From: "Christoph Lameter (Ampere)" <cl@gentwo.org>
To: Yang Shi <yang@os.amperecomputing.com>
Cc: muchun.song@linux.dev, osalvador@suse.de, david@redhat.com,
akpm@linux-foundation.org, catalin.marinas@arm.com,
will@kernel.org, carl@os.amperecomputing.com,
linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: hugetlb: avoid soft lockup when mprotect with PROT_MTE
Date: Fri, 26 Sep 2025 09:29:54 -0700 (PDT) [thread overview]
Message-ID: <1038c7c7-81d6-f273-6fa1-93eb7206d5ed@gentwo.org> (raw)
In-Reply-To: <20250926162034.1785899-1-yang@os.amperecomputing.com>
On Fri, 26 Sep 2025, Yang Shi wrote:
> When calling mprotect() with PROT_MTE, kernel will initialize MTE tags
> for every single page in the affected area. Soft lockup was observed
> when doing this for large HugeTLB memory area in our customer's workload
> (~300GB memory):
AFAICT this is a bug fix. The hugetlb path should be doing a
cond_resched() like the base page code does.
It is not MTE specific. If other processing takes a long time in the loop
(setting up terabyte size mappings for hugetlb for example) then the
softlockup could also be triggered on non MTE workloads.
Reviewed-by: Christoph Lameter (Ampere) <cl@gentwo.org>
next prev parent reply other threads:[~2025-09-26 16:29 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-26 16:20 Yang Shi
2025-09-26 16:29 ` Christoph Lameter (Ampere) [this message]
2025-09-26 16:56 ` Catalin Marinas
2025-09-26 17:51 ` Yang Shi
2025-09-29 8:29 ` David Hildenbrand
2025-09-29 16:15 ` Yang Shi
2025-09-29 9:27 ` Oscar Salvador
2025-09-29 9:55 ` Anshuman Khandual
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