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SubjectRe: [PATCH v6 2/2] PCI: Try best to allocate pref mmio 64bit above 4g
On Thu, Dec 19, 2013 at 1:44 PM, Yinghai Lu <yinghai@kernel.org> wrote:

Let me see if I can figure out what you're trying to do here. Please
correct me if I'm wrong:

> When one of children resources does not support MEM_64, MEM_64 for
> bridge get reset, so pull down whole pref resource on the bridge under 4G.

When we allocate space for a bridge's prefetchable window, we
currently look at the devices behind the bridge and put the window
below 4GB if any of those children has a 32-bit prefetchable BAR.

This maximizes the use of prefetch, at the cost of using more 32-bit
address space.

> If the bridge support pref mem 64, will only allocate that with pref mem64 to
> children that support it.
> For children resources if they only support pref mem 32, will allocate them
> from non pref mem instead.

You are changing this so that we will always try to put a bridge's
64-bit prefetchable window above 4GB, regardless of what devices are
behind the bridge. If a device behind the bridge has a 32-bit
prefetchable BAR, we will place that BAR in the bridge's 32-bit
non-prefetchable window.

This minimizes the use of the 32-bit address space, at the cost of not
being able to use prefetch as much.

> If the bridge only support 32bit pref mmio, will still have all children pref
> mmio under that.

Obviously, if a bridge has a prefetchable window that's only 32 bits,
64-bit prefetchable BARs behind the bridge will have to be in that
32-bit prefetchable window or the 32-bit non-prefetchable window. And
if the bridge has no prefetchable window at all, every memory BAR
behind the bridge will have to be in the 32-bit non-prefetchable
window.

I'll look at the actual patch later; I just want to make sure I
understand your intent first.

