From 5d2efba64b231a1733c4048d1708d77e07f26426 Mon Sep 17 00:00:00 2001 From: Linas Vepstas Date: Mon, 30 Oct 2006 16:15:59 +1100 Subject: [POWERPC] Use 4kB iommu pages even on 64kB-page systems The 10Gigabit ethernet device drivers appear to be able to chew up all 256MB of TCE mappings on pSeries systems, as evidenced by numerous error messages: iommu_alloc failed, tbl c0000000010d5c48 vaddr c0000000d875eff0 npages 1 Some experimentation indicates that this is essentially because one 1500 byte ethernet MTU gets mapped as a 64K DMA region when the large 64K pages are enabled. Thus, it doesn't take much to exhaust all of the available DMA mappings for a high-speed card. This patch changes the iommu allocator to work with its own unique, distinct page size. Although the patch is long, its actually quite simple: it just #defines a distinct IOMMU_PAGE_SIZE and then uses this in all the places that matter. As a side effect, it also dramatically improves network performance on platforms with H-calls on iommu translation inserts/removes (since we no longer call it 16 times for a 1500 bytes packet when the iommu HW is still 4k). In the future, we might want to make the IOMMU_PAGE_SIZE a variable in the iommu_table instance, thus allowing support for different HW page sizes in the iommu itself. Signed-off-by: Linas Vepstas Signed-off-by: Benjamin Herrenschmidt Acked-by: Olof Johansson Acked-by: Stephen Rothwell Signed-off-by: Paul Mackerras --- arch/powerpc/kernel/iommu.c | 77 ++++++++++++++++++++++++++------------------- 1 file changed, 45 insertions(+), 32 deletions(-) (limited to 'arch/powerpc/kernel/iommu.c') diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index f88a2a675d90..ba6b7256084b 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -47,6 +47,17 @@ static int novmerge = 0; static int novmerge = 1; #endif +static inline unsigned long iommu_num_pages(unsigned long vaddr, + unsigned long slen) +{ + unsigned long npages; + + npages = IOMMU_PAGE_ALIGN(vaddr + slen) - (vaddr & IOMMU_PAGE_MASK); + npages >>= IOMMU_PAGE_SHIFT; + + return npages; +} + static int __init setup_iommu(char *str) { if (!strcmp(str, "novmerge")) @@ -178,10 +189,10 @@ static dma_addr_t iommu_alloc(struct iommu_table *tbl, void *page, } entry += tbl->it_offset; /* Offset into real TCE table */ - ret = entry << PAGE_SHIFT; /* Set the return dma address */ + ret = entry << IOMMU_PAGE_SHIFT; /* Set the return dma address */ /* Put the TCEs in the HW table */ - ppc_md.tce_build(tbl, entry, npages, (unsigned long)page & PAGE_MASK, + ppc_md.tce_build(tbl, entry, npages, (unsigned long)page & IOMMU_PAGE_MASK, direction); @@ -203,7 +214,7 @@ static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr, unsigned long entry, free_entry; unsigned long i; - entry = dma_addr >> PAGE_SHIFT; + entry = dma_addr >> IOMMU_PAGE_SHIFT; free_entry = entry - tbl->it_offset; if (((free_entry + npages) > tbl->it_size) || @@ -270,7 +281,7 @@ int iommu_map_sg(struct device *dev, struct iommu_table *tbl, /* Init first segment length for backout at failure */ outs->dma_length = 0; - DBG("mapping %d elements:\n", nelems); + DBG("sg mapping %d elements:\n", nelems); spin_lock_irqsave(&(tbl->it_lock), flags); @@ -285,9 +296,8 @@ int iommu_map_sg(struct device *dev, struct iommu_table *tbl, } /* Allocate iommu entries for that segment */ vaddr = (unsigned long)page_address(s->page) + s->offset; - npages = PAGE_ALIGN(vaddr + slen) - (vaddr & PAGE_MASK); - npages >>= PAGE_SHIFT; - entry = iommu_range_alloc(tbl, npages, &handle, mask >> PAGE_SHIFT, 0); + npages = iommu_num_pages(vaddr, slen); + entry = iommu_range_alloc(tbl, npages, &handle, mask >> IOMMU_PAGE_SHIFT, 0); DBG(" - vaddr: %lx, size: %lx\n", vaddr, slen); @@ -301,14 +311,14 @@ int iommu_map_sg(struct device *dev, struct iommu_table *tbl, /* Convert entry to a dma_addr_t */ entry += tbl->it_offset; - dma_addr = entry << PAGE_SHIFT; - dma_addr |= s->offset; + dma_addr = entry << IOMMU_PAGE_SHIFT; + dma_addr |= (s->offset & ~IOMMU_PAGE_MASK); - DBG(" - %lx pages, entry: %lx, dma_addr: %lx\n", + DBG(" - %lu pages, entry: %lx, dma_addr: %lx\n", npages, entry, dma_addr); /* Insert into HW table */ - ppc_md.tce_build(tbl, entry, npages, vaddr & PAGE_MASK, direction); + ppc_md.tce_build(tbl, entry, npages, vaddr & IOMMU_PAGE_MASK, direction); /* If we are in an open segment, try merging */ if (segstart != s) { @@ -323,7 +333,7 @@ int iommu_map_sg(struct device *dev, struct iommu_table *tbl, DBG(" can't merge, new segment.