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In Documentation/admin-guide/blockdev/zoned_loop.rst, add the
description of the zone_append and ordered_zone_append configuration
arguments of zloop "add" command (device creation).
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The zone append operation processing for zloop devices is similar to any
other command, that is, the operation is processed as a command work
item, without any special serialization between the work items (beside
the zone mutex for mutually exclusive code sections).
This processing is fine and gives excellent performance. However, it has
a side effect: zone append operation are very often reordered and
processed in a sequence that is very different from their issuing order
by the user. This effect is very visible using an XFS file system on top
of a zloop device. A simple file write leads to many file extents as the
data writes using zone append are reordered and so result in the
physical order being different than the file logical order.
E.g. executing:
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..4095]: 2162688..2166783
1: [4096..6143]: 2168832..2170879
2: [6144..8191]: 2166784..2168831
3: [8192..10239]: 2170880..2172927
4: [10240..12287]: 2174976..2177023
5: [12288..14335]: 2172928..2174975
6: [14336..20479]: 2177024..2183167
For 10 IOs, 6 extents are created.
This is fine and actually allows to exercise XFS zone garbage collection
very well. However, this also makes debugging/working on XFS data
placement harder as the underlying device will most of the time reorder
IOs, resulting in many file extents.
Allow a user to mitigate this with the new ordered_zone_append
configuration parameter. For a zloop device created with this parameter
specified, the sector of a zone append command is set early, when the
command is submitted by the block layer with the zloop_queue_rq()
function, instead of in the zloop_rw() function which is exectued later
in the command work item context. This change ensures that more often
than not, zone append operations data end up being written in the same
order as the command submission by the user.
In the case of XFS, this leads to far less file data extents. E.g., for
the previous example, we get a single file data extent for the written
file.
$ dd if=/dev/zero of=/mnt/test bs=1M count=10 && sync
$ xfs_bmap /mnt/test
/mnt/test:
0: [0..20479]: 2162688..2183167
Since we cannot use a mutex in the context of the zloop_queue_rq()
function to atomically set a zone append operation sector to the target
zone write pointer location and increment that the write pointer, a new
per-zone spinlock is introduced to protect a zone write pointer access
and modifications. To check a zone write pointer location and set a zone
append operation target sector to that value, the function
zloop_set_zone_append_sector() is introduced and called from
zloop_queue_rq().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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A zloop zoned block device declares to the block layer that it supports
zone append operations. That is, a zloop device ressembles an NVMe ZNS
devices supporting zone append.
This native support is fine but it does not allow exercising the block
layer zone write plugging emulation of zone append, as is done with SCSI
or ATA SMR HDDs.
Introduce the zone_append configuration parameter to allow creating a
zloop device without native support for zone append, thus relying on the
block layer zone append emulation. If not specified, zone append support
is enabled by default. Otherwise, a value of 0 disables native zone
append and a value of 1 enables it.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The function zloop_rw() already checks early that a request is fully
contained within the target zone. So this check does not need to be done
again for regular writes to sequential zones. Furthermore, since zone
append operations are always directed to the zone write pointer
location, we do not need to check for their alignment to that value
after setting it. So turn the "if" checking the write pointer alignment
into an "else if".
While at it, improve the comment describing the write pointer
modification and how this value is corrected in case of error.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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zloop_rw() will fail any regular write operation that targets a full
sequential zone. The check for this is indirect and achieved by checking
the write pointer alignment of the write operation. But this check is
ineffective for zone append operations since these are alwasy
automatically directed at a zone write pointer.
Prevent zone append operations from being executed in a full zone with
an explicit check of the zone condition.
Fixes: eb0570c7df23 ("block: new zoned loop block device driver")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The write pointer of zones that are in the full condition is always
invalid. Reflect that fact by setting the write pointer of full zones
to ULLONG_MAX.
Fixes: eb0570c7df23 ("block: new zoned loop block device driver")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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throtl_slice is now a constant. Remove the variable and use the constant
directly where needed.
Cc: Yu Kuai <yukuai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Reviewed-by: Yu Kuai <yukuai@fnnas.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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After the removal of CONFIG_BLK_DEV_THROTTLING_LOW, it is no longer
necessary to enable block accounting, so remove the call to
blk_stat_enable_accounting(). With that, the track_bio_latency variable
is no longer used and can be deleted from struct throtl_data. Also,
including blk-stat.h is no longer necessary.
Fixes: bf20ab538c81 ("blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW")
Cc: Yu Kuai <yukuai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Reviewed-by: Yu Kuai <yukuai@fnnas.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Commit d61fcfa4bb18 ("blk-throttle: choose a small throtl_slice for SSD")
introduced device type specific throttle slices if BLK_DEV_THROTTLING_LOW
was enabled. Commit bf20ab538c81 ("blk-throttle: remove
CONFIG_BLK_DEV_THROTTLING_LOW") removed support for BLK_DEV_THROTTLING_LOW,
but left the device type specific throttle slices in place. This
effectively changed throttling behavior on systems with SSD which now use
a different and non-configurable slice time compared to non-SSD devices.
Practical impact is that throughput tests with low configured throttle
values (65536 bps) experience less than expected throughput on SSDs,
presumably due to rounding errors associated with the small throttle slice
time used for those devices. The same tests pass when setting the throttle
values to 65536 * 4 = 262144 bps.
The original code sets the throttle slice time to DFL_THROTL_SLICE_HD if
CONFIG_BLK_DEV_THROTTLING_LOW is disabled. Restore that code to fix the
problem. With that, DFL_THROTL_SLICE_SSD is no longer necessary. Revert to
the original code and re-introduce DFL_THROTL_SLICE to replace both
DFL_THROTL_SLICE_HD and DFL_THROTL_SLICE_SSD. This effectively reverts
commit d61fcfa4bb18 ("blk-throttle: choose a small throtl_slice for SSD").
