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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 B8828C4363A for ; Mon, 26 Oct 2020 11:55:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 32C5822281 for ; Mon, 26 Oct 2020 11:55:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="beAfxtxV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 32C5822281 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 659316B006C; Mon, 26 Oct 2020 07:55:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5E2256B006E; Mon, 26 Oct 2020 07:55:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4AA9E6B0070; Mon, 26 Oct 2020 07:55:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0254.hostedemail.com [216.40.44.254]) by kanga.kvack.org (Postfix) with ESMTP id 1AD416B006C for ; Mon, 26 Oct 2020 07:55:00 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id A7834181AC9CB for ; Mon, 26 Oct 2020 11:54:59 +0000 (UTC) X-FDA: 77413920318.15.crush37_510b62b27273 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin15.hostedemail.com (Postfix) with ESMTP id 901ED1814B0C8 for ; Mon, 26 Oct 2020 11:54:59 +0000 (UTC) X-HE-Tag: crush37_510b62b27273 X-Filterd-Recvd-Size: 7396 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf14.hostedemail.com (Postfix) with ESMTP for ; Mon, 26 Oct 2020 11:54:59 +0000 (UTC) Received: from kernel.org (unknown [87.70.96.83]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5891822265; Mon, 26 Oct 2020 11:54:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603713297; bh=JL5L+tjAdTtgTIzF1IyLb8dhJjCHzTjL2OJ0c6FU4w4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=beAfxtxVzIWG7/PQSB9oT8HrWkddsR0PDdaGNijlEC3AuMvcZUXxJY9R8puB77jj0 rPlZw+P1uGuAIqPmVzWmAkw1wLYd5tKrK+EpdZCOH48DMhCjDSmOkzAPgP4u1ZC3/i Sc+DoqTEeolhEbCvCJLclcbZXLgz0JV5qw710moE= Date: Mon, 26 Oct 2020 13:54:43 +0200 From: Mike Rapoport To: David Hildenbrand Cc: Andrew Morton , Albert Ou , Andy Lutomirski , Benjamin Herrenschmidt , Borislav Petkov , Catalin Marinas , Christian Borntraeger , Christoph Lameter , "David S. Miller" , Dave Hansen , David Rientjes , "Edgecombe, Rick P" , "H. Peter Anvin" , Heiko Carstens , Ingo Molnar , Joonsoo Kim , "Kirill A. Shutemov" , Len Brown , Michael Ellerman , Mike Rapoport , Palmer Dabbelt , Paul Mackerras , Paul Walmsley , Pavel Machek , Pekka Enberg , Peter Zijlstra , "Rafael J. Wysocki" , Thomas Gleixner , Vasily Gorbik , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pm@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH 1/4] mm: introduce debug_pagealloc_map_pages() helper Message-ID: <20201026115443.GF1154158@kernel.org> References: <20201025101555.3057-1-rppt@kernel.org> <20201025101555.3057-2-rppt@kernel.org> <8720c067-7dc5-2b02-918b-e54dd642bfd6@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8720c067-7dc5-2b02-918b-e54dd642bfd6@redhat.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Oct 26, 2020 at 12:05:13PM +0100, David Hildenbrand wrote: > On 25.10.20 11:15, Mike Rapoport wrote: > > From: Mike Rapoport > > > > When CONFIG_DEBUG_PAGEALLOC is enabled, it unmaps pages from the > > kernel direct mapping after free_pages(). The pages than need to be > > mapped back before they could be used. Theese mapping operations use > > __kernel_map_pages() guarded with with debug_pagealloc_enabled(). > > > > The only place that calls __kernel_map_pages() without checking > > whether DEBUG_PAGEALLOC is enabled is the hibernation code that > > presumes availability of this function when ARCH_HAS_SET_DIRECT_MAP > > is set. Still, on arm64, __kernel_map_pages() will bail out when > > DEBUG_PAGEALLOC is not enabled but