\n"); } else { outs->dma_length += s->length; - DBG(" merged, new len: %lx\n", outs->dma_length); + DBG(" merged, new len: %ux\n", outs->dma_length); } } @@ -367,9 +377,8 @@ int iommu_map_sg(struct device *dev, struct iommu_table *tbl, if (s->dma_length != 0) { unsigned long vaddr, npages; - vaddr = s->dma_address & PAGE_MASK; - npages = (PAGE_ALIGN(s->dma_address + s->dma_length) - vaddr) - >> PAGE_SHIFT; + vaddr = s->dma_address & IOMMU_PAGE_MASK; + npages = iommu_num_pages(s->dma_address, s->dma_length); __iommu_free(tbl, vaddr, npages); s->dma_address = DMA_ERROR_CODE; s->dma_length = 0; @@ -398,8 +407,7 @@ void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist, if (sglist->dma_length == 0) break; - npages = (PAGE_ALIGN(dma_handle + sglist->dma_length) - - (dma_handle & PAGE_MASK)) >> PAGE_SHIFT; + npages = iommu_num_pages(dma_handle,sglist->dma_length); __iommu_free(tbl, dma_handle, npages); sglist++; } @@ -532,12 +540,11 @@ dma_addr_t iommu_map_single(struct iommu_table *tbl, void *vaddr, BUG_ON(direction == DMA_NONE); uaddr = (unsigned long)vaddr; - npages = PAGE_ALIGN(uaddr + size) - (uaddr & PAGE_MASK); - npages >>= PAGE_SHIFT; + npages = iommu_num_pages(uaddr, size); if (tbl) { dma_handle = iommu_alloc(tbl, vaddr, npages, direction, - mask >> PAGE_SHIFT, 0); + mask >> IOMMU_PAGE_SHIFT, 0); if (dma_handle == DMA_ERROR_CODE) { if (printk_ratelimit()) { printk(KERN_INFO "iommu_alloc failed, " @@ -545,7 +552,7 @@ dma_addr_t iommu_map_single(struct iommu_table *tbl, void *vaddr, tbl, vaddr, npages); } } else - dma_handle |= (uaddr & ~PAGE_MASK); + dma_handle |= (uaddr & ~IOMMU_PAGE_MASK); } return dma_handle; @@ -554,11 +561,14 @@ dma_addr_t iommu_map_single(struct iommu_table *tbl, void *vaddr, void iommu_unmap_single(struct iommu_table *tbl, dma_addr_t dma_handle, size_t size, enum dma_data_direction direction) { + unsigned int npages; + BUG_ON(direction == DMA_NONE); - if (tbl) - iommu_free(tbl, dma_handle, (PAGE_ALIGN(dma_handle + size) - - (dma_handle & PAGE_MASK)) >> PAGE_SHIFT); + if (tbl) { + npages = iommu_num_pages(dma_handle, size); + iommu_free(tbl, dma_handle, npages); + } } /* Allocates a contiguous real buffer and creates mappings over it. @@ -570,11 +580,11 @@ void *iommu_alloc_coherent(struct iommu_table *tbl, size_t size, { void *ret = NULL; dma_addr_t mapping; - unsigned int npages, order; + unsigned int order; + unsigned int nio_pages, io_order; struct page *page; size = PAGE_ALIGN(size); - npages = size >> PAGE_SHIFT; order = get_order(size); /* @@ -598,8 +608,10 @@ void *iommu_alloc_coherent(struct iommu_table *tbl, size_t size, memset(ret, 0, size); /* Set up tces to cover the allocated range */ - mapping = iommu_alloc(tbl, ret, npages, DMA_BIDIRECTIONAL, - mask >> PAGE_SHIFT, order); + nio_pages = size >> IOMMU_PAGE_SHIFT; + io_order = get_iommu_order(size); + mapping = iommu_alloc(tbl, ret, nio_pages, DMA_BIDIRECTIONAL, + mask >> IOMMU_PAGE_SHIFT, io_order); if (mapping == DMA_ERROR_CODE) { free_pages((unsigned long)ret, order); return NULL; @@ -611,12 +623,13 @@ void *iommu_alloc_coherent(struct iommu_table *tbl, size_t size, void iommu_free_coherent(struct iommu_table *tbl, size_t size, void *vaddr, dma_addr_t dma_handle) { - unsigned int npages; - if (tbl) { + unsigned int nio_pages; + + size = PAGE_ALIGN(size); + nio_pages = size >> IOMMU_PAGE_SHIFT; + iommu_free(tbl, dma_handle, nio_pages); size = PAGE_ALIGN(size); - npages = size >> PAGE_SHIFT; - iommu_free(tbl, dma_handle, npages); free_pages((unsigned long)vaddr, get_order(size)); } } -- cgit v1.2.3