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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2020-11-21 22:17:22 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-11-22 10:48:22 -0800 |
| commit | 66383800df9cbdbf3b0c34d5a51bf35bcdb72fd2 (patch) | |
| tree | 8172ec6d41fcdbd0af75ce75135f793b52ce5125 /mm/madvise.c | |
| parent | 488dac0c9237647e9b8f788b6a342595bfa40bda (diff) | |
| download | lwn-66383800df9cbdbf3b0c34d5a51bf35bcdb72fd2.tar.gz lwn-66383800df9cbdbf3b0c34d5a51bf35bcdb72fd2.zip | |
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%.
Fixes: e6e88712e43b ("mm: optimise madvise WILLNEED")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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>
Link: https://lkml.kernel.org/r/20201109134851.29692-1-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/madvise.c')
| -rw-r--r-- | mm/madvise.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/madvise.c b/mm/madvise.c index 7e773f949ef9..a8d8d48a57fe 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -226,7 +226,7 @@ static void force_shm_swapin_readahead(struct vm_area_struct *vma, 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(); |