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yaml --- r: 338740 b: refs/heads/master c: e749eb9 h: refs/heads/master v: v3
git-mirror · Dec 12, 2012 · aa0be8f · aa0be8f
1 parent 7d4c954
commit aa0be8f
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Showing 3 changed files with 9 additions and 4 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 712cd386fdc983d318fecf302a2a9cb8e9de90c9
+refs/heads/master: e749eb95531ac8349df47f8d46ce2641dcb16589
diff --git a/trunk/arch/s390/include/asm/page.h b/trunk/arch/s390/include/asm/page.h
@@ -158,6 +158,9 @@ static inline int page_reset_referenced(unsigned long addr)
  * race against modification of the referenced bit. This function
  * should therefore only be called if it is not mapped in any
  * address space.
+ *
+ * Note that the bit gets set whenever page content is changed. That means
+ * also when the page is modified by DMA or from inside the kernel.
  */
 #define __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
 static inline int page_test_and_clear_dirty(unsigned long pfn, int mapped)

diff --git a/trunk/mm/rmap.c b/trunk/mm/rmap.c
@@ -1151,9 +1151,11 @@ void page_remove_rmap(struct page *page)
 	 * containing the swap entry, but page not yet written to swap.
 	 *
 	 * And we can skip it on file pages, so long as the filesystem
-	 * participates in dirty tracking; but need to catch shm and tmpfs
-	 * and ramfs pages which have been modified since creation by read
-	 * fault.
+	 * participates in dirty tracking (note that this is not only an
+	 * optimization but also solves problems caused by dirty flag in
+	 * storage key getting set by a write from inside kernel); but need to
+	 * catch shm and tmpfs and ramfs pages which have been modified since
+	 * creation by read fault.
 	 *
 	 * Note that mapping must be decided above, before decrementing
 	 * mapcount (which luckily provides a barrier): once page is unmapped,