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1530 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Ingo Molnar
|
8e94367b8d |
Merge branch into tip/master: 'sched/core'
# New commits in sched/core:
7c8cd569ff66 ("docs: Update Schedstat version to 17")
011b3a14dc66 ("sched/stats: Print domain name in /proc/schedstat")
1c055a0f5d3b ("sched: Move sched domain name out of CONFIG_SCHED_DEBUG")
3b2a793ea70f ("sched: Report the different kinds of imbalances in /proc/schedstat")
c3856c9ce6b8 ("sched/fair: Cleanup in migrate_degrades_locality() to improve readability")
a430d99e3490 ("sched/fair: Fix value reported by hot tasks pulled in /proc/schedstat")
ee8118c1f186 ("sched/fair: Update comments after sched_tick() rename.")
af98d8a36a96 ("sched/fair: Fix CPU bandwidth limit bypass during CPU hotplug")
7675361ff9a1 ("sched: deadline: Cleanup goto label in pick_earliest_pushable_dl_task")
7d5265ffcd8b ("rseq: Validate read-only fields under DEBUG_RSEQ config")
2a77e4be12cb ("sched/fair: Untangle NEXT_BUDDY and pick_next_task()")
95d9fed3a2ae ("sched/fair: Mark m*_vruntime() with __maybe_unused")
0429489e0928 ("sched/fair: Fix variable declaration position")
61b82dfb6b7e ("sched/fair: Do not try to migrate delayed dequeue task")
736c55a02c47 ("sched/fair: Rename cfs_rq.nr_running into nr_queued")
43eef7c3a4a6 ("sched/fair: Remove unused cfs_rq.idle_nr_running")
31898e7b87dd ("sched/fair: Rename cfs_rq.idle_h_nr_running into h_nr_idle")
9216582b0bfb ("sched/fair: Removed unsued cfs_rq.h_nr_delayed")
1a49104496d3 ("sched/fair: Use the new cfs_rq.h_nr_runnable")
c2a295bffeaf ("sched/fair: Add new cfs_rq.h_nr_runnable")
7b8a702d9438 ("sched/fair: Rename h_nr_running into h_nr_queued")
c907cd44a108 ("sched: Unify HK_TYPE_{TIMER|TICK|MISC} to HK_TYPE_KERNEL_NOISE")
6010d245ddc9 ("sched/isolation: Consolidate housekeeping cpumasks that are always identical")
1174b9344bc7 ("sched/isolation: Make "isolcpus=nohz" equivalent to "nohz_full"")
ae5c677729e9 ("sched/core: Remove HK_TYPE_SCHED")
a76328d44c7a ("sched/fair: Remove CONFIG_CFS_BANDWIDTH=n definition of cfs_bandwidth_used()")
3a181f20fb4e ("sched/deadline: Consolidate Timer Cancellation")
53916d5fd3c0 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
d4742f6ed7ea ("sched/deadline: Correctly account for allocated bandwidth during hotplug")
41d4200b7103 ("sched/deadline: Restore dl_server bandwidth on non-destructive root domain changes")
59297e2093ce ("sched: add READ_ONCE to task_on_rq_queued")
108ad0999085 ("sched: Don't try to catch up excess steal time.")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Peter Zijlstra
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66951e4860 |
sched/fair: Fix update_cfs_group() vs DELAY_DEQUEUE
Normally dequeue_entities() will continue to dequeue an empty group entity;
except DELAY_DEQUEUE changes things -- it retains empty entities such that they
might continue to compete and burn off some lag.
However, doing this results in update_cfs_group() re-computing the cgroup
weight 'slice' for an empty group, which it (rightly) figures isn't much at
all. This in turn means that the delayed entity is not competing at the
expected weight. Worse, the very low weight causes its lag to be inflated,
which combined with avg_vruntime() using scale_load_down(), leads to artifacts.
As such, don't adjust the weight for empty group entities and let them compete
at their original weight.
