In iperf experiments running linux as the Tx side (TCP client) with
10 threads results in a severe performance drop when TSO is disabled,
indicating a weakness in the software that can be avoided by using
the scalable IOMMU arena DMA allocation.
Baseline numbers before this patch:
with default settings (TSO enabled) : 9-9.5 Gbps
Disable TSO using ethtool- drops badly: 2-3 Gbps.
After this patch, iperf client with 10 threads, can give a
throughput of at least 8.5 Gbps, even when TSO is disabled.
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx>
---
arch/sparc/kernel/pci_impl.h | 7 ++-
arch/sparc/kernel/pci_sun4v.c | 201 +++++++++++++++++++----------------------
2 files changed, 99 insertions(+), 109 deletions(-)
diff --git a/arch/sparc/kernel/pci_impl.h b/arch/sparc/kernel/pci_impl.h
index 75803c7..2236c37 100644
--- a/arch/sparc/kernel/pci_impl.h
+++ b/arch/sparc/kernel/pci_impl.h
@@ -142,7 +142,12 @@ struct pci_pbm_info {
struct strbuf stc;
/* IOMMU state, potentially shared by both PBM segments. */
- struct iommu *iommu;
+#ifdef notyet
+ struct iommu_table *iommu;
+#else
+ /* change only pci_sun4v and DMA to use new iommu_table for now */
+ void *iommu;
+#endif
/* Now things for the actual PCI bus probes. */
unsigned int pci_first_busno;
diff --git a/arch/sparc/kernel/pci_sun4v.c b/arch/sparc/kernel/pci_sun4v.c
index 49d33b1..964b69d 100644
--- a/arch/sparc/kernel/pci_sun4v.c
+++ b/arch/sparc/kernel/pci_sun4v.c
@@ -20,14 +20,17 @@
#include <asm/irq.h>
#include <asm/hypervisor.h>
#include <asm/prom.h>
+#include <linux/hash.h>
#include "pci_impl.h"
#include "iommu_common.h"
+#include <linux/iommu-common.h>
#include "pci_sun4v.h"
#define DRIVER_NAME "pci_sun4v"
#define PFX DRIVER_NAME ": "
+static DEFINE_PER_CPU(unsigned int, iommu_pool_hash);
static unsigned long vpci_major = 1;
static unsigned long vpci_minor = 1;
@@ -132,7 +135,7 @@ static void *dma_4v_alloc_coherent(struct device *dev, size_t size,
struct dma_attrs *attrs)
{
unsigned long flags, order, first_page, npages, n;
- struct iommu *iommu;
+ struct iommu_table *iommu;
struct page *page;
void *ret;
long entry;
@@ -155,11 +158,10 @@ static void *dma_4v_alloc_coherent(struct device *dev, size_t size,
iommu = dev->archdata.iommu;
- spin_lock_irqsave(&iommu->lock, flags);
- entry = iommu_range_alloc(dev, iommu, npages, NULL);
- spin_unlock_irqrestore(&iommu->lock, flags);
+ entry = iommu_tbl_range_alloc(dev, iommu, npages, NULL,
+ __raw_get_cpu_var(iommu_pool_hash));
- if (unlikely(entry == DMA_ERROR_CODE))
+ if (unlikely(entry == IOMMU_ERROR_CODE))
goto range_alloc_fail;
*dma_addrp = (iommu->page_table_map_base +
@@ -188,22 +190,35 @@ static void *dma_4v_alloc_coherent(struct device *dev, size_t size,
return ret;
iommu_map_fail:
- /* Interrupts are disabled. */
- spin_lock(&iommu->lock);
- iommu_range_free(iommu, *dma_addrp, npages);
- spin_unlock_irqrestore(&iommu->lock, flags);
+ iommu_tbl_range_free(iommu, *dma_addrp, npages, false, NULL);
range_alloc_fail:
free_pages(first_page, order);
return NULL;
}
+static void dma_4v_iommu_demap(void *demap_arg, unsigned long entry,
+ unsigned long npages)
+{
+ u32 devhandle = *(u32 *)demap_arg;
+ unsigned long num;
+
+ do {
+ num = pci_sun4v_iommu_demap(devhandle,
+ HV_PCI_TSBID(0, entry),
+ npages);
+
+ entry += num;
+ npages -= num;
+ } while (npages != 0);
+}
+
static void dma_4v_free_coherent(struct device *dev, size_t size, void *cpu,
