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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 D9DD4C2D0A3 for ; Thu, 29 Oct 2020 07:54:34 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2BA1A21531 for ; Thu, 29 Oct 2020 07:54:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="smkJOo6e" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2BA1A21531 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 62C616B006C; Thu, 29 Oct 2020 03:54:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 60C2C6B006E; Thu, 29 Oct 2020 03:54:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 519426B0070; Thu, 29 Oct 2020 03:54:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0039.hostedemail.com [216.40.44.39]) by kanga.kvack.org (Postfix) with ESMTP id 2630B6B006C for ; Thu, 29 Oct 2020 03:54:33 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id BBBC2180AD815 for ; Thu, 29 Oct 2020 07:54:32 +0000 (UTC) X-FDA: 77424200784.27.cream01_06160c72728b Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin27.hostedemail.com (Postfix) with ESMTP id 9BEDF3D668 for ; Thu, 29 Oct 2020 07:54:32 +0000 (UTC) X-HE-Tag: cream01_06160c72728b X-Filterd-Recvd-Size: 5104 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Thu, 29 Oct 2020 07:54:31 +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 E3F1620EDD; Thu, 29 Oct 2020 07:54:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603958070; bh=5V9raRTAO8xn/TWxASurP3gs711BOhAaxxP12fBIpug=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=smkJOo6ejvJldTmaaqqEFjGX6LWRb76WicHCvCBcrN9qOMMNByoTCZCyPYd8JouA6 FsHRDDeFim9xIzvbeq0FyT0w7eXPAkBTo6qZkKSqULTgH8mtDPy6sKAI1NlM6RXbk0 gkAxCVUoVSgKd/P/vRphpHr37cKvq2I6Usohfbtc= Date: Thu, 29 Oct 2020 09:54:16 +0200 From: Mike Rapoport To: "Edgecombe, Rick P" Cc: "akpm@linux-foundation.org" , "david@redhat.com" , "cl@linux.com" , "gor@linux.ibm.com" , "hpa@zytor.com" , "peterz@infradead.org" , "catalin.marinas@arm.com" , "dave.hansen@linux.intel.com" , "borntraeger@de.ibm.com" , "penberg@kernel.org" , "iamjoonsoo.kim@lge.com" , "linux-mm@kvack.org" , "will@kernel.org" , "aou@eecs.berkeley.edu" , "kirill@shutemov.name" , "rientjes@google.com" , "rppt@linux.ibm.com" , "paulus@samba.org" , "hca@linux.ibm.com" , "pavel@ucw.cz" , "bp@alien8.de" , "sparclinux@vger.kernel.org" , "mpe@ellerman.id.au" , "luto@kernel.org" , "davem@davemloft.net" , "tglx@linutronix.de" , "rjw@rjwysocki.net" , "linux-riscv@lists.infradead.org" , "benh@kernel.crashing.org" , "linuxppc-dev@lists.ozlabs.org" , "x86@kernel.org" , "linux-pm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "palmer@dabbelt.com" , "Brown, Len" , "mingo@redhat.com" , "linux-s390@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "paul.walmsley@sifive.com" Subject: Re: [PATCH 2/4] PM: hibernate: improve robustness of mapping pages in the direct map Message-ID: <20201029075416.GJ1428094@kernel.org> References: <20201025101555.3057-1-rppt@kernel.org> <20201025101555.3057-3-rppt@kernel.org> <3b4b2b3559bd3dc68adcddf99415bae57152cb6b.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3b4b2b3559bd3dc68adcddf99415bae57152cb6b.camel@intel.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 Wed, Oct 28, 2020 at 09:15:38PM +0000, Edgecombe, Rick P wrote: > On Sun, 2020-10-25 at 12:15 +0200, Mike Rapoport wrote: > > + if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) { > > + unsigned long addr = (unsigned > > long)page_address(page); > > + int ret; > > + > > + if (enable) > > + ret = set_direct_map_default_noflush(page); > > + else > > + ret = set_direct_map_invalid_noflush(page); > > + > > + if (WARN_ON(ret)) > > + return; > > + > > + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); > > + } else { > > + debug_pagealloc_map_pages(page, 1, enable); > > + } > > Looking at the arm side again, I think this might actually introduce a > regression for the arm/hibernate/DEBUG_PAGEALLOC combo. > > Unlike __kernel_map_pages(), it looks like arm's cpa will always bail > in the set_direct_map_() functions if rodata_full is false. > > So if rodata_full was disabled but debug page alloc is on, then this > would now skip remapping the pages. I guess the significance depends > on whether hibernate could actually try to save any DEBUG_PAGEALLOC > unmapped pages. Looks like it to me though. __kernel_map_pages() on arm64 will also bail out if rodata_full is false: void __kernel_map_pages(struct page *page, int numpages, int enable) { if (!debug_pagealloc_enabled() && !rodata_full) return; set_memory_valid((unsigned long)page_address(page), numpages, enable); } So using set_direct_map() to map back pages removed from the direct map with __kernel_map_pages() seems safe to me. -- Sincerely yours, Mike.