staging: drm/imx: fix double free bug in error path

[karo-tx-linux.git] / mm / internal.h

diff --git a/mm/internal.h b/mm/internal.h
index b84d571a64aec8858a48402a8c17c14889f1802a..8228054d5d8b03679efaaaee7e1be7e2df98a93b 100644 (file)
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -12,6 +12,7 @@
 #define __MM_INTERNAL_H
 
 #include <linux/mm.h>
+#include <linux/rmap.h>
 
 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
                unsigned long floor, unsigned long ceiling);
@@ -91,6 +92,11 @@ extern unsigned long highest_memmap_pfn;
 extern int isolate_lru_page(struct page *page);
 extern void putback_lru_page(struct page *page);
 
+/*
+ * in mm/rmap.c:
+ */
+extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
+
 /*
  * in mm/page_alloc.c
  */
@@ -368,4 +374,51 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
 #define ALLOC_CPUSET           0x40 /* check for correct cpuset */
 #define ALLOC_CMA              0x80 /* allow allocations from CMA areas */
 
+/*
+ * Unnecessary readahead harms performance, especially for SSD devices, where
+ * large reads are significantly more expensive than small ones.
+ * These implements simple swap random access detection. In swap page fault: if
+ * the page is found in swapcache, decrease a counter in the vma, otherwise we
+ * need to perform sync swapin and the counter is increased.  Optionally swapin
+ * will perform readahead if the counter is below a threshold.
+ */
+#ifdef CONFIG_SWAP
+#define SWAPRA_MISS_THRESHOLD  (100)
+#define SWAPRA_MAX_MISS ((SWAPRA_MISS_THRESHOLD) * 10)
+static inline void swap_cache_hit(struct vm_area_struct *vma)
+{
+       if (vma && vma->anon_vma)
+               atomic_dec_if_positive(&vma->anon_vma->swapra_miss);
+}
+
+static inline void swap_cache_miss(struct vm_area_struct *vma)
+{
+       if (!vma || !vma->anon_vma)
+               return;
+       if (atomic_read(&vma->anon_vma->swapra_miss) < SWAPRA_MAX_MISS)
+               atomic_inc(&vma->anon_vma->swapra_miss);
+}
+
+static inline int swap_cache_skip_readahead(struct vm_area_struct *vma)
+{
+       if (!vma || !vma->anon_vma)
+               return 0;
+       return atomic_read(&vma->anon_vma->swapra_miss) >
+               SWAPRA_MISS_THRESHOLD;
+}
+#else
+static inline void swap_cache_hit(struct vm_area_struct *vma)
+{
+}
+
+static inline void swap_cache_miss(struct vm_area_struct *vma)
+{
+}
+
+static inline int swap_cache_skip_readahead(struct vm_area_struct *vma)
+{
+       return 0;
+}
+#endif /* CONFIG_SWAP */
+
 #endif /* __MM_INTERNAL_H */