From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
To: Greg KH <gregkh@linuxfoundation.org>,
Jing Xiangfeng <jingxiangfeng@huawei.com>
Cc: catalin.marinas@arm.com, will@kernel.org,
akpm@linux-foundation.org, paul.walmsley@sifive.com,
palmer@dabbelt.com, aou@eecs.berkeley.edu, rppt@kernel.org,
lorenzo.pieralisi@arm.com, guohanjun@huawei.com,
sudeep.holla@arm.com, rjw@rjwysocki.net, lenb@kernel.org,
song.bao.hua@hisilicon.com, ardb@kernel.org,
anshuman.khandual@arm.com, bhelgaas@google.com, guro@fb.com,
robh+dt@kernel.org, stable@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, frowand.list@gmail.com,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-riscv@lists.infradead.org,
wangkefeng.wang@huawei.com
Subject: Re: [PATCH stable v5.10 0/7] arm64: Default to 32-bit wide ZONE_DMA
Date: Thu, 04 Mar 2021 15:05:32 +0100 [thread overview]
Message-ID: <9bc396116372de5b538d71d8f9ae9c3259f1002e.camel@suse.de> (raw)
In-Reply-To: <YEDkmj6cchMPAq2h@kroah.com>
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Hi Greg.
On Thu, 2021-03-04 at 14:46 +0100, Greg KH wrote:
> On Wed, Mar 03, 2021 at 03:33:12PM +0800, Jing Xiangfeng wrote:
> > Using two distinct DMA zones turned out to be problematic. Here's an
> > attempt go back to a saner default.
>
> What problem does this solve? How does this fit into the stable kernel
> rules?
We changed the way we setup memory zones in arm64 in order to cater for
Raspberry Pi 4's weird DMA constraints: ZONE_DMA spans the lower 1GB of memory
and ZONE_DMA32 the rest of the 32bit address space. Since you can't allocate
memory that crosses zone boundaries, this broke crashkernel allocations on big
machines. This series fixes all this by parsing the HW description and checking
for DMA constrained buses. When not found, the unnecessary zone creation is
skipped.
That said, I have no clue whether this falls or not into the stable kernel
rules.
Regards,
Nicolas
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next prev parent reply other threads:[~2021-03-04 14:07 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-03 7:33 [PATCH stable v5.10 0/7] arm64: Default to 32-bit wide ZONE_DMA Jing Xiangfeng
2021-03-03 7:33 ` [PATCH stable v5.10 1/7] arm64: mm: Move reserve_crashkernel() into mem_init() Jing Xiangfeng
2021-03-03 7:33 ` [PATCH stable v5.10 2/7] arm64: mm: Move zone_dma_bits initialization into zone_sizes_init() Jing Xiangfeng
2021-03-03 7:33 ` [PATCH stable v5.10 3/7] of/address: Introduce of_dma_get_max_cpu_address() Jing Xiangfeng
2021-03-03 7:33 ` [PATCH stable v5.10 4/7] of: unittest: Add test for of_dma_get_max_cpu_address() Jing Xiangfeng
2021-03-03 7:33 ` [PATCH stable v5.10 5/7] arm64: mm: Set ZONE_DMA size based on devicetree's dma-ranges Jing Xiangfeng
2021-03-03 7:33 ` [PATCH stable v5.10 6/7] arm64: mm: Set ZONE_DMA size based on early IORT scan Jing Xiangfeng
2021-03-03 7:33 ` [PATCH stable v5.10 7/7] mm: Remove examples from enum zone_type comment Jing Xiangfeng
2021-03-04 13:46 ` [PATCH stable v5.10 0/7] arm64: Default to 32-bit wide ZONE_DMA Greg KH
2021-03-04 14:05 ` Nicolas Saenz Julienne [this message]
2021-03-04 14:17 ` Greg KH
2021-03-04 15:09 ` Nicolas Saenz Julienne
2021-03-07 15:24 ` Greg KH
2021-03-08 3:20 ` Jing Xiangfeng
2021-03-08 9:58 ` Greg KH
2021-05-11 12:35 ` Kefeng Wang
2021-05-12 12:06 ` Greg KH
2021-06-23 6:59 ` Kefeng Wang
2021-06-23 7:12 ` Greg KH
2021-06-23 7:25 ` Kefeng Wang
2021-06-23 7:34 ` Greg KH
2021-06-23 8:01 ` Kefeng Wang
2021-06-25 10:19 ` Greg KH
2021-06-26 1:19 ` Kefeng Wang
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