linux-arm.git - Russell King's ARM Linux kernel tree

Age	Commit message (Collapse)	Author
2025-01-25	mm: alloc_pages_bulk: rename API	Luiz Capitulino
	The previous commit removed the page_list argument from alloc_pages_bulk_noprof() along with the alloc_pages_bulk_list() function. Now that only the *_array() flavour of the API remains, we can do the following renaming (along with the _noprof() ones): alloc_pages_bulk_array -> alloc_pages_bulk alloc_pages_bulk_array_mempolicy -> alloc_pages_bulk_mempolicy alloc_pages_bulk_array_node -> alloc_pages_bulk_node Link: https://lkml.kernel.org/r/275a3bbc0be20fbe9002297d60045e67ab3d4ada.1734991165.git.luizcap@redhat.com Signed-off-by: Luiz Capitulino <luizcap@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Yunsheng Lin <linyunsheng@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-13	vfio/virtio: Add PRE_COPY support for live migration	Yishai Hadas
	Add PRE_COPY support for live migration. This functionality may reduce the downtime upon STOP_COPY as of letting the target machine to get some 'initial data' from the source once the machine is still in its RUNNING state and let it prepares itself pre-ahead to get the final STOP_COPY data. As the Virtio specification does not support reading partial or incremental device contexts. This means that during the PRE_COPY state, the vfio-virtio driver reads the full device state. As the device state can be changed and the benefit is highest when the pre copy data closely matches the final data we read it in a rate limiter mode. This means we avoid reading new data from the device for a specified time interval after the last read. With PRE_COPY enabled, we observed a downtime reduction of approximately 70-75% in various scenarios compared to when PRE_COPY was disabled, while keeping the total migration time nearly the same. Signed-off-by: Yishai Hadas <yishaih@nvidia.com> Link: https://lore.kernel.org/r/20241113115200.209269-7-yishaih@nvidia.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2024-11-13	vfio/virtio: Add support for the basic live migration functionality	Yishai Hadas
	Add support for basic live migration functionality in VFIO over virtio-net devices, aligned with the virtio device specification 1.4. This includes the following VFIO features: VFIO_MIGRATION_STOP_COPY, VFIO_MIGRATION_P2P. The implementation registers with the VFIO subsystem using vfio_pci_core and then incorporates the virtio-specific logic for the migration process. The migration follows the definitions in uapi/vfio.h and leverages the virtio VF-to-PF admin queue command channel for execution device parts related commands. Additional Notes: ----------------- The kernel protocol between the source and target devices contains a header with metadata, including record size, tag, and flags. The record size allows the target to recognize and read a complete image from the source before passing the device part data. This adheres to the virtio device specification, which mandates that partial device parts cannot be supplied. The tag and flags serve as placeholders for future extensions of the kernel protocol between the source and target, ensuring backward and forward compatibility. Both the source and target comply with the virtio device specification by using a device part object with a unique ID as part of the migration process. Since this resource is limited to a maximum of 255, its lifecycle is confined to periods with an active live migration flow. According to the virtio specification, a device has only two modes: RUNNING and STOPPED. As a result, certain VFIO transitions (i.e., RUNNING_P2P->STOP, STOP->RUNNING_P2P) are treated as no-ops. When transitioning to RUNNING_P2P, the device state is set to STOP, and it will remain STOPPED until the transition out of RUNNING_P2P->RUNNING, at which point it returns to RUNNING. During transition to STOP, the virtio device only stops initiating outgoing requests(e.g. DMA, MSIx, etc.) but still must accept incoming operations. Signed-off-by: Yishai Hadas <yishaih@nvidia.com> Link: https://lore.kernel.org/r/20241113115200.209269-6-yishaih@nvidia.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>