On Jun 19, 2007 22:38 +0530, Aneesh Kumar K.V wrote:
> This is what i have modified. I am yet to build test it. I am looking at
> forward porting the
> mballoc patches and was planning to send it together.
> +int ext4_reserve_local(struct super_block *sb, int blocks)
> +{
> + preempt_disable();
> + rs = sbi->s_reservation_slots + smp_processor_id();
Should this be instead "rs = sbi->s_reservation_slots + get_cpu()"
> + spin_lock(&rs->rs_lock);
> + if (likely(rs->rs_reserved >= blocks)) {
> + rs->rs_reserved -= blocks;
> + rc = 0;
> + }
> + spin_unlock(&rs->rs_lock);
> +
> + preempt_enable();
And "put_cpu()" here?
> +void ext4_rebalance_reservation(struct ext4_reservation_slot *rs, __u64 free)
> +{
> + /* chunk is a number of block every used
> + * slot will get. make sure it isn't 0 */
> + chunk = free + used_slots - 1;
> + do_div(chunk, used_slots);
> +
> + for_each_possible_cpu(i) {
> + if (free < chunk)
> + chunk = free;
> + if (rs[i].rs_reserved || i == smp_processor_id()) {
> + rs[i].rs_reserved = chunk;
> + free -= chunk;
> + BUG_ON(free < 0);
> + }
> + }
Should we be assigning reservations to offline CPUs? Doesn't it make sense
to assign 0 reservation to offline CPUs until they come back? In the first
loop, if it is "for_each_possible_cpu()" it would drop reservations from
offline CPUs, and then the bottom one is "for_each_online_cpu()".
Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.
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