Fixes: 152e11f6df29 ("sched/fair: Implement delayed dequeue")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20250110115720.GA17405@noisy.programming.kicks-ass.net
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Peter Zijlstra
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6d71a9c616 |
sched/fair: Fix EEVDF entity placement bug causing scheduling lag
I noticed this in my traces today:
turbostat-1222 [006] d..2. 311.935649: reweight_entity: (ffff888108f13e00-ffff88885ef38440-6)
{ weight: 1048576 avg_vruntime: 3184159639071 vruntime: 3184159640194 (-1123) deadline: 3184162621107 } ->
{ weight: 2 avg_vruntime: 3184177463330 vruntime: 3184748414495 (-570951165) deadline: 4747605329439 }
turbostat-1222 [006] d..2. 311.935651: reweight_entity: (ffff888108f13e00-ffff88885ef38440-6)
{ weight: 2 avg_vruntime: 3184177463330 vruntime: 3184748414495 (-570951165) deadline: 4747605329439 } ->
{ weight: 1048576 avg_vruntime: 3184176414812 vruntime: 3184177464419 (-1049607) deadline: 3184180445332 }
Which is a weight transition: 1048576 -> 2 -> 1048576.
One would expect the lag to shoot out *AND* come back, notably:
-1123*1048576/2 = -588775424
-588775424*2/1048576 = -1123
Except the trace shows it is all off. Worse, subsequent cycles shoot it
out further and further.
This made me have a very hard look at reweight_entity(), and
specifically the ->on_rq case, which is more prominent with
DELAY_DEQUEUE.
And indeed, it is all sorts of broken. While the computation of the new
lag is correct, the computation for the new vruntime, using the new lag
is broken for it does not consider the logic set out in place_entity().
With the below patch, I now see things like:
migration/12-55 [012] d..3. 309.006650: reweight_entity: (ffff8881e0e6f600-ffff88885f235f40-12)
{ weight: 977582 avg_vruntime: 4860513347366 vruntime: 4860513347908 (-542) deadline: 4860516552475 } ->
{ weight: 2 avg_vruntime: 4860528915984 vruntime: 4860793840706 (-264924722) deadline: 6427157349203 }
migration/14-62 [014] d..3. 309.006698: reweight_entity: (ffff8881e0e6cc00-ffff88885f3b5f40-15)
{ weight: 2 avg_vruntime: 4874472992283 vruntime: 4939833828823 (-65360836540) deadline: 6316614641111 } ->
{ weight: 967149 avg_vruntime: 4874217684324 vruntime: 4874217688559 (-4235) deadline: 4874220535650 }
Which isn't perfect yet, but much closer.
Reported-by: Doug Smythies <dsmythies@telus.net>
Reported-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fixes: eab03c23c2a1 ("sched/eevdf: Fix vruntime adjustment on reweight")
Link: https://lore.kernel.org/r/20250109105959.GA2981@noisy.programming.kicks-ass.net
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Swapnil Sapkal
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3b2a793ea7 |
sched: Report the different kinds of imbalances in /proc/schedstat
In /proc/schedstat, lb_imbalance reports the sum of imbalances
discovered in sched domains with each call to sched_balance_rq(), which is
not very useful because lb_imbalance does not mention whether the imbalance
is due to load, utilization, nr_tasks or misfit_tasks. Remove this field
from /proc/schedstat.
Currently there is no field in /proc/schedstat to report different types
of imbalances. Introduce new fields in /proc/schedstat to report the
total imbalances in load, utilization, nr_tasks or misfit_tasks.
Added fields to /proc/schedstat:
- lb_imbalance_load: Total imbalance due to load.
- lb_imbalance_util: Total imbalance due to utilization.
- lb_imbalance_task: Total imbalance due to number of tasks.
- lb_imbalance_misfit: Total imbalance due to misfit tasks.
Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://lore.kernel.org/r/20241220063224.17767-4-swapnil.sapkal@amd.com
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Peter Zijlstra
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c3856c9ce6 |
sched/fair: Cleanup in migrate_degrades_locality() to improve readability
migrate_degrade_locality() would return {1, 0, -1} respectively to
indicate that migration would degrade-locality, would improve
locality, would be ambivalent to locality improvements.
