On Wed, Jan 8, 2014 at 4:24 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > [+cc Yinghai] > > On Wed, Jan 8, 2014 at 11:17 AM, threeTigers Lin > <threeflytigers@xxxxxxxxx> wrote: >> From f7a37ed1c61b5939ccef810e28b25ecf3bfa9077 Mon Sep 17 00:00:00 2001 >> From: linmuhui <linmuhui@xxxxxxxxxx> >> Date: Thu, 9 Jan 2014 01:03:12 +0800 >> Subject: [PATCH] PCI: Allocate prefetch mmio resource first when possible > > This patch is not in the standard format and does not apply cleanly. > See Documentation/SubmittingPatches. > >> Hi Bjorn, >> >> PCI bus resources will be set up at pci_bridge_check_ranges() or >> pci_read_bridge_bases(). In both cases, we can find that the PCI bus' >> non-pref mmio will be assigned to bus->resource[1] and pref mmio will be >> assigned to bus->resource[2]. So, in the scenario that we need to allocate >> pref resources from PCI bus such as hotplug operation, the bus' non-pref >> mmio will be quickly eaten up first if we try to allocate bus resources in >> the order from bus->resource[0] to bus->resource[PCI_BRIDGE_RESOURCE_NUM - >> 1] in the function pci_bus_alloc_resource(), even though there is enough >> pref mmio resource of the bus. This may lead to the later requester who want >> to allocate non-pref mmio cannot allocate the resource from the bus. So, I >> think the order of allocating PCI bus resources in function >> pci_bus_alloc_resource() should be changed to try pref mmio first when >> possible. > > Don't we do this already? The code in __pci_assign_resource() looks > like it should prefer an exact prefetching match. > > If that code doesn't work, we should fix it there. I don't want to > fiddle with pci_bus_for_each_resource() for this -- that's a really > arcane place to hide such a fix. Looks like he was trying to do sorting work like we try to do with root bus resource before, but with new patches in pci/resource, we do NOT need to do that anymore. Hi, Lin, Can you check linus/master + pci/next + pci/resource and http://patchwork.ozlabs.org/patch/303740/ PCI: Try best to allocate pref mmio 64bit above 4g would fix the problem in your setup? Thanks Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
