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From:   nao.horiguchi@gmail.com
To:     linux-mm@kvack.org
Cc:     mhocko@kernel.org, akpm@linux-foundation.org,
        mike.kravetz@oracle.com, osalvador@suse.de, tony.luck@intel.com,
        david@redhat.com, aneesh.kumar@linux.vnet.ibm.com,
        zeil@yandex-team.ru, naoya.horiguchi@nec.com,
        linux-kernel@vger.kernel.org
Subject: [PATCH v3 02/15] mm, hwpoison: remove recalculating hpage
Date:   Wed, 24 Jun 2020 15:01:24 +0000
Message-Id: <20200624150137.7052-3-nao.horiguchi@gmail.com>
In-Reply-To: <20200624150137.7052-1-nao.horiguchi@gmail.com>
References: <20200624150137.7052-1-nao.horiguchi@gmail.com>
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From: Naoya Horiguchi <naoya.horiguchi@nec.com>

hpage is never used after try_to_split_thp_page() in memory_failure(),
so we don't have to update hpage.  So let's not recalculate/use hpage.

Suggested-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
---
 mm/memory-failure.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git v5.8-rc1-mmots-2020-06-20-21-44/mm/memory-failure.c v5.8-rc1-mmots-2020-06-20-21-44_patched/mm/memory-failure.c
index e5d0c14c2332..d2d6010764e7 100644
--- v5.8-rc1-mmots-2020-06-20-21-44/mm/memory-failure.c
+++ v5.8-rc1-mmots-2020-06-20-21-44_patched/mm/memory-failure.c
@@ -1342,7 +1342,6 @@ int memory_failure(unsigned long pfn, int flags)
 		}
 		unlock_page(p);
 		VM_BUG_ON_PAGE(!page_count(p), p);
-		hpage = compound_head(p);
 	}
 
 	/*
@@ -1414,11 +1413,8 @@ int memory_failure(unsigned long pfn, int flags)
 	/*
 	 * Now take care of user space mappings.
 	 * Abort on fail: __delete_from_page_cache() assumes unmapped page.
-	 *
-	 * When the raw error page is thp tail page, hpage points to the raw
-	 * page after thp split.
 	 */
-	if (!hwpoison_user_mappings(p, pfn, flags, &hpage)) {
+	if (!hwpoison_user_mappings(p, pfn, flags, &p)) {
 		action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);
 		res = -EBUSY;
 		goto out;
-- 
2.17.1