X-Git-Url: https://git.kernelconcepts.de/?a=blobdiff_plain;f=mm%2Ffadvise.c;h=a430131125815803ba25a7014917c6118087dd5c;hb=4dd72b4a47a5309333c8ddf9ec7df3380dede30d;hp=6c707bfe02fde002feae9ea2fab3fc9647c3baa0;hpb=3ef500a53f8c44ca82decf79dd8138fd07c7739d;p=karo-tx-linux.git

diff --git a/mm/fadvise.c b/mm/fadvise.c
index 6c707bfe02fd..a43013112581 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -139,7 +139,20 @@ SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
 		}
 
 		if (end_index >= start_index) {
-			unsigned long count = invalidate_mapping_pages(mapping,
+			unsigned long count;
+
+			/*
+			 * It's common to FADV_DONTNEED right after
+			 * the read or write that instantiates the
+			 * pages, in which case there will be some
+			 * sitting on the local LRU cache. Try to
+			 * avoid the expensive remote drain and the
+			 * second cache tree walk below by flushing
+			 * them out right away.
+			 */
+			lru_add_drain();
+
+			count = invalidate_mapping_pages(mapping,
 						start_index, end_index);
 
 			/*