From: Michael Walle <michael@walle.cc>
To: saravanak@google.com
Cc: ardb@kernel.org, devicetree@vger.kernel.org,
frowand.list@gmail.com, gregkh@linuxfoundation.org,
grygorii.strashko@ti.com, kernel-team@android.com,
laurent.pinchart@ideasonboard.com, lenb@kernel.org,
linux-acpi@vger.kernel.org, linux-efi@vger.kernel.org,
linux-kernel@vger.kernel.org, maz@kernel.org, rafael@kernel.org,
rjw@rjwysocki.net, robh+dt@kernel.org, tglx@linutronix.de,
tomi.valkeinen@ti.com, Michael Walle <michael@walle.cc>
Subject: Re: [PATCH v2 16/17] driver core: Refactor fw_devlink feature
Date: Tue, 29 Dec 2020 04:34:40 +0100 [thread overview]
Message-ID: <20201229033440.32142-1-michael@walle.cc> (raw)
In-Reply-To: <20201121020232.908850-17-saravanak@google.com>
> The current implementation of fw_devlink is very inefficient because it
> tries to get away without creating fwnode links in the name of saving
> memory usage. Past attempts to optimize runtime at the cost of memory
> usage were blocked with request for data showing that the optimization
> made significant improvement for real world scenarios.
>
> We have those scenarios now. There have been several reports of boot
> time increase in the order of seconds in this thread [1]. Several OEMs
> and SoC manufacturers have also privately reported significant
> (350-400ms) increase in boot time due to all the parsing done by
> fw_devlink.
>
> So this patch uses all the setup done by the previous patches in this
> series to refactor fw_devlink to be more efficient. Most of the code has
> been moved out of firmware specific (DT mostly) code into driver core.
>
> This brings the following benefits:
> - Instead of parsing the device tree multiple times during bootup,
> fw_devlink parses each fwnode node/property only once and creates
> fwnode links. The rest of the fw_devlink code then just looks at these
> fwnode links to do rest of the work.
>
> - Makes it much easier to debug probe issue due to fw_devlink in the
> future. fw_devlink=on blocks the probing of devices if they depend on
> a device that hasn't been added yet. With this refactor, it'll be very
> easy to tell what that device is because we now have a reference to
> the fwnode of the device.
>
> - Much easier to add fw_devlink support to ACPI and other firmware
> types. A refactor to move the common bits from DT specific code to
> driver core was in my TODO list as a prerequisite to adding ACPI
> support to fw_devlink. This series gets that done.
>
> [1] - https://lore.kernel.org/linux-omap/ea02f57e-871d-cd16-4418-c1da4bbc4696@ti.com/
> Signed-off-by: Saravana Kannan <saravanak@google.com>
> Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Tested-by: Grygorii Strashko <grygorii.strashko@ti.com>
git bisect show that this commit broke my board in 5.11-rc1:
[ 2.294375] sysfs: cannot create duplicate filename '/devices/virtual/devlink/0000:00:00.1--0000:00:00.1'
[ 2.303999] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.11.0-rc1-00016-ga0fb284b267 #267
[ 2.312125] Hardware name: Kontron SMARC-sAL28 (4 Lane) (DT)
[ 2.317804] Call trace:
[ 2.320253] dump_backtrace+0x0/0x1b8
[ 2.323936] show_stack+0x20/0x70
[ 2.327263] dump_stack+0xd8/0x134
[ 2.330677] sysfs_warn_dup+0x6c/0x88
[ 2.334351] sysfs_create_dir_ns+0xe8/0x100
[ 2.338547] kobject_add_internal+0x9c/0x290
[ 2.342833] kobject_add+0xa0/0x108
[ 2.346331] device_add+0xfc/0x798
[ 2.349746] device_link_add+0x454/0x5e0
[ 2.353682] fw_devlink_create_devlink+0xb8/0xc8
[ 2.358316] __fw_devlink_link_to_suppliers+0x84/0x180
[ 2.363474] __fw_devlink_link_to_suppliers+0x134/0x180
[ 2.368718] device_add+0x778/0x798
[ 2.372217] device_register+0x28/0x38
[ 2.375979] __mdiobus_register+0x94/0x340
[ 2.380089] of_mdiobus_register+0xb4/0x380
[ 2.384285] enetc_pf_probe+0x73c/0xb10
[ 2.388132] local_pci_probe+0x48/0xb8
[ 2.391896] pci_device_probe+0x120/0x1c0
[ 2.395920] really_probe+0xec/0x3c0
[ 2.399505] driver_probe_device+0x60/0xc0
[ 2.403614] device_driver_attach+0x7c/0x88
[ 2.407810] __driver_attach+0x60/0xe8
[ 2.411570] bus_for_each_dev+0x7c/0xd0
[ 2.415419] driver_attach+0x2c/0x38
[ 2.419004] bus_add_driver+0x194/0x1f8
[ 2.422851] driver_register+0x6c/0x128
[ 2.426698] __pci_register_driver+0x4c/0x58
[ 2.430983] enetc_pf_driver_init+0x2c/0x38
[ 2.435181] do_one_initcall+0x54/0x2d8
[ 2.439029] kernel_init_freeable+0x1fc/0x268
[ 2.443403] kernel_init+0x1c/0x120
[ 2.446904] ret_from_fork+0x10/0x30
[ 2.450502] kobject_add_internal failed for 0000:00:00.1--0000:00:00.1 with -EEXIST, don't try to register things with the same name in the same directory.
