From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4B49BC32771 for ; Mon, 20 Jan 2020 06:32:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 264892073A for ; Mon, 20 Jan 2020 06:32:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726442AbgATGcA (ORCPT ); Mon, 20 Jan 2020 01:32:00 -0500 Received: from foss.arm.com ([217.140.110.172]:56234 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725837AbgATGcA (ORCPT ); Mon, 20 Jan 2020 01:32:00 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2FA5A31B; Sun, 19 Jan 2020 22:31:59 -0800 (PST) Received: from [10.162.16.78] (p8cg001049571a15.blr.arm.com [10.162.16.78]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9CEDF3F52E; Sun, 19 Jan 2020 22:35:30 -0800 (PST) Subject: Re: [Patch v2 3/4] mm/page_alloc.c: pass all bad reasons to bad_page() To: Wei Yang , akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, rientjes@google.com References: <20200120030415.15925-1-richardw.yang@linux.intel.com> <20200120030415.15925-4-richardw.yang@linux.intel.com> From: Anshuman Khandual Message-ID: Date: Mon, 20 Jan 2020 12:03:20 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20200120030415.15925-4-richardw.yang@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/20/2020 08:34 AM, Wei Yang wrote: > Now we can pass all bad reasons to __dump_page(). > > Signed-off-by: Wei Yang > --- > mm/page_alloc.c | 52 ++++++++++++++++++++++++++----------------------- > 1 file changed, 28 insertions(+), 24 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index a43b9d2482f2..a7b793c739fc 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -609,7 +609,7 @@ static inline int __maybe_unused bad_range(struct zone *zone, struct page *page) > } > #endif > > -static void bad_page(struct page *page, const char *reason, > +static void bad_page(struct page *page, int nr, const char **reason, > unsigned long bad_flags) > { > static unsigned long resume; > @@ -638,7 +638,7 @@ static void bad_page(struct page *page, const char *reason, > > pr_alert("BUG: Bad page state in process %s pfn:%05lx\n", > current->comm, page_to_pfn(page)); > - __dump_page(page, 1, &reason); > + __dump_page(page, nr, reason); > bad_flags &= page->flags; > if (bad_flags) > pr_alert("bad because of flags: %#lx(%pGp)\n", > @@ -1027,27 +1027,25 @@ static inline bool page_expected_state(struct page *page, > > static void free_pages_check_bad(struct page *page) > { > - const char *bad_reason; > - unsigned long bad_flags; > - > - bad_reason = NULL; > - bad_flags = 0; > + const char *bad_reason[5]; s/5/NR_BAD_PAGE_REASONS > + unsigned long bad_flags = 0; > + int nr = 0; > > if (unlikely(atomic_read(&page->_mapcount) != -1)) > - bad_reason = "nonzero mapcount"; > + bad_reason[nr++] = "nonzero mapcount"; > if (unlikely(page->mapping != NULL)) > - bad_reason = "non-NULL mapping"; > + bad_reason[nr++] = "non-NULL mapping"; > if (unlikely(page_ref_count(page) != 0)) > - bad_reason = "nonzero _refcount"; > + bad_reason[nr++] = "nonzero _refcount"; > if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) { > - bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set"; > + bad_reason[nr++] = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set"; > bad_flags = PAGE_FLAGS_CHECK_AT_FREE; > } > #ifdef CONFIG_MEMCG > if (unlikely(page->mem_cgroup)) > - bad_reason = "page still charged to cgroup"; > + bad_reason[nr++] = "page still charged to cgroup"; > #endif > - bad_page(page, bad_reason, bad_flags); > + bad_page(page, nr, bad_reason, bad_flags); > } > > static inline int free_pages_check(struct page *page) > @@ -1062,6 +1060,7 @@ static inline int free_pages_check(struct page *page) > > static int free_tail_pages_check(struct page *head_page, struct page *page) > { > + const char *reason; > int ret = 1; > > /* > @@ -1078,7 +1077,8 @@ static int free_tail_pages_check(struct page *head_page, struct page *page) > case 1: > /* the first tail page: ->mapping may be compound_mapcount() */ > if (unlikely(compound_mapcount(page))) { > - bad_page(page, "nonzero compound_mapcount", 0); > + reason = "nonzero compound_mapcount"; > + bad_page(page, 1, &reason, 0); > goto out; > } > break; > @@ -1090,17 +1090,20 @@ static int free_tail_pages_check(struct page *head_page, struct page *page) > break; > default: > if (page->mapping != TAIL_MAPPING) { > - bad_page(page, "corrupted mapping in tail page", 0); > + reason = "corrupted mapping in tail page"; > + bad_page(page, 1, &reason, 0); > goto out; > } > break; > } > if (unlikely(!PageTail(page))) { > - bad_page(page, "PageTail not set", 0); > + reason = "PageTail not set"; > + bad_page(page, 1, &reason, 0); > goto out; > } > if (unlikely(compound_head(page) != head_page)) { > - bad_page(page, "compound_head not consistent", 0); > + reason = "compound_head not consistent"; > + bad_page(page, 1, &reason, 0); > goto out; > } > ret = 0; > @@ -2041,29 +2044,30 @@ static inline void expand(struct zone *zone, struct page *page, > > static void check_new_page_bad(struct page *page) > { > - const char *bad_reason = NULL; > + const char *bad_reason[5]; s/5/NR_BAD_PAGE_REASONS > unsigned long bad_flags = 0; > + int nr = 0; > > if (unlikely(atomic_read(&page->_mapcount) != -1)) > - bad_reason = "nonzero mapcount"; > + bad_reason[nr++] = "nonzero mapcount"; > if (unlikely(page->mapping != NULL)) > - bad_reason = "non-NULL mapping"; > + bad_reason[nr++] = "non-NULL mapping"; > if (unlikely(page_ref_count(page) != 0)) > - bad_reason = "nonzero _refcount"; > + bad_reason[nr++] = "nonzero _refcount"; > if (unlikely(page->flags & __PG_HWPOISON)) { > /* Don't complain about hwpoisoned pages */ > page_mapcount_reset(page); /* remove PageBuddy */ > return; > } > if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) { > - bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set"; > + bad_reason[nr++] = "PAGE_FLAGS_CHECK_AT_PREP flag set"; > bad_flags = PAGE_FLAGS_CHECK_AT_PREP; > } > #ifdef CONFIG_MEMCG > if (unlikely(page->mem_cgroup)) > - bad_reason = "page still charged to cgroup"; > + bad_reason[nr++] = "page still charged to cgroup"; > #endif > - bad_page(page, bad_reason, bad_flags); > + bad_page(page, 1, bad_reason, bad_flags); This should be 'nr' here instead ? > } > > /* >