[PATCH v12 10/21] PCI: Consider additional PF's IOV BAR alignment in sizing and assigning
Bjorn Helgaas
bhelgaas at google.com
Tue Feb 24 19:41:52 AEDT 2015
On Tue, Feb 24, 2015 at 02:34:06AM -0600, Bjorn Helgaas wrote:
> From: Wei Yang <weiyang at linux.vnet.ibm.com>
>
> When sizing and assigning resources, we divide the resources into two
> lists: the requested list and the additional list. We don't consider the
> alignment of additional VF(n) BAR space.
>
> This is reasonable because the alignment required for the VF(n) BAR space
> is the size of an individual VF BAR, not the size of the space for *all*
> VFs. But some platforms, e.g., PowerNV, require additional alignment.
>
> Consider the additional IOV BAR alignment when sizing and assigning
> resources. When there is not enough system MMIO space, the PF's IOV BAR
> alignment will not contribute to the bridge. When there is enough system
> MMIO space, the additional alignment will contribute to the bridge.
I don't understand the ""when there is not enough system MMIO space" part.
How do we tell if there's enough MMIO space?
> Also, take advantage of pci_dev_resource::min_align to store this
> additional alignment.
This comment doesn't seem to make sense; this patch doesn't save anything
in min_align.
Another question below...
> [bhelgaas: changelog, printk cast]
> Signed-off-by: Wei Yang <weiyang at linux.vnet.ibm.com>
> Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
> ---
> drivers/pci/setup-bus.c | 83 ++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 70 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index e3e17f3c0f0f..affbceae560f 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -99,8 +99,8 @@ static void remove_from_list(struct list_head *head,
> }
> }
>
> -static resource_size_t get_res_add_size(struct list_head *head,
> - struct resource *res)
> +static struct pci_dev_resource *res_to_dev_res(struct list_head *head,
> + struct resource *res)
> {
> struct pci_dev_resource *dev_res;
>
> @@ -109,17 +109,37 @@ static resource_size_t get_res_add_size(struct list_head *head,
> int idx = res - &dev_res->dev->resource[0];
>
> dev_printk(KERN_DEBUG, &dev_res->dev->dev,
> - "res[%d]=%pR get_res_add_size add_size %llx\n",
> + "res[%d]=%pR res_to_dev_res add_size %llx min_align %llx\n",
> idx, dev_res->res,
> - (unsigned long long)dev_res->add_size);
> + (unsigned long long)dev_res->add_size,
> + (unsigned long long)dev_res->min_align);
>
> - return dev_res->add_size;
> + return dev_res;
> }
> }
>
> - return 0;
> + return NULL;
> +}
> +
> +static resource_size_t get_res_add_size(struct list_head *head,
> + struct resource *res)
> +{
> + struct pci_dev_resource *dev_res;
> +
> + dev_res = res_to_dev_res(head, res);
> + return dev_res ? dev_res->add_size : 0;
> +}
> +
> +static resource_size_t get_res_add_align(struct list_head *head,
> + struct resource *res)
> +{
> + struct pci_dev_resource *dev_res;
> +
> + dev_res = res_to_dev_res(head, res);
> + return dev_res ? dev_res->min_align : 0;
> }
>
> +
> /* Sort resources by alignment */
> static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head)
> {
> @@ -368,8 +388,9 @@ static void __assign_resources_sorted(struct list_head *head,
> LIST_HEAD(save_head);
> LIST_HEAD(local_fail_head);
> struct pci_dev_resource *save_res;
> - struct pci_dev_resource *dev_res, *tmp_res;
> + struct pci_dev_resource *dev_res, *tmp_res, *dev_res2;
> unsigned long fail_type;
> + resource_size_t add_align, align;
>
> /* Check if optional add_size is there */
> if (!realloc_head || list_empty(realloc_head))
> @@ -384,10 +405,38 @@ static void __assign_resources_sorted(struct list_head *head,
> }
>
> /* Update res in head list with add_size in realloc_head list */
> - list_for_each_entry(dev_res, head, list)
> + list_for_each_entry_safe(dev_res, tmp_res, head, list) {
> dev_res->res->end += get_res_add_size(realloc_head,
> dev_res->res);
>
> + /*
> + * There are two kinds of additional resources in the list:
> + * 1. bridge resource -- IORESOURCE_STARTALIGN
> + * 2. SR-IOV resource -- IORESOURCE_SIZEALIGN
> + * Here just fix the additional alignment for bridge
> + */
> + if (!(dev_res->res->flags & IORESOURCE_STARTALIGN))
> + continue;
> +
> + add_align = get_res_add_align(realloc_head, dev_res->res);
> +
> + /* Reorder the list by their alignment */
Why do we need to reorder the list by alignment?