While at it, also remove MAX_THROTL_SLICE since it is not used anymore.
Fixes: bf20ab538c81 ("blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW")
Cc: Yu Kuai <yukuai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Reviewed-by: Yu Kuai <yukuai@fnnas.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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If the next discard range is contiguous with the current range being
considered, it's cheaper to expand the current range than to append an
additional bio.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Integrated amplifier LEAK Stereo 230 by IAG Limited has built-in
ESS9038Q2M DAC served by XMOS controller. It supports both DSD Native
and DSD-over-PCM (DoP) operational modes. But it doesn't work properly
by default and tries DSD-to-PCM conversion. USB quirks below allow it
to operate as designed.
Add DSD_RAW quirk flag for IAG Limited devices (vendor ID 0x2622)
Add DSD format quirk for LEAK Stereo 230 (USB ID 0x2622:0x0061)
Signed-off-by: Ivan Zhaldak <i.v.zhaldak@gmail.com>
Cc: <stable@vger.kernel.org>
Link: https://patch.msgid.link/20251117125848.30769-1-i.v.zhaldak@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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__snd_vortex_probe() uses pci_read_config_word() that returns PCIBIOS_*
codes (positive values on error). However, the function checks 'err < 0'
which can never be true for PCIBIOS_* codes, causing errors to be silently
ignored.
Check for non-zero return value and convert PCIBIOS_* codes using
pcibios_err_to_errno() into normal errno before returning them.
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
Reviewed-by: Philipp Stanner <phasta@kernel.org>
Link: https://patch.msgid.link/20251117065559.1138-1-vulab@iscas.ac.cn
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Reading the interrupt register `SUN4I_REG_INT_ADDR` causes all of its bits
to be reset. If we ever reach the condition of handling more than
`SUN4I_CAN_MAX_IRQ` IRQs, we will have read the register and reset all its
bits but without actually handling the interrupt inside of the loop body.
This may, among other issues, cause us to never `netif_wake_queue()` again
after a transmission interrupt.
Fixes: 0738eff14d81 ("can: Allwinner A10/A20 CAN Controller support - Kernel module")
Cc: stable@vger.kernel.org
Co-developed-by: Thomas Mühlbacher <tmuehlbacher@posteo.net>
Signed-off-by: Thomas Mühlbacher <tmuehlbacher@posteo.net>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://patch.msgid.link/20251116-sun4i-fix-loop-v1-1-3d76d3f81950@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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Marc Kleine-Budde <mkl@pengutronix.de> says:
The bulk-out callback gs_usb_xmit_callback() does not take care of the
cleanup of failed transfers of URBs. The 1st patch adds the missing
cleanup.
The bulk-in callback gs_usb_receive_bulk_callback() accesses the buffer of
the URB without checking how much data has actually been received. The last
2 patches fix this problem.
Link: https://patch.msgid.link/20251114-gs_usb-fix-usb-callbacks-v1-0-a29b42eacada@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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accessing data
The URB received in gs_usb_receive_bulk_callback() contains a struct
gs_host_frame. The length of the data after the header depends on the
gs_host_frame hf::flags and the active device features (e.g. time
stamping).
Introduce a new function gs_usb_get_minimum_length() and check that we have
at least received the required amount of data before accessing it. Only
copy the data to that skb that has actually been received.
Fixes: d08e973a77d1 ("can: gs_usb: Added support for the GS_USB CAN devices")
Link: https://patch.msgid.link/20251114-gs_usb-fix-usb-callbacks-v1-3-a29b42eacada@pengutronix.de
[mkl: rename gs_usb_get_minimum_length() -> +gs_usb_get_minimum_rx_length()]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
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Add a randomized algorithm that runs newidle balancing proportional to
its success rate.
This improves schbench significantly:
6.18-rc4: 2.22 Mrps/s
6.18-rc4+revert: 2.04 Mrps/s
6.18-rc4+revert+random: 2.18 Mrps/S
Conversely, per Adam Li this affects SpecJBB slightly, reducing it by 1%:
6.17: -6%
6.17+revert: 0%
6.17+revert+random: -1%
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Chris Mason <clm@meta.com>
Link: https://lkml.kernel.org/r/6825c50d-7fa7-45d8-9b81-c6e7e25738e2@meta.com
Link: https://patch.msgid.link/20251107161739.770122091@infradead.org
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Simplify code by adding a few variables.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Chris Mason <clm@meta.com>
Link: https://patch.msgid.link/20251107161739.655208666@infradead.org
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Pull out the !sd check to simplify code.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Chris Mason <clm@meta.com>
Link: https://patch.msgid.link/20251107161739.525916173@infradead.org
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Many people reported regressions on their database workloads due to:
155213a2aed4 ("sched/fair: Bump sd->max_newidle_lb_cost when newidle balance fails")
For instance Adam Li reported a 6% regression on SpecJBB.
Conversely this will regress schbench again; on my machine from 2.22
Mrps/s down to 2.04 Mrps/s.
Reported-by: Joseph Salisbury <joseph.salisbury@oracle.com>
Reported-by: Adam Li <adamli@os.amperecomputing.com>
Reported-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reported-by: Hazem Mohamed Abuelfotoh <abuehaze@amazon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Chris Mason <clm@meta.com>
Link: https://lkml.kernel.org/r/20250626144017.1510594-2-clm@fb.com
Link: https://lkml.kernel.org/r/006c9df2-b691-47f1-82e6-e233c3f91faf@oracle.com
Link: https://patch.msgid.link/20251107161739.406147760@infradead.org
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Reimplement NEXT_BUDDY preemption to take into account the deadline and
eligibility of the wakee with respect to the waker. In the event
multiple buddies could be considered, the one with the earliest deadline
is selected.