dma_addr_t dvma, struct dma_attrs *attrs)
{
struct pci_pbm_info *pbm;
- struct iommu *iommu;
- unsigned long flags, order, npages, entry;
+ struct iommu_table *iommu;
+ unsigned long order, npages, entry;
u32 devhandle;
npages = IO_PAGE_ALIGN(size) >> IO_PAGE_SHIFT;
@@ -211,22 +226,7 @@ static void dma_4v_free_coherent(struct device *dev, size_t size, void *cpu,
pbm = dev->archdata.host_controller;
devhandle = pbm->devhandle;
entry = ((dvma - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
-
- spin_lock_irqsave(&iommu->lock, flags);
-
- iommu_range_free(iommu, dvma, npages);
-
- do {
- unsigned long num;
-
- num = pci_sun4v_iommu_demap(devhandle, HV_PCI_TSBID(0, entry),
- npages);
- entry += num;
- npages -= num;
- } while (npages != 0);
-
- spin_unlock_irqrestore(&iommu->lock, flags);
-
+ iommu_tbl_range_free(iommu, dvma, npages, true, &devhandle);
order = get_order(size);
if (order < 10)
free_pages((unsigned long)cpu, order);
@@ -237,7 +237,7 @@ static dma_addr_t dma_4v_map_page(struct device *dev, struct page *page,
enum dma_data_direction direction,
struct dma_attrs *attrs)
{
- struct iommu *iommu;
+ struct iommu_table *iommu;
unsigned long flags, npages, oaddr;
unsigned long i, base_paddr;
u32 bus_addr, ret;
@@ -253,11 +253,10 @@ static dma_addr_t dma_4v_map_page(struct device *dev, struct page *page,
npages = IO_PAGE_ALIGN(oaddr + sz) - (oaddr & IO_PAGE_MASK);
npages >>= IO_PAGE_SHIFT;
- spin_lock_irqsave(&iommu->lock, flags);
- entry = iommu_range_alloc(dev, iommu, npages, NULL);
- spin_unlock_irqrestore(&iommu->lock, flags);
+ entry = iommu_tbl_range_alloc(dev, iommu, npages, NULL,
+ __raw_get_cpu_var(iommu_pool_hash));
- if (unlikely(entry == DMA_ERROR_CODE))
+ if (unlikely(entry == IOMMU_ERROR_CODE))
goto bad;
bus_addr = (iommu->page_table_map_base +
@@ -287,15 +286,11 @@ static dma_addr_t dma_4v_map_page(struct device *dev, struct page *page,
bad:
if (printk_ratelimit())
WARN_ON(1);
- return DMA_ERROR_CODE;
+ return IOMMU_ERROR_CODE;
iommu_map_fail:
- /* Interrupts are disabled. */
- spin_lock(&iommu->lock);
- iommu_range_free(iommu, bus_addr, npages);
- spin_unlock_irqrestore(&iommu->lock, flags);
-
- return DMA_ERROR_CODE;
+ iommu_tbl_range_free(iommu, bus_addr, npages, false, NULL);
+ return IOMMU_ERROR_CODE;
}
static void dma_4v_unmap_page(struct device *dev, dma_addr_t bus_addr,
@@ -303,9 +298,8 @@ static void dma_4v_unmap_page(struct device *dev, dma_addr_t bus_addr,
struct dma_attrs *attrs)
{
struct pci_pbm_info *pbm;
- struct iommu *iommu;
- unsigned long flags, npages;
- long entry;
+ struct iommu_table *iommu;
+ unsigned long npages;
u32 devhandle;
if (unlikely(direction == DMA_NONE)) {
@@ -321,22 +315,7 @@ static void dma_4v_unmap_page(struct device *dev, dma_addr_t bus_addr,
npages = IO_PAGE_ALIGN(bus_addr + sz) - (bus_addr & IO_PAGE_MASK);
npages >>= IO_PAGE_SHIFT;
bus_addr &= IO_PAGE_MASK;
-
- spin_lock_irqsave(&iommu->lock, flags);
-
- iommu_range_free(iommu, bus_addr, npages);
-
- entry = (bus_addr - iommu->page_table_map_base) >> IO_PAGE_SHIFT;
- do {
- unsigned long num;
-
- num = pci_sun4v_iommu_demap(devhandle, HV_PCI_TSBID(0, entry),
- npages);
- entry += num;
- npages -= num;
- } while (npages != 0);
-
- spin_unlock_irqrestore(&iommu->lock, flags);
+ iommu_tbl_range_free(iommu, bus_addr, npages, true, &devhandle);
}
static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
