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Date: Thu, 29 Oct 2009 10:10:22 -0700
From: Yinghai Lu <yinghai@...nel.org>
To: Jesse Barnes <jbarnes@...tuousgeek.org>
CC: Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Alex Chiang <achiang@...com>,
Bjorn Helgaas <bjorn.helgaas@...com>,
Ingo Molnar <mingo@...e.hu>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
Ivan Kokshaysky <ink@...assic.park.msu.ru>
Subject: Re: [PATCH 1/2] pci: release that leaf bridge' resource index is
not used -v6
Jesse Barnes wrote:
> On Thu, 29 Oct 2009 02:52:00 -0700
> Yinghai Lu <yinghai@...nel.org> wrote:
>
>> only for index < 3
>>
>> v2: Jesse doesn't like it is in find_free_bus_resource...
>> try to move out of pci_bus_size_bridges loop.
>> need to apply after:
>> [PATCH] pci: pciehp update the slot bridge res to get big
>> range for pcie devices - v4 v3: add pci_setup_bridge calling after
>> pci_bridge_release_not_used_res. only clear release those res for x86.
>> v4: Bjorn want to release use dev instead of bus.
>> v5: Kenji pointed out it will have problem with several level bridge.
>> so let only handle leaf bridge.
>> v6: address Kenji's request (new pci_bus_release...). and change
>> applying order move back release to pci_assign_unassigned_resource
>>
>> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
>
> Starting to look better...
>
>> ---
>> drivers/pci/setup-bus.c | 65
>> +++++++++++++++++++++++++++++++++++++++++++++++-
>> include/linux/pci.h | 1 2 files changed, 65 insertions(+), 1
>> deletion(-)
>>
>> Index: linux-2.6/drivers/pci/setup-bus.c
>> ===================================================================
>> --- linux-2.6.orig/drivers/pci/setup-bus.c
>> +++ linux-2.6/drivers/pci/setup-bus.c
>> @@ -573,13 +573,68 @@ void __ref pci_bus_assign_resources(cons
>> }
>> EXPORT_SYMBOL(pci_bus_assign_resources);
>>
>> +static void pci_bridge_release_not_used_res(struct pci_bus *bus)
>
> Can we call these functions something else? Maybe
> pci_bridge_release_unused() with a kdoc comment describing exactly what
> it does and why?
ok.
>
>> +{
>> + int idx;
>> + bool changed = false;
>> + struct pci_dev *dev;
>> + struct resource *r;
>> + unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
>> + IORESOURCE_PREFETCH;
>> +
>> + /* for pci bridges res only */
>> + dev = bus->self;
>> + for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_BRIDGE_RESOURCES
>> + 3;
>> + idx++) {
>> + r = &dev->resource[idx];
>> + if (!(r->flags & type_mask))
>> + continue;
>> + if (!r->parent)
>> + continue;
>> + /* if there is no child under that, we should
>> release it */
>> + if (r->child)
>> + continue;
>> + if (!release_resource(r)) {
>> + dev_info(&dev->dev, "resource %d %pRt
>> released\n",
>> + idx, r);
>> + r->flags = 0;
>> + changed = true;
>> + }
>> + }
>> +
>> + if (changed)
>> + pci_setup_bridge(bus);
>> +}
>> +
>> +void __ref pci_bus_release_bridges_not_used_res(struct pci_bus *bus)
>
> Likewise, maybe pci_bus_release_unused_bridge_res or something, with
> comments again.
ok
>
>> +{
>> + struct pci_bus *b;
>> +
>> + /* If the bus is cardbus, do nothing */
>> + if (bus->self && (bus->self->class >> 8) ==
>> PCI_CLASS_BRIDGE_CARDBUS)
>> + return;
>> +
>> + /* We only release the resources under the leaf bridge */
>> + if (list_empty(&bus->children)) {
>> + if (!pci_is_root_bus(bus))
>> + pci_bridge_release_not_used_res(bus);
>> + return;
>> + }
>> +
>> + /* Scan child buses if the bus is not leaf */
>> + list_for_each_entry(b, &bus->children, node)
>> + pci_bus_release_bridges_not_used_res(b);
>> +}
>> +EXPORT_SYMBOL(pci_bus_release_bridges_not_used_res);
>> +
>> static void pci_bus_dump_res(struct pci_bus *bus)
>> {
>> int i;
>>
>> for (i = 0; i < PCI_BUS_NUM_RESOURCES; i++) {
>> struct resource *res = bus->resource[i];
>> - if (!res || !res->end)
>> +
>> + if (!res || !res->end || !res->flags)
>> continue;
>>
>> dev_printk(KERN_DEBUG, &bus->dev, "resource %d
>> %pRt\n", i, res); @@ -608,6 +663,14 @@
>> pci_assign_unassigned_resources(void) {
>> struct pci_bus *bus;
>>
>> + /*
>> + * Try to release leaf bridge's resources that there is not
>> child
>> + * under it
>> + */
>> + list_for_each_entry(bus, &pci_root_buses, node) {
>> + pci_bus_release_bridges_not_used_res(bus);
>> + }
>> +
>
> Also I wonder if we need to make this a command line option that isn't
> run by default?
thinking:
1. try not to touch bridge resource and do the allocation and record the fail device
2. release leaf bridge for those failed device
3. do second around bus_size and allocation.
>
> Really, as Eric says, we need a real dynamic allocation system with the
> ability to move devices around at some point. Any volunteers? :)
that will need suspend driver and rescan allocation and wakeup driver...
YH
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