From: <dan.j.williams@intel.com>
To: "Koralahalli Channabasappa,
Smita" <Smita.KoralahalliChannabasappa@amd.com>,
Alison Schofield <alison.schofield@intel.com>
Cc: <linux-cxl@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<nvdimm@lists.linux.dev>, <linux-fsdevel@vger.kernel.org>,
<linux-pm@vger.kernel.org>, Davidlohr Bueso <dave@stgolabs.net>,
"Jonathan Cameron" <jonathan.cameron@huawei.com>,
Dave Jiang <dave.jiang@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Ira Weiny <ira.weiny@intel.com>,
"Dan Williams" <dan.j.williams@intel.com>,
Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Len Brown <len.brown@intel.com>, Pavel Machek <pavel@kernel.org>,
Li Ming <ming.li@zohomail.com>,
Jeff Johnson <jeff.johnson@oss.qualcomm.com>,
"Ying Huang" <huang.ying.caritas@gmail.com>,
Yao Xingtao <yaoxt.fnst@fujitsu.com>,
Peter Zijlstra <peterz@infradead.org>,
Greg KH <gregkh@linuxfoundation.org>,
Nathan Fontenot <nathan.fontenot@amd.com>,
Terry Bowman <terry.bowman@amd.com>,
Robert Richter <rrichter@amd.com>,
Benjamin Cheatham <benjamin.cheatham@amd.com>,
PradeepVineshReddy Kodamati <PradeepVineshReddy.Kodamati@amd.com>,
Zhijian Li <lizhijian@fujitsu.com>
Subject: Re: [PATCH v5 0/7] Add managed SOFT RESERVE resource handling
Date: Wed, 23 Jul 2025 08:24:13 -0700 [thread overview]
Message-ID: <6880fe9dbb6ec_e74a1004b@dwillia2-mobl4.notmuch> (raw)
In-Reply-To: <4ac55e2c-54a9-4fab-b0c5-2a928faef33e@amd.com>
Koralahalli Channabasappa, Smita wrote:
[..]
> That said, I'm still evaluating better options to more robustly
> coordinate probe ordering between cxl_acpi, cxl_port, cxl_mem and
> cxl_region and looking for suggestions here.
I never quite understood the arguments around why
wait_for_device_probe() does not work, but I did find a bug in my prior
thinking on the way towards this RFC [1]. The misunderstanding was that
MODULE_SOFTDEP() only guarantees that the module gets loaded eventually,
but it does not guarantee that the softdep has completed init before the
caller performs its own init.
It works sometimes, and that is probably what misled me about that
contract. request_module() is synchronous. With that in place I now see
what wait_for_device_probe() does the right thing. It flushes cxl_pci
attach for devices present at boot, and all follow-on probe work gets
flushed as well.
With that in hand the RFC now has a stable quiesce point to walk the CXL
topology and make decisions. The RFC is effectively a fix for platforms
where CXL loses the MODULE_SOFTDEP() race.
[1]: http://lore.kernel.org/68808fb4e4cbf_137e6b100cc@dwillia2-xfh.jf.intel.com.notmuch
next prev parent reply other threads:[~2025-07-23 15:24 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-15 18:04 [PATCH v5 0/7] Add managed SOFT RESERVE resource handling Smita Koralahalli
2025-07-15 18:04 ` [PATCH v5 1/7] cxl/acpi: Refactor cxl_acpi_probe() to always schedule fallback DAX registration Smita Koralahalli
2025-07-22 21:04 ` dan.j.williams
2025-07-23 0:45 ` Alison Schofield
2025-07-23 7:34 ` dan.j.williams
2025-07-15 18:04 ` [PATCH v5 2/7] cxl/core: Rename suspend.c to probe_state.c and remove CONFIG_CXL_SUSPEND Smita Koralahalli
2025-07-22 21:44 ` dan.j.williams
2025-07-15 18:04 ` [PATCH v5 3/7] cxl/acpi: Add background worker to coordinate with cxl_mem probe completion Smita Koralahalli
2025-07-17 0:24 ` Dave Jiang
2025-07-23 7:31 ` dan.j.williams
2025-07-23 16:13 ` dan.j.williams
2025-08-05 3:58 ` Zhijian Li (Fujitsu)
2025-08-20 23:14 ` Alison Schofield
2025-08-21 2:30 ` Zhijian Li (Fujitsu)
2025-08-22 3:56 ` Koralahalli Channabasappa, Smita
2025-08-25 7:50 ` Zhijian Li (Fujitsu)
2025-08-27 6:30 ` Zhijian Li (Fujitsu)
2025-08-28 23:21 ` Koralahalli Channabasappa, Smita
2025-09-01 2:46 ` Zhijian Li (Fujitsu)
2025-07-29 15:48 ` Koralahalli Channabasappa, Smita
2025-07-30 16:09 ` dan.j.williams
2025-07-15 18:04 ` [PATCH v5 4/7] cxl/region: Introduce SOFT RESERVED resource removal on region teardown Smita Koralahalli
2025-07-17 0:42 ` Dave Jiang
2025-07-15 18:04 ` [PATCH v5 5/7] dax/hmem: Save the DAX HMEM platform device pointer Smita Koralahalli
2025-07-15 18:04 ` [PATCH v5 6/7] dax/hmem, cxl: Defer DAX consumption of SOFT RESERVED resources until after CXL region creation Smita Koralahalli
2025-07-15 18:04 ` [PATCH v5 7/7] dax/hmem: Preserve fallback SOFT RESERVED regions if DAX HMEM loads late Smita Koralahalli
2025-07-15 21:07 ` [PATCH v5 0/7] Add managed SOFT RESERVE resource handling Alison Schofield
2025-07-16 6:01 ` Koralahalli Channabasappa, Smita
2025-07-16 20:20 ` Alison Schofield
2025-07-16 21:29 ` Koralahalli Channabasappa, Smita
2025-07-16 23:48 ` Alison Schofield
2025-07-17 17:58 ` Koralahalli Channabasappa, Smita
2025-07-17 19:06 ` Dave Jiang
2025-07-17 23:20 ` Koralahalli Channabasappa, Smita
2025-07-17 23:30 ` Dave Jiang
2025-07-23 15:24 ` dan.j.williams [this message]
2025-07-21 7:38 ` Zhijian Li (Fujitsu)
2025-07-22 20:07 ` dan.j.williams
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