diff mbox series

[8/8] mm: fix madvise WILLNEED performance problem

Message ID 20201122061722.Tef3ViFuW%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [1/8] mm/madvise: fix memory leak from process_madvise | expand

Commit Message

Andrew Morton Nov. 22, 2020, 6:17 a.m. UTC 
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: mm: fix madvise WILLNEED performance problem

The calculation of the end page index was incorrect, leading to a
regression of 70% when running stress-ng.  With this fix, we instead
see a performance improvement of 3%.

Link: https://lkml.kernel.org/r/20201109134851.29692-1-willy@infradead.org
Fixes: e6e88712e43b ("mm: optimise madvise WILLNEED")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: kernel test robot <rong.a.chen@intel.com>
Tested-by: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: "Chen, Rong A" <rong.a.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/madvise.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

--- a/mm/madvise.c~mm-fix-madvise-willneed-performance-problem
+++ a/mm/madvise.c
@@ -226,7 +226,7 @@  static void force_shm_swapin_readahead(s
 		struct address_space *mapping)
 {
 	XA_STATE(xas, &mapping->i_pages, linear_page_index(vma, start));
-	pgoff_t end_index = end / PAGE_SIZE;
+	pgoff_t end_index = linear_page_index(vma, end + PAGE_SIZE - 1);
 	struct page *page;
 
 	rcu_read_lock();