[IA64] make uncached allocator more node aware

The uncached allocator has a function, uncached_get_new_chunk(), that needs
to be serialized on a per node basis. It also has a global variable,
allocated_granules, which should be defined on a per node basis and protected
by that serialization. Additionally, all error returns from functions called
(like ia64_pal_mc_drain()) should be handled appropriately.

Signed-off-by: Dean Nelson <dcn@sgi.com>
Acked-by: Jes Sorenson <jes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 57 insertions, 29 deletions

diff --git a/arch/ia64/kernel/uncached.c b/arch/ia64/kernel/uncached.c
index 5f03b9e524dd..4c73a6763669 100644
--- a/arch/ia64/kernel/uncached.c
+++ b/arch/ia64/kernel/uncached.c
@@ -32,32 +32,38 @@
 
 extern void __init efi_memmap_walk_uc(efi_freemem_callback_t, void *);
 
-#define MAX_UNCACHED_GRANULES   5
-static int allocated_granules;
+struct uncached_pool {
+        struct gen_pool *pool;
+        struct mutex add_chunk_mutex;   /* serialize adding a converted chunk */
+        int nchunks_added;              /* #of converted chunks added to pool */
+        atomic_t status;                /* smp called function's return status*/
+};
+
+#define MAX_CONVERTED_CHUNKS_PER_NODE   2
 
-struct gen_pool *uncached_pool[MAX_NUMNODES];
+struct uncached_pool uncached_pools[MAX_NUMNODES];
 
 
 static void uncached_ipi_visibility(void *data)
 {
         int status;
+        struct uncached_pool *uc_pool = (struct uncached_pool *)data;
 
         status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
         if ((status != PAL_VISIBILITY_OK) &&
             (status != PAL_VISIBILITY_OK_REMOTE_NEEDED))
-                printk(KERN_DEBUG "pal_prefetch_visibility() returns %i on "
-                       "CPU %i\n", status, raw_smp_processor_id());
+                atomic_inc(&uc_pool->status);
 }
 
 
 static void uncached_ipi_mc_drain(void *data)
 {
         int status;
+        struct uncached_pool *uc_pool = (struct uncached_pool *)data;
 
         status = ia64_pal_mc_drain();
-        if (status)
-                printk(KERN_WARNING "ia64_pal_mc_drain() failed with %i on "
-                       "CPU %i\n", status, raw_smp_processor_id());
+        if (status != PAL_STATUS_SUCCESS)
+                atomic_inc(&uc_pool->status);
 }
 
 
@@ -70,21 +76,34 @@ static void uncached_ipi_mc_drain(void *data)
  * This is accomplished by first allocating a granule of cached memory pages
  * and then converting them to uncached memory pages.
  */
-static int uncached_add_chunk(struct gen_pool *pool, int nid)
+static int uncached_add_chunk(struct uncached_pool *uc_pool, int nid)
 {
         struct page *page;
-        int status, i;
+        int status, i, nchunks_added = uc_pool->nchunks_added;
         unsigned long c_addr, uc_addr;
 
-        if (allocated_granules >= MAX_UNCACHED_GRANULES)
+        if (mutex_lock_interruptible(&uc_pool->add_chunk_mutex) != 0)
+                return -1;      /* interrupted by a signal */
+
+        if (uc_pool->nchunks_added > nchunks_added) {
+                /* someone added a new chunk while we were waiting */
+                mutex_unlock(&uc_pool->add_chunk_mutex);
+                return 0;
+        }
+
+        if (uc_pool->nchunks_added >= MAX_CONVERTED_CHUNKS_PER_NODE) {
+                mutex_unlock(&uc_pool->add_chunk_mutex);
                 return -1;
+        }
 
         /* attempt to allocate a granule's worth of cached memory pages */
 
         page = alloc_pages_node(nid, GFP_KERNEL | __GFP_ZERO,
                                 IA64_GRANULE_SHIFT-PAGE_SHIFT);
-        if (!page)
+        if (!page) {
+                mutex_unlock(&uc_pool->add_chunk_mutex);
                 return -1;
+        }
 
