From: Will Deacon <will@kernel.org> To: Anshuman Khandual <anshuman.khandual@arm.com> Cc: "Mark Rutland" <mark.rutland@arm.com>, "David Hildenbrand" <david@redhat.com>, "Catalin Marinas" <catalin.marinas@arm.com>, linux-kernel@vger.kernel.org, "Mike Rapoport" <rppt@linux.ibm.com>, linux-mm@kvack.org, "Jérôme Glisse" <jglisse@redhat.com>, "James Morse" <james.morse@arm.com>, "Dan Williams" <dan.j.williams@intel.com>, "Robin Murphy" <robin.murphy@arm.com>, "Ard Biesheuvel" <ardb@kernel.org>, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH V2 1/2] arm64/mm: Fix pfn_valid() for ZONE_DEVICE based memory Date: Thu, 11 Feb 2021 12:21:43 +0000 [thread overview] Message-ID: <20210211122143.GC29894@willie-the-truck> (raw) In-Reply-To: <23e5eb93-a39c-c68e-eac1-c5ccf9036079@arm.com> On Thu, Feb 11, 2021 at 05:40:35PM +0530, Anshuman Khandual wrote: > On 2/11/21 5:23 PM, Will Deacon wrote: > > On Fri, Feb 05, 2021 at 06:55:53PM +0000, Will Deacon wrote: > >> On Wed, Feb 03, 2021 at 09:20:39AM +0530, Anshuman Khandual wrote: > >>> On 2/2/21 6:26 PM, David Hildenbrand wrote: > >>>> On 02.02.21 13:51, Will Deacon wrote: > >>>>> On Tue, Feb 02, 2021 at 01:39:29PM +0100, David Hildenbrand wrote: > >>>>>> As I expressed already, long term we should really get rid of the arm64 > >>>>>> variant and rather special-case the generic one. Then we won't go out of > >>>>>> sync - just as it happened with ZONE_DEVICE handling here. > >>>>> > >>>>> Why does this have to be long term? This ZONE_DEVICE stuff could be the > >>>>> carrot on the stick :) > >>>> > >>>> Yes, I suggested to do it now, but Anshuman convinced me that doing a > >>>> simple fix upfront might be cleaner --- for example when it comes to > >>>> backporting :) > >>> > >>> Right. The current pfn_valid() breaks for ZONE_DEVICE memory and this fixes > >>> the problem in the present context which can be easily backported if required. > >>> > >>> Changing or rather overhauling the generic code with new configs as proposed > >>> earlier (which I am planning to work on subsequently) would definitely be an > >>> improvement for the current pfn_valid() situation in terms of maintainability > >>> but then it should not stop us from fixing the problem now. > >> > >> Alright, I've mulled this over a bit. I don't agree that this patch helps > >> with maintainability (quite the opposite, in fact), but perfection is the > >> enemy of the good so I'll queue the series for 5.12. However, I'll revert > >> the changes at the first sign of a problem, so please do work towards a > >> generic solution which can replace this in the medium term. > > > > ... and dropped. These patches appear to be responsible for a boot > > regression reported by CKI: > > Ahh, boot regression ? These patches only change the behaviour > for non boot memory only. Sure, but this thing is horribly fragile, which is why I was nervous about touching it in the first place ;) > > https://lore.kernel.org/r/cki.8D1CB60FEC.K6NJMEFQPV@redhat.com > > Will look into the logs and see if there is something pointing to > the problem. We don't have a log yet, but I've asked whether earlycon works on the problematic machine (the failure seems to be specific to a certain TX2). Either way, this is too late for 5.12 now. Will
WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org> To: Anshuman Khandual <anshuman.khandual@arm.com> Cc: "Mark Rutland" <mark.rutland@arm.com>, "David Hildenbrand" <david@redhat.com>, "Catalin Marinas" <catalin.marinas@arm.com>, linux-kernel@vger.kernel.org, "Mike Rapoport" <rppt@linux.ibm.com>, linux-mm@kvack.org, "Jérôme Glisse" <jglisse@redhat.com>, "James Morse" <james.morse@arm.com>, "Dan Williams" <dan.j.williams@intel.com>, "Robin Murphy" <robin.murphy@arm.com>, "Ard Biesheuvel" <ardb@kernel.org>, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH V2 1/2] arm64/mm: Fix pfn_valid() for ZONE_DEVICE based memory Date: Thu, 11 Feb 2021 12:21:43 +0000 [thread overview] Message-ID: <20210211122143.GC29894@willie-the-truck> (raw) In-Reply-To: <23e5eb93-a39c-c68e-eac1-c5ccf9036079@arm.com> On Thu, Feb 11, 2021 at 05:40:35PM +0530, Anshuman Khandual wrote: > On 2/11/21 5:23 PM, Will Deacon wrote: > > On Fri, Feb 05, 2021 at 06:55:53PM +0000, Will Deacon wrote: > >> On