• Yinghai Lu's avatar
    sparse irq_desc[] array: core kernel and x86 changes · 0b8f1efa
    Yinghai Lu authored
    Impact: new feature
    
    Problem on distro kernels: irq_desc[NR_IRQS] takes megabytes of RAM with
    NR_CPUS set to large values. The goal is to be able to scale up to much
    larger NR_IRQS value without impacting the (important) common case.
    
    To solve this, we generalize irq_desc[NR_IRQS] to an (optional) array of
    irq_desc pointers.
    
    When CONFIG_SPARSE_IRQ=y is used, we use kzalloc_node to get irq_desc,
    this also makes the IRQ descriptors NUMA-local (to the site that calls
    request_irq()).
    
    This gets rid of the irq_cfg[] static array on x86 as well: irq_cfg now
    uses desc->chip_data for x86 to store irq_cfg.
    Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    0b8f1efa
proc.c 5.66 KB