This patch improves readability by changing the return value to mean:
* Any positive value degrades locality
* 0 migration doesn't affect locality
* Any negative value improves locality
[Swapnil: Fixed comments around code and wrote commit log]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Not-yet-signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241220063224.17767-3-swapnil.sapkal@amd.com
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Peter Zijlstra
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a430d99e34 |
sched/fair: Fix value reported by hot tasks pulled in /proc/schedstat
In /proc/schedstat, lb_hot_gained reports the number hot tasks pulled
during load balance. This value is incremented in can_migrate_task()
if the task is migratable and hot. After incrementing the value,
load balancer can still decide not to migrate this task leading to wrong
accounting. Fix this by incrementing stats when hot tasks are detached.
This issue only exists in detach_tasks() where we can decide to not
migrate hot task even if it is migratable. However, in detach_one_task(),
we migrate it unconditionally.
[Swapnil: Handled the case where nr_failed_migrations_hot was not accounted properly and wrote commit log]
Fixes: d31980846f96 ("sched: Move up affinity check to mitigate useless redoing overhead")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reported-by: "Gautham R. Shenoy" <gautham.shenoy@amd.com>
Not-yet-signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241220063224.17767-2-swapnil.sapkal@amd.com
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Sebastian Andrzej Siewior
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ee8118c1f1 |
sched/fair: Update comments after sched_tick() rename.
scheduler_tick() was renamed to sched_tick() in 86dd6c04ef9f2
("sched/balancing: Rename scheduler_tick() => sched_tick()").
Update comments still referring to scheduler_tick.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20241219085839.302378-1-bigeasy@linutronix.de
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Vishal Chourasia
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af98d8a36a |
sched/fair: Fix CPU bandwidth limit bypass during CPU hotplug
CPU controller limits are not properly enforced during CPU hotplug operations, particularly during CPU offline. When a CPU goes offline, throttled processes are unintentionally being unthrottled across all CPUs in the system, allowing them to exceed their assigned quota limits. Consider below for an example, Assigning 6.25% bandwidth limit to a cgroup in a 8 CPU system, where, workload is running 8 threads for 20 seconds at 100% CPU utilization, expected (user+sys) time = 10 seconds. $ cat /sys/fs/cgroup/test/cpu.max 50000 100000 $ ./ebizzy -t 8 -S 20 // non-hotplug case real 20.00 s user 10.81 s // intended behaviour sys 0.00 s $ ./ebizzy -t 8 -S 20 // hotplug case real 20.00 s user 14.43 s // Workload is able to run for 14 secs sys 0.00 s // when it should have only run for 10 secs During CPU hotplug, scheduler domains are rebuilt and cpu_attach_domain is called for every active CPU to update the root domain. That ends up calling rq_offline_fair which un-throttles any throttled hierarchies. Unthrottling should only occur for the CPU being hotplugged to allow its throttled processes to become runnable and get migrated to other CPUs. With current patch applied, $ ./ebizzy -t 8 -S 20 // hotplug case real 21.00 s user 10.16 s // intended behaviour sys 0.00 s This also has another symptom, when a CPU goes offline, and if the cfs_rq is not in throttled state and the runtime_remaining still had plenty remaining, it gets reset to 1 here, causing