Sync wakeups are treated differently to every other type of wakeup. The
WF_SYNC assumption is that the waker promises to sleep in the very near
future. This is violated in enough cases that WF_SYNC should be treated
as a suggestion instead of a contract. If a waker does go to sleep almost
immediately then the delay in wakeup is negligible. In other cases, it's
throttled based on the accumulated runtime of the waker so there is a
chance that some batched wakeups have been issued before preemption.
For all other wakeups, preemption happens if the wakee has a earlier
deadline than the waker and eligible to run.
While many workloads were tested, the two main targets were a modified
dbench4 benchmark and hackbench because the are on opposite ends of the
spectrum -- one prefers throughput by avoiding preemption and the other
relies on preemption.
First is the dbench throughput data even though it is a poor metric but
it is the default metric. The test machine is a 2-socket machine and the
backing filesystem is XFS as a lot of the IO work is dispatched to kernel
threads. It's important to note that these results are not representative
across all machines, especially Zen machines, as different bottlenecks
are exposed on different machines and filesystems.
dbench4 Throughput (misleading but traditional)
6.18-rc1 6.18-rc1
vanilla sched-preemptnext-v5
Hmean 1 1268.80 ( 0.00%) 1269.74 ( 0.07%)
Hmean 4 3971.74 ( 0.00%) 3950.59 ( -0.53%)
Hmean 7 5548.23 ( 0.00%) 5420.08 ( -2.31%)
Hmean 12 7310.86 ( 0.00%) 7165.57 ( -1.99%)
Hmean 21 8874.53 ( 0.00%) 9149.04 ( 3.09%)
Hmean 30 9361.93 ( 0.00%) 10530.04 ( 12.48%)
Hmean 48 9540.14 ( 0.00%) 11820.40 ( 23.90%)
Hmean 79 9208.74 ( 0.00%) 12193.79 ( 32.42%)
Hmean 110 8573.12 ( 0.00%) 11933.72 ( 39.20%)
Hmean 141 7791.33 ( 0.00%) 11273.90 ( 44.70%)
Hmean 160 7666.60 ( 0.00%) 10768.72 ( 40.46%)
As throughput is misleading, the benchmark is modified to use a short
loadfile report the completion time duration in milliseconds.
dbench4 Loadfile Execution Time
6.18-rc1 6.18-rc1
vanilla sched-preemptnext-v5
Amean 1 14.62 ( 0.00%) 14.69 ( -0.46%)
Amean 4 18.76 ( 0.00%) 18.85 ( -0.45%)
Amean 7 23.71 ( 0.00%) 24.38 ( -2.82%)
Amean 12 31.25 ( 0.00%) 31.87 ( -1.97%)
Amean 21 45.12 ( 0.00%) 43.69 ( 3.16%)
Amean 30 61.07 ( 0.00%) 54.33 ( 11.03%)
Amean 48 95.91 ( 0.00%) 77.22 ( 19.49%)
Amean 79 163.38 ( 0.00%) 123.08 ( 24.66%)
Amean 110 243.91 ( 0.00%) 175.11 ( 28.21%)
Amean 141 343.47 ( 0.00%) 239.10 ( 30.39%)
Amean 160 401.15 ( 0.00%) 283.73 ( 29.27%)
Stddev 1 0.52 ( 0.00%) 0.51 ( 2.45%)
Stddev 4 1.36 ( 0.00%) 1.30 ( 4.04%)
Stddev 7 1.88 ( 0.00%) 1.87 ( 0.72%)
Stddev 12 3.06 ( 0.00%) 2.45 ( 19.83%)
Stddev 21 5.78 ( 0.00%) 3.87 ( 33.06%)
Stddev 30 9.85 ( 0.00%) 5.25 ( 46.76%)
Stddev 48 22.31 ( 0.00%) 8.64 ( 61.27%)
Stddev 79 35.96 ( 0.00%) 18.07 ( 49.76%)
Stddev 110 59.04 ( 0.00%) 30.93 ( 47.61%)
Stddev 141 85.38 ( 0.00%) 40.93 ( 52.06%)
Stddev 160 96.38 ( 0.00%) 39.72 ( 58.79%)
That is still looking good and the variance is reduced quite a bit.
Finally, fairness is a concern so the next report tracks how many
milliseconds does it take for all clients to complete a workfile. This
one is tricky because dbench makes to effort to synchronise clients so
the durations at benchmark start time differ substantially from typical
runtimes. This problem could be mitigated by warming up the benchmark
for a number of minutes but it's a matter of opinion whether that
counts as an evasion of inconvenient results.
