From: David Laight <david.laight.linux@gmail.com>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@redhat.com>,
David Hildenbrand <david@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf/events: Replace READ_ONCE() with standard pgtable accessors
Date: Wed, 8 Apr 2026 13:49:23 +0100 [thread overview]
Message-ID: <20260408134923.3a44a703@pumpkin> (raw)
In-Reply-To: <1267a6c0-f8e7-4708-96da-4d131b5c6069@arm.com>
On Tue, 7 Apr 2026 08:58:46 +0530
Anshuman Khandual <anshuman.khandual@arm.com> wrote:
> On 27/02/26 11:57 AM, Anshuman Khandual wrote:
> > Replace raw READ_ONCE() dereferences of pgtable entries with corresponding
> > standard page table accessors pxdp_get() in perf_get_pgtable_size(). These
> > accessors default to READ_ONCE() on platforms that don't override them. So
> > there is no functional change on such platforms.
> >
> > However arm64 platform is being extended to support 128 bit page tables via
> > a new architecture feature i.e FEAT_D128 in which case READ_ONCE() will not
> > provide required single copy atomic access for 128 bit page table entries.
> > Although pxdp_get() accessors can later be overridden on arm64 platform to
> > extend required single copy atomicity support on 128 bit entries.
>
Did you consider enhancing READ_ONCE() to support 128bit accesses on arm64?
David
prev parent reply other threads:[~2026-04-08 12:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-27 6:27 [PATCH] perf/events: Replace READ_ONCE() with standard pgtable accessors Anshuman Khandual
2026-02-27 20:55 ` David Hildenbrand (Arm)
2026-02-28 16:49 ` SeongJae Park
2026-03-09 3:26 ` Anshuman Khandual
2026-04-07 3:28 ` Anshuman Khandual
2026-04-07 6:48 ` David Hildenbrand (Arm)
2026-04-07 6:53 ` Anshuman Khandual
2026-04-07 7:18 ` Peter Zijlstra
2026-04-08 10:58 ` Anshuman Khandual
2026-04-08 11:16 ` Peter Zijlstra
2026-04-08 12:49 ` David Laight [this message]
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