Bjorn

> -v2: Add release bridge res support with bridge mem res for pref_mem children res.
> -v3: refresh and make it can be applied early before for_each_dev_res patchset.
> -v4: fix non-pref mmio 64bit support found by Guo Chao.
>
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> Tested-by: Guo Chao <yan@linux.vnet.ibm.com>
> ---
> drivers/pci/setup-bus.c | 138 ++++++++++++++++++++++++++++++++----------------
> drivers/pci/setup-res.c | 20 ++++++-
> 2 files changed, 111 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 138bdd6..b29504f 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -713,12 +713,11 @@ static void pci_bridge_check_ranges(struct pci_bus *bus)
> bus resource of a given type. Note: we intentionally skip
> the bus resources which have already been assigned (that is,
> have non-NULL parent resource). */
> -static struct resource *find_free_bus_resource(struct pci_bus *bus, unsigned long type)
> +static struct resource *find_free_bus_resource(struct pci_bus *bus,
> + unsigned long type_mask, unsigned long type)
> {
> int i;
> struct resource *r;
> - unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
> - IORESOURCE_PREFETCH;
>
> pci_bus_for_each_resource(bus, r, i) {
> if (r == &ioport_resource || r == &iomem_resource)
> @@ -815,7 +814,8 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
> resource_size_t add_size, struct list_head *realloc_head)
> {
> struct pci_dev *dev;
> - struct resource *b_res = find_free_bus_resource(bus, IORESOURCE_IO);
> + struct resource *b_res = find_free_bus_resource(bus, IORESOURCE_IO,
> + IORESOURCE_IO);
> resource_size_t size = 0, size0 = 0, size1 = 0;
> resource_size_t children_add_size = 0;
> resource_size_t min_align, align;
> @@ -915,15 +915,17 @@ static inline resource_size_t calculate_mem_align(resource_size_t *aligns,
> * guarantees that all child resources fit in this size.
> */
> static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
> - unsigned long type, resource_size_t min_size,
> - resource_size_t add_size,
> - struct list_head *realloc_head)
> + unsigned long type, unsigned long type2,
> + unsigned long type3,
> + resource_size_t min_size, resource_size_t add_size,
> + struct list_head *realloc_head)
> {
> struct pci_dev *dev;
> resource_size_t min_align, align, size, size0, size1;
> resource_size_t aligns[12]; /* Alignments from 1Mb to 2Gb */
> int order, max_order;
> - struct resource *b_res = find_free_bus_resource(bus, type);
> + struct resource *b_res = find_free_bus_resource(bus,
> + mask | IORESOURCE_PREFETCH, type);
> unsigned int mem64_mask = 0;
> resource_size_t children_add_size = 0;
>
> @@ -944,7 +946,9 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
> struct resource *r = &dev->resource[i];
> resource_size_t r_size;
>
> - if (r->parent || (r->flags & mask) != type)
> + if (r->parent || ((r->flags & mask) != type &&
> + (r->flags & mask) != type2 &&
> + (r->flags & mask) != type3))
> continue;
> r_size = resource_size(r);
> #ifdef CONFIG_PCI_IOV
> @@ -1117,8 +1121,9 @@ void __ref __pci_bus_size_bridges(struct pci_bus *bus,
> struct list_head *realloc_head)
> {
> struct pci_dev *dev;
> - unsigned long mask, prefmask;
> + unsigned long mask, prefmask, type2 = 0, type3 = 0;
> resource_size_t additional_mem_size = 0, additional_io_size = 0;
> + struct resource *b_res;
>
> list_for_each_entry(dev, &bus->devices, bus_list) {
> struct pci_bus *b = dev->subordinate;
> @@ -1163,15 +1168,34 @@ void __ref __pci_bus_size_bridges(struct pci_bus *bus,
> has already been allocated by arch code, try
> non-prefetchable range for both types of PCI memory
> resources. */
> + b_res = &bus->self->resource[PCI_BRIDGE_RESOURCES];
> mask = IORESOURCE_MEM;
> prefmask = IORESOURCE_MEM | IORESOURCE_PREFETCH;
> - if (pbus_size_mem(bus, prefmask, prefmask,
> + if (b_res[2].flags & IORESOURCE_MEM_64) {
> + prefmask |= IORESOURCE_MEM_64;
> + if (pbus_size_mem(bus, prefmask, prefmask,
> + prefmask, prefmask,
> realloc_head ? 0 : additional_mem_size,
> - additional_mem_size, realloc_head))
> - mask = prefmask; /* Success, size non-prefetch only. */
> - else
> - additional_mem_size += additional_mem_size;
> - pbus_size_mem(bus, mask, IORESOURCE_MEM,
> + additional_mem_size, realloc_head)) {
> + /* Success, size non-pref64 only. */
> + mask = prefmask;
> + type2 = prefmask & ~IORESOURCE_MEM_64;
> + type3 = prefmask & ~IORESOURCE_PREFETCH;
> + }
> + }
> + if (!type2) {
> + prefmask &= ~IORESOURCE_MEM_64;
> + if (pbus_size_mem(bus, prefmask, prefmask,
> + prefmask, prefmask,
> + realloc_head ? 0 : additional_mem_size,
> + additional_mem_size, realloc_head)) {
