Subject: Re: [PATCH v4 15/21] powerpc/pci: Delay creating pci_dn

From: Gavin Shan <[email-masked]>
Date: Mon, 11 May 2015 17:21:36 +1000

On Sun, May 10, 2015 at 12:55:51AM +1000, Alexey Kardashevskiy wrote:
>On 05/01/2015 04:03 PM, Gavin Shan wrote:
>>The pci_dn instances are allocated from memblock or bootmem when
>>creating PCI controller (hoses) in setup_arch(). The PCI hotplug,
>>which will be supported by proceeding patches, will release PCI
>>device nodes and their corresponding pci_dn on unplugging event.
>>The pci_dn instance memory chunks alloed from memblock or bootmem
>>are hard to reused after being released.
>>
>>The patch delay creating pci_dn so that they can be allocated from
>>slab. In turn, the memory chunks for them can be reused after being
>>released without problem. The creation of eeh_dev instances, which
>>depends on pci_dn, is delayed a bit as well.
>>
>>Signed-off-by: Gavin Shan <[email-masked]>
>>---
>>  arch/powerpc/include/asm/ppc-pci.h     |  1 -
>>  arch/powerpc/kernel/eeh_dev.c          |  2 +-
>>  arch/powerpc/kernel/pci_dn.c           | 40 +++++++++++++++++++---------------
>>  arch/powerpc/platforms/maple/pci.c     | 35 +++++++++++++++++------------
>>  arch/powerpc/platforms/pasemi/pci.c    |  3 ---
>>  arch/powerpc/platforms/powermac/pci.c  | 39 ++++++++++++++++++++-------------
>>  arch/powerpc/platforms/powernv/pci.c   |  3 ---
>>  arch/powerpc/platforms/pseries/setup.c |  1 -
>>  8 files changed, 68 insertions(+), 56 deletions(-)
>>
>>diff --git a/arch/powerpc/include/asm/ppc-pci.h b/arch/powerpc/include/asm/ppc-pci.h
>>index 4122a86..7388316 100644
>>--- a/arch/powerpc/include/asm/ppc-pci.h
>>+++ b/arch/powerpc/include/asm/ppc-pci.h
>>@@ -40,7 +40,6 @@ void *traverse_pci_dn(struct pci_dn *root,
>>  		      void *(*fn)(struct pci_dn *, void *),
>>  		      void *data);
>>
>>-extern void pci_devs_phb_init(void);
>>  extern void pci_devs_phb_init_dynamic(struct pci_controller *phb);
>>
>>  /* From rtas_pci.h */
>>diff --git a/arch/powerpc/kernel/eeh_dev.c b/arch/powerpc/kernel/eeh_dev.c
>>index aabba94..f33ce5b 100644
>>--- a/arch/powerpc/kernel/eeh_dev.c
>>+++ b/arch/powerpc/kernel/eeh_dev.c
>>@@ -110,4 +110,4 @@ static int __init eeh_dev_phb_init(void)
>>  	return 0;
>>  }
>>
>>-core_initcall(eeh_dev_phb_init);
>>+core_initcall_sync(eeh_dev_phb_init);
>>diff --git a/arch/powerpc/kernel/pci_dn.c b/arch/powerpc/kernel/pci_dn.c
>>index b3b4df9..d3833af 100644
>>--- a/arch/powerpc/kernel/pci_dn.c
>>+++ b/arch/powerpc/kernel/pci_dn.c
>>@@ -277,7 +277,7 @@ void *update_dn_pci_info(struct device_node *dn, void *data)
>>  	struct device_node *parent;
>>  	struct pci_dn *pdn;
>>
>>-	pdn = zalloc_maybe_bootmem(sizeof(*pdn), GFP_KERNEL);
>>+	pdn = kzalloc(sizeof(*pdn), GFP_KERNEL);
>>  	if (pdn == NULL)
>>  		return NULL;
>>  	dn->data = pdn;
>>@@ -442,33 +442,37 @@ void pci_devs_phb_init_dynamic(struct pci_controller *phb)
>>  	traverse_pci_devices(dn, update_dn_pci_info, phb);
>>  }
>>
>>-/**
>>+static void pci_dev_pdn_setup(struct pci_dev *pdev)
>>+{
>>+	struct pci_dn *pdn;
>>+
>>+	if (pdev->dev.archdata.pci_data)
>>+		return;
>>+
>>+	/* Setup the fast path */
>>+	pdn = pci_get_pdn(pdev);
>>+	pdev->dev.archdata.pci_data = pdn;
>>+}
>>+DECLARE_PCI_FIXUP_EARLY(PCI_ANY_ID, PCI_ANY_ID, pci_dev_pdn_setup);
>
>
>How does moving of the chunk above help to "Delay creating pci_dn"?
>

