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    SubjectRe: [RFC 1/3]block: seperate CFQ io context management code
    Hi,

    Two of nitpicks below ..


    2012-01-04 3:53 PM, Shaohua Li Wrote:
    > CFQ's io context management creates a per-device io context for each task.
    > It's quite generic. Separate it from CFQ, and use it for fiops I/O scheduler.
    >
    > Signed-off-by: Shaohua Li<shaohua.li@intel.com>
    > ---

    [snip]

    > +int ioc_builder_init(struct ioc_builder *builder)
    > +{
    > + if (!builder->alloc_ioc || !builder->free_ioc)
    > + return -ENOMEM;
    > +
    > + builder->ioc_count = alloc_percpu(unsigned long);
    > + if (!builder->ioc_count)
    > + return -ENOMEM;
    > +
    > + builder->ioc_gone = NULL;
    > + spin_lock_init(&builder->ioc_gone_lock);
    > +
    > + return 0;
    > +}
    > +EXPORT_SYMBOL(ioc_builder_init);
    > +
    > +void io_context_builder_exit(struct ioc_builder *builder)

    It'd be better using 'ioc_builder_exit' as a name for consistency, IMHO.


    > +{
    > + DECLARE_COMPLETION_ONSTACK(all_gone);
    > +
    > + builder->ioc_gone =&all_gone;
    > + /* ioc_gone's update must be visible before reading ioc_count */
    > + smp_wmb();
    > +
    > + /*
    > + * this also protects us from entering cfq_slab_kill() with
    > + * pending RCU callbacks
    > + */
    > + if (elv_ioc_count_read(*builder->ioc_count))
    > + wait_for_completion(&all_gone);
    > +
    > + free_percpu(builder->ioc_count);
    > +}
    > +EXPORT_SYMBOL(io_context_builder_exit);

    [snip]

    > +static void queue_data_cic_free_rcu(struct rcu_head *head)
    > +{
    > + struct dev_io_context *cic;
    > + struct ioc_builder *builder;
    > +
    > + cic = container_of(head, struct dev_io_context, rcu_head);
    > + builder = cic->builder;
    > +
    > + builder->free_ioc(builder, cic);
    > + elv_ioc_count_dec(*builder->ioc_count);
    > +
    > + if (builder->ioc_gone) {
    > + /*
    > + * CFQ scheduler is exiting, grab exit lock and check

    s/CFQ/IO/ ?

    Thanks.
    Namhyung Kim


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