         /* convert the memory pages from cached to uncached */
 
@@ -102,11 +121,14 @@ static int uncached_add_chunk(struct gen_pool *pool, int nid)
         flush_tlb_kernel_range(uc_addr, uc_adddr + IA64_GRANULE_SIZE);
 
         status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
-        if (!status) {
-                status = smp_call_function(uncached_ipi_visibility, NULL, 0, 1);
-                if (status)
+        if (status == PAL_VISIBILITY_OK_REMOTE_NEEDED) {
+                atomic_set(&uc_pool->status, 0);
+                status = smp_call_function(uncached_ipi_visibility, uc_pool,
+                                           0, 1);
+                if (status || atomic_read(&uc_pool->status))
                         goto failed;
-        }
+        } else if (status != PAL_VISIBILITY_OK)
+                goto failed;
 
         preempt_disable();
 
@@ -120,20 +142,24 @@ static int uncached_add_chunk(struct gen_pool *pool, int nid)
 
         preempt_enable();
 
-        ia64_pal_mc_drain();
-        status = smp_call_function(uncached_ipi_mc_drain, NULL, 0, 1);
-        if (status)
+        status = ia64_pal_mc_drain();
+        if (status != PAL_STATUS_SUCCESS)
+                goto failed;
+        atomic_set(&uc_pool->status, 0);
+        status = smp_call_function(uncached_ipi_mc_drain, uc_pool, 0, 1);
+        if (status || atomic_read(&uc_pool->status))
                 goto failed;
 
         /*
          * The chunk of memory pages has been converted to uncached so now we
          * can add it to the pool.
          */
-        status = gen_pool_add(pool, uc_addr, IA64_GRANULE_SIZE, nid);
+        status = gen_pool_add(uc_pool->pool, uc_addr, IA64_GRANULE_SIZE, nid);
         if (status)
                 goto failed;
 
-        allocated_granules++;
+        uc_pool->nchunks_added++;
+        mutex_unlock(&uc_pool->add_chunk_mutex);
         return 0;
 
         /* failed to convert or add the chunk so give it back to the kernel */
@@ -142,6 +168,7 @@ failed:
                 ClearPageUncached(&page[i]);
 
         free_pages(c_addr, IA64_GRANULE_SHIFT-PAGE_SHIFT);
+        mutex_unlock(&uc_pool->add_chunk_mutex);
         return -1;
 }
 
@@ -158,7 +185,7 @@ failed:
 unsigned long uncached_alloc_page(int starting_nid)
 {
         unsigned long uc_addr;
-        struct gen_pool *pool;
+        struct uncached_pool *uc_pool;
         int nid;
 
         if (unlikely(starting_nid >= MAX_NUMNODES))
@@ -171,14 +198,14 @@ unsigned long uncached_alloc_page(int starting_nid)
         do {
                 if (!node_online(nid))
                         continue;
-                pool = uncached_pool[nid];
-                if (pool == NULL)
+                uc_pool = &uncached_pools[nid];
+                if (uc_pool->pool == NULL)
                         continue;
                 do {
-                        uc_addr = gen_pool_alloc(pool, PAGE_SIZE);
+                        uc_addr = gen_pool_alloc(uc_pool->pool, PAGE_SIZE);
                         if (uc_addr != 0)
                                 return uc_addr;
-                } while (uncached_add_chunk(pool, nid) == 0);
+                } while (uncached_add_chunk(uc_pool, nid) == 0);
 
         } while ((nid = (nid + 1) % MAX_NUMNODES) != starting_nid);
 
@@ -197,7 +224,7 @@ EXPORT_SYMBOL(uncached_alloc_page);
 void uncached_free_page(unsigned long uc_addr)
 {
         int nid = paddr_to_nid(uc_addr - __IA64_UNCACHED_OFFSET);
-        struct gen_pool *pool = uncached_pool[nid];
+        struct gen_pool *pool = uncached_pools[nid].pool;
 
         if (unlikely(pool == NULL))
                 return;
@@ -224,7 +251,7 @@ static int __init uncached_build_memmap(unsigned long uc_start,
                                         unsigned long uc_end, void *arg)
 {
         int nid = paddr_to_nid(uc_start - __IA64_UNCACHED_OFFSET);
-        struct gen_pool *pool = uncached_pool[nid];
+        struct gen_pool *pool = uncached_pools[nid].pool;
         size_t size = uc_end - uc_start;
 
         touch_softlockup_watchdog();
@@ -242,7 +269,8 @@ static int __init uncached_init(void)
         int nid;
 
         for_each_online_node(nid) {
-                uncached_pool[nid] = gen_pool_create(PAGE_SHIFT, nid);
+                uncached_pools[nid].pool = gen_pool_create(PAGE_SHIFT, nid);
+                mutex_init(&uncached_pools[nid].add_chunk_mutex);
         }
 
         efi_memmap_walk_uc(uncached_build_memmap, NULL);