Re: [RFC][PATCH 6/8] RSS controller shares allocation

Pavel Emelianov
2006-11-10T09:11:28Z

Balbir Singh wrote:
> Support shares assignment and propagation.
>
> Signed-off-by: Balbir Singh <balbir@in.ibm.com>
> ---
>
> kernel/res_group/memctlr.c | 59 ++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 58 insertions(+), 1 deletion(-)

[snip]

> +static void recalc_and_propagate(struct memctlr *res, struct memctlr *parres)
> +{
> + struct resource_group *child = NULL;
> + int child_divisor;
> + u64 numerator;
> + struct memctlr *child_res;
> +
> + if (parres) {
> + if (res->shares.max_shares == SHARE_DONT_CARE ||
> + parres->shares.max_shares == SHARE_DONT_CARE)
> + return;
> +
> + child_divisor = parres->shares.child_shares_divisor;
> + if (child_divisor == 0)
> + return;
> +
> + numerator = (u64)(parres->shares.unused_min_shares *
> + res->shares.max_shares);
> + do_div(numerator, child_divisor);
> + numerator = (u64)(parres->nr_pages * numerator);
> + do_div(numerator, SHARE_DEFAULT_DIVISOR);
> + res->nr_pages = numerator;
> + }
> +
> + for_each_child(child, res->rgroup) {
> + child_res = get_memctlr(child);
> + BUG_ON(!child_res);
> + recalc_and_propagate(child_res, res);

Recursion? Won't it eat all the stack in case of a deep tree?

> + }
> +
> +}
> +
> +static void memctlr_shares_changed(struct res_shares *shares)
> +{
> + struct memctlr *res, *parres;
> +
> + res = get_memctlr_from_shares(shares);
> + if (!res)
> + return;
> +
> + if (is_res_group_root(res->rgroup))
> + parres = NULL;
> + else
> + parres = get_memctlr((struct container *)res->rgroup->parent);
> +
> + recalc_and_propagate(res, parres);
> +}
> +
> struct res_controller memctlr_rg = {
> .name = res_ctlr_name,
> .ctlr_id = NO_RES_ID,
> .alloc_shares_struct = memctlr_alloc_instance,
> .free_shares_struct = memctlr_free_instance,
> .move_task = memctlr_move_task,
> - .shares_changed = NULL,
> + .shares_changed = memctlr_shares_changed,

I didn't find where in this patches this callback is called.