dbench4 All Clients Loadfile Execution Time
6.18-rc1 6.18-rc1
vanilla sched-preemptnext-v5
Amean 1 15.06 ( 0.00%) 15.07 ( -0.03%)
Amean 4 603.81 ( 0.00%) 524.29 ( 13.17%)
Amean 7 855.32 ( 0.00%) 1331.07 ( -55.62%)
Amean 12 1890.02 ( 0.00%) 2323.97 ( -22.96%)
Amean 21 3195.23 ( 0.00%) 2009.29 ( 37.12%)
Amean 30 13919.53 ( 0.00%) 4579.44 ( 67.10%)
Amean 48 25246.07 ( 0.00%) 5705.46 ( 77.40%)
Amean 79 29701.84 ( 0.00%) 15509.26 ( 47.78%)
Amean 110 22803.03 ( 0.00%) 23782.08 ( -4.29%)
Amean 141 36356.07 ( 0.00%) 25074.20 ( 31.03%)
Amean 160 17046.71 ( 0.00%) 13247.62 ( 22.29%)
Stddev 1 0.47 ( 0.00%) 0.49 ( -3.74%)
Stddev 4 395.24 ( 0.00%) 254.18 ( 35.69%)
Stddev 7 467.24 ( 0.00%) 764.42 ( -63.60%)
Stddev 12 1071.43 ( 0.00%) 1395.90 ( -30.28%)
Stddev 21 1694.50 ( 0.00%) 1204.89 ( 28.89%)
Stddev 30 7945.63 ( 0.00%) 2552.59 ( 67.87%)
Stddev 48 14339.51 ( 0.00%) 3227.55 ( 77.49%)
Stddev 79 16620.91 ( 0.00%) 8422.15 ( 49.33%)
Stddev 110 12912.15 ( 0.00%) 13560.95 ( -5.02%)
Stddev 141 20700.13 ( 0.00%) 14544.51 ( 29.74%)
Stddev 160 9079.16 ( 0.00%) 7400.69 ( 18.49%)
This is more of a mixed bag but it at least shows that fairness
is not crippled.
The hackbench results are more neutral but this is still important.
It's possible to boost the dbench figures by a large amount but only by
crippling the performance of a workload like hackbench. The WF_SYNC
behaviour is important for these workloads and is why the WF_SYNC
changes are not a separate patch.
hackbench-process-pipes
6.18-rc1 6.18-rc1
vanilla sched-preemptnext-v5
Amean 1 0.2657 ( 0.00%) 0.2150 ( 19.07%)
Amean 4 0.6107 ( 0.00%) 0.6060 ( 0.76%)
Amean 7 0.7923 ( 0.00%) 0.7440 ( 6.10%)
Amean 12 1.1500 ( 0.00%) 1.1263 ( 2.06%)
Amean 21 1.7950 ( 0.00%) 1.7987 ( -0.20%)
Amean 30 2.3207 ( 0.00%) 2.5053 ( -7.96%)
Amean 48 3.5023 ( 0.00%) 3.9197 ( -11.92%)
Amean 79 4.8093 ( 0.00%) 5.2247 ( -8.64%)
Amean 110 6.1160 ( 0.00%) 6.6650 ( -8.98%)
Amean 141 7.4763 ( 0.00%) 7.8973 ( -5.63%)
Amean 172 8.9560 ( 0.00%) 9.3593 ( -4.50%)
Amean 203 10.4783 ( 0.00%) 10.8347 ( -3.40%)
Amean 234 12.4977 ( 0.00%) 13.0177 ( -4.16%)
Amean 265 14.7003 ( 0.00%) 15.5630 ( -5.87%)
Amean 296 16.1007 ( 0.00%) 17.4023 ( -8.08%)
Processes using pipes are impacted but the variance (not presented) indicates
it's close to noise and the results are not always reproducible. If executed
across multiple reboots, it may show neutral or small gains so the worst
measured results are presented.
Hackbench using sockets is more reliably neutral as the wakeup
mechanisms are different between sockets and pipes.
hackbench-process-sockets
6.18-rc1 6.18-rc1
vanilla sched-preemptnext-v2
Amean 1 0.3073 ( 0.00%) 0.3263 ( -6.18%)
Amean 4 0.7863 ( 0.00%) 0.7930 ( -0.85%)
Amean 7 1.3670 ( 0.00%) 1.3537 ( 0.98%)
Amean 12 2.1337 ( 0.00%) 2.1903 ( -2.66%)
Amean 21 3.4683 ( 0.00%) 3.4940 ( -0.74%)
Amean 30 4.7247 ( 0.00%) 4.8853 ( -3.40%)
Amean 48 7.6097 ( 0.00%) 7.8197 ( -2.76%)
Amean 79 14.7957 ( 0.00%) 16.1000 ( -8.82%)
Amean 110 21.3413 ( 0.00%) 21.9997 ( -3.08%)
Amean 141 29.0503 ( 0.00%) 29.0353 ( 0.05%)
Amean 172 36.4660 ( 0.00%) 36.1433 ( 0.88%)
Amean 203 39.7177 ( 0.00%) 40.5910 ( -2.20%)
Amean 234 42.1120 ( 0.00%) 43.5527 ( -3.42%)
Amean 265 45.7830 ( 0.00%) 50.0560 ( -9.33%)
Amean 296 50.7043 ( 0.00%) 54.3657 ( -7.22%)
As schbench has been mentioned in numerous bugs recently, the results
are interesting. A test case that represents the default schbench
behaviour is
schbench Wakeup Latency (usec)
6.18.0-rc1 6.18.0-rc1
vanilla sched-preemptnext-v5
Amean Wakeup-50th-80 7.17 ( 0.00%) 6.00 ( 16.28%)
Amean Wakeup-90th-80 46.56 ( 0.00%) 19.78 ( 57.52%)
Amean Wakeup-99th-80 119.61 ( 0.00%) 89.94 ( 24.80%)
Amean Wakeup-99.9th-80 3193.78 ( 0.00%) 328.22 ( 89.72%)
schbench Requests Per Second (ops/sec)
6.18.0-rc1 6.18.0-rc1
vanilla sched-preemptnext-v5
Hmean RPS-20th-80 8900.91 ( 0.00%) 9176.78 ( 3.10%)
Hmean RPS-50th-80 8987.41 ( 0.00%) 9217.89 ( 2.56%)
Hmean RPS-90th-80 9123.73 ( 0.00%) 9273.25 ( 1.64%)
Hmean RPS-max-80 9193.50 ( 0.00%) 9301.47 ( 1.17%)
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251112122521.1331238-3-mgorman@techsingularity.net
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The NEXT_BUDDY feature reinforces wakeup preemption to encourage the last
wakee to be scheduled sooner on the assumption that the waker/wakee share
cache-hot data. In CFS, it was paired with LAST_BUDDY to switch back on
the assumption that the pair of tasks still share data but also relied
on START_DEBIT and the exact WAKEUP_PREEMPTION implementation to get
good results.
