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From: "Dan Horák" <dan@danny.cz>
To: linuxppc-dev@lists.ozlabs.org
Subject: a possible issue with radix MMU on P9
Date: Thu, 11 May 2023 09:55:58 +0200	[thread overview]
Message-ID: <20230511095558.56663a50f86bdc4cd97700b7@danny.cz> (raw)

Hi all,

we have been struggling with an issue in the bdwgc project (garbage
collector) on P9 systems for a while [1]. There were some test failing
on P9, but not on P8 or other platforms (x86, s390x, aarch64). Recently
the upstream developer has found out there is likely a problem in the
kernel memory mgmt [2], there is a reproduction scenario included. I
have rechecked the original code on P9 with hash MMU and it worked. Thus
I believe there is a problem in the radix MMU code on Power, where it
behaves differently. My testing was using Fedora, which means recent
kernels up to 6.4-rc1.

[1] https://github.com/ivmai/bdwgc/issues/479
[2] https://github.com/ivmai/bdwgc/issues/479#issuecomment-1535274481


	Thanks,

		Dan

             reply	other threads:[~2023-05-11  8:01 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-11  7:55 Dan Horák [this message]
2023-05-11 12:16 ` a possible issue with radix MMU on P9 Michael Ellerman

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