Wed, Feb 03, 2021 at 09:20:39AM +0530, Anshuman Khandual wrote: > >>> On 2/2/21 6:26 PM, David Hildenbrand wrote: > >>>> On 02.02.21 13:51, Will Deacon wrote: > >>>>> On Tue, Feb 02, 2021 at 01:39:29PM +0100, David Hildenbrand wrote: > >>>>>> As I expressed already, long term we should really get rid of the arm64 > >>>>>> variant and rather special-case the generic one. Then we won't go out of > >>>>>> sync - just as it happened with ZONE_DEVICE handling here. > >>>>> > >>>>> Why does this have to be long term? This ZONE_DEVICE stuff could be the > >>>>> carrot on the stick :) > >>>> > >>>> Yes, I suggested to do it now, but Anshuman convinced me that doing a > >>>> simple fix upfront might be cleaner --- for example when it comes to > >>>> backporting :) > >>> > >>> Right. The current pfn_valid() breaks for ZONE_DEVICE memory and this fixes > >>> the problem in the present context which can be easily backported if required. > >>> > >>> Changing or rather overhauling the generic code with new configs as proposed > >>> earlier (which I am planning to work on subsequently) would definitely be an > >>> improvement for the current pfn_valid() situation in terms of maintainability > >>> but then it should not stop us from fixing the problem now. > >> > >> Alright, I've mulled this over a bit. I don't agree that this patch helps > >> with maintainability (quite the opposite, in fact), but perfection is the > >> enemy of the good so I'll queue the series for 5.12. However, I'll revert > >> the changes at the first sign of a problem, so please do work towards a > >> generic solution which can replace this in the medium term. > > > > ... and dropped. These patches appear to be responsible for a boot > > regression reported by CKI: > > Ahh, boot regression ? These patches only change the behaviour > for non boot memory only. Sure, but this thing is horribly fragile, which is why I was nervous about touching it in the first place ;) > > https://lore.kernel.org/r/cki.8D1CB60FEC.K6NJMEFQPV@redhat.com > > Will look into the logs and see if there is something pointing to > the problem. We don't have a log yet, but I've asked whether earlycon works on the problematic machine (the failure seems to be specific to a certain TX2). Either way, this is too late for 5.12 now. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-02-11 12:25 UTC|newest] Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-02-02 4:11 [PATCH V2 0/2] arm64/mm: Fix pfn_valid() for ZONE_DEVICE based memory Anshuman Khandual 2021-02-02 4:11 ` Anshuman Khandual 2021-02-02 4:11 ` [PATCH V2 1/2] " Anshuman Khandual 2021-02-02 4:11 ` Anshuman Khandual 2021-02-02 12:32 ` Will Deacon 2021-02-02 12:32 ` Will Deacon 2021-02-02 12:35 ` Will Deacon 2021-02-02 12:35 ` Will Deacon 2021-02-02 12:39 ` David Hildenbrand 2021-02-02 12:39 ` David Hildenbrand 2021-02-02 12:51 ` Will Deacon 2021-02-02 12:51 ` Will Deacon 2021-02-02 12:56 ` David Hildenbrand 2021-02-02 12:56 ` David Hildenbrand 2021-02-03 3:50 ` Anshuman Khandual 2021-02-03 3:50 ` Anshuman Khandual 2021-02-05 18:55 ` Will Deacon 2021-02-05 18:55 ` Will Deacon 2021-02-11 11:53 ` Will Deacon 2021-02-11 11:53 ` Will Deacon 2021-02-11 12:10 ` Anshuman Khandual 2021-02-11 12:10 ` Anshuman Khandual 2021-02-11 12:21 ` Will Deacon [this message] 2021-02-11 12:21 ` Will Deacon 2021-02-11 12:35 ` David Hildenbrand 2021-02-11 12:35 ` David Hildenbrand 2021-03-03 19:04 ` Catalin Marinas 2021-03-03 19:04 ` Catalin Marinas 2021-03-03 19:24 ` David Hildenbrand 2021-03-03 19:24 ` David Hildenbrand 2021-03-03 21:24 ` Will Deacon 2021-03-03 21:24 ` Will Deacon 2021-03-04 3:31 ` Anshuman Khandual 2021-03-04 3:31 ` Anshuman Khandual 2021-03-04 8:12 ` David Hildenbrand 2021-03-04 8:12 ` David Hildenbrand 2021-03-04 9:36 ` Will Deacon 2021-03-04 9:36 ` Will Deacon 2021-03-05 4:22 ` Anshuman Khandual 2021-03-05 4:22 ` Anshuman Khandual 2021-02-02 4:11 ` [PATCH V2 2/2] arm64/mm: Reorganize pfn_valid() Anshuman Khandual 2021-02-02 4:11 ` Anshuman Khandual 2021-02-02 8:26 ` David Hildenbrand 2021-02-02 8:26 ` David Hildenbrand 2021-02-05 18:52 ` [PATCH V2 0/2] arm64/mm: Fix pfn_valid() for ZONE_DEVICE based memory Will Deacon 2021-02-05 18:52 ` Will Deacon
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