the runtime_remaining of cfs_rq to be quickly depleted. Note: hotplug operation (online, offline) was performed in while(1) loop v3: https://lore.kernel.org/all/20241210102346.228663-2-vishalc@linux.ibm.com v2: https://lore.kernel.org/all/20241207052730.1746380-2-vishalc@linux.ibm.com v1: https://lore.kernel.org/all/20241126064812.809903-2-vishalc@linux.ibm.com Suggested-by: Zhang Qiao <zhangqiao22@huawei.com> Signed-off-by: Vishal Chourasia <vishalc@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Vincent Guittot <vincent.guittot@linaro.org> Tested-by: Madadi Vineeth Reddy <vineethr@linux.ibm.com> Tested-by: Samir Mulani <samir@linux.ibm.com> Link: https://lore.kernel.org/r/20241212043102.584863-2-vishalc@linux.ibm.com |
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Linus Torvalds
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acd855a949 |
- Prevent incorrect dequeueing of the deadline dlserver helper task and fix
its time accounting - Properly track the CFS runqueue runnable stats - Check the total number of all queued tasks in a sched fair's runqueue hierarchy before deciding to stop the tick - Fix the scheduling of the task that got woken last (NEXT_BUDDY) by preventing those from being delayed -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEzv7L6UO9uDPlPSfHEsHwGGHeVUoFAmdexEsACgkQEsHwGGHe VUpFqA//SIIbNJEIQEwGkFrYpGwVpSISm94L4ENsrkWbJWQlALwQEBJF9Me/DOZH vHaX3o+cMxt26W7o0NKyPcvYtulnOr33HZA/uxK35MDaUinSA3Spt3jXHfR3n0mL ljNQQraWHGaJh7dzKMZoxP6DR78/Z0yotXjt33xeBFMSJuzGsklrbIiSJ6c4m/3u Y1lrQT8LncsxJMYIPAKtBAc9hvJfGFV6IOTaTfxP0oTuDo/2qTNVHm7to40wk3NW kb0lf2kjVtE6mwMfEm49rtjE3h0VnPJKGKoEkLi9IQoPbQq9Uf4i9VSmRe3zqPAz yBxV8BAu2koscMZzqw1CTnd9c/V+/A9qOOHfDo72I5MriJ1qVWCEsqB1y3u2yT6n XjwFDbPiVKI8H9YlsZpWERocCRypshevPNlYOF93PlK+YTXoMWaXMQhec5NDzLLw Se1K2sCi3U8BMdln0dH6nhk0unzNKQ8UKzrMFncSjnpWhpJ69uxyUZ/jL//6bvfi Z+7G4U54mUhGyOAaUSGH/20TnZRWJ7NJC542omFgg9v0VLxx+wnZyX4zJIV0jvRr 6voYmYDCO8zn/hO67VBJuei97ayIzxDNP1tVl15LzcvRcIGWNUPOwp5jijv8vDJG lJhQrMF6w4fgPItC20FvptlDvpP9cItSzyyOeg074HjDS53QN2Y= =jOb3 -----END PGP SIGNATURE----- Merge tag 'sched_urgent_for_v6.13_rc3-p2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Borislav Petkov: - Prevent incorrect dequeueing of the deadline dlserver helper task and fix its time accounting - Properly track the CFS runqueue runnable stats - Check the total number of all queued tasks in a sched fair's runqueue hierarchy before deciding to stop the tick - Fix the scheduling of the task that got woken last (NEXT_BUDDY) by preventing those from being delayed * tag 'sched_urgent_for_v6.13_rc3-p2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/dlserver: Fix dlserver time accounting sched/dlserver: Fix dlserver double enqueue sched/eevdf: More PELT vs DELAYED_DEQUEUE sched/fair: Fix sched_can_stop_tick() for fair tasks sched/fair: Fix NEXT_BUDDY |
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Vineeth Pillai (Google)
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c7f7e9c731 |
sched/dlserver: Fix dlserver time accounting
dlserver time is accounted when:
- dlserver is active and the dlserver proxies the cfs task.
- dlserver is active but deferred and cfs task runs after being picked
through the normal fair class pick.
dl_server_update is called in two places to make sure that both the
above times are accounted for. But it doesn't check if dlserver is
active or not. Now that we have this dl_server_active flag, we can
consolidate dl_server_update into one place and all we need to check is
whether dlserver is active or not. When dlserver is active there is only
two possible conditions:
- dlserver is deferred.
- cfs task is running on behalf of dlserver.
