From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: akpm@linux-foundation.org, Andrea Arcangeli <aarcange@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>, Yang Shi <yang.shi@linux.alibaba.com>,
Ralph Campbell <rcampbell@nvidia.com>,
John Hubbard <jhubbard@nvidia.com>,
William Kucharski <william.kucharski@oracle.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [PATCHv4 3/8] khugepaged: Drain all LRU caches before scanning pages
Date: Thu, 16 Apr 2020 19:00:21 +0300 [thread overview]
Message-ID: <20200416160026.16538-4-kirill.shutemov@linux.intel.com> (raw)
In-Reply-To: <20200416160026.16538-1-kirill.shutemov@linux.intel.com>
Having a page in LRU add cache offsets page refcount and gives
false-negative on PageLRU(). It reduces collapse success rate.
Drain all LRU add caches before scanning. It happens relatively
rare and should not disturb the system too much.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-and-Tested-by: Zi Yan <ziy@nvidia.com>
Acked-by: Yang Shi <yang.shi@linux.alibaba.com>
---
mm/khugepaged.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 6e69dc9a9fb1..0b75b9821f44 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2078,6 +2078,8 @@ static void khugepaged_do_scan(void)
barrier(); /* write khugepaged_pages_to_scan to local stack */
+ lru_add_drain_all();
+
while (progress < pages) {
if (!khugepaged_prealloc_page(&hpage, &wait))
break;
--
2.26.1
next prev parent reply other threads:[~2020-04-16 16:00 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-16 16:00 [PATCHv4 0/8] thp/khugepaged improvements and CoW semantics Kirill A. Shutemov
2020-04-16 16:00 ` [PATCHv4 1/8] khugepaged: Add self test Kirill A. Shutemov
2020-04-16 16:00 ` [PATCHv4 2/8] khugepaged: Do not stop collapse if less than half PTEs are referenced Kirill A. Shutemov
2020-04-16 16:00 ` Kirill A. Shutemov [this message]
2020-04-16 16:00 ` [PATCHv4 4/8] khugepaged: Drain LRU add pagevec after swapin Kirill A. Shutemov
2020-04-17 4:41 ` Andrew Morton
2020-04-17 14:59 ` Kirill A. Shutemov
2020-04-16 16:00 ` [PATCHv4 5/8] khugepaged: Allow to collapse a page shared across fork Kirill A. Shutemov
2020-04-16 16:00 ` [PATCHv4 6/8] khugepaged: Allow to collapse PTE-mapped compound pages Kirill A. Shutemov
2020-04-16 16:00 ` [PATCHv4 7/8] thp: Change CoW semantics for anon-THP Kirill A. Shutemov
2020-04-21 0:48 ` [thp] fd80f22b29: vm-scalability.median 10.3% improvement kernel test robot
2020-04-16 16:00 ` [PATCHv4 8/8] khugepaged: Introduce 'max_ptes_shared' tunable Kirill A. Shutemov
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