From: Oscar Salvador <osalvador@suse.de>
To: Gavin Shan <gshan@redhat.com>
Cc: Aditya Gupta <adityag@linux.ibm.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Danilo Krummrich <dakr@kernel.org>,
David Hildenbrand <david@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Mahesh J Salgaonkar <mahesh@linux.ibm.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Sourabh Jain <sourabhjain@linux.ibm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [REPORT] Softlockups on PowerNV with upstream
Date: Thu, 10 Apr 2025 10:23:13 +0200 [thread overview]
Message-ID: <Z_d_8fyQzGuwzbIv@localhost.localdomain> (raw)
In-Reply-To: <dc4c0d4e-a9a5-4fa5-b39d-4248fba26043@redhat.com>
On Thu, Apr 10, 2025 at 03:35:19PM +1000, Gavin Shan wrote:
> Thanks, Oscar. You're correct that the overhead is introduced by for_each_present_section_nr().
> I already had the fix, working on IBM's Power9 machine, where the issue can be
> reproduced. Please see the attached patch.
>
> I'm having most tests on ARM64 machine for the fix.
Looks good to me.
But we need a comment explaining why block_id is set to ULONG_MAX
at the beginning as this might not be obvious.
Also, do we need
if (block_id != ULONG_MAX && memory_block_id(nr) == block_id) ?
Cannot just be
if (memory_block_id(nr) == block_id) ?
AFAICS, the first time we loop through 'memory_block_id(nr) == ULONG_MAX'
will evaluate false and and we will set block_id afterwards.
Either way looks fine to me.
Another way I guess would be:
--
Oscar Salvador
SUSE Labs
next prev parent reply other threads:[~2025-04-10 8:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-09 18:03 Aditya Gupta
2025-04-10 1:35 ` Gavin Shan
2025-04-10 11:38 ` Aditya Gupta
2025-04-10 5:25 ` Oscar Salvador
2025-04-10 5:35 ` Gavin Shan
2025-04-10 8:23 ` Oscar Salvador [this message]
2025-04-10 9:44 ` Gavin Shan
2025-04-10 11:49 ` Aditya Gupta
2025-04-10 12:22 ` Aditya Gupta
2025-04-10 12:32 ` Gavin Shan
2025-04-10 11:44 ` Aditya Gupta
2025-04-10 12:26 ` Aditya Gupta
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