From: Sudeep Holla <sudeep.holla@arm.com>
To: Jeremy Linton <jeremy.linton@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
john.garry@huawei.com, Will Deacon <will.deacon@arm.com>,
Shaokun Zhang <zhangshaokun@hisilicon.com>,
qiuzhenfa@hisilicon.com, guohanjun@huawei.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/2] arm64: cacheinfo: Update cache_line_size detected from PPTT
Date: Mon, 29 Apr 2019 12:06:36 +0100 [thread overview]
Message-ID: <20190429110453.GA23929@e107155-lin> (raw)
In-Reply-To: <8d9b4fcd-23be-be06-6afa-8cabb1e889c2@arm.com>
On Fri, Apr 26, 2019 at 12:18:33PM -0500, Jeremy Linton wrote:
> Hi,
>
> On 4/25/19 8:40 PM, Shaokun Zhang wrote:
> > cache_line_size is derived from CTR_EL0.CWG field and is called mostly
> > for I/O device drivers. For HiSilicon certain plantform, like the
>
> But there are core users too? Thinkgs like blk-mq, the trace ring buffer,
> iommu/iova, slub/slab. And a quick look seems to indicate a number of those
> users are going to be checking the cache line size before the cachinfo is
> populated (it happens fairly late via device_initcall() and a hp notifier).
> Is it going to be a problem if the value changes?
>
Yes, I agree with that and share the same concern. If the users of these
can't get updated with the new value once cacheinfo is populated, then
we need to figure to solve this differently(I mean still from PPTT or
firmware info as we don't have anything more reliable).
--
Regards,
Sudeep
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next prev parent reply other threads:[~2019-04-29 11:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-26 1:40 [PATCH 1/2] ACPI/PPTT: Add variable to record max cache line size Shaokun Zhang
2019-04-26 1:40 ` [PATCH 2/2] arm64: cacheinfo: Update cache_line_size detected from PPTT Shaokun Zhang
2019-04-26 17:18 ` Jeremy Linton
2019-04-27 16:12 ` Catalin Marinas
2019-04-29 11:12 ` Sudeep Holla
2019-04-29 11:06 ` Sudeep Holla [this message]
2019-04-27 16:16 ` Catalin Marinas
2019-04-30 1:32 ` Zhangshaokun
2019-04-26 17:02 ` [PATCH 1/2] ACPI/PPTT: Add variable to record max cache line size Jeremy Linton
2019-04-29 11:26 ` Sudeep Holla
2019-04-30 2:19 ` Zhangshaokun
2019-04-30 2:13 ` Zhangshaokun
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