lkml.org 
[lkml]   [2009]   [Aug]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 02/24] io-controller: Core of the elevator fair queuing
    Hi Vivek,

    Vivek Goyal wrote:
    > o This is core of the io scheduler implemented at elevator layer. This is a mix
    > of cpu CFS scheduler and CFQ IO scheduler. Some of the bits from CFS have
    > to be derived so that we can support hierarchical scheduling. Without
    > cgroups or with-in group, we should essentially get same behavior as CFQ.
    >
    > o This patch only shows non-hierarchical bits. Hierarhical code comes in later
    > patches.
    >
    > o This code is the building base of introducing fair queuing logic in common
    > elevator layer so that it can be used by all the four IO schedulers.

    > +static void enqueue_io_entity(struct io_entity *entity)
    > +{
    > + struct io_service_tree *st = entity->st;
    > + struct io_sched_data *sd = io_entity_sched_data(entity);
    > +
    > + /* In case task ioprio class changed while entity was off tree */
    > + io_entity_update_prio(entity);
    > + st->nr_active++;
    > + sd->nr_active++;
    > + entity->on_st = 1;
    > + place_entity(st, entity, 0);
    > + __enqueue_io_entity(st, entity);
    > +}

    > +static void put_prev_io_entity(struct io_entity *entity)
    > +{
    > + struct io_service_tree *st = entity->st;
    > + struct io_sched_data *sd = io_entity_sched_data(entity);
    > +
    > + st->active_entity = NULL;
    > + sd->active_entity = NULL;
    > +
    > + if (unlikely(entity->ioprio_changed)) {
    > + dequeue_io_entity(entity);
    > + io_entity_update_prio(entity);

    That call to io_entity_update_prio() looks redundant with the one in
    enqueue_io_entity().

    > + enqueue_io_entity(entity);
    > + } else
    > + __enqueue_io_entity(st, entity);
    > +}

    Jerome


    \
     
     \ /
      Last update: 2009-08-19 18:05    [W:0.031 / U:0.072 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site