set_direct_map_invalid_noflush() > > may render some pages not present in the direct map and hibernation > > code won't be able to save such pages. > > > > To make page allocation debugging and hibernation interaction more > > robust, the dependency on DEBUG_PAGEALLOC or ARCH_HAS_SET_DIRECT_MAP > > has to be made more explicit. > > > > Start with combining the guard condition and the call to > > __kernel_map_pages() into a single debug_pagealloc_map_pages() > > function to emphasize that __kernel_map_pages() should not be called > > without DEBUG_PAGEALLOC and use this new function to map/unmap pages > > when page allocation debug is enabled. > > > > As the only remaining user of kernel_map_pages() is the hibernation > > code, mode that function into kernel/power/snapshot.c closer to a > > caller. > > s/mode/move/ > > > > > Signed-off-by: Mike Rapoport --- > > include/linux/mm.h | 16 +++++++--------- kernel/power/snapshot.c > > | 11 +++++++++++ mm/memory_hotplug.c | 3 +-- mm/page_alloc.c > > | 6 ++---- mm/slab.c | 8 +++----- 5 files changed, 24 > > insertions(+), 20 deletions(-) > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h index > > ef360fe70aaf..14e397f3752c 100644 --- a/include/linux/mm.h +++ > > b/include/linux/mm.h @@ -2927,21 +2927,19 @@ static inline bool > > debug_pagealloc_enabled_static(void) #if > > defined(CONFIG_DEBUG_PAGEALLOC) || > > defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP) extern void > > __kernel_map_pages(struct page *page, int numpages, int enable); > > > > -/* - * When called in DEBUG_PAGEALLOC context, the call should most > > likely be - * guarded by debug_pagealloc_enabled() or > > debug_pagealloc_enabled_static() - */ -static inline void > > -kernel_map_pages(struct page *page, int numpages, int enable) > > +static inline void debug_pagealloc_map_pages(struct page *page, + > > int numpages, int enable) { - __kernel_map_pages(page, numpages, > > enable); + if (debug_pagealloc_enabled_static()) + > > __kernel_map_pages(page, numpages, enable); } + #ifdef > > CONFIG_HIBERNATION extern bool kernel_page_present(struct page > > *page); #endif /* CONFIG_HIBERNATION */ #else /* > > CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_DIRECT_MAP */ -static > > inline void -kernel_map_pages(struct page *page, int numpages, int > > enable) {} +static inline void debug_pagealloc_map_pages(struct page > > *page, + int numpages, int enable) {} #ifdef > > CONFIG_HIBERNATION static inline bool kernel_page_present(struct page > > *page) { return true; } #endif /* CONFIG_HIBERNATION */ diff --git > > a/kernel/power/snapshot.c b/kernel/power/snapshot.c index > > 46b1804c1ddf..fa499466f645 100644 --- a/kernel/power/snapshot.c +++ > > b/kernel/power/snapshot.c @@ -76,6 +76,17 @@ static inline void > > hibernate_restore_protect_page(void *page_address) {} static inline > > void hibernate_restore_unprotect_page(void *page_address) {} #endif > > /* CONFIG_STRICT_KERNEL_RWX && CONFIG_ARCH_HAS_SET_MEMORY */ > > > > +#if defined(CONFIG_DEBUG_PAGEALLOC) || > > defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP) +static inline void > > +kernel_map_pages(struct page *page, int numpages, int enable) +{ + > > __kernel_map_pages(page, numpages, enable); +} +#else +static inline > > void +kernel_map_pages(struct page *page, int numpages, int enable) > > {} +#endif + > > That change should go into a separate patch. Hmm, I beleive you refer to moving kernel_map_pages() to snapshot.c, right? > For the debug_pagealloc_map_pages() parts > > Reviewed-by: David Hildenbrand Thanks! > -- > Thanks, > > David / dhildenb > -- Sincerely yours, Mike.