x86: cpa, use page pool
Switch the split page code to use the page pool. We do this
unconditionally to avoid different behaviour with and without
DEBUG_PAGEALLOC enabled.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 831462c..e5d29a1 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -411,20 +411,29 @@
static int split_large_page(pte_t *kpte, unsigned long address)
{
unsigned long flags, pfn, pfninc = 1;
- gfp_t gfp_flags = GFP_KERNEL;
unsigned int i, level;
pte_t *pbase, *tmp;
pgprot_t ref_prot;
struct page *base;
-#ifdef CONFIG_DEBUG_PAGEALLOC
- gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
-#endif
- base = alloc_pages(gfp_flags, 0);
- if (!base)
- return -ENOMEM;
-
+ /*
+ * Get a page from the pool. The pool list is protected by the
+ * pgd_lock, which we have to take anyway for the split
+ * operation:
+ */
spin_lock_irqsave(&pgd_lock, flags);
+ if (list_empty(&page_pool)) {
+ spin_unlock_irqrestore(&pgd_lock, flags);
+ return -ENOMEM;
+ }
+
+ base = list_first_entry(&page_pool, struct page, lru);
+ list_del(&base->lru);
+ pool_pages--;
+
+ if (pool_pages < pool_low)
+ pool_low = pool_pages;
+
/*
* Check for races, another CPU might have split this page
* up for us already:
@@ -469,11 +478,17 @@
base = NULL;
out_unlock:
+ /*
+ * If we dropped out via the lookup_address check under
+ * pgd_lock then stick the page back into the pool:
+ */
+ if (base) {
+ list_add(&base->lru, &page_pool);
+ pool_pages++;
+ } else
+ pool_used++;
spin_unlock_irqrestore(&pgd_lock, flags);
- if (base)
- __free_pages(base, 0);
-
return 0;
}