It's already in "Delay creating pci_dn", isn't it? :-)

>
>>+
>>+/*
>>   * pci_devs_phb_init - Initialize phbs and pci devs under them.
>>- *
>>- * This routine walks over all phb's (pci-host bridges) on the
>>- * system, and sets up assorted pci-related structures
>>+ *
>>+ * This routine walks over all phb's (pci-host bridges) on
>>+ * the system, and sets up assorted pci-related structures
>>   * (including pci info in the device node structs) for each
>>   * pci device found underneath.  This routine runs once,
>>   * early in the boot sequence.
>>   */
>>-void __init pci_devs_phb_init(void)
>>+static int __init pci_devs_phb_init(void)
>>  {
>>  	struct pci_controller *phb, *tmp;
>>
>>  	/* This must be done first so the device nodes have valid pci info! */
>>  	list_for_each_entry_safe(phb, tmp, &hose_list, list_node)
>>  		pci_devs_phb_init_dynamic(phb);
>>-}
>>-
>>-static void pci_dev_pdn_setup(struct pci_dev *pdev)
>>-{
>>-	struct pci_dn *pdn;
>>
>>-	if (pdev->dev.archdata.pci_data)
>>-		return;
>>-
>>-	/* Setup the fast path */
>>-	pdn = pci_get_pdn(pdev);
>>-	pdev->dev.archdata.pci_data = pdn;
>>+	return 0;
>>  }
>>-DECLARE_PCI_FIXUP_EARLY(PCI_ANY_ID, PCI_ANY_ID, pci_dev_pdn_setup);
>>+
>>+core_initcall(pci_devs_phb_init);
>>diff --git a/arch/powerpc/platforms/maple/pci.c b/arch/powerpc/platforms/maple/pci.c
>>index a923230..04a69a8 100644
>>--- a/arch/powerpc/platforms/maple/pci.c
>>+++ b/arch/powerpc/platforms/maple/pci.c
>>@@ -568,6 +568,26 @@ void maple_pci_irq_fixup(struct pci_dev *dev)
>>  	DBG(" <- maple_pci_irq_fixup\n");
>>  }
>>
>>+static int maple_pci_root_bridge_prepare(struct pci_host_bridge *bridge)
>>+{
>>+	struct pci_controller *hose = pci_bus_to_host(bridge->bus);
>>+	struct device_node *np, *child;
>>+
>>+	if (hose != u3_agp)
>>+		return 0;
>>+
>>+	/* Fixup the PCI<->OF mapping for U3 AGP due to bus renumbering. We
>>+	 * assume there is no P2P bridge on the AGP bus, which should be a
>>+	 * safe assumptions hopefully.
>>+	 */
>>+	np = hose->dn;
>>+	PCI_DN(np)->busno = 0xf0;
>>+	for_each_child_of_node(np, child)
>>+		PCI_DN(child)->busno = 0xf0;
>>+
>>+	return 0;
>>+}
>>+
>>  void __init maple_pci_init(void)
>>  {
>>  	struct device_node *np, *root;
>>@@ -605,20 +625,7 @@ void __init maple_pci_init(void)
>>  	if (ht && maple_add_bridge(ht) != 0)
>>  		of_node_put(ht);
>>
>>-	/* Setup the linkage between OF nodes and PHBs */
>>-	pci_devs_phb_init();
>>-
>>-	/* Fixup the PCI<->OF mapping for U3 AGP due to bus renumbering. We
>>-	 * assume there is no P2P bridge on the AGP bus, which should be a
>>-	 * safe assumptions hopefully.
>>-	 */
>>-	if (u3_agp) {
>>-		struct device_node *np = u3_agp->dn;
>>-		PCI_DN(np)->busno = 0xf0;
>>-		for (np = np->child; np; np = np->sibling)
>>-			PCI_DN(np)->busno = 0xf0;
>>-	}
>>-
>>+	ppc_md.pcibios_root_bridge_prepare = maple_pci_root_bridge_prepare;
>>  	/* Tell pci.c to not change any resource allocations.  */
>>  	pci_add_flags(PCI_PROBE_ONLY);
>>  }
>>diff --git a/arch/powerpc/platforms/pasemi/pci.c b/arch/powerpc/platforms/pasemi/pci.c
>>index f3a68a0..10c4e8f 100644
>>--- a/arch/powerpc/platforms/pasemi/pci.c
