From 80b20dd853a2b00802e6254dc9f690f0da1a925c Mon Sep 17 00:00:00 2001 From: mark gross Date: Fri, 18 Apr 2008 13:53:58 -0700 Subject: [PATCH] PCI: pci-iommu-iotlb-flushing-speedup The following patch is an update to use an array instead of a list of IOVA's in the implementation of defered iotlb flushes. It takes inspiration from sba_iommu.c I like this implementation better as it encapsulates the batch process within intel-iommu.c, and no longer touches iova.h (which is shared) Performance data: Netperf 32byte UDP streaming 2.6.25-rc3-mm1: IOMMU-strict : 58Mps @ 62% cpu NO-IOMMU : 71Mbs @ 41% cpu List-based IOMMU-default-batched-IOTLB flush: 66Mbps @ 57% cpu with this patch: IOMMU-strict : 73Mps @ 75% cpu NO-IOMMU : 74Mbs @ 42% cpu Array-based IOMMU-default-batched-IOTLB flush: 72Mbps @ 62% cpu Signed-off-by: Cc: Grant Grundler Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- drivers/pci/intel-iommu.c | 76 ++++++++++++++++++++------------------- drivers/pci/iova.h | 2 -- 2 files changed, 40 insertions(+), 38 deletions(-) diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index 8690a0d45d7..301c68fab03 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -59,8 +59,17 @@ static void flush_unmaps_timeout(unsigned long data); DEFINE_TIMER(unmap_timer, flush_unmaps_timeout, 0, 0); static struct intel_iommu *g_iommus; + +#define HIGH_WATER_MARK 250 +struct deferred_flush_tables { + int next; + struct iova *iova[HIGH_WATER_MARK]; + struct dmar_domain *domain[HIGH_WATER_MARK]; +}; + +static struct deferred_flush_tables *deferred_flush; + /* bitmap for indexing intel_iommus */ -static unsigned long *g_iommus_to_flush; static int g_num_of_iommus; static DEFINE_SPINLOCK(async_umap_flush_lock); @@ -68,10 +77,6 @@ static LIST_HEAD(unmaps_to_do); static int timer_on; static long list_size; -static int high_watermark; - -static struct dentry *intel_iommu_debug, *debug; - static void domain_remove_dev_info(struct dmar_domain *domain); @@ -1692,7 +1697,7 @@ int __init init_dmars(void) struct dmar_rmrr_unit *rmrr; struct pci_dev *pdev; struct intel_iommu *iommu; - int nlongs, i, ret, unit = 0; + int i, ret, unit = 0; /* * for each drhd @@ -1711,17 +1716,16 @@ int __init init_dmars(void) */ } - nlongs = BITS_TO_LONGS(g_num_of_iommus); - g_iommus_to_flush = kzalloc(nlongs * sizeof(unsigned long), GFP_KERNEL); - if (!g_iommus_to_flush) { - printk(KERN_ERR "Intel-IOMMU: " - "Allocating bitmap array failed\n"); - return -ENOMEM; - } - g_iommus = kzalloc(g_num_of_iommus * sizeof(*iommu), GFP_KERNEL); if (!g_iommus) { - kfree(g_iommus_to_flush); + ret = -ENOMEM; + goto error; + } + + deferred_flush = kzalloc(g_num_of_iommus * + sizeof(struct deferred_flush_tables), GFP_KERNEL); + if (!deferred_flush) { + kfree(g_iommus); ret = -ENOMEM; goto error; } @@ -1970,42 +1974,48 @@ error: static void flush_unmaps(void) { - struct iova *node, *n; - unsigned long flags; - int i; + int i, j; - spin_lock_irqsave(&async_umap_flush_lock, flags); timer_on = 0; /* just flush them all */ for (i = 0; i < g_num_of_iommus; i++) { - if (test_and_clear_bit(i, g_iommus_to_flush)) + if (deferred_flush[i].next) { iommu_flush_iotlb_global(&g_iommus[i], 0); + for (j = 0; j < deferred_flush[i].next; j++) { + __free_iova(&deferred_flush[i].domain[j]->iovad, + deferred_flush[i].iova[j]); + } + deferred_flush[i].next = 0; + } } - list_for_each_entry_safe(node, n, &unmaps_to_do, list) { - /* free iova */ - list_del(&node->list); - __free_iova(&((struct dmar_domain *)node->dmar)->iovad, node); - - } list_size = 0; - spin_unlock_irqrestore(&async_umap_flush_lock, flags); } static void flush_unmaps_timeout(unsigned long data) { + unsigned long flags; + + spin_lock_irqsave(&async_umap_flush_lock, flags); flush_unmaps(); + spin_unlock_irqrestore(&async_umap_flush_lock, flags); } static void add_unmap(struct dmar_domain *dom, struct iova *iova) { unsigned long flags; + int next, iommu_id; spin_lock_irqsave(&async_umap_flush_lock, flags); - iova->dmar = dom; - list_add(&iova->list, &unmaps_to_do); - set_bit((dom->iommu - g_iommus), g_iommus_to_flush); + if (list_size == HIGH_WATER_MARK) + flush_unmaps(); + + iommu_id = dom->iommu - g_iommus; + next = deferred_flush[iommu_id].next; + deferred_flush[iommu_id].domain[next] = dom; + deferred_flush[iommu_id].iova[next] = iova; + deferred_flush[iommu_id].next++; if (!timer_on) { mod_timer(&unmap_timer, jiffies + msecs_to_jiffies(10)); @@ -2054,8 +2064,6 @@ static void intel_unmap_single(struct device *dev, dma_addr_t dev_addr, * queue up the release of the unmap to save the 1/6th of the * cpu used up by the iotlb flush operation... */ - if (list_size > high_watermark) - flush_unmaps(); } } @@ -2380,10 +2388,6 @@ int __init intel_iommu_init(void) if (dmar_table_init()) return -ENODEV; - high_watermark = 250; - intel_iommu_debug = debugfs_create_dir("intel_iommu", NULL); - debug = debugfs_create_u32("high_watermark", S_IWUGO | S_IRUGO, - intel_iommu_debug, &high_watermark); iommu_init_mempool(); dmar_init_reserved_ranges(); diff --git a/drivers/pci/iova.h b/drivers/pci/iova.h index 2f1317801b2..228f6c94b69 100644 --- a/drivers/pci/iova.h +++ b/drivers/pci/iova.h @@ -24,8 +24,6 @@ struct iova { struct rb_node node; unsigned long pfn_hi; /* IOMMU dish out addr hi */ unsigned long pfn_lo; /* IOMMU dish out addr lo */ - struct list_head list; - void *dmar; }; /* holds all the iova translations for a domain */