NEXT_BUDDY has been disabled since commit 0ec9fab3d186 ("sched: Improve
latencies and throughput") and LAST_BUDDY was removed in commit 5e963f2bd465
("sched/fair: Commit to EEVDF"). The reasoning is not clear but as vruntime
spread is mentioned so the expectation is that NEXT_BUDDY had an impact
on overall fairness. It was not noted why LAST_BUDDY was removed but it
is assumed that it's very difficult to reason what LAST_BUDDY's correct
and effective behaviour should be while still respecting EEVDFs goals.
Peter Zijlstra noted during review;
I think I was just struggling to make sense of things and figured
less is more and axed it.
I have vague memories trying to work through the dynamics of
a wakeup-stack and the EEVDF latency requirements and getting
a head-ache.
NEXT_BUDDY is easier to reason about given that it's a point-in-time
decision on the wakees deadline and eligibilty relative to the waker. Enable
NEXT_BUDDY as a preparation path to document that the decision to ignore
the current implementation is deliberate. While not presented, the results
were at best neutral and often much more variable.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251112122521.1331238-2-mgorman@techsingularity.net
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Increase the sched_tick_remote WARN_ON timeout to remove false
positives due to temporarily busy HK cpus. The suggestion
was 30 seconds to catch really stuck remote tick processing
but not trigger it too easily.
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://patch.msgid.link/20250911161300.437944-1-pauld@redhat.com
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Also serialize the possiblty much more frequent newidle balancing for
the 'expensive' domains that have SD_BALANCE set.
Initial benchmarking by K Prateek and Tim showed no negative effect.
Split out from the larger patch moving sched_balance_running around
for ease of bisect and such.
Suggested-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Seconded-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/df068896-82f9-458d-8fff-5a2f654e8ffd@amd.com
Link: https://patch.msgid.link/6fed119b723c71552943bfe5798c93851b30a361.1762800251.git.tim.c.chen@linux.intel.com
# Conflicts:
# kernel/sched/fair.c
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The NUMA sched domain sets the SD_SERIALIZE flag by default, allowing
only one NUMA load balancing operation to run system-wide at a time.
Currently, each sched group leader directly under NUMA domain attempts
to acquire the global sched_balance_running flag via cmpxchg() before
checking whether load balancing is due or whether it is the designated
load balancer for that NUMA domain. On systems with a large number
of cores, this causes significant cache contention on the shared
sched_balance_running flag.
This patch reduces unnecessary cmpxchg() operations by first checking
that the balancer is the designated leader for a NUMA domain from
should_we_balance(), and the balance interval has expired before
trying to acquire sched_balance_running to load balance a NUMA
domain.
On a 2-socket Granite Rapids system with sub-NUMA clustering enabled,
running an OLTP workload, 7.8% of total CPU cycles were previously spent
in sched_balance_domain() contending on sched_balance_running before
this change.
: 104 static __always_inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new)
: 105 {
: 106 return arch_cmpxchg(&v->counter, old, new);
0.00 : ffffffff81326e6c: xor %eax,%eax
0.00 : ffffffff81326e6e: mov $0x1,%ecx
0.00 : ffffffff81326e73: lock cmpxchg %ecx,0x2394195(%rip) # ffffffff836bb010 <sched_balance_running>
: 110 sched_balance_domains():
: 12234 if (atomic_cmpxchg_acquire(&sched_balance_running, 0, 1))
99.39 : ffffffff81326e7b: test %eax,%eax
0.00 : ffffffff81326e7d: jne ffffffff81326e99 <sched_balance_domains+0x209>
: 12238 if (time_after_eq(jiffies, sd->last_balance + interval)) {
0.00 : ffffffff81326e7f: mov 0x14e2b3a(%rip),%rax # ffffffff828099c0 <jiffies_64>
0.00 : ffffffff81326e86: sub 0x48(%r14),%rax
0.00 : ffffffff81326e8a: cmp %rdx,%rax
After applying this fix, sched_balance_domain() is gone from the profile
and there is a 5% throughput improvement.
[peterz: made it so that redo retains the 'lock' and split out the
CPU_NEWLY_IDLE change to a separate patch]
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Chen Yu <yu.c.chen@intel.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Reviewed-by: Srikar Dronamraju <srikar@linux.ibm.com>
Tested-by: Mohini Narkhede <mohini.narkhede@intel.com>
Tested-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://patch.msgid.link/6fed119b723c71552943bfe5798c93851b30a361.1762800251.git.tim.c.chen@linux.intel.com
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Blktests test cases nvme/014, 057 and 058 fail occasionally due to a
lockdep WARN. As reported in the Closes tag URL, the WARN indicates that
a deadlock can happen due to the dependency among disk->open_mutex,
kblockd workqueue completion and partition_scan_work completion.
To avoid the lockdep WARN and the potential deadlock, cut the dependency
by running the partition_scan_work not by kblockd workqueue but by
nvme_wq.