@@ -349,7 +328,7 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
unsigned int max_seg_size;
unsigned long seg_boundary_size;
int outcount, incount, i;
- struct iommu *iommu;
+ struct iommu_table *iommu;
unsigned long base_shift;
long err;
@@ -371,7 +350,7 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
/* Init first segment length for backout at failure */
outs->dma_length = 0;
- spin_lock_irqsave(&iommu->lock, flags);
+ local_irq_save(flags);
iommu_batch_start(dev, prot, ~0UL);
@@ -391,10 +370,11 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
/* Allocate iommu entries for that segment */
paddr = (unsigned long) SG_ENT_PHYS_ADDRESS(s);
npages = iommu_num_pages(paddr, slen, IO_PAGE_SIZE);
- entry = iommu_range_alloc(dev, iommu, npages, &handle);
+ entry = iommu_tbl_range_alloc(dev, iommu, npages, &handle,
+ __raw_get_cpu_var(iommu_pool_hash));
/* Handle failure */
- if (unlikely(entry == DMA_ERROR_CODE)) {
+ if (unlikely(entry == IOMMU_ERROR_CODE)) {
if (printk_ratelimit())
printk(KERN_INFO "iommu_alloc failed, iommu %p paddr %lx"
" npages %lx\n", iommu, paddr, npages);
@@ -451,11 +431,11 @@ static int dma_4v_map_sg(struct device *dev, struct scatterlist *sglist,
if (unlikely(err < 0L))
goto iommu_map_failed;
- spin_unlock_irqrestore(&iommu->lock, flags);
+ local_irq_restore(flags);
if (outcount < incount) {
outs = sg_next(outs);
- outs->dma_address = DMA_ERROR_CODE;
+ outs->dma_address = IOMMU_ERROR_CODE;
outs->dma_length = 0;
}
@@ -469,15 +449,15 @@ iommu_map_failed:
vaddr = s->dma_address & IO_PAGE_MASK;
npages = iommu_num_pages(s->dma_address, s->dma_length,
IO_PAGE_SIZE);
- iommu_range_free(iommu, vaddr, npages);
+ iommu_tbl_range_free(iommu, vaddr, npages, false, NULL);
/* XXX demap? XXX */
- s->dma_address = DMA_ERROR_CODE;
+ s->dma_address = IOMMU_ERROR_CODE;
s->dma_length = 0;
}
if (s == outs)
break;
}
- spin_unlock_irqrestore(&iommu->lock, flags);
+ local_irq_restore(flags);
return 0;
}
@@ -488,7 +468,7 @@ static void dma_4v_unmap_sg(struct device *dev, struct scatterlist *sglist,
{
struct pci_pbm_info *pbm;
struct scatterlist *sg;
- struct iommu *iommu;
+ struct iommu_table *iommu;
unsigned long flags;
u32 devhandle;
@@ -498,33 +478,23 @@ static void dma_4v_unmap_sg(struct device *dev, struct scatterlist *sglist,
pbm = dev->archdata.host_controller;
devhandle = pbm->devhandle;
- spin_lock_irqsave(&iommu->lock, flags);
+ local_irq_save(flags);
sg = sglist;
while (nelems--) {
dma_addr_t dma_handle = sg->dma_address;
unsigned int len = sg->dma_length;
- unsigned long npages, entry;
+ unsigned long npages;
if (!len)
break;
npages = iommu_num_pages(dma_handle, len, IO_PAGE_SIZE);
- iommu_range_free(iommu, dma_handle, npages);
-
- entry = ((dma_handle - iommu->page_table_map_base) >> IO_PAGE_SHIFT);
- while (npages) {
- unsigned long num;
-
- num = pci_sun4v_iommu_demap(devhandle, HV_PCI_TSBID(0, entry),
- npages);
- entry += num;
- npages -= num;
- }
-
+ iommu_tbl_range_free(iommu, dma_handle, npages,
+ true, &devhandle);
sg = sg_next(sg);
}
- spin_unlock_irqrestore(&iommu->lock, flags);
+ local_irq_restore(flags);
}
static struct dma_map_ops sun4v_dma_ops = {
@@ -536,6 +506,10 @@ static struct dma_map_ops sun4v_dma_ops = {
.unmap_sg = dma_4v_unmap_sg,
};
+static struct iommu_ops dma_4v_iommu_ops = {
+ .demap = dma_4v_iommu_demap,
+};
+
static void pci_sun4v_scan_bus(struct pci_pbm_info *pbm, struct device *parent)
{
