memcg: add interface to move charge at task migration
[linux-2.6.git] / mm / highmem.c
index b36b83b..9c1e627 100644 (file)
@@ -26,7 +26,6 @@
 #include <linux/init.h>
 #include <linux/hash.h>
 #include <linux/highmem.h>
-#include <linux/blktrace_api.h>
 #include <asm/tlbflush.h>
 
 /*
@@ -67,6 +66,25 @@ pte_t * pkmap_page_table;
 
 static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait);
 
+/*
+ * Most architectures have no use for kmap_high_get(), so let's abstract
+ * the disabling of IRQ out of the locking in that case to save on a
+ * potential useless overhead.
+ */
+#ifdef ARCH_NEEDS_KMAP_HIGH_GET
+#define lock_kmap()             spin_lock_irq(&kmap_lock)
+#define unlock_kmap()           spin_unlock_irq(&kmap_lock)
+#define lock_kmap_any(flags)    spin_lock_irqsave(&kmap_lock, flags)
+#define unlock_kmap_any(flags)  spin_unlock_irqrestore(&kmap_lock, flags)
+#else
+#define lock_kmap()             spin_lock(&kmap_lock)
+#define unlock_kmap()           spin_unlock(&kmap_lock)
+#define lock_kmap_any(flags)    \
+               do { spin_lock(&kmap_lock); (void)(flags); } while (0)
+#define unlock_kmap_any(flags)  \
+               do { spin_unlock(&kmap_lock); (void)(flags); } while (0)
+#endif
+
 static void flush_all_zero_pkmaps(void)
 {
        int i;
@@ -113,9 +131,9 @@ static void flush_all_zero_pkmaps(void)
  */
 void kmap_flush_unused(void)
 {
-       spin_lock(&kmap_lock);
+       lock_kmap();
        flush_all_zero_pkmaps();
-       spin_unlock(&kmap_lock);
+       unlock_kmap();
 }
 
 static inline unsigned long map_new_virtual(struct page *page)
@@ -145,10 +163,10 @@ start:
 
                        __set_current_state(TASK_UNINTERRUPTIBLE);
                        add_wait_queue(&pkmap_map_wait, &wait);
-                       spin_unlock(&kmap_lock);
+                       unlock_kmap();
                        schedule();
                        remove_wait_queue(&pkmap_map_wait, &wait);
-                       spin_lock(&kmap_lock);
+                       lock_kmap();
 
                        /* Somebody else might have mapped it while we slept */
                        if (page_address(page))
@@ -184,29 +202,59 @@ void *kmap_high(struct page *page)
         * For highmem pages, we can't trust "virtual" until
         * after we have the lock.
         */
-       spin_lock(&kmap_lock);
+       lock_kmap();
        vaddr = (unsigned long)page_address(page);
        if (!vaddr)
                vaddr = map_new_virtual(page);
        pkmap_count[PKMAP_NR(vaddr)]++;
        BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 2);
-       spin_unlock(&kmap_lock);
+       unlock_kmap();
        return (void*) vaddr;
 }
 
 EXPORT_SYMBOL(kmap_high);
 
+#ifdef ARCH_NEEDS_KMAP_HIGH_GET
+/**
+ * kmap_high_get - pin a highmem page into memory
+ * @page: &struct page to pin
+ *
+ * Returns the page's current virtual memory address, or NULL if no mapping
+ * exists.  When and only when a non null address is returned then a
+ * matching call to kunmap_high() is necessary.
+ *
+ * This can be called from any context.
+ */
+void *kmap_high_get(struct page *page)
+{
+       unsigned long vaddr, flags;
+
+       lock_kmap_any(flags);
+       vaddr = (unsigned long)page_address(page);
+       if (vaddr) {
+               BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 1);
+               pkmap_count[PKMAP_NR(vaddr)]++;
+       }
+       unlock_kmap_any(flags);
+       return (void*) vaddr;
+}
+#endif
+
 /**
  * kunmap_high - map a highmem page into memory
  * @page: &struct page to unmap
+ *
+ * If ARCH_NEEDS_KMAP_HIGH_GET is not defined then this may be called
+ * only from user context.
  */
 void kunmap_high(struct page *page)
 {
        unsigned long vaddr;
        unsigned long nr;
+       unsigned long flags;
        int need_wakeup;
 
-       spin_lock(&kmap_lock);
+       lock_kmap_any(flags);
        vaddr = (unsigned long)page_address(page);
        BUG_ON(!vaddr);
        nr = PKMAP_NR(vaddr);
@@ -232,7 +280,7 @@ void kunmap_high(struct page *page)
                 */
                need_wakeup = waitqueue_active(&pkmap_map_wait);
        }
-       spin_unlock(&kmap_lock);
+       unlock_kmap_any(flags);
 
        /* do wake-up, if needed, race-free outside of the spin lock */
        if (need_wakeup)
@@ -373,3 +421,55 @@ void __init page_address_init(void)
 }
 
 #endif /* defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL) */
+
+#if defined(CONFIG_DEBUG_HIGHMEM) && defined(CONFIG_TRACE_IRQFLAGS_SUPPORT)
+
+void debug_kmap_atomic(enum km_type type)
+{
+       static int warn_count = 10;
+
+       if (unlikely(warn_count < 0))
+               return;
+
+       if (unlikely(in_interrupt())) {
+               if (in_nmi()) {
+                       if (type != KM_NMI && type != KM_NMI_PTE) {
+                               WARN_ON(1);
+                               warn_count--;
+                       }
+               } else if (in_irq()) {
+                       if (type != KM_IRQ0 && type != KM_IRQ1 &&
+                           type != KM_BIO_SRC_IRQ && type != KM_BIO_DST_IRQ &&
+                           type != KM_BOUNCE_READ && type != KM_IRQ_PTE) {
+                               WARN_ON(1);
+                               warn_count--;
+                       }
+               } else if (!irqs_disabled()) {  /* softirq */
+                       if (type != KM_IRQ0 && type != KM_IRQ1 &&
+                           type != KM_SOFTIRQ0 && type != KM_SOFTIRQ1 &&
+                           type != KM_SKB_SUNRPC_DATA &&
+                           type != KM_SKB_DATA_SOFTIRQ &&
+                           type != KM_BOUNCE_READ) {
+                               WARN_ON(1);
+                               warn_count--;
+                       }
+               }
+       }
+
+       if (type == KM_IRQ0 || type == KM_IRQ1 || type == KM_BOUNCE_READ ||
+                       type == KM_BIO_SRC_IRQ || type == KM_BIO_DST_IRQ ||
+                       type == KM_IRQ_PTE || type == KM_NMI ||
+                       type == KM_NMI_PTE ) {
+               if (!irqs_disabled()) {
+                       WARN_ON(1);
+                       warn_count--;
+               }
+       } else if (type == KM_SOFTIRQ0 || type == KM_SOFTIRQ1) {
+               if (irq_count() == 0 && !irqs_disabled()) {
+                       WARN_ON(1);
+                       warn_count--;
+               }
+       }
+}
+
+#endif