mm, pagealloc: micro-optimisation: save two branches on hot page allocation path

[linux-2.6-microblaze.git] / mm / internal.h

diff --git a/mm/internal.h b/mm/internal.h
index 3cf20ab..129659f 100644 (file)
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -63,6 +63,29 @@ static inline unsigned long ra_submit(struct file_ra_state *ra,
                                        ra->start, ra->size, ra->async_size);
 }
 
+/**
+ * page_evictable - test whether a page is evictable
+ * @page: the page to test
+ *
+ * Test whether page is evictable--i.e., should be placed on active/inactive
+ * lists vs unevictable list.
+ *
+ * Reasons page might not be evictable:
+ * (1) page's mapping marked unevictable
+ * (2) page is part of an mlocked VMA
+ *
+ */
+static inline bool page_evictable(struct page *page)
+{
+       bool ret;
+
+       /* Prevent address_space of inode and swap cache from being freed */
+       rcu_read_lock();
+       ret = !mapping_unevictable(page_mapping(page)) && !PageMlocked(page);
+       rcu_read_unlock();
+       return ret;
+}
+
 /*
  * Turn a non-refcounted page (->_refcount == 0) into refcounted with
  * a count of one.
@@ -377,10 +400,10 @@ static inline struct file *maybe_unlock_mmap_for_io(struct vm_fault *vmf,
        /*
         * FAULT_FLAG_RETRY_NOWAIT means we don't want to wait on page locks or
         * anything, so we only pin the file and drop the mmap_sem if only
-        * FAULT_FLAG_ALLOW_RETRY is set.
+        * FAULT_FLAG_ALLOW_RETRY is set, while this is the first attempt.
         */
-       if ((flags & (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT)) ==
-           FAULT_FLAG_ALLOW_RETRY) {
+       if (fault_flag_allow_retry_first(flags) &&
+           !(flags & FAULT_FLAG_RETRY_NOWAIT)) {
                fpin = get_file(vmf->vma->vm_file);
                up_read(&vmf->vma->vm_mm->mmap_sem);
        }
@@ -532,7 +555,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
 #else
 #define ALLOC_NOFRAGMENT         0x0
 #endif
-#define ALLOC_KSWAPD           0x200 /* allow waking of kswapd */
+#define ALLOC_KSWAPD           0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */
 
 enum ttu_flags;
 struct tlbflush_unmap_batch;