>>+++ b/arch/powerpc/platforms/pasemi/pci.c
>>@@ -229,9 +229,6 @@ void __init pas_pci_init(void)
>>  			of_node_get(np);
>>
>>  	of_node_put(root);
>>-
>>-	/* Setup the linkage between OF nodes and PHBs */
>>-	pci_devs_phb_init();
>>  }
>>
>>  void __iomem *pasemi_pci_getcfgaddr(struct pci_dev *dev, int offset)
>>diff --git a/arch/powerpc/platforms/powermac/pci.c b/arch/powerpc/platforms/powermac/pci.c
>>index 59ab16f..368716f 100644
>>--- a/arch/powerpc/platforms/powermac/pci.c
>>+++ b/arch/powerpc/platforms/powermac/pci.c
>>@@ -878,6 +878,29 @@ void pmac_pci_irq_fixup(struct pci_dev *dev)
>>  #endif /* CONFIG_PPC32 */
>>  }
>>
>>+#ifdef CONFIG_PPC64
>>+static int pmac_pci_root_bridge_prepare(struct pci_hot_bridge *bridge)
>>+{
>>+	struct pci_controller *hose = pci_bus_to_host(bridge->bus);
>>+	struct device_node *np, *child;
>>+
>>+	if (hose != u3_agp)
>>+		return 0;
>>+
>>+	/* Fixup the PCI<->OF mapping for U3 AGP due to bus renumbering. We
>>+	 * assume there is no P2P bridge on the AGP bus, which should be a
>>+	 * safe assumptions for now. We should do something better in the
>>+	 * future though
>>+	 */
>>+	np = hose->dn;
>>+	PCI_DN(np)->busno = 0xf0;
>>+	for_each_child_of_node(np, child)
>>+		PCI_DN(child)->busno = 0xf0;
>>+
>>+	return 0;
>>+}
>>+#endif /* CONFIG_PPC64 */
>>+
>>  void __init pmac_pci_init(void)
>>  {
>>  	struct device_node *np, *root;
>>@@ -914,22 +937,8 @@ void __init pmac_pci_init(void)
>>  	if (ht && pmac_add_bridge(ht) != 0)
>>  		of_node_put(ht);
>>
>>-	/* Setup the linkage between OF nodes and PHBs */
>>-	pci_devs_phb_init();
>>-
>>-	/* Fixup the PCI<->OF mapping for U3 AGP due to bus renumbering. We
>>-	 * assume there is no P2P bridge on the AGP bus, which should be a
>>-	 * safe assumptions for now. We should do something better in the
>>-	 * future though
>>-	 */
>>-	if (u3_agp) {
>>-		struct device_node *np = u3_agp->dn;
>>-		PCI_DN(np)->busno = 0xf0;
>>-		for (np = np->child; np; np = np->sibling)
>>-			PCI_DN(np)->busno = 0xf0;
>>-	}
>>  	/* pmac_check_ht_link(); */
>>-
>>+	ppc_md.pcibios_root_bridge_prepare = pmac_pci_root_bridge_prepare;
>>  #else /* CONFIG_PPC64 */
>>  	init_p2pbridge();
>>  	init_second_ohare();
>>diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
>>index 60e6d65..21a4eb3 100644
>>--- a/arch/powerpc/platforms/powernv/pci.c
>>+++ b/arch/powerpc/platforms/powernv/pci.c
>>@@ -819,9 +819,6 @@ void __init pnv_pci_init(void)
>>  	for_each_compatible_node(np, NULL, "ibm,ioda2-phb")
>>  		pnv_pci_init_ioda2_phb(np);
>>
>>-	/* Setup the linkage between OF nodes and PHBs */
>>-	pci_devs_phb_init();
>>-
>>  	/* Configure IOMMU DMA hooks */
>>  	ppc_md.tce_build = pnv_tce_build_vm;
>>  	ppc_md.tce_free = pnv_tce_free_vm;
>>diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
>>index df6a704..5f80758 100644
>>--- a/arch/powerpc/platforms/pseries/setup.c
>>+++ b/arch/powerpc/platforms/pseries/setup.c
>>@@ -482,7 +482,6 @@ static void __init find_and_init_phbs(void)
>>  	}
>>
>>  	of_node_put(root);
>>-	pci_devs_phb_init();
>>
>>  	/*
>>  	 * PCI_PROBE_ONLY and PCI_REASSIGN_ALL_BUS can be set via properties
>>

Thanks,
Gavin