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Closes: https://lore.kernel.org/linux-block/CAHj4cs8mJ+R_GmQm9R8ebResKAWUE8kF5+_WVg0v8zndmqd6BQ@mail.gmail.com/
Link: https://lore.kernel.org/linux-block/oeyzci6ffshpukpfqgztsdeke5ost5hzsuz4rrsjfmvpqcevax@5nhnwbkzbrpa/
Fixes: 1f021341eef4 ("nvme-multipath: defer partition scanning")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
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Commit 7e091add9c43 "nvme-auth: update sc_c in host response" added
the sc_c variable to the dhchap queue context structure which is
appropriately set during negotiate and then used in the host response.
This breaks secure concat connections with a Linux target as the target
code wasn't updated at the same time. This patch fixes this by adding a
new sc_c variable to the host hash calculations.
Fixes: 7e091add9c43 ("nvme-auth: update sc_c in host response")
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Reviewed-by: Martin George <marting@netapp.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
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Since vcpu local clock is no longer affected by ntp,
remove comment about ntp correction sync for function
kvm_gen_kvmclock_update.
Signed-off-by: Lei Chen <lei.chen@smartx.com>
Link: https://patch.msgid.link/20250819152027.1687487-4-lei.chen@smartx.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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This reverts commit 7e44e4495a398eb553ce561f29f9148f40a3448f.
Commit 7e44e4495a39 ("x86: kvm: rate-limit global clock updates")
intends to use a kvmclock_update_work to sync ntp corretion
across all vcpus kvmclock, which is based on commit 0061d53daf26f
("KVM: x86: limit difference between kvmclock updates")
Since kvmclock has been switched to mono raw, this commit can be
reverted.
Signed-off-by: Lei Chen <lei.chen@smartx.com>
Link: https://patch.msgid.link/20250819152027.1687487-3-lei.chen@smartx.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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This reverts commit 332967a3eac06f6379283cf155c84fe7cd0537c2.
Commit 332967a3eac0 ("x86: kvm: introduce periodic global clock
updates") introduced a 300s interval work to sync ntp corrections
across all vcpus.
Since commit 53fafdbb8b21 ("KVM: x86: switch KVMCLOCK base to
monotonic raw clock"), kvmclock switched to mono raw clock,
we can no longer take ntp into consideration.
Signed-off-by: Lei Chen <lei.chen@smartx.com>
Link: https://patch.msgid.link/20250819152027.1687487-2-lei.chen@smartx.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Stash apic->lapic_timer in a local "ktimer" variable in
advance_periodic_target_expiration() to eliminate a few unaligned wraps,
and to make the code easier to read overall.
No functional change intended.
Link: https://patch.msgid.link/20251113205114.1647493-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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When advancing the target expiration for the guest's APIC timer in periodic
mode, set the expiration to "now" if the target expiration is in the past
(similar to what is done in update_target_expiration()). Blindly adding
the period to the previous target expiration can result in KVM generating
a practically unbounded number of hrtimer IRQs due to programming an
expired timer over and over. In extreme scenarios, e.g. if userspace
pauses/suspends a VM for an extended duration, this can even cause hard
lockups in the host.
Currently, the bug only affects Intel CPUs when using the hypervisor timer
(HV timer), a.k.a. the VMX preemption timer. Unlike the software timer,
a.k.a. hrtimer, which KVM keeps running even on exits to userspace, the
HV timer only runs while the guest is active. As a result, if the vCPU
does not run for an extended duration, there will be a huge gap between
the target expiration and the current time the vCPU resumes running.
Because the target expiration is incremented by only one period on each
timer expiration, this leads to a series of timer expirations occurring
rapidly after the vCPU/VM resumes.
More critically, when the vCPU first triggers a periodic HV timer
expiration after resuming, advancing the expiration by only one period
will result in a target expiration in the past. As a result, the delta
may be calculated as a negative value. When the delta is converted into
an absolute value (tscdeadline is an unsigned u64), the resulting value
can overflow what the HV timer is capable of programming. I.e. the large
value will exceed the VMX Preemption Timer's maximum bit width of
cpu_preemption_timer_multi + 32, and thus cause KVM to switch from the
HV timer to the software timer (hrtimers).
After switching to the software timer, periodic timer expiration callbacks
may be executed consecutively within a single clock interrupt handler,
because hrtimers honors KVM's request for an expiration in the past and
immediately re-invokes KVM's callback after reprogramming. And because
the interrupt handler runs with IRQs disabled, restarting KVM's hrtimer
over and over until the target expiration is advanced to "now" can result
in a hard lockup.
E.g. the following hard lockup was triggered in the host when running a
Windows VM (only relevant because it used the APIC timer in periodic mode)
after resuming the VM from a long suspend (in the host).
NMI watchdog: Watchdog detected hard LOCKUP on cpu 45
...
RIP: 0010:advance_periodic_target_expiration+0x4d/0x80 [kvm]
...
RSP: 0018:ff4f88f5d98d8ef0 EFLAGS: 00000046
RAX: fff0103f91be678e RBX: fff0103f91be678e RCX: 00843a7d9e127bcc
RDX: 0000000000000002 RSI: 0052ca4003697505 RDI: ff440d5bfbdbd500
RBP: ff440d5956f99200 R08: ff2ff2a42deb6a84 R09: 000000000002a6c0
R10: 0122d794016332b3 R11: 0000000000000000 R12: ff440db1af39cfc0
R13: ff440db1af39cfc0 R14: ffffffffc0d4a560 R15: ff440db1af39d0f8
FS: 00007f04a6ffd700(0000) GS:ff440db1af380000(0000) knlGS:000000e38a3b8000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000d5651feff8 CR3: 000000684e038002 CR4: 0000000000773ee0
PKRU: 55555554
Call Trace:
<IRQ>
apic_timer_fn+0x31/0x50 [kvm]
__hrtimer_run_queues+0x100/0x280
hrtimer_interrupt+0x100/0x210
? ttwu_do_wakeup+0x19/0x160
smp_apic_timer_interrupt+0x6a/0x130
apic_timer_interrupt+0xf/0x20
</IRQ>
Moreover, if the suspend duration of the virtual machine is not long enough
to trigger a hard lockup in this scenario, since commit 98c25ead5eda
("KVM: VMX: Move preemption timer <=> hrtimer dance to common x86"), KVM
will continue using the software timer until the guest reprograms the APIC
timer in some way. Since the periodic timer does not require frequent APIC
timer register programming, the guest may continue to use the software
timer in perpetuity.
