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From: Oscar Salvador <osalvador@suse.de>
To: akpm@linux-foundation.org
Cc: mhocko@suse.com, linux-mm@kvack.org, mike.kravetz@oracle.com,
	david@redhat.com, aneesh.kumar@linux.vnet.ibm.com,
	naoya.horiguchi@nec.com, linux-kernel@vger.kernel.org,
	Oscar Salvador <osalvador@suse.de>,
	Oscar Salvador <osalvador@suse.com>
Subject: [PATCH v4 14/15] mm,hwpoison: Return 0 if the page is already poisoned in soft-offline
Date: Thu, 16 Jul 2020 14:38:08 +0200	[thread overview]
Message-ID: <20200716123810.25292-15-osalvador@suse.de> (raw)
In-Reply-To: <20200716123810.25292-1-osalvador@suse.de>

Currently, there is an inconsistency when calling soft-offline from
different paths on a page that is already poisoned.

1) madvise:

        madvise_inject_error skips any poisoned page and continues
        the loop.
        If that was the only page to madvise, it returns 0.

2) /sys/devices/system/memory/:

        When calling soft_offline_page_store()->soft_offline_page(),
        we return -EBUSY in case the page is already poisoned.
        This is inconsistent with a) the above example and b)
        memory_failure, where we return 0 if the page was poisoned.

Fix this by dropping the PageHWPoison() check in madvise_inject_error,
and let soft_offline_page return 0 if it finds the page already poisoned.

Please, note that this represents a user-api change, since now the
return error when calling soft_offline_page_store()->soft_offline_page()
will be different.

Signed-off-by: Oscar Salvador <osalvador@suse.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
---
 mm/madvise.c        | 3 ---
 mm/memory-failure.c | 4 ++--
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 226f0fcf0828..7b5ca96108cd 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -920,9 +920,6 @@ static int madvise_inject_error(int behavior,
 		 */
 		put_page(page);
 
-		if (PageHWPoison(page))
-			continue;
-
 		if (behavior == MADV_SOFT_OFFLINE) {
 			pr_info("Soft offlining pfn %#lx at process virtual address %#lx\n",
 				 pfn, start);
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index c6c83337708a..2b2aa5a76b9b 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1781,7 +1781,7 @@ static int __soft_offline_page(struct page *page)
 		unlock_page(page);
 		put_page(page);
 		pr_info("soft offline: %#lx page already poisoned\n", pfn);
-		return -EBUSY;
+		return 0;
 	}
 
 	if (!PageHuge(page))
@@ -1881,7 +1881,7 @@ int soft_offline_page(unsigned long pfn)
 
 	if (PageHWPoison(page)) {
 		pr_info("soft offline: %#lx page already poisoned\n", pfn);
-		return -EBUSY;
+		return 0;
 	}
 
 	get_online_mems();
-- 
2.26.2


  parent reply	other threads:[~2020-07-16 12:38 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-16 12:37 [PATCH v4 00/15] Hwpoison soft-offline rework Oscar Salvador
2020-07-16 12:37 ` [PATCH v4 01/15] mm,hwpoison: cleanup unused PageHuge() check Oscar Salvador
2020-07-16 12:37 ` [PATCH v4 02/15] mm, hwpoison: remove recalculating hpage Oscar Salvador
2020-07-16 12:37 ` [PATCH v4 03/15] mm,madvise: call soft_offline_page() without MF_COUNT_INCREASED Oscar Salvador
2020-07-16 23:15   ` Mike Kravetz
2020-07-16 12:37 ` [PATCH v4 04/15] mm,madvise: Refactor madvise_inject_error Oscar Salvador
2020-07-16 12:37 ` [PATCH v4 05/15] mm,hwpoison-inject: don't pin for hwpoison_filter Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 06/15] mm,hwpoison: Un-export get_hwpoison_page and make it static Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 07/15] mm,hwpoison: Kill put_hwpoison_page Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 08/15] mm,hwpoison: remove MF_COUNT_INCREASED Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 09/15] mm,hwpoison: remove flag argument from soft offline functions Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 10/15] mm,hwpoison: Unify THP handling for hard and soft offline Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 11/15] mm,hwpoison: Rework soft offline for free pages Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 12/15] mm,hwpoison: Rework soft offline for in-use pages Oscar Salvador
2020-07-17  6:55   ` HORIGUCHI NAOYA(堀口 直也)
     [not found]   ` <f7387d64d0024d15a1bc821a8e19b8f0@DB7PR04MB5180.eurprd04.prod.outlook.com>
2020-07-20  8:27     ` osalvador
2020-07-22  8:08       ` osalvador
2020-07-23 10:19         ` Oscar Salvador
2020-07-16 12:38 ` [PATCH v4 13/15] mm,hwpoison: Refactor soft_offline_huge_page and __soft_offline_page Oscar Salvador
2020-07-16 12:38 ` Oscar Salvador [this message]
2020-07-16 12:38 ` [PATCH v4 15/15] mm,hwpoison: introduce MF_MSG_UNSPLIT_THP Oscar Salvador
2020-07-16 12:38 ` [PATCH] x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support Oscar Salvador
2020-07-16 12:43   ` osalvador
2020-07-17 14:49 ` [PATCH v4 00/15] Hwpoison soft-offline rework Qian Cai

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