This series parallelizes the mlx5_vdpa device suspend and resume operations through the firmware async API. The purpose is to reduce live migration downtime. The series starts with changing the VQ suspend and resume commands to the async API. After that, the switch is made to issue multiple commands of the same type in parallel. Finally, a bonus improvement is thrown in: keep the notifierd enabled during suspend but make it a NOP. Upon resume make sure that the link state is forwarded. This shaves around 30ms per device constant time. For 1 vDPA device x 32 VQs (16 VQPs), on a large VM (256 GB RAM, 32 CPUs x 2 threads per core), the improvements are: +-------------------+--------+--------+-----------+ | operation | Before | After | Reduction | |-------------------+--------+--------+-----------| | mlx5_vdpa_suspend | 37 ms | 2.5 ms | 14x | | mlx5_vdpa_resume | 16 ms | 5 ms | 3x | +-------------------+--------+--------+-----------+ Note for the maintainers: The first patch contains changes for mlx5_core. This must be applied into the mlx5-vhost tree [0] first. Once this patch is applied on mlx5-vhost, the change has to be pulled from mlx5-vdpa into the vhost tree and only then the remaining patches can be applied. [0] https://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux.git/log/?h=mlx5-vhost Dragos Tatulea (7): net/mlx5: Support throttled commands from async API vdpa/mlx5: Introduce error logging function vdpa/mlx5: Use async API for vq query command vdpa/mlx5: Use async API for vq modify commands vdpa/mlx5: Parallelize device suspend vdpa/mlx5: Parallelize device resume vdpa/mlx5: Keep notifiers during suspend but ignore drivers/net/ethernet/mellanox/mlx5/core/cmd.c | 21 +- drivers/vdpa/mlx5/core/mlx5_vdpa.h | 7 + drivers/vdpa/mlx5/net/mlx5_vnet.c | 435 +++++++++++++----- 3 files changed, 333 insertions(+), 130 deletions(-) -- 2.45.2