Fixes: a110a81c52a9 ("sched/deadline: Deferrable dl server")
Signed-off-by: "Vineeth Pillai (Google)" <vineeth@bitbyteword.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Marcel Ziswiler <marcel.ziswiler@codethink.co.uk> # ROCK 5B
Link: https://lore.kernel.org/r/20241213032244.877029-2-vineeth@bitbyteword.org
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Linus Torvalds
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df9e2102de |
- Remove wrong enqueueing of a task for a later wakeup when a task blocks on
a RT mutex - Do not setup a new deadline entity on a boosted task as that has happened already - Update preempt= kernel command line param - Prevent needless softirqd wakeups in the idle task's context - Detect the case where the idle load balancer CPU becomes busy and avoid unnecessary load balancing invocation - Remove an unnecessary load balancing need_resched() call in nohz_csd_func() - Allow for raising of SCHED_SOFTIRQ softirq type on RT but retain the warning to catch any other cases - Remove a wrong warning when a cpuset update makes the task affinity no longer a subset of the cpuset -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEzv7L6UO9uDPlPSfHEsHwGGHeVUoFAmdWvHYACgkQEsHwGGHe VUrJ6g//eEwmHpa9+at3UvXrVlcYQmZsQpgL2ksjVE0n4KXFeUavwCR4h6SJzvcD RDF9AyDuPAoCqy5DhL5wTXPG/4AnnISqAEkoP7h7YO76P7ks6+HD7t31pCF/uqCH yqS4vc1RJ6yW8otcCpR7rOPEQ49Klqc1KTFTNAFLc6MNEb/SVH5Ih+wFL5Mj/W3I UkBEtUy1oR2Q4QPhJ+0sr0LAI1AwjykdbkWzOhs6D1kPaRqdV4Atgc2fwioLIvhO s++lev9BmGx02dmrRWRmIBL9S9ycSLT1qx28sbzlS+PZMGYqOnImVOW5+EPr+ovK fILc0m8sLD6GyZHIPgeIT2+DqSvDTQOGQwXyUYmoarI+BWGGSz6iZGn4RrZHMRQo cpqYV9z7F2t3X1hPfhrH+40BXJeMMX+wd4ahXNA44QD6Bf7I+zPUfsrfnrR4BwV7 qpXhBzXOuZrgOKolIwJmHIxyLtd79idYccGvjIME5rwj8eBg0J7zmjzoVewqUXsb F9ualvq6twxUIdD4XiClpi+E16Z2Ot3PplNIohosVrUDRDUgvTBbTuDZnUuOkXbb wV26XKuYKQYfx5UfJBSYL3DCfCttkKCVrPX2oiqw6PKNXw9BM8BQIux+XQH2jvIg wOPqZWZf2VIoQJU2N+twc/BAIRAF7CNr/ioTJlXQ1hsOIlTp3kk= =XLf1 -----END PGP SIGNATURE----- Merge tag 'sched_urgent_for_v6.13_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Borislav Petkov: - Remove wrong enqueueing of a task for a later wakeup when a task blocks on a RT mutex - Do not setup a new deadline entity on a boosted task as that has happened already - Update preempt= kernel command line param - Prevent needless softirqd wakeups in the idle task's context - Detect the case where the idle load balancer CPU becomes busy and avoid unnecessary load balancing invocation - Remove an unnecessary load balancing need_resched() call in nohz_csd_func() - Allow for raising of SCHED_SOFTIRQ softirq type on RT but retain the warning to catch any other cases - Remove a wrong warning when a cpuset update makes the task affinity no longer a subset of the cpuset * tag 'sched_urgent_for_v6.13_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking: rtmutex: Fix wake_q logic in task_blocks_on_rt_mutex sched/deadline: Fix warning in migrate_enable for boosted tasks sched/core: Update kernel boot parameters for LAZY preempt. sched/core: Prevent wakeup of ksoftirqd during idle load balance sched/fair: Check idle_cpu() before need_resched() to detect ilb CPU turning busy sched/core: Remove the unnecessary need_resched() check in nohz_csd_func() softirq: Allow raising SCHED_SOFTIRQ from SMP-call-function on RT kernel sched: fix warning in sched_setaffinity sched/deadline: Fix replenish_dl_new_period dl_server condition |
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Peter Zijlstra
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2a77e4be12 |
sched/fair: Untangle NEXT_BUDDY and pick_next_task()
There are 3 sites using set_next_buddy() and only one is conditional
on NEXT_BUDDY, the other two sites are unconditional; to note:
- yield_to_task()
- cgroup dequeue / pick optimization
However, having NEXT_BUDDY control both the wakeup-preemption and the
picking side of things means its near useless.
