Source code for crash.subsystem.storage.blocksq

# -*- coding: utf-8 -*-
# vim:set shiftwidth=4 softtabstop=4 expandtab textwidth=79:

from typing import Iterable, Tuple

from crash.util.symbols import Types
from crash.types.list import list_for_each_entry
from crash.cache.syscache import kernel, jiffies_to_msec

import gdb

class NoQueueError(RuntimeError):
    pass

types = Types(['struct request'])

def for_each_request_in_queue(queue: gdb.Value) -> Iterable[gdb.Value]:
    """
    Iterates over each ``struct request`` in request_queue

    This method iterates over the ``request_queue``'s queuelist and
    returns a request for each member.

    Args:
        queue: The ``struct request_queue`` used to iterate.  The value
            must be of type ``struct request_queue``.

    Yields:
        :obj:`gdb.Value`: Each ``struct request`` contained within the
        ``request_queue``'s queuelist.  The value is of type ``struct request``.
    """
    if int(queue) == 0:
        raise NoQueueError("Queue is NULL")
    return list_for_each_entry(queue['queue_head'], types.request_type,
                               'queuelist')

def request_age_ms(request: gdb.Value) -> int:
    """
    Returns the age of the request in milliseconds

    This method returns the difference between the current time
    (``jiffies``) and the request's ``start_time``, in milliseconds.

    Args:
        request: The ``struct request`` used to determine age.  The value
            is of type ``struct request``.

    Returns:
        :obj:`int`: Difference between the request's ``start_time`` and
            current ``jiffies`` in milliseconds.
    """
    return jiffies_to_msec(kernel.jiffies - request['start_time'])

def requests_in_flight(queue: gdb.Value) -> Tuple[int, int]:
    """
    Report how many requests are in flight for this queue

    Args:
        queue: The request queue to inspect for requests in flight.
            The value must be of type ``struct request_queue``.

    Returns:
        (:obj:`int`, :obj:`int`): The requests in flight.  The first member of
        the 2-tuple is the number of read requests, the second is the number
        of write requests.
    """
    return (int(queue['in_flight'][0]),
            int(queue['in_flight'][1]))