linux-kernel - [PATCH v6 02/12] mm, hwpoison: remove recalculating hpage

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Date:   Thu,  6 Aug 2020 18:49:13 +0000
From:   nao.horiguchi@...il.com
To:     linux-mm@...ck.org
Cc:     mhocko@...nel.org, akpm@...ux-foundation.org,
        mike.kravetz@...cle.com, osalvador@...e.de, tony.luck@...el.com,
        david@...hat.com, aneesh.kumar@...ux.vnet.ibm.com,
        zeil@...dex-team.ru, cai@....pw, naoya.horiguchi@....com,
        linux-kernel@...r.kernel.org
Subject: [PATCH v6 02/12] mm, hwpoison: remove recalculating hpage

From: Naoya Horiguchi <naoya.horiguchi@....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@...ux.ibm.com>
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@....com>
Signed-off-by: Oscar Salvador <osalvador@...e.com>
Reviewed-by: Mike Kravetz <mike.kravetz@...cle.com>
---
 mm/memory-failure.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git v5.8-rc7-mmotm-2020-07-27-18-18/mm/memory-failure.c v5.8-rc7-mmotm-2020-07-27-18-18_patched/mm/memory-failure.c
index 3d2d61f1c6e9..f8d200417e0f 100644
--- v5.8-rc7-mmotm-2020-07-27-18-18/mm/memory-failure.c
+++ v5.8-rc7-mmotm-2020-07-27-18-18_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