Fixes: d8f2f498d9ed ("x86/kvm: fix LAPIC timer drift when guest uses periodic mode")
Cc: stable@vger.kernel.org
Signed-off-by: fuqiang wang <fuqiang.wng@gmail.com>
[sean: massage comments and changelog]
Link: https://patch.msgid.link/20251113205114.1647493-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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When restarting an hrtimer to emulate a the guest's APIC timer in periodic
mode, explicitly set the expiration using the target expiration computed
by advance_periodic_target_expiration() instead of adding the period to
the existing timer. This will allow making adjustments to the expiration,
e.g. to deal with expirations far in the past, without having to implement
the same logic in both advance_periodic_target_expiration() and
apic_timer_fn().
Cc: stable@vger.kernel.org
Signed-off-by: fuqiang wang <fuqiang.wng@gmail.com>
[sean: split to separate patch, write changelog]
Link: https://patch.msgid.link/20251113205114.1647493-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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WARN and don't restart the hrtimer if KVM's callback runs with the guest's
APIC timer in periodic mode but with a period of '0', as not advancing the
hrtimer's deadline would put the CPU into an infinite loop of hrtimer
events. Observing a period of '0' should be impossible, even when the
hrtimer is running on a different CPU than the vCPU, as KVM is supposed to
cancel the hrtimer before changing (or zeroing) the period, e.g. when
switching from periodic to one-shot.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251113205114.1647493-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Use the normal, checked versions for get_user() and put_user() instead of
the double-underscore versions that omit range checks, as the checked
versions are actually measurably faster on modern CPUs (12%+ on Intel,
25%+ on AMD).
The performance hit on the unchecked versions is almost entirely due to
the added LFENCE on CPUs where LFENCE is serializing (which is effectively
all modern CPUs), which was added by commit 304ec1b05031 ("x86/uaccess:
Use __uaccess_begin_nospec() and uaccess_try_nospec"). The small
optimizations done by commit b19b74bc99b1 ("x86/mm: Rework address range
check in get_user() and put_user()") likely shave a few cycles off, but
the bulk of the extra latency comes from the LFENCE.
Don't bother trying to open-code an equivalent for performance reasons, as
the loss of inlining (e.g. see commit ea6f043fc984 ("x86: Make __get_user()
generate an out-of-line call") is largely a non-factor (ignoring setups
where RET is something entirely different),
As measured across tens of millions of calls of guest PTE reads in
FNAME(walk_addr_generic):
__get_user() get_user() open-coded open-coded, no LFENCE
Intel (EMR) 75.1 67.6 75.3 65.5
AMD (Turin) 68.1 51.1 67.5 49.3
Note, Hyper-V MSR emulation is not a remotely hot path, but convert it
anyways for consistency, and because there is a general desire to remove
__{get,put}_user() entirely.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Closes: https://lore.kernel.org/all/CAHk-=wimh_3jM9Xe8Zx0rpuf8CPDu6DkRCGb44azk0Sz5yqSnw@mail.gmail.com
Cc: Borislav Petkov <bp@alien8.de>
Link: https://patch.msgid.link/20251106210206.221558-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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We have reworked namespaces sufficiently that all this special-casing
shouldn't be needed anymore
Link: https://patch.msgid.link/20251117-eidesstattlich-apotheke-36d2e644079f@brauner
Signed-off-by: Christian Brauner <brauner@kernel.org>
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For years I wondered why the floppy driver does not just work on
sparc64, e.g:
root@SUNW_375_0066:# disktype /dev/fd0
disktype: Can't open /dev/fd0: No such device or address
[ 525.341906] disktype: attempt to access beyond end of device
fd0: rw=0, sector=0, nr_sectors = 16 limit=8
[ 525.341991] floppy: error 10 while reading block 0
Turns out floppy.c __floppy_read_block_0 tries to read one page for
the first test read to determine the disk size and thus fails if that
is greater than 4k. Adjust minimum MAX_DISK_SIZE to PAGE_SIZE to fix
floppy on sparc64 and likely all other PAGE_SIZE != 4KB configs.
Cc: stable@vger.kernel.org
Signed-off-by: René Rebe <rene@exactco.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The free_kick_syncs_rcu() rcu-callback only invoke kvfree() to
release per-cpu ksyncs object, this can use kvfree_rcu() replace
call_rcu() to release per-cpu ksyncs object in the free_kick_syncs().
Signed-off-by: Zqiang <qiang.zhang@linux.dev>
Signed-off-by: Tejun Heo <tj@kernel.org>
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For PREEMPT_RT kernels, the kick_cpus_irq_workfn() be invoked in
the per-cpu irq_work/* task context and there is no rcu-read critical
section to protect. this commit therefore use IRQ_WORK_INIT_HARD() to
initialize the per-cpu rq->scx.kick_cpus_irq_work in the
init_sched_ext_class().
Signed-off-by: Zqiang <qiang.zhang@linux.dev>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Make sure to drop the references taken to the component devices by
of_find_device_by_node() during probe on probe failure (e.g. probe
deferral) and on driver unbind.
