arch/tile: support 4KB page size as well as 64KB

The Tilera architecture traditionally supports 64KB page sizes
to improve TLB utilization and improve performance when the
hardware is being used primarily to run a single application.

For more generic server scenarios, it can be beneficial to run
with 4KB page sizes, so this commit allows that to be specified
(by modifying the arch/tile/include/hv/pagesize.h header).

As part of this change, we also re-worked the PTE management
slightly so that PTE writes all go through a __set_pte() function
where we can do some additional validation.  The set_pte_order()
function was eliminated since the "order" argument wasn't being used.

One bug uncovered was in the PCI DMA code, which wasn't properly
flushing the specified range.  This was benign with 64KB pages,
but with 4KB pages we were getting some larger flushes wrong.

The per-cpu memory reservation code also needed updating to
conform with the newer percpu stuff; before it always chose 64KB,
and that was always correct, but with 4KB granularity we now have
to pay closer attention and reserve the amount of memory that will
be requested when the percpu code starts allocating.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

1 files changed, 12 insertions, 8 deletions

diff --git a/arch/tile/kernel/setup.c b/arch/tile/kernel/setup.c
index f185736..3696b18 100644
--- a/arch/tile/kernel/setup.c
+++ b/arch/tile/kernel/setup.c
@@ -59,6 +59,8 @@ unsigned long __initdata node_memmap_pfn[MAX_NUMNODES];
 unsigned long __initdata node_percpu_pfn[MAX_NUMNODES];
 unsigned long __initdata node_free_pfn[MAX_NUMNODES];
 
+static unsigned long __initdata node_percpu[MAX_NUMNODES];
+
 #ifdef CONFIG_HIGHMEM
 /* Page frame index of end of lowmem on each controller. */
 unsigned long __cpuinitdata node_lowmem_end_pfn[MAX_NUMNODES];
@@ -554,7 +556,6 @@ static void __init setup_bootmem_allocator(void)
 		reserve_bootmem(crashk_res.start,
 			crashk_res.end - crashk_res.start + 1, 0);
 #endif
-
 }
 
 void *__init alloc_remap(int nid, unsigned long size)
@@ -568,11 +569,13 @@ void *__init alloc_remap(int nid, unsigned long size)
 
 static int __init percpu_size(void)
 {
-	int size = ALIGN(__per_cpu_end - __per_cpu_start, PAGE_SIZE);
-#ifdef CONFIG_MODULES
-	if (size < PERCPU_ENOUGH_ROOM)
-		size = PERCPU_ENOUGH_ROOM;
-#endif
+	int size = __per_cpu_end - __per_cpu_start;
+	size += PERCPU_MODULE_RESERVE;
+	size += PERCPU_DYNAMIC_EARLY_SIZE;
+	if (size < PCPU_MIN_UNIT_SIZE)
+		size = PCPU_MIN_UNIT_SIZE;
+	size = roundup(size, PAGE_SIZE);
+
 	/* In several places we assume the per-cpu data fits on a huge page. */
 	BUG_ON(kdata_huge && size > HPAGE_SIZE);
 	return size;
@@ -589,7 +592,6 @@ static inline unsigned long alloc_bootmem_pfn(int size, unsigned long goal)
 static void __init zone_sizes_init(void)
 {
 	unsigned long zones_size[MAX_NR_ZONES] = { 0 };
-	unsigned long node_percpu[MAX_NUMNODES] = { 0 };
 	int size = percpu_size();
 	int num_cpus = smp_height * smp_width;
 	int i;
@@ -674,7 +676,7 @@ static void __init zone_sizes_init(void)
 		NODE_DATA(i)->bdata = NODE_DATA(0)->bdata;
 
 		free_area_init_node(i, zones_size, start, NULL);
-		printk(KERN_DEBUG "  DMA zone: %ld per-cpu pages\n",
+		printk(KERN_DEBUG "  Normal zone: %ld per-cpu pages\n",
 		       PFN_UP(node_percpu[i]));
 
 		/* Track the type of memory on each node */
@@ -1312,6 +1314,8 @@ static void *__init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
 
 	BUG_ON(size % PAGE_SIZE != 0);
 	pfn_offset[nid] += size / PAGE_SIZE;
+	BUG_ON(node_percpu[nid] < size);
+	node_percpu[nid] -= size;
 	if (percpu_pfn[cpu] == 0)
 		percpu_pfn[cpu] = pfn;
 	return pfn_to_kaddr(pfn);