• Jens Axboe's avatar
    block: initial patch for on-stack per-task plugging · 73c10101
    Jens Axboe authored
    This patch adds support for creating a queuing context outside
    of the queue itself. This enables us to batch up pieces of IO
    before grabbing the block device queue lock and submitting them to
    the IO scheduler.
    The context is created on the stack of the process and assigned in
    the task structure, so that we can auto-unplug it if we hit a schedule
    The current queue plugging happens implicitly if IO is submitted to
    an empty device, yet callers have to remember to unplug that IO when
    they are going to wait for it. This is an ugly API and has caused bugs
    in the past. Additionally, it requires hacks in the vm (->sync_page()
    callback) to handle that logic. By switching to an explicit plugging
    scheme we make the API a lot nicer and can get rid of the ->sync_page()
    hack in the vm.
    Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
blk-flush.c 12.3 KB