Fixes: 453c3364632a ("drm/mediatek: Add ovl_adaptor support for MT8195")
Cc: stable@vger.kernel.org # 6.4
Cc: Nancy.Lin <nancy.lin@mediatek.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20250923152340.18234-6-johan@kernel.org/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
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Make sure to drop the reference taken to each component device during
probe on probe failure (e.g. probe deferral) and on driver unbind.
Fixes: 6ea6f8276725 ("drm/mediatek: Use correct device pointer to get CMDQ client register")
Cc: stable@vger.kernel.org # 5.12
Cc: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20250923152340.18234-4-johan@kernel.org/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
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The Mediatek DRM driver allocates private data for components without a
platform driver but as the lifetime is tied to each component device,
the memory is never freed.
Tie the allocation lifetime to the DRM platform device so that the
memory is released on probe failure (e.g. probe deferral) and when the
driver is unbound.
Fixes: c0d36de868a6 ("drm/mediatek: Move clk info from struct mtk_ddp_comp to sub driver private data")
Cc: stable@vger.kernel.org # 5.12
Cc: CK Hu <ck.hu@mediatek.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20250923152340.18234-3-johan@kernel.org/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
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Make sure to unmap and release the component iomap and clock on probe
failure (e.g. probe deferral) and on driver unbind.
Note that unlike of_iomap(), devm_of_iomap() also checks whether the
region is already mapped.
Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
Cc: stable@vger.kernel.org # 4.7
Cc: CK Hu <ck.hu@mediatek.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20250923152340.18234-2-johan@kernel.org/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
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The i2c adapter for ddc might not be available yet due to e.g. its
module not yet being loaded. To handle that defer probing rather then
returning a fatal error when probing.
Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>
Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
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Implement the Automated Built-In Self-Test ABIST functionality
provided by the HDMIv2 IP and expose it through the "hdmi_abist"
debugfs file.
Write "1" to this file to activate ABIST, or "0" to deactivate.
The ABIST functionality can be used to validate that the HDMI
Transmitter itself works and that can output a valid image to
the HDMI Display that is connected.
This is especially useful when trying to rule out any possible
issue that is related to the display pipeline, as the HDMI Tx
is always the last component; this means that HDMI ABIST can be
used even without prior display controller pipeline configuration.
The expected output is a 100% color bar (rainbow) test pattern.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20251023-mediatek-drm-hdmi-v2-v11-10-7873ec4a1edf@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
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Add support for the newer HDMI-TX (Encoder) v2 and DDC v2 IPs
found in MediaTek's MT8195, MT8188 SoC and their variants, and
including support for display modes up to 4k60 and for HDMI
Audio, as per the HDMI 2.0 spec.
HDCP and CEC functionalities are also supported by this hardware,
but are not included in this commit and that also poses a slight
difference between the V2 and V1 controllers in how they handle
Hotplug Detection (HPD).
While the v1 controller was using the CEC controller to check
HDMI cable connection and disconnection, in this driver the v2
one does not.
This is due to the fact that on parts with v2 designs, like the
MT8195 SoC, there is one CEC controller shared between the HDMI
Transmitter (HDMI-TX) and Receiver (HDMI-RX): before eventually
adding support to use the CEC HW to wake up the HDMI controllers
it is necessary to have support for one TX, one RX *and* for both
at the same time.
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20251023-mediatek-drm-hdmi-v2-v11-9-7873ec4a1edf@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
ddc_v2
ddc_v2
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Add an interlace_allowed bool member to struct mtk_hdmi_ver_conf
which will be used to signal whether interlaced modes are supported
by the bridge (in our case, the HDMI IP), and enable it for HDMIv2.
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20251023-mediatek-drm-hdmi-v2-v11-8-7873ec4a1edf@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
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In preparation for adding the HDMI TX v2 driver, and to allow
a future modernization of the HDMI v1 one, perform changes
that enable the usage of the HDMI Helpers provided by DRM.
Check if the HDMI driver provides the function pointers to
hdmi_{clear,write}_infoframe used by the HDMI Helper API and,
if present, add DRM_BRIDGE_OP_HDMI to the drm_bridge ops,
enabling the drm API to register the bridge as HDMI and to use
the HDMI Helper functions.
If the hdmi_{write,clear}_infoframe pointers are not assigned,
vendor and product strings and HDMI helpers will not be used,
hence this commit brings no functional changes to drivers that
have not been refactored to use the new helpers.
This also means that, in the current state, there is effectively
no functional change to mtk_hdmi and its other components.
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20251023-mediatek-drm-hdmi-v2-v11-7-7873ec4a1edf@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
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In preparation for adding the new HDMI TX v2 IP driver, assign the
pointer to the DDC adapter to struct drm_bridge during probe.
This commit brings no functional changes.
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20251023-mediatek-drm-hdmi-v2-v11-6-7873ec4a1edf@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
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In preparation for adding a new driver for HDMIv2, for which CEC
is not strictly required, change the of_get_compatible_child()
failure error to -EOPNOTSUPP to be able to differentiate between
error conditions in mtk_hdmi_dt_parse_pdata().
In that case, if -EOPNOTSUPP is returned, this driver will print
an informative message saying that CEC support is unavailable,
as the devicetree node for that was not found, but after that,
function mtk_hdmi_dt_parse_pdata() will not return error to
the caller.
This will not change functionality of the mtk_hdmi (v1) driver
as that is still checking whether CEC is present and, if not,
will fail probing with an error saying that CEC is required
by HDMIv1.
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20251023-mediatek-drm-hdmi-v2-v11-5-7873ec4a1edf@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
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