[PATCH] modify the IO_TLB_SEGSIZE to io_tlb_segsize configurable as flexible requirement about SW-IOMMU.

xiaomin1
2015-02-05T07:06:48Z

The maximum of SW-IOMMU is limited to 2^11*128 = 256K.
While in different platform and different requirements this seems improper.
So modify the IO_TLB_SEGSIZE to io_tlb_segsize as configurable is make sense.

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Zhang Dongxing <dongxing.zhang@intel.com>
Signed-off-by: xiaomin1 <xiaoming.wang@intel.com>
---
arch/mips/cavium-octeon/dma-octeon.c | 2 +-
arch/mips/netlogic/common/nlm-dma.c | 2 +-
drivers/xen/swiotlb-xen.c | 6 +++---
include/linux/swiotlb.h | 8 +------
lib/swiotlb.c | 39 ++++++++++++++++++++++++----------
5 files changed, 34 insertions(+), 23 deletions(-)

diff --git a/arch/mips/cavium-octeon/dma-octeon.c b/arch/mips/cavium-octeon/dma-octeon.c
index 3778655..a521af6 100644
--- a/arch/mips/cavium-octeon/dma-octeon.c
+++ b/arch/mips/cavium-octeon/dma-octeon.c
@@ -312,7 +312,7 @@ void __init plat_swiotlb_setup(void)
swiotlbsize = 64 * (1<<20);
#endif
swiotlb_nslabs = swiotlbsize >> IO_TLB_SHIFT;
- swiotlb_nslabs = ALIGN(swiotlb_nslabs, IO_TLB_SEGSIZE);
+ swiotlb_nslabs = ALIGN(swiotlb_nslabs, io_tlb_segsize);
swiotlbsize = swiotlb_nslabs << IO_TLB_SHIFT;

octeon_swiotlb = alloc_bootmem_low_pages(swiotlbsize);
diff --git a/arch/mips/netlogic/common/nlm-dma.c b/arch/mips/netlogic/common/nlm-dma.c
index f3d4ae8..eeffa8f 100644
--- a/arch/mips/netlogic/common/nlm-dma.c
+++ b/arch/mips/netlogic/common/nlm-dma.c
@@ -99,7 +99,7 @@ void __init plat_swiotlb_setup(void)

swiotlbsize = 1 << 20; /* 1 MB for now */
swiotlb_nslabs = swiotlbsize >> IO_TLB_SHIFT;
- swiotlb_nslabs = ALIGN(swiotlb_nslabs, IO_TLB_SEGSIZE);
+ swiotlb_nslabs = ALIGN(swiotlb_nslabs, io_tlb_segsize);
swiotlbsize = swiotlb_nslabs << IO_TLB_SHIFT;

nlm_swiotlb = alloc_bootmem_low_pages(swiotlbsize);
diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 810ad41..3b3e9fe 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -164,11 +164,11 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
dma_addr_t dma_handle;
phys_addr_t p = virt_to_phys(buf);

- dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
+ dma_bits = get_order(io_tlb_segsize << IO_TLB_SHIFT) + PAGE_SHIFT;

i = 0;
do {
- int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE);
+ int slabs = min(nslabs - i, (unsigned long)io_tlb_segsize);

do {
rc = xen_create_contiguous_region(
@@ -187,7 +187,7 @@ static unsigned long xen_set_nslabs(unsigned long nr_tbl)
{
if (!nr_tbl) {
xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
- xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
+ xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, io_tlb_segsize);
} else
xen_io_tlb_nslabs = nr_tbl;

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index e7a018e..13506db 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -8,13 +8,7 @@ struct dma_attrs;
struct scatterlist;

extern int swiotlb_force;
-
-/*
- * Maximum allowable number of contiguous slabs to map,
- * must be a power of 2. What is the appropriate value ?
- * The complexity of {map,unmap}_single is linearly dependent on this value.
- */
-#define IO_TLB_SEGSIZE 128
+extern int io_tlb_segsize;

/*
* log of the size of each IO TLB slab. The number of slabs is command line
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 4abda07..50c415a 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -56,6 +56,15 @@
int swiotlb_force;

