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Message-Id: <1433351167-125878-32-git-send-email-kirill.shutemov@linux.intel.com>
Date: Wed, 3 Jun 2015 20:06:02 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Andrea Arcangeli <aarcange@...hat.com>,
Hugh Dickins <hughd@...gle.com>
Cc: Dave Hansen <dave.hansen@...el.com>, Mel Gorman <mgorman@...e.de>,
Rik van Riel <riel@...hat.com>,
Vlastimil Babka <vbabka@...e.cz>,
Christoph Lameter <cl@...two.org>,
Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
Steve Capper <steve.capper@...aro.org>,
"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
Johannes Weiner <hannes@...xchg.org>,
Michal Hocko <mhocko@...e.cz>,
Jerome Marchand <jmarchan@...hat.com>,
Sasha Levin <sasha.levin@...cle.com>,
linux-kernel@...r.kernel.org, linux-mm@...ck.org,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCHv6 31/36] thp, mm: split_huge_page(): caller need to lock page
We're going to use migration entries instead of compound_lock() to
stabilize page refcounts. Setup and remove migration entries require
page to be locked.
Some of split_huge_page() callers already have the page locked. Let's
require everybody to lock the page before calling split_huge_page().
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Tested-by: Sasha Levin <sasha.levin@...cle.com>
Acked-by: Vlastimil Babka <vbabka@...e.cz>
---
mm/memory-failure.c | 10 ++++++++--
mm/migrate.c | 8 ++++++--
2 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 1cf7f2988422..0d9989a36d32 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1143,15 +1143,18 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
put_page(hpage);
return -EBUSY;
}
+ lock_page(hpage);
if (unlikely(split_huge_page(hpage))) {
pr_err("MCE: %#lx: thp split failed\n", pfn);
if (TestClearPageHWPoison(p))
atomic_long_sub(nr_pages, &num_poisoned_pages);
+ unlock_page(hpage);
put_page(p);
if (p != hpage)
put_page(hpage);
return -EBUSY;
}
+ unlock_page(hpage);
VM_BUG_ON_PAGE(!page_count(p), p);
hpage = compound_head(p);
}
@@ -1714,10 +1717,13 @@ int soft_offline_page(struct page *page, int flags)
return -EBUSY;
}
if (!PageHuge(page) && PageTransHuge(hpage)) {
- if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {
+ lock_page(page);
+ ret = split_huge_page(hpage);
+ unlock_page(page);
+ if (unlikely(ret)) {
pr_info("soft offline: %#lx: failed to split THP\n",
pfn);
- return -EBUSY;
+ return ret;
}
}
diff --git a/mm/migrate.c b/mm/migrate.c
index dfd24cb7afc6..8bb2107b8751 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -933,9 +933,13 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page,
goto out;
}
- if (unlikely(PageTransHuge(page)))
- if (unlikely(split_huge_page(page)))
+ if (unlikely(PageTransHuge(page))) {
+ lock_page(page);
+ rc = split_huge_page(page);
+ unlock_page(page);
+ if (rc)
goto out;
+ }
rc = __unmap_and_move(page, newpage, force, mode);
--
2.1.4
--
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