> + if (add_align > dev_res->res->start) {
> + dev_res->res->start = add_align;
> + dev_res->res->end = add_align +
> + resource_size(dev_res->res);
> +
> + list_for_each_entry(dev_res2, head, list) {
> + align = pci_resource_alignment(dev_res2->dev,
> + dev_res2->res);
> + if (add_align > align)
> + list_move_tail(&dev_res->list,
> + &dev_res2->list);
> + }
> + }
> +
> + }
> +
> /* Try updated head list with add_size added */
> assign_requested_resources_sorted(head, &local_fail_head);
>
> @@ -962,6 +1011,8 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
> struct resource *b_res = find_free_bus_resource(bus,
> mask | IORESOURCE_PREFETCH, type);
> resource_size_t children_add_size = 0;
> + resource_size_t children_add_align = 0;
> + resource_size_t add_align = 0;
>
> if (!b_res)
> return -ENOSPC;
> @@ -986,6 +1037,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
> /* put SRIOV requested res to the optional list */
> if (realloc_head && i >= PCI_IOV_RESOURCES &&
> i <= PCI_IOV_RESOURCE_END) {
> + add_align = max(pci_resource_alignment(dev, r), add_align);
> r->end = r->start - 1;
> add_to_list(realloc_head, dev, r, r_size, 0/* don't care */);
> children_add_size += r_size;
> @@ -1016,19 +1068,23 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
> if (order > max_order)
> max_order = order;
>
> - if (realloc_head)
> + if (realloc_head) {
> children_add_size += get_res_add_size(realloc_head, r);
> + children_add_align = get_res_add_align(realloc_head, r);
> + add_align = max(add_align, children_add_align);
> + }
> }
> }
>
> min_align = calculate_mem_align(aligns, max_order);
> min_align = max(min_align, window_alignment(bus, b_res->flags));
> size0 = calculate_memsize(size, min_size, 0, resource_size(b_res), min_align);
> + add_align = max(min_align, add_align);
> if (children_add_size > add_size)
> add_size = children_add_size;
> size1 = (!realloc_head || (realloc_head && !add_size)) ? size0 :
> calculate_memsize(size, min_size, add_size,
> - resource_size(b_res), min_align);
> + resource_size(b_res), add_align);
> if (!size0 && !size1) {
> if (b_res->start || b_res->end)
> dev_info(&bus->self->dev, "disabling bridge window %pR to %pR (unused)\n",
> @@ -1040,10 +1096,11 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
> b_res->end = size0 + min_align - 1;
> b_res->flags |= IORESOURCE_STARTALIGN;
> if (size1 > size0 && realloc_head) {
> - add_to_list(realloc_head, bus->self, b_res, size1-size0, min_align);
> - dev_printk(KERN_DEBUG, &bus->self->dev, "bridge window %pR to %pR add_size %llx\n",
> + add_to_list(realloc_head, bus->self, b_res, size1-size0, add_align);
> + dev_printk(KERN_DEBUG, &bus->self->dev, "bridge window %pR to %pR add_size %llx add_align %llx\n",
> b_res, &bus->busn_res,
> - (unsigned long long)size1-size0);
> + (unsigned long long) (size1 - size0),
> + (unsigned long long) add_align);
> }
> return 0;
> }
>
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