struct property *prop;
@@ -550,37 +524,40 @@ static void pci_sun4v_scan_bus(struct pci_pbm_info *pbm, struct device *parent)
}
static unsigned long probe_existing_entries(struct pci_pbm_info *pbm,
- struct iommu *iommu)
+ struct iommu_table *iommu)
{
- struct iommu_arena *arena = &iommu->arena;
- unsigned long i, cnt = 0;
+ struct iommu_pool *pool;
+ unsigned long i, pool_nr, cnt = 0;
u32 devhandle;
devhandle = pbm->devhandle;
- for (i = 0; i < arena->limit; i++) {
- unsigned long ret, io_attrs, ra;
-
- ret = pci_sun4v_iommu_getmap(devhandle,
- HV_PCI_TSBID(0, i),
- &io_attrs, &ra);
- if (ret == HV_EOK) {
- if (page_in_phys_avail(ra)) {
- pci_sun4v_iommu_demap(devhandle,
- HV_PCI_TSBID(0, i), 1);
- } else {
- cnt++;
- __set_bit(i, arena->map);
+ for (pool_nr = 0; pool_nr < iommu->nr_pools; pool_nr++) {
+ pool = &(iommu->arena_pool[pool_nr]);
+ for (i = pool->start; i <= pool->end; i++) {
+ unsigned long ret, io_attrs, ra;
+
+ ret = pci_sun4v_iommu_getmap(devhandle,
+ HV_PCI_TSBID(0, i),
+ &io_attrs, &ra);
+ if (ret == HV_EOK) {
+ if (page_in_phys_avail(ra)) {
+ pci_sun4v_iommu_demap(devhandle,
+ HV_PCI_TSBID(0, i),
+ 1);
+ } else {
+ cnt++;
+ __set_bit(i, iommu->map);
+ }
}
}
}
-
return cnt;
}
static int pci_sun4v_iommu_init(struct pci_pbm_info *pbm)
{
static const u32 vdma_default[] = { 0x80000000, 0x80000000 };
- struct iommu *iommu = pbm->iommu;
+ struct iommu_table *iommu = pbm->iommu;
unsigned long num_tsb_entries, sz;
u32 dma_mask, dma_offset;
const u32 *vdma;
@@ -601,7 +578,6 @@ static int pci_sun4v_iommu_init(struct pci_pbm_info *pbm)
dma_offset = vdma[0];
/* Setup initial software IOMMU state. */
- spin_lock_init(&iommu->lock);
iommu->ctx_lowest_free = 1;
iommu->page_table_map_base = dma_offset;
iommu->dma_addr_mask = dma_mask;
@@ -609,13 +585,13 @@ static int pci_sun4v_iommu_init(struct pci_pbm_info *pbm)
/* Allocate and initialize the free area map. */
sz = (num_tsb_entries + 7) / 8;
sz = (sz + 7UL) & ~7UL;
- iommu->arena.map = kzalloc(sz, GFP_KERNEL);
- if (!iommu->arena.map) {
+ iommu->map = kzalloc(sz, GFP_KERNEL);
+ if (!iommu->map) {
printk(KERN_ERR PFX "Error, kmalloc(arena.map) failed.\n");
return -ENOMEM;
}
- iommu->arena.limit = num_tsb_entries;
-
+ iommu_tbl_pool_init(iommu, num_tsb_entries, IO_PAGE_SHIFT,
+ &dma_4v_iommu_ops, false /* no large_pool */);
sz = probe_existing_entries(pbm, iommu);
if (sz)
printk("%s: Imported %lu TSB entries from OBP\n",
@@ -924,7 +900,7 @@ static int pci_sun4v_probe(struct platform_device *op)
static int hvapi_negotiated = 0;
struct pci_pbm_info *pbm;
struct device_node *dp;
- struct iommu *iommu;
+ struct iommu_table *iommu;
u32 devhandle;
int i, err;
@@ -973,7 +949,7 @@ static int pci_sun4v_probe(struct platform_device *op)
goto out_err;
}
- iommu = kzalloc(sizeof(struct iommu), GFP_KERNEL);
+ iommu = kzalloc(sizeof(struct iommu_table), GFP_KERNEL);
if (!iommu) {
printk(KERN_ERR PFX "Could not allocate pbm iommu\n");
goto out_free_controller;
@@ -1016,8 +992,17 @@ static struct platform_driver pci_sun4v_driver = {
.probe = pci_sun4v_probe,
};
+static void setup_iommu_pool_hash(void)
+{
+ unsigned int i;
+
+ for_each_possible_cpu(i)
+ per_cpu(iommu_pool_hash, i) = hash_32(i, IOMMU_POOL_HASHBITS);
+}
+
static int __init pci_sun4v_init(void)
{
+ setup_iommu_pool_hash();
return platform_driver_register(&pci_sun4v_driver);
}
--
1.7.1
--
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