Looks like it will generate that link twice? Let me know if I can help
testing.
See also: https://lavalab.kontron.com/scheduler/job/3894#L831
-michael
next prev parent reply other threads:[~2020-12-29 3:36 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-21 2:02 [PATCH v2 00/17] Refactor fw_devlink to significantly improve boot time Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 01/17] Revert "driver core: Avoid deferred probe due to fw_devlink_pause/resume()" Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 02/17] Revert "driver core: Rename dev_links_info.defer_sync to defer_hook" Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 03/17] Revert "driver core: Don't do deferred probe in parallel with kernel_init thread" Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 04/17] Revert "driver core: Remove check in driver_deferred_probe_force_trigger()" Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 05/17] Revert "of: platform: Batch fwnode parsing when adding all top level devices" Saravana Kannan
2020-12-07 22:18 ` Rob Herring
2020-11-21 2:02 ` [PATCH v2 06/17] Revert "driver core: fw_devlink: Add support for batching fwnode parsing" Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 07/17] driver core: Add fwnode_init() Saravana Kannan
2020-12-06 7:26 ` Leon Romanovsky
2020-12-07 19:25 ` Saravana Kannan
2020-12-07 19:53 ` Leon Romanovsky
2020-12-07 20:36 ` Saravana Kannan
2020-12-08 6:34 ` Leon Romanovsky
2020-12-07 22:20 ` Rob Herring
2020-11-21 2:02 ` [PATCH v2 08/17] driver core: Add fwnode link support Saravana Kannan
2020-12-06 7:48 ` Leon Romanovsky
2020-12-07 19:25 ` Saravana Kannan
2020-12-07 19:56 ` Leon Romanovsky
2020-12-07 22:21 ` Rob Herring
2020-11-21 2:02 ` [PATCH v2 09/17] driver core: Allow only unprobed consumers for SYNC_STATE_ONLY device links Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 10/17] device property: Add fwnode_is_ancestor_of() and fwnode_get_next_parent_dev() Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 11/17] driver core: Redefine the meaning of fwnode_operations.add_links() Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 12/17] driver core: Add fw_devlink_parse_fwtree() Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 13/17] driver core: Use device's fwnode to check if it is waiting for suppliers Saravana Kannan
2022-06-27 11:42 ` Abel Vesa
2022-06-27 22:30 ` Saravana Kannan
2022-06-28 15:24 ` Abel Vesa
2022-06-28 15:44 ` Abel Vesa
2022-06-28 15:55 ` Abel Vesa
2022-06-28 18:09 ` Saravana Kannan
2023-01-05 14:47 ` Dmitry Baryshkov
2020-11-21 2:02 ` [PATCH v2 14/17] of: property: Update implementation of add_links() to create fwnode links Saravana Kannan
2020-12-07 22:37 ` Rob Herring
2020-11-21 2:02 ` [PATCH v2 15/17] efi: " Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 16/17] driver core: Refactor fw_devlink feature Saravana Kannan
2020-11-23 16:00 ` [driver core] 95f755a4ef: will-it-scale.per_process_ops 2.2% improvement kernel test robot
2020-12-11 14:11 ` [PATCH v2 16/17] driver core: Refactor fw_devlink feature Qian Cai
2020-12-11 16:34 ` Robin Murphy
2020-12-11 17:51 ` Saravana Kannan
2020-12-11 18:03 ` Marc Zyngier
2020-12-11 18:20 ` Saravana Kannan
2020-12-11 19:07 ` Marc Zyngier
2020-12-11 22:29 ` Saravana Kannan
2020-12-29 3:34 ` Michael Walle [this message]
2021-01-05 19:00 ` Saravana Kannan
2021-01-05 21:03 ` Michael Walle
2021-01-06 23:29 ` Saravana Kannan
2020-11-21 2:02 ` [PATCH v2 17/17] driver core: Delete pointless parameter in fwnode_operations.add_links Saravana Kannan
2020-12-07 22:38 ` Rob Herring
2020-11-24 8:29 ` [PATCH v2 00/17] Refactor fw_devlink to significantly improve boot time Tomi Valkeinen
2020-11-24 17:25 ` Saravana Kannan
2020-12-03 19:05 ` Saravana Kannan
2020-12-09 18:16 ` Greg Kroah-Hartman
2020-12-09 20:24 ` Saravana Kannan
2020-12-10 9:26 ` Greg Kroah-Hartman
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