linux-kernel - Re: [PATCH 2/2] erofs: address D-cache aliasing

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Message-ID: <da52a0d3-9a3b-4465-bf17-cf2ad8044330@linux.alibaba.com>
Date: Wed, 9 Jul 2025 21:53:10 +0800
From: Gao Xiang <hsiangkao@...ux.alibaba.com>
To: Stefan Kerkmann <s.kerkmann@...gutronix.de>, linux-erofs@...ts.ozlabs.org
Cc: LKML <linux-kernel@...r.kernel.org>, Jan Kiszka <jan.kiszka@...mens.com>
Subject: Re: [PATCH 2/2] erofs: address D-cache aliasing

Hi Stefan,

On 2025/7/9 19:25, Stefan Kerkmann wrote:
> Hi Gao, Hi Jan,
> 
> On 7/9/25 5:46 AM, Gao Xiang wrote:
>> Flush the D-cache before unlocking folios for compressed inodes, as
>> they are dirtied during decompression.
>>
>> Avoid calling flush_dcache_folio() on every CPU write, since it's more
>> like playing whack-a-mole without real benefit.
>>
>> It has no impact on x86 and arm64/risc-v: on x86, flush_dcache_folio()
>> is a no-op, and on arm64/risc-v, PG_dcache_clean (PG_arch_1) is clear
>> for new page cache folios.  However, certain ARM boards are affected,
>> as reported.
>>
>> Fixes: 3883a79abd02 ("staging: erofs: introduce VLE decompression support")
>> Closes: https://lore.kernel.org/r/c1e51e16-6cc6-49d0-a63e-4e9ff6c4dd53@pengutronix.de
>> Closes: https://lore.kernel.org/r/38d43fae-1182-4155-9c5b-ffc7382d9917@siemens.com
>> Cc: Jan Kiszka <jan.kiszka@...mens.com>
>> Cc: Stefan Kerkmann <s.kerkmann@...gutronix.de>
>> Signed-off-by: Gao Xiang <hsiangkao@...ux.alibaba.com>
>> ---
>> Hi Jan and Stefan,
>>
>> if possible, please help test this patch on your arm devices,
>> many thanks!  I will submit this later but if it's urgent you
>> could also apply this locally in advance.
>>
> 
> Thank you for the fix and great work, it solved the issue I was seeing locally!

Thanks for your confirmation too!

Thanks,
Gao Xiang