_balloon()Raushaniya Maksudova2014-11-111-1/+4
| | | | | | | | | | | 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>
* Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds2014-10-181-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 ...
| * virtio_balloon: enable VQs early on restoreMichael S. Tsirkin2014-10-151-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | 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>
* | mm/balloon_compaction: add vmstat counters and kpageflags bitKonstantin Khlebnikov2014-10-091-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | mm/balloon_compaction: remove balloon mapping and flag AS_BALLOON_MAPKonstantin Khlebnikov2014-10-091-47/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | mm/balloon_compaction: redesign ballooned pages managementKonstantin Khlebnikov2014-10-091-8/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* virtio_balloon: don't crash if virtqueue is broken.Rusty Russell2014-03-131-5/+3
| | | | | | | | 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>
* virtio_balloon: don't softlockup on huge balloon changes.Rusty Russell2014-03-131-0/+6
| | | | | | | | | | | | | | | 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>
* Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds2014-01-221-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | 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()
| * drivers: virtio: Mark function virtballoon_migratepage() as static in ↵Rashika Kheria2014-01-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | virtio_balloon: update_balloon_size(): update correct fieldLuiz Capitulino2013-12-051-1/+1
|/ | | | | | | | | | | | | 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 855e0c5288177bcb193f6f6316952d2490478e1c 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: 855e0c5288177bcb193f6f6316952d2490478e1c
* virtio: use size-based config accessors.Rusty Russell2013-10-171-6/+4
| | | | | | | | | 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>
* virtio: pm: use CONFIG_PM_SLEEP instead of CONFIG_PMAaron Lu2013-09-231-2/+2
| | | | | | | | | | | 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>
* Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds2013-07-101-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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"
| * virtio_balloon: leak_balloon(): only tell host if we got pages deflatedLuiz Capitulino2013-07-021-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* | mm: correctly update zone->managed_pagesJiang Liu2013-07-031-3/+4
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* virtio_balloon: use simplified virtqueue accessors.Rusty Russell2013-03-201-3/+3
| | | | | | We never add buffers with input and output parts, so use the new accessors. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio: use module_virtio_driver.Rusty Russell2013-02-131-12/+1
| | | | Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Drivers: virtio: remove __dev* attributes.Greg Kroah-Hartman2013-01-031-2/+2
| | | | | | | | | | | | | | | | 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>
* Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds2012-12-201-4/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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. ...
| * virtio: Convert dev_printk(KERN_<LEVEL> to dev_<level>(Joe Perches2012-12-181-4/+3
| | | | | | | | | | | | | | | | | | 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>
* | virtio_balloon: introduce migration primitives to balloon pagesRafael Aquini2012-12-111-19/+132
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
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