From: Pingfan Liu <kernelfans@gmail.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: x86@kernel.org, linux-acpi@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Len Brown <lenb@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 4/4] x86/mm: remove bottom-up allocation style for x86_64
Date: Wed, 9 Jan 2019 10:44:41 +0800 [thread overview]
Message-ID: <CAFgQCTtaNteN37hpDOmjR7Cjoqaza0suxE9EOfdpDW3DbAsrcw@mail.gmail.com> (raw)
In-Reply-To: <7706aaac-c00b-8a11-a7a1-cb95b5a01581@intel.com>
On Wed, Jan 9, 2019 at 1:33 AM Dave Hansen <dave.hansen@intel.com> wrote:
>
> On 1/7/19 10:13 PM, Pingfan Liu wrote:
> > On Tue, Jan 8, 2019 at 1:42 AM Dave Hansen <dave.hansen@intel.com> wrote:
> >> Why is this 0x100000 open-coded? Why is this needed *now*?
> >>
> >
> > Memory under 1MB should be used by BIOS. For x86_64, after
> > e820__memblock_setup(), the memblock allocator has already been ready
> > to work. But there are two factors to in order to
> > set_alloc_range(0x100000, end). The major one is to be compatible with
> > x86_32, please refer to alloc_low_pages->memblock_find_in_range() uses
> > [min_pfn_mapped, max_pfn_mapped] to limit the range, which is ready to
> > be allocated from. The minor one is to prevent unexpected allocation
> > from memblock allocator through allow_low_pages() at very early stage.
>
> Wow, that's a ton of critical information which was neither commented
> upon or referenced in the changelog. Can you fix this up in the next
> version, please?
Sure.
Thanks,
Pingfan
next prev parent reply other threads:[~2019-01-09 2:44 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-07 8:24 [RFC PATCH 0/4] x86_64/mm: remove bottom-up allocation style by pushing forward the parsing of mem hotplug info Pingfan Liu
2019-01-07 8:24 ` [RFC PATCH 1/4] acpi: change the topo of acpi_table_upgrade() Pingfan Liu
2019-01-07 10:55 ` Rafael J. Wysocki
2019-01-07 8:24 ` [RFC PATCH 2/4] x86/setup: parse acpi to get hotplug info before init_mem_mapping() Pingfan Liu
2019-01-07 12:52 ` Pingfan Liu
2019-01-07 17:11 ` Dave Hansen
2019-01-08 6:30 ` Pingfan Liu
2019-01-07 8:24 ` [RFC PATCH 3/4] x86/mm: set allowed range for memblock allocator Pingfan Liu
2019-01-07 8:24 ` [RFC PATCH 4/4] x86/mm: remove bottom-up allocation style for x86_64 Pingfan Liu
2019-01-07 17:42 ` Dave Hansen
2019-01-08 6:13 ` Pingfan Liu
2019-01-08 6:37 ` Juergen Gross
2019-01-08 17:32 ` Dave Hansen
2019-01-09 2:44 ` Pingfan Liu [this message]
2019-01-07 17:03 ` [RFC PATCH 0/4] x86_64/mm: remove bottom-up allocation style by pushing forward the parsing of mem hotplug info Dave Hansen
2019-01-08 5:49 ` Pingfan Liu
2019-01-08 10:05 ` Chao Fan
2019-01-08 13:27 ` Pingfan Liu
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