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,URIBL_BLOCKED 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 8938AC00A89 for ; Thu, 5 Nov 2020 11:33:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C513B20867 for ; Thu, 5 Nov 2020 11:33:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="O5NamY7Z" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C513B20867 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 3CC776B00EB; Thu, 5 Nov 2020 06:33:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 356716B00EC; Thu, 5 Nov 2020 06:33:57 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1F7256B00ED; Thu, 5 Nov 2020 06:33:57 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0212.hostedemail.com [216.40.44.212]) by kanga.kvack.org (Postfix) with ESMTP id C9B356B00EB for ; Thu, 5 Nov 2020 06:33:56 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 6986F362A for ; Thu, 5 Nov 2020 11:33:56 +0000 (UTC) X-FDA: 77450155272.29.aunt88_3411882272c9 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 48D5918086CA0 for ; Thu, 5 Nov 2020 11:33:56 +0000 (UTC) X-HE-Tag: aunt88_3411882272c9 X-Filterd-Recvd-Size: 7965 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Nov 2020 11:33:55 +0000 (UTC) Received: from kernel.org (unknown [2.55.183.164]) (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 B88CD2078E; Thu, 5 Nov 2020 11:33:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604576034; bh=XF8AFYO6bCr4yR/xfLGLwsLQBboi2XjYzZ3lYdi07mQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=O5NamY7Z8bpeRF5e27pgfGmymIeBQK9j8XG2gMXDjk8aw+eMLitnhVpAzHAcLwHhk Sau6clNChqmtpHyfG8qukI1nlUaCTcmwOyX21+Rglf3ECyVc+/suIMbLHw9rP9no/V w2/7NKEKvUcFmM9Q4PjHmX+gHCO2wRPhSdhuvRyw= Date: Thu, 5 Nov 2020 13:33:33 +0200 From: Mike Rapoport To: Vlastimil Babka Cc: Andrew Morton , Albert Ou , Andy Lutomirski , Benjamin Herrenschmidt , Borislav Petkov , Catalin Marinas , Christian Borntraeger , Christoph Lameter , "David S. Miller" , Dave Hansen , David Hildenbrand , David Rientjes , "Edgecombe, Rick P" , "H. Peter Anvin" , Heiko Carstens , Ingo Molnar , Joonsoo Kim , "Kirill A . Shutemov" , "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, "Rafael J . Wysocki" Subject: Re: [PATCH v4 2/4] PM: hibernate: make direct map manipulations more explicit Message-ID: <20201105113333.GY4879@kernel.org> References: <20201103162057.22916-1-rppt@kernel.org> <20201103162057.22916-3-rppt@kernel.org> <9a0780b4-35f8-0ded-c473-d8ab4a26ade5@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9a0780b4-35f8-0ded-c473-d8ab4a26ade5@suse.cz> 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 Wed, Nov 04, 2020 at 06:40:28PM +0100, Vlastimil Babka wrote: > On 11/3/20 5:20 PM, Mike Rapoport wrote: > > From: Mike Rapoport > > > > When DEBUG_PAGEALLOC or ARCH_HAS_SET_DIRECT_MAP is enabled a page may be > > not present in the direct map and has to be explicitly mapped before it > > could be copied. > > > > Introduce hibernate_map_page() that will explicitly use > > set_direct_map_{default,invalid}_noflush() for ARCH_HAS_SET_DIRECT_MAP case > > and debug_pagealloc_map_pages() for DEBUG_PAGEALLOC case. > > > > The remapping of the pages in safe_copy_page() presumes that it only > > changes protection bits in an existing PTE and so it is safe to ignore > > return value of set_direct_map_{default,invalid}_noflush(). > > > > Still, add a pr_warn() so that future changes in set_memory APIs will not > > silently break hibernation. > > > > Signed-off-by: Mike Rapoport > > Acked-by: Rafael J. Wysocki > > Reviewed-by: David Hildenbrand > > Acked-by: Kirill A. Shutemov > > Acked-by: Vlastimil Babka > > The bool param is a bit more acceptable here, being a private API. But if > debug_pagealloc_map_pages() becomes split, then it might be easier to split > this one too... Let's split here as well. > > --- > > include/linux/mm.h | 12 ------------ > > kernel/power/snapshot.c | 32 ++++++++++++++++++++++++++++++-- > > 2 files changed, 30 insertions(+), 14 deletions(-) > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index 1fc0609056dc..14e397f3752c 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -2927,16 +2927,6 @@ 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) > > -{ > > - __kernel_map_pages(page, numpages, enable); > > -} > > - > > static inline void debug_pagealloc_map_pages(struct page *page, > > int numpages, int enable) > > { > > @@ -2948,8 +2938,6 @@ static inline void debug_pagealloc_map_pages(struct page *page, > > 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 > > diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c > > index 46b1804c1ddf..57d54b9d84bb 100644 > > --- a/kernel/power/snapshot.c > > +++ b/kernel/power/snapshot.c > > @@ -76,6 +76,34 @@ 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 */ > > +static inline void hibernate_map_page(struct page *page, int enable) > > +{ > > + if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) { > > + unsigned long addr = (unsigned long)page_address(page); > > + int ret; > > + > > + /* > > + * This should not fail because remapping a page here means > > + * that we only update protection bits in an existing PTE. > > + * It is still worth to have a warning here if something > > + * changes and this will no longer be the case. > > + */ > > + if (enable) > > + ret = set_direct_map_default_noflush(page); > > + else > > + ret = set_direct_map_invalid_noflush(page); > > + > > + if (ret) { > > + pr_warn_once("Failed to remap page\n"); > > + return; > > + } > > + > > + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); > > + } else { > > + debug_pagealloc_map_pages(page, 1, enable); > > + } > > +} > > + > > static int swsusp_page_is_free(struct page *); > > static void swsusp_set_page_forbidden(struct page *); > > static void swsusp_unset_page_forbidden(struct page *); > > @@ -1355,9 +1383,9 @@ static void safe_copy_page(void *dst, struct page *s_page) > > if (kernel_page_present(s_page)) { > > do_copy_page(dst, page_address(s_page)); > > } else { > > - kernel_map_pages(s_page, 1, 1); > > + hibernate_map_page(s_page, 1); > > do_copy_page(dst, page_address(s_page)); > > - kernel_map_pages(s_page, 1, 0); > > + hibernate_map_page(s_page, 0); > > } > > } > > > -- Sincerely yours, Mike.