From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f181.google.com (mail-ob0-f181.google.com [209.85.214.181]) by kanga.kvack.org (Postfix) with ESMTP id 4130D6B0253 for ; Mon, 10 Aug 2015 04:29:26 -0400 (EDT) Received: by obbhe7 with SMTP id he7so22398716obb.0 for ; Mon, 10 Aug 2015 01:29:26 -0700 (PDT) Received: from BLU004-OMC1S29.hotmail.com (blu004-omc1s29.hotmail.com. [65.55.116.40]) by mx.google.com with ESMTPS id 15si1628756oib.131.2015.08.10.01.29.25 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 10 Aug 2015 01:29:25 -0700 (PDT) Message-ID: Subject: Re: [PATCH 1/2] mm/hwpoison: fix fail to split THP w/ refcount held References: <20150810081019.GA21282@hori1.linux.bs1.fc.nec.co.jp> From: Wanpeng Li Date: Mon, 10 Aug 2015 16:29:18 +0800 MIME-Version: 1.0 In-Reply-To: <20150810081019.GA21282@hori1.linux.bs1.fc.nec.co.jp> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Naoya Horiguchi Cc: Andrew Morton , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Hi Naoya, On 8/10/15 4:10 PM, Naoya Horiguchi wrote: > On Mon, Aug 10, 2015 at 02:32:30PM +0800, Wanpeng Li wrote: >> THP pages will get a refcount in madvise_hwpoison() w/ MF_COUNT_INCREASED >> flag, however, the refcount is still held when fail to split THP pages. >> >> Fix it by reducing the refcount of THP pages when fail to split THP. >> >> Signed-off-by: Wanpeng Li > It seems that the same conditional put_page() would be added to > "soft offline: %#lx page already poisoned" branch too, right? PageHWPoison() is just called before the soft_offline_page() in madvise_hwpoion(). I think the PageHWPosion() check in soft_offline_page() makes more sense for the other soft_offline_page() callsites which don't have the refcount held. Regards, Wanpeng Li > >> --- >> mm/memory-failure.c | 2 ++ >> 1 files changed, 2 insertions(+), 0 deletions(-) >> >> diff --git a/mm/memory-failure.c b/mm/memory-failure.c >> index 8077b1c..56b8a71 100644 >> --- a/mm/memory-failure.c >> +++ b/mm/memory-failure.c >> @@ -1710,6 +1710,8 @@ int soft_offline_page(struct page *page, int flags) >> if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) { >> pr_info("soft offline: %#lx: failed to split THP\n", >> pfn); >> + if (flags & MF_COUNT_INCREASED) >> + put_page(page); >> return -EBUSY; >> } >> } >> -- >> 1.7.1 >> >> -- >> To unsubscribe, send a message with 'unsubscribe linux-mm' in >> the body to majordomo@kvack.org. For more info on Linux MM, >> see: http://www.linux-mm.org/ . >> Don't email: email@kvack.org -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org