X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=mm%2Fkhugepaged.c;h=58b0d9c502a1a4ebac2a6820af0c4287f9997438;hb=2d0f6b0aab9afbd6fdf3514cb4acc249d7aebf9c;hp=e749e568e1eabc9367c8c731149dfd9473aeadf4;hpb=9b14b066796d0e8bd05f200f30cb4222f8c0f9f1;p=linux-2.6-microblaze.git

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index e749e568e1ea..58b0d9c502a1 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -56,6 +56,9 @@ enum scan_result {
 #define CREATE_TRACE_POINTS
 #include <trace/events/huge_memory.h>
 
+static struct task_struct *khugepaged_thread __read_mostly;
+static DEFINE_MUTEX(khugepaged_mutex);
+
 /* default scan 8*512 pte (or vmas) every 30 second */
 static unsigned int khugepaged_pages_to_scan __read_mostly;
 static unsigned int khugepaged_pages_collapsed;
@@ -914,6 +917,18 @@ static struct page *khugepaged_alloc_hugepage(bool *wait)
 
 static bool khugepaged_prealloc_page(struct page **hpage, bool *wait)
 {
+	/*
+	 * If the hpage allocated earlier was briefly exposed in page cache
+	 * before collapse_file() failed, it is possible that racing lookups
+	 * have not yet completed, and would then be unpleasantly surprised by
+	 * finding the hpage reused for the same mapping at a different offset.
+	 * Just release the previous allocation if there is any danger of that.
+	 */
+	if (*hpage && page_count(*hpage) > 1) {
+		put_page(*hpage);
+		*hpage = NULL;
+	}
+
 	if (!*hpage)
 		*hpage = khugepaged_alloc_hugepage(wait);
 
@@ -1709,7 +1724,7 @@ static void collapse_file(struct mm_struct *mm,
 				xas_unlock_irq(&xas);
 				page_cache_sync_readahead(mapping, &file->f_ra,
 							  file, index,
-							  PAGE_SIZE);
+							  end - index);
 				/* drain pagevecs to help isolate_lru_page() */
 				lru_add_drain();
 				page = find_lock_page(mapping, index);
@@ -2292,8 +2307,6 @@ static void set_recommended_min_free_kbytes(void)
 
 int start_stop_khugepaged(void)
 {
-	static struct task_struct *khugepaged_thread __read_mostly;
-	static DEFINE_MUTEX(khugepaged_mutex);
 	int err = 0;
 
 	mutex_lock(&khugepaged_mutex);
@@ -2320,3 +2333,11 @@ fail:
 	mutex_unlock(&khugepaged_mutex);
 	return err;
 }
+
+void khugepaged_min_free_kbytes_update(void)
+{
+	mutex_lock(&khugepaged_mutex);
+	if (khugepaged_enabled() && khugepaged_thread)
+		set_recommended_min_free_kbytes();
+	mutex_unlock(&khugepaged_mutex);
+}