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From: Christoph Hellwig <hch@lst.de>
To: Dusty Mabe <dusty@dustymabe.com>
Cc: Minchan Kim <minchan@kernel.org>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Jens Axboe <axboe@kernel.dk>,
	linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
	Christoph Hellwig <hch@lst.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	marmijo@redhat.com
Subject: Re: XFS metadata CRC errors on zram block device on ppc64le architecture
Date: Wed, 2 Aug 2023 11:41:06 +0200	[thread overview]
Message-ID: <20230802094106.GA28187@lst.de> (raw)
In-Reply-To: <b2d40565-7868-ba15-4bb1-fca6f0df076b@dustymabe.com>

On Tue, Aug 01, 2023 at 11:31:37PM -0400, Dusty Mabe wrote:
> We ran a kernel bisect and narrowed it down to offending commit af8b04c6:
> 
> ```
> [root@ibm-p8-kvm-03-guest-02 linux]# git bisect good
> af8b04c63708fa730c0257084fab91fb2a9cecc4 is the first bad commit
> commit af8b04c63708fa730c0257084fab91fb2a9cecc4
> Author: Christoph Hellwig <hch@lst.de>
> Date:   Tue Apr 11 19:14:46 2023 +0200
> 
>     zram: simplify bvec iteration in __zram_make_request
>     
>     bio_for_each_segment synthetize bvecs that never cross page boundaries, so
>     don't duplicate that work in an inner loop.

> Any ideas on how to fix the problem?

So the interesting cases are:

  - ppc64 usually uses 64k page sizes
  - ppc64 is somewhat cache incoherent (compared to say x86)

Let me think of this a bit more.

  reply	other threads:[~2023-08-02  9:41 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-02  3:31 XFS metadata CRC errors on zram block device on ppc64le architecture Dusty Mabe
2023-08-02  9:41 ` Christoph Hellwig [this message]
2023-08-02 11:03   ` Hannes Reinecke
2023-08-02 12:00     ` Dusty Mabe
2023-08-03 21:32       ` Dusty Mabe
2023-08-04  3:25         ` Sergey Senozhatsky
2023-08-04 13:42           ` Christoph Hellwig
2023-08-04 14:20             ` Hannes Reinecke
2023-08-04 16:28           ` Linux regression tracking (Thorsten Leemhuis)
2023-08-04 16:22 ` Linux regression tracking #adding (Thorsten Leemhuis)
2023-08-05 12:16   ` Linux regression tracking #update (Thorsten Leemhuis)

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