From: Ard Biesheuvel <ardb@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
Wupeng Ma <mawupeng1@huawei.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
X86 ML <x86@kernel.org>,
hpa@zyccr.com, Darren Hart <dvhart@infradead.org>,
Andy Shevchenko <andy@infradead.org>,
Mike Rapoport <rppt@kernel.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Joerg Roedel <jroedel@suse.de>,
songmuchun@bytedance.com, macro@orcam.me.uk,
Frederic Weisbecker <frederic@kernel.org>,
W_Armin@gmx.de, John Garry <john.garry@huawei.com>,
Sean Christopherson <seanjc@google.com>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
chenhuacai@kernel.org, David Hildenbrand <david@redhat.com>,
gpiccoli@igalia.com, Mark Rutland <mark.rutland@arm.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Linux Doc Mailing List <linux-doc@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
linux-efi <linux-efi@vger.kernel.org>,
linux-ia64@vger.kernel.org, platform-driver-x86@vger.kernel.org,
Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [PATCH v2 7/9] mm: Calc the right pfn if page size is not 4K
Date: Thu, 21 Apr 2022 00:39:32 +0200 [thread overview]
Message-ID: <CAMj1kXFkso9i8OqHOA_XMu90mrSsSqR1uSmcUTxnD0SxStuTpw@mail.gmail.com> (raw)
In-Reply-To: <20220420152749.d41097e7d53ccd6a2a2aea5f@linux-foundation.org>
On Thu, 21 Apr 2022 at 00:27, Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Tue, 19 Apr 2022 20:29:27 +0200 Ard Biesheuvel <ardb@kernel.org> wrote:
>
> > > > --- a/mm/page_alloc.c
> > > > +++ b/mm/page_alloc.c
> > > > @@ -7870,7 +7870,7 @@ static void __init find_zone_movable_pfns_for_nodes(void)
> > > >
> > > > usable_startpfn = memblock_region_memory_base_pfn(r);
> > > >
> > > > - if (usable_startpfn < 0x100000) {
> > > > + if (usable_startpfn < PHYS_PFN(SZ_4G)) {
> > > > mem_below_4gb_not_mirrored = true;
> > > > continue;
> > > > }
> > >
> > > Regardless PFN value should never be encoded directly.
> > >
> > > Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
> >
> > Acked-by: Ard Biesheuvel <ardb@kernel.org>
> >
> > Andrew, can you please take this one through the -mm tree? The rest of
> > the series needs a bit more work, but is an obvious fix and there is
> > no point in holding it up.
>
> Sure.
>
> I'm not seeing any description of the runtime effects of this
> shortcoming. I tentatively queued the fix for 5.18, without a
> cc:stable for backporting. But that might not be the best decision?
>
As far as I can tell, mirrored memory is only used on x86 today, where
pages are always 4k.
However, the whole notion of memory below 4 GB being special is a
x86-ism, and so this logic does not appear to extrapolate to other
architectures anyway, and probably needs more work.
So definitely not a backportable fix, but just an incremental
improvement, so either 5.18 or 5.19 should be fine afaict (and no
cc:stable)
next prev parent reply other threads:[~2022-04-20 22:40 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-14 10:13 [PATCH v2 0/9] introduce mirrored memory support for arm64 Wupeng Ma
2022-04-14 10:13 ` [PATCH v2 1/9] efi: Make efi_print_memmap() public Wupeng Ma
2022-04-14 10:13 ` [PATCH v2 2/9] arm64: efi: Add fake memory support Wupeng Ma
2022-04-14 10:13 ` [PATCH v2 3/9] efi: Make efi_find_mirror() public Wupeng Ma
2022-04-14 10:13 ` [PATCH v2 4/9] arm64/mirror: arm64 enabling - find mirrored memory ranges Wupeng Ma
2022-04-14 10:13 ` [PATCH v2 5/9] mm: Ratelimited mirrored memory related warning messages Wupeng Ma
2022-04-14 10:13 ` [PATCH v2 6/9] mm: Demote warning message in vmemmap_verify() to debug level Wupeng Ma
2022-04-14 10:13 ` [PATCH v2 7/9] mm: Calc the right pfn if page size is not 4K Wupeng Ma
2022-04-19 9:59 ` David Hildenbrand
2022-04-19 11:14 ` Anshuman Khandual
2022-04-19 18:29 ` Ard Biesheuvel
2022-04-20 22:27 ` Andrew Morton
2022-04-20 22:39 ` Ard Biesheuvel [this message]
2022-04-14 10:13 ` [PATCH v2 8/9] efi: Disable mirror feature if kernelcore is not specified Wupeng Ma
2022-04-14 10:13 ` [PATCH v2 9/9] ia64/efi: Code simplification in efi_init Wupeng Ma
2022-04-14 10:22 ` [PATCH v2 0/9] introduce mirrored memory support for arm64 Ard Biesheuvel
2022-04-16 1:32 ` mawupeng
2022-04-19 18:32 ` Ard Biesheuvel
2022-04-20 2:13 ` mawupeng
2022-04-19 7:01 ` [PATCH 0/2] Add support to relocate kernel image to mirrored region Wupeng Ma
2022-04-19 7:01 ` [PATCH 1/2] arm64/boot/KASLR: " Wupeng Ma
2022-04-19 7:01 ` [PATCH 2/2] arm64/boot: Add support to relocate kernel image to mirrored region without kaslr Wupeng Ma
2022-05-03 9:58 ` [PATCH 0/2] Add support to relocate kernel image to mirrored region Ard Biesheuvel
2022-05-07 9:28 ` mawupeng
2022-05-19 11:09 ` mawupeng
2022-05-20 6:52 ` Ard Biesheuvel
2022-05-20 6:52 ` Ard Biesheuvel
2022-05-23 11:48 ` mawupeng
2022-05-23 1:18 ` mawupeng
2022-05-23 14:41 ` Ard Biesheuvel
2022-05-24 1:11 ` mawupeng
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