From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 10A5F13A27D for ; Thu, 23 May 2024 02:31:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.190 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716431523; cv=none; b=smSJ6pYuHloaMfz+CKr+olUzcXS1fjw3AZjmcLT8O0Q/9vMBJLoV+tCVDhiM0VxiK2BgibFbcf08Wva7c8S0CSCZ279FBp7QfEqGYVh9r6viMk9lDZkwbuWRe55buKNBsNtrHvQ+5KdYMe+PN0tt5ho0rJQulc2BKTcMxI7iWVE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716431523; c=relaxed/simple; bh=QPiCRoMJCdqxYeyF3+8N6zkCZsq57c/9eWMOOeRn4ws=; h=Subject:To:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=tMf9H1xoAjjAFfoVQ8npqL8aT5cOJjN0ptvYVT0y4QKY98R1opRmLExt+oS9GUsUsguu/sOj5B8stQVG904MRAe9tlBeEm5b+qhG5BQRAmF+0evBZMl86so6SpSPYSduPxpueTXzQSUSq+SNIMEAUR+WUoYXBgZjJ/VvwvSnHyY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.190 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.214]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4VlBtv32yrz1ysLB; Thu, 23 May 2024 10:28:55 +0800 (CST) Received: from canpemm500002.china.huawei.com (unknown [7.192.104.244]) by mail.maildlp.com (Postfix) with ESMTPS id C27F21A016C; Thu, 23 May 2024 10:31:57 +0800 (CST) Received: from [10.173.135.154] (10.173.135.154) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Thu, 23 May 2024 10:31:57 +0800 Subject: Re: [PATCH v3 3/5] mm/memory-failure: improve memory failure action_result messages To: Jane Chu , , , , , References: <20240521235429.2368017-1-jane.chu@oracle.com> <20240521235429.2368017-4-jane.chu@oracle.com> From: Miaohe Lin Message-ID: Date: Thu, 23 May 2024 10:31:56 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20240521235429.2368017-4-jane.chu@oracle.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To canpemm500002.china.huawei.com (7.192.104.244) On 2024/5/22 7:54, Jane Chu wrote: > Added two explicit MF_MSG messages describing failure in get_hwpoison_page. > Attemped to document the definition of various action names, and made a few > adjustment to the action_result() calls. > > Signed-off-by: Jane Chu Thanks for your patch. This really improves the code. > --- > include/linux/mm.h | 2 ++ > include/ras/ras_event.h | 2 ++ > mm/memory-failure.c | 38 +++++++++++++++++++++++++++++++++----- > 3 files changed, 37 insertions(+), 5 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 9849dfda44d4..b4598c6a393a 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -4111,6 +4111,7 @@ enum mf_action_page_type { > MF_MSG_DIFFERENT_COMPOUND, > MF_MSG_HUGE, > MF_MSG_FREE_HUGE, > + MF_MSG_GET_HWPOISON, > MF_MSG_UNMAP_FAILED, > MF_MSG_DIRTY_SWAPCACHE, > MF_MSG_CLEAN_SWAPCACHE, > @@ -4124,6 +4125,7 @@ enum mf_action_page_type { > MF_MSG_BUDDY, > MF_MSG_DAX, > MF_MSG_UNSPLIT_THP, > + MF_MSG_ALREADY_POISONED, > MF_MSG_UNKNOWN, > }; > > diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h > index c011ea236e9b..b3f6832a94fe 100644 > --- a/include/ras/ras_event.h > +++ b/include/ras/ras_event.h > @@ -360,6 +360,7 @@ TRACE_EVENT(aer_event, > EM ( MF_MSG_DIFFERENT_COMPOUND, "different compound page after locking" ) \ > EM ( MF_MSG_HUGE, "huge page" ) \ > EM ( MF_MSG_FREE_HUGE, "free huge page" ) \ > + EM ( MF_MSG_GET_HWPOISON, "get hwpoison page" ) \ > EM ( MF_MSG_UNMAP_FAILED, "unmapping failed page" ) \ > EM ( MF_MSG_DIRTY_SWAPCACHE, "dirty swapcache page" ) \ > EM ( MF_MSG_CLEAN_SWAPCACHE, "clean swapcache page" ) \ > @@ -373,6 +374,7 @@ TRACE_EVENT(aer_event, > EM ( MF_MSG_BUDDY, "free buddy page" ) \ > EM ( MF_MSG_DAX, "dax page" ) \ > EM ( MF_MSG_UNSPLIT_THP, "unsplit thp" ) \ > + EM ( MF_MSG_ALREADY_POISONED, "already poisoned" ) \ > EMe ( MF_MSG_UNKNOWN, "unknown page" ) > > /* > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 739311e121af..1e22d73c9329 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -879,6 +879,28 @@ static int kill_accessing_process(struct task_struct *p, unsigned long pfn, > return ret > 0 ? -EHWPOISON : -EFAULT; > } > > +/* > + * MF_IGNORED - The m-f() handler marks the page as PG_hwpoisoned'ed. > + * But it could not do more to isolate the page from being accessed again, > + * nor does it kill the process. This is extremely rare and one of the > + * potential causes is that the page state has been changed due to > + * underlying race condition. This is the most severe outcomes. > + * > + * MF_FAILED - The m-f() handler marks the page as PG_hwpoisoned'ed. It > + * should have killed the process, but it can't isolate the page, due to > + * conditions such as extra pin, unmap failure, etc. Accessing the page > + * again will trigger another MCE and the process will be killed by the > + * m-f() handler immediately. > + * > + * MF_DELAYED - The m-f() handler marks the page as PG_hwpoisoned'ed. The > + * page is unmapped, but perhaps remains in LRU or file mapping. An attempt Would the page remain in LRU or file mapping? IIUC, MF_DELAYED is returned from two functions: 1. me_swapcache_dirty. Page lives in swap cache and removed from LRU. 2. kvm_gmem_error_folio. Page range is unmapped. It seems page won't be in the LRU or page cache. Or am I miss something? > + * to access the page again will trigger page fault and the PF handler > + * will kill the process. > + * > + * MF_RECOVERED - The m-f() handler marks the page as PG_hwpoisoned'ed. > + * The page has been completely isolated, that is, unmapped, taken out of > + * the buddy system, or hole-punnched out of the file mapping. > + */ > static const char *action_name[] = { > [MF_IGNORED] = "Ignored", > [MF_FAILED] = "Failed", > @@ -893,6 +915,7 @@ static const char * const action_page_types[] = { > [MF_MSG_DIFFERENT_COMPOUND] = "different compound page after locking", > [MF_MSG_HUGE] = "huge page", > [MF_MSG_FREE_HUGE] = "free huge page", > + [MF_MSG_GET_HWPOISON] = "get hwpoison page", > [MF_MSG_UNMAP_FAILED] = "unmapping failed page", > [MF_MSG_DIRTY_SWAPCACHE] = "dirty swapcache page", > [MF_MSG_CLEAN_SWAPCACHE] = "clean swapcache page", > @@ -906,6 +929,7 @@ static const char * const action_page_types[] = { > [MF_MSG_BUDDY] = "free buddy page", > [MF_MSG_DAX] = "dax page", > [MF_MSG_UNSPLIT_THP] = "unsplit thp", > + [MF_MSG_ALREADY_POISONED] = "already poisoned", > [MF_MSG_UNKNOWN] = "unknown page", > }; > > @@ -1013,12 +1037,13 @@ static int me_kernel(struct page_state *ps, struct page *p) > > /* > * Page in unknown state. Do nothing. > + * This is a catch-all in case we fail to make sense of the page state. > */ > static int me_unknown(struct page_state *ps, struct page *p) > { > pr_err("%#lx: Unknown page state\n", page_to_pfn(p)); > unlock_page(p); > - return MF_FAILED; > + return MF_IGNORED; > } > > /* > @@ -2055,6 +2080,8 @@ static int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *hugetlb > if (flags & MF_ACTION_REQUIRED) { > folio = page_folio(p); > res = kill_accessing_process(current, folio_pfn(folio), flags); > + action_result(pfn, MF_MSG_ALREADY_POISONED, MF_FAILED); > + return res; We might reuse the below "return res;"? > } > return res; Besides from the above possible nits, this patch looks good to me. Acked-by: Miaohe Lin Thanks. .