From: Logan Gunthorpe <logang@deltatee.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>,
Len Brown <lenb@kernel.org>,
Saket Dumbre <saket.dumbre@intel.com>,
Bjorn Helgaas <bhelgaas@google.com>,
linux-acpi@vger.kernel.org, acpica-devel@lists.linux.dev,
linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
Lukas Wunner <lukas@wunner.de>,
"Natu, Mahesh" <mahesh.natu@intel.com>
Subject: Re: [PATCH RFC 4/7] PCI/P2PDMA: Prefer providers with better HMAT performance
Date: Mon, 17 Aug 2026 10:09:42 -0600 [thread overview]
Message-ID: <3dc699d8-a5d1-4100-b717-07fd0956e61d@deltatee.com> (raw)
In-Reply-To: <20260816123836.GC66924@unreal>
On 2026-08-16 06:38, Leon Romanovsky wrote:
>> This feels backwards to me. If ACPI is kind enough to include
>> information on P2PDMA support then I feel like we should use it
>> exclusively. Not prioritize the old janky whitelists.
>
> Right now, there is no ACPI support, and I chose to prioritize
> existing systems that already have some form of support over an ACPI
> solution that does not yet exist.
But don't we know whether ACPI is advertising support now? Certainly if
ACPI indicates support we should use it above all other considerations
today. Otherwise fall back on the white lists. And that should always
work. Even on my old hardware because the ACPI on that machine doesn't
advertise support, so it should fall back on the whitelist. I see no
need to ever check the whitelist before checking ACPI.
Logan
next prev parent reply other threads:[~2026-08-17 16:09 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-12 19:47 [PATCH RFC 0/7] PCI/HMAT: Describe P2PDMA reachability and performance Leon Romanovsky
2026-08-12 19:47 ` [PATCH RFC 1/7] ACPICA: Define PCIe P2P latency and bandwidth information Leon Romanovsky
2026-08-13 10:13 ` Rafael J. Wysocki (Intel)
2026-08-13 11:01 ` Leon Romanovsky
2026-08-12 19:47 ` [PATCH RFC 2/7] ACPI: HMAT: Make PCIe P2P paths available to consumers Leon Romanovsky
2026-08-12 19:47 ` [PATCH RFC 3/7] PCI/P2PDMA: Authorize HMAT-described cross-host-bridge P2P Leon Romanovsky
2026-08-12 19:47 ` [PATCH RFC 4/7] PCI/P2PDMA: Prefer providers with better HMAT performance Leon Romanovsky
2026-08-14 3:50 ` Logan Gunthorpe
2026-08-16 12:38 ` Leon Romanovsky
2026-08-17 16:09 ` Logan Gunthorpe [this message]
2026-08-17 18:27 ` Leon Romanovsky
2026-08-12 19:47 ` [PATCH RFC 5/7] ACPI: HMAT: Add KUnit tests for PCIe P2P matrix semantics Leon Romanovsky
2026-08-12 19:47 ` [PATCH RFC 6/7] PCI/P2PDMA: Add KUnit tests for HMAT policy boundaries Leon Romanovsky
2026-08-12 19:47 ` [PATCH RFC 7/7] PCI/P2PDMA: Add KUnit tests for HMAT provider ranking Leon Romanovsky
2026-08-24 20:15 ` [PATCH RFC 0/7] PCI/HMAT: Describe P2PDMA reachability and performance Alison Schofield
2026-08-24 20:24 ` Natu, Mahesh
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