> + /* Success, size non-prefetch only. */
> + mask = prefmask;
> + } else
> + additional_mem_size += additional_mem_size;
> + type2 = type3 = IORESOURCE_MEM;
> + }
> + pbus_size_mem(bus, mask, IORESOURCE_MEM, type2, type3,
> realloc_head ? 0 : additional_mem_size,
> additional_mem_size, realloc_head);
> break;
> @@ -1257,42 +1281,66 @@ static void __ref __pci_bridge_assign_resources(const struct pci_dev *bridge,
> static void pci_bridge_release_resources(struct pci_bus *bus,
> unsigned long type)
> {
> - int idx;
> - bool changed = false;
> - struct pci_dev *dev;
> + struct pci_dev *dev = bus->self;
> struct resource *r;
> unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
> - IORESOURCE_PREFETCH;
> + IORESOURCE_PREFETCH | IORESOURCE_MEM_64;
> + unsigned old_flags = 0;
> + struct resource *b_res;
> + int idx = 1;
>
> - dev = bus->self;
> - for (idx = PCI_BRIDGE_RESOURCES; idx <= PCI_BRIDGE_RESOURCE_END;
> - idx++) {
> - r = &dev->resource[idx];
> - if ((r->flags & type_mask) != type)
> - continue;
> - if (!r->parent)
> - continue;
> - /*
> - * if there are children under that, we should release them
> - * all
> - */
> - release_child_resources(r);
> - if (!release_resource(r)) {
> - dev_printk(KERN_DEBUG, &dev->dev,
> - "resource %d %pR released\n", idx, r);
> - /* keep the old size */
> - r->end = resource_size(r) - 1;
> - r->start = 0;
> - r->flags = 0;
> - changed = true;
> - }
> - }
> + b_res = &dev->resource[PCI_BRIDGE_RESOURCES];
> +
> + /*
> + * 1. if there is io port assign fail, will release bridge
> + * io port.
> + * 2. if there is non pref mmio assign fail, release bridge
> + * nonpref mmio.
> + * 3. if there is 64bit pref mmio assign fail, and bridge pref
> + * is 64bit, release bridge pref mmio.
> + * 4. if there is pref mmio assign fail, and bridge pref is
> + * 32bit mmio, release bridge pref mmio
> + * 5. if there is pref mmio assign fail, and bridge pref is not
> + * assigned, release bridge nonpref mmio.
> + */
> + if (type & IORESOURCE_IO)
> + idx = 0;
> + else if (!(type & IORESOURCE_PREFETCH))
> + idx = 1;
> + else if ((type & IORESOURCE_MEM_64) &&
> + (b_res[2].flags & IORESOURCE_MEM_64))
> + idx = 2;
> + else if (!(b_res[2].flags & IORESOURCE_MEM_64) &&
> + (b_res[2].flags & IORESOURCE_PREFETCH))
> + idx = 2;
> + else
> + idx = 1;
> +
> + r = &b_res[idx];
> +
> + if (!r->parent)
> + return;
> +
> + /*
> + * if there are children under that, we should release them
> + * all
> + */
> + release_child_resources(r);
> + if (!release_resource(r)) {
> + type = old_flags = r->flags & type_mask;
> + dev_printk(KERN_DEBUG, &dev->dev, "resource %d %pR released\n",
> + PCI_BRIDGE_RESOURCES + idx, r);
> + /* keep the old size */
> + r->end = resource_size(r) - 1;
> + r->start = 0;
> + r->flags = 0;
>
> - if (changed) {
> /* avoiding touch the one without PREF */
> if (type & IORESOURCE_PREFETCH)
> type = IORESOURCE_PREFETCH;
> __pci_setup_bridge(bus, type);
> + /* for next child res under same bridge */
> + r->flags = old_flags;
> }
> }
>
> @@ -1471,7 +1519,7 @@ void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus)
> LIST_HEAD(fail_head);
> struct pci_dev_resource *fail_res;
> unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
> - IORESOURCE_PREFETCH;
> + IORESOURCE_PREFETCH | IORESOURCE_MEM_64;
> int pci_try_num = 1;
> enum enable_type enable_local;
>
> diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
> index 5c060b1..2c659e4 100644
> --- a/drivers/pci/setup-res.c
> +++ b/drivers/pci/setup-res.c
> @@ -208,15 +208,31 @@ static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
>
> /* First, try exact prefetching match.. */
> ret = pci_bus_alloc_resource(bus, res, size, align, min,
> - IORESOURCE_PREFETCH,
> + IORESOURCE_PREFETCH | IORESOURCE_MEM_64,
> pcibios_align_resource, dev);
>
> - if (ret < 0 && (res->flags & IORESOURCE_PREFETCH)) {
> + if (ret < 0 &&
> + (res->flags & (IORESOURCE_PREFETCH | IORESOURCE_MEM_64)) ==
> + (IORESOURCE_PREFETCH | IORESOURCE_MEM_64)) {
> + /*
> + * That failed.
> + *
> + * Try below 4g pref
> + */
> + ret = pci_bus_alloc_resource(bus, res, size, align, min,
> + IORESOURCE_PREFETCH,
> + pcibios_align_resource, dev);
> + }
> +
> + if (ret < 0 &&
> + (res->flags & (IORESOURCE_PREFETCH | IORESOURCE_MEM_64))) {
> /*
> * That failed.
> *
> * But a prefetching area can handle a non-prefetching
> * window (it will just not perform as well).
> + *
> + * Also can put 64bit under 32bit range. (below 4g).
> */
> ret = pci_bus_alloc_resource(bus, res, size, align, min, 0,
> pcibios_align_resource, dev);
> --
> 1.8.4
>


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