Hi Vivek, There's no need to travel the iocg->group_data for each iog when exiting a elevator, that costs too much. An alternative solution is reseting iocg_id as soon as an io group unlinking from a iocg. Make a decision that whether it's need to carry out deleting action by checking iocg_id.
Signed-off-by: Gui Jianfeng <[email protected]> --- block/elevator-fq.c | 29 ++++++++++------------------- 1 files changed, 10 insertions(+), 19 deletions(-) diff --git a/block/elevator-fq.c b/block/elevator-fq.c index d779282..b26fe0f 100644 --- a/block/elevator-fq.c +++ b/block/elevator-fq.c @@ -2218,8 +2218,6 @@ void io_group_cleanup(struct io_group *iog) BUG_ON(iog->sched_data.active_entity != NULL); BUG_ON(entity != NULL && entity->tree != NULL); - iog->iocg_id = 0; - /* * Wait for any rcu readers to exit before freeing up the group. * Primarily useful when io_get_io_group() is called without queue @@ -2376,6 +2374,7 @@ remove_entry: group_node); efqd = rcu_dereference(iog->key); hlist_del_rcu(&iog->group_node); + iog->iocg_id = 0; spin_unlock_irqrestore(&iocg->lock, flags); spin_lock_irqsave(efqd->queue->queue_lock, flags); @@ -2403,35 +2402,27 @@ done: void io_group_check_and_destroy(struct elv_fq_data *efqd, struct io_group *iog) { struct io_cgroup *iocg; - unsigned short id = iog->iocg_id; - struct hlist_node *n; - struct io_group *__iog; unsigned long flags; struct cgroup_subsys_state *css; rcu_read_lock(); - BUG_ON(!id); - css = css_lookup(&io_subsys, id); + css = css_lookup(&io_subsys, iog->iocg_id); - /* css can't go away as associated io group is still around */ - BUG_ON(!css); + if (!css) + goto out; iocg = container_of(css, struct io_cgroup, css); spin_lock_irqsave(&iocg->lock, flags); - hlist_for_each_entry_rcu(__iog, n, &iocg->group_data, group_node) { - /* - * Remove iog only if it is still in iocg list. Cgroup - * deletion could have deleted it already. - */ - if (__iog == iog) { - hlist_del_rcu(&iog->group_node); - __io_destroy_group(efqd, iog); - break; - } + + if (iog->iocg_id) { + hlist_del_rcu(&iog->group_node); + __io_destroy_group(efqd, iog); } + spin_unlock_irqrestore(&iocg->lock, flags); +out: rcu_read_unlock(); } -- 1.5.4.rc3 _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
