From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, feng.tang@intel.com,
hannes@cmpxchg.org, linux-mm@kvack.org,
mm-commits@vger.kernel.org, rong.a.chen@intel.com,
torvalds@linux-foundation.org, william.kucharski@oracle.com,
willy@infradead.org, zhengjun.xing@linux.intel.com
Subject: [patch 8/8] mm: fix madvise WILLNEED performance problem
Date: Sat, 21 Nov 2020 22:17:22 -0800 [thread overview]
Message-ID: <20201122061722.Tef3ViFuW%akpm@linux-foundation.org> (raw)
In-Reply-To: <20201121221631.948ae4655e913a319d61700a@linux-foundation.org>
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(-)
--- 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();
_
prev parent reply other threads:[~2020-11-22 6:17 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-22 6:16 incoming Andrew Morton
2020-11-22 6:16 ` [patch 1/8] mm/madvise: fix memory leak from process_madvise Andrew Morton
2020-11-22 6:17 ` [patch 2/8] compiler-clang: remove version check for BPF Tracing Andrew Morton
2020-11-22 6:17 ` [patch 3/8] mm: fix phys_to_target_node() and memory_add_physaddr_to_nid() exports Andrew Morton
2020-11-22 6:17 ` [patch 4/8] mm: fix readahead_page_batch for retry entries Andrew Morton
2020-11-22 6:17 ` [patch 5/8] mm: memcg/slab: fix root memcg vmstats Andrew Morton
2020-11-22 6:17 ` [patch 6/8] mm/userfaultfd: do not access vma->vm_mm after calling handle_userfault() Andrew Morton
2020-11-22 6:17 ` [patch 7/8] libfs: fix error cast of negative value in simple_attr_write() Andrew Morton
2020-11-22 6:17 ` Andrew Morton [this message]
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