/*
+ * Maximum allowable number of contiguous slabs to map,
+ * must be a power of 2. What is the appropriate value ?
+ * define io_tlb_segsize as a parameter
+ * which can be changed dynamically in config file for special usage.
+ * The complexity of {map,unmap}_single is linearly dependent on this value.
+ */
+int io_tlb_segsize = 128;
+
+/*
* Used to do a quick range check in swiotlb_tbl_unmap_single and
* swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
* API.
@@ -97,12 +106,20 @@ static DEFINE_SPINLOCK(io_tlb_lock);
static int late_alloc;

static int __init
+setup_io_tlb_segsize(char *str)
+{
+ get_option(&str, &io_tlb_segsize);
+ return 0;
+}
+__setup("io_tlb_segsize=", setup_io_tlb_segsize);
+
+static int __init
setup_io_tlb_npages(char *str)
{
if (isdigit(*str)) {
io_tlb_nslabs = simple_strtoul(str, &str, 0);
- /* avoid tail segment of size < IO_TLB_SEGSIZE */
- io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+ /* avoid tail segment of size < io_tlb_segsize */
+ io_tlb_nslabs = ALIGN(io_tlb_nslabs, io_tlb_segsize);
}
if (*str == ',')
++str;
@@ -183,7 +200,7 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)

/*
* Allocate and initialize the free list array. This array is used
- * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
+ * to find contiguous free memory regions of size up to io_tlb_segsize
* between io_tlb_start and io_tlb_end.
*/
io_tlb_list = memblock_virt_alloc(
@@ -193,7 +210,7 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)),
PAGE_SIZE);
for (i = 0; i < io_tlb_nslabs; i++) {
- io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+ io_tlb_list[i] = io_tlb_segsize - OFFSET(i, io_tlb_segsize);
io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
}
io_tlb_index = 0;
@@ -217,7 +234,7 @@ swiotlb_init(int verbose)

if (!io_tlb_nslabs) {
io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
- io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+ io_tlb_nslabs = ALIGN(io_tlb_nslabs, io_tlb_segsize);
}

bytes = io_tlb_nslabs << IO_TLB_SHIFT;
@@ -249,7 +266,7 @@ swiotlb_late_init_with_default_size(size_t default_size)

if (!io_tlb_nslabs) {
io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
- io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
+ io_tlb_nslabs = ALIGN(io_tlb_nslabs, io_tlb_segsize);
}

/*
@@ -308,7 +325,7 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)

/*
* Allocate and initialize the free list array. This array is used
- * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
+ * to find contiguous free memory regions of size up to io_tlb_segsize
* between io_tlb_start and io_tlb_end.
*/
io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL,
@@ -324,7 +341,7 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
goto cleanup4;

for (i = 0; i < io_tlb_nslabs; i++) {
- io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
+ io_tlb_list[i] = io_tlb_segsize - OFFSET(i, io_tlb_segsize);
io_tlb_orig_addr[i] = INVALID_PHYS_ADDR;
}
io_tlb_index = 0;
@@ -493,7 +510,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,

for (i = index; i < (int) (index + nslots); i++)
io_tlb_list[i] = 0;
- for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && io_tlb_list[i]; i--)
+ for (i = index - 1; (OFFSET(i, io_tlb_segsize) != io_tlb_segsize - 1) && io_tlb_list[i]; i--)
io_tlb_list[i] = ++count;
tlb_addr = io_tlb_start + (index << IO_TLB_SHIFT);

@@ -571,7 +588,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
*/
spin_lock_irqsave(&io_tlb_lock, flags);
{
- count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
+ count = ((index + nslots) < ALIGN(index + 1, io_tlb_segsize) ?
io_tlb_list[index + nslots] : 0);
/*
* Step 1: return the slots to the free list, merging the
@@ -585,7 +602,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
* Step 2: merge the returned slots with the preceding slots,
* if available (non zero)
*/
- for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
+ for (i = index - 1; (OFFSET(i, io_tlb_segsize) != io_tlb_segsize -1) && io_tlb_list[i]; i--)
io_tlb_list[i] = ++count;
}
spin_unlock_irqrestore(&io_tlb_lock, flags);
--
1.7.9.5