From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx160.postini.com [74.125.245.160]) by kanga.kvack.org (Postfix) with SMTP id 0BF066B0062 for ; Fri, 7 Dec 2012 02:25:44 -0500 (EST) Date: Fri, 7 Dec 2012 08:25:41 +0100 From: Borislav Petkov Subject: Re: [PATCH] MCE: fix an error of mce_bad_pages statistics Message-ID: <20121207072541.GA27708@liondog.tnic> References: <50C15A35.5020007@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <50C15A35.5020007@huawei.com> Sender: owner-linux-mm@kvack.org List-ID: To: Xishi Qiu Cc: WuJianguo , Liujiang , andi@firstfloor.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Fri, Dec 07, 2012 at 10:53:41AM +0800, Xishi Qiu wrote: > On x86 platform, if we use "/sys/devices/system/memory/soft_offline_page" to offline a > free page twice, the value of mce_bad_pages will be added twice. So this is an error, > since the page was already marked HWPoison, we should skip the page and don't add the > value of mce_bad_pages. > > $ cat /proc/meminfo | grep HardwareCorrupted > > soft_offline_page() > get_any_page() > atomic_long_add(1, &mce_bad_pages) > > The free page which marked HWPoison is still managed by page buddy allocator. So when > offlining it again, get_any_page() always returns 0 with > "pr_info("%s: %#lx free buddy page\n", __func__, pfn);". > > When page is allocated, the PageBuddy is removed in bad_page(), then get_any_page() > returns -EIO with pr_info("%s: %#lx: unknown zero refcount page type %lx\n", so > mce_bad_pages will not be added. > > Signed-off-by: Xishi Qiu > i>>?Signed-off-by: Jiang Liu > --- > mm/memory-failure.c | 5 +++++ > 1 files changed, 5 insertions(+), 0 deletions(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 8b20278..02a522e 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1375,6 +1375,11 @@ static int get_any_page(struct page *p, unsigned long pfn, int flags) > if (flags & MF_COUNT_INCREASED) > return 1; > > + if (PageHWPoison(p)) { > + pr_info("%s: %#lx page already poisoned\n", __func__, pfn); > + return -EBUSY; > + } Shouldn't this be done in soft_offline_page() instead, like it is done in soft_offline_huge_page() for hugepages? Thanks. -- Regards/Gruss, Boris. -- 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