Fixes: 147f3efaa241 ("sched/fair: Implement an EEVDF-like scheduling policy")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20241129101541.GA33464@noisy.programming.kicks-ass.net
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Andy Shevchenko
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95d9fed3a2 |
sched/fair: Mark m*_vruntime() with __maybe_unused
When max_vruntime() is unused, it prevents kernel builds with clang,
`make W=1` and CONFIG_WERROR=y:
kernel/sched/fair.c:526:19: error: unused function 'max_vruntime' [-Werror,-Wunused-function]
526 | static inline u64 max_vruntime(u64 max_vruntime, u64 vruntime)
| ^~~~~~~~~~~~
Fix this by marking them with __maybe_unused (all cases for the sake of
symmetry).
See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static
inline functions for W=1 build").
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20241202173546.634433-1-andriy.shevchenko@linux.intel.com
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Vincent Guittot
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0429489e09 |
sched/fair: Fix variable declaration position
Move variable declaration at the beginning of the function Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lore.kernel.org/r/20241202174606.4074512-12-vincent.guittot@linaro.org |
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Vincent Guittot
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61b82dfb6b |
sched/fair: Do not try to migrate delayed dequeue task
Migrating a delayed dequeued task doesn't help in balancing the number of runnable tasks in the system. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lore.kernel.org/r/20241202174606.4074512-11-vincent.guittot@linaro.org |
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Vincent Guittot
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736c55a02c |
sched/fair: Rename cfs_rq.nr_running into nr_queued
Rename cfs_rq.nr_running into cfs_rq.nr_queued which better reflects the reality as the value includes both the ready to run tasks and the delayed dequeue tasks. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lore.kernel.org/r/20241202174606.4074512-10-vincent.guittot@linaro.org |
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Vincent Guittot
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43eef7c3a4 |
sched/fair: Remove unused cfs_rq.idle_nr_running
cfs_rq.idle_nr_running field is not used anywhere so we can remove the
useless associated computation. Last user went in commit 5e963f2bd465
("sched/fair: Commit to EEVDF").
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/20241202174606.4074512-9-vincent.guittot@linaro.org
|
||
|
Vincent Guittot
|
31898e7b87 |
sched/fair: Rename cfs_rq.idle_h_nr_running into h_nr_idle
Use same naming convention as others starting with h_nr_* and rename idle_h_nr_running into h_nr_idle. The "running" is not correct anymore as it includes delayed dequeue tasks as well. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lore.kernel.org/r/20241202174606.4074512-8-vincent.guittot@linaro.org |
||
|
Vincent Guittot
|
9216582b0b |
sched/fair: Removed unsued cfs_rq.h_nr_delayed
h_nr_delayed is not used anymore. We now have: - h_nr_runnable which tracks tasks ready to run - h_nr_queued which tracks enqueued tasks either ready to run or delayed dequeue Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lore.kernel.org/r/20241202174606.4074512-7-vincent.guittot@linaro.org |
||
|
Vincent Guittot
|
1a49104496 |
sched/fair: Use the new cfs_rq.h_nr_runnable
Use the new h_nr_runnable that tracks only queued and runnable tasks in the statistics that are used to balance the system: - PELT runnable_avg - deciding if a group is overloaded or has spare capacity - numa stats - reduced capacity management - load balance - nohz kick It should be noticed that the rq->nr_running still counts the delayed dequeued tasks as delayed dequeue is a fair feature that is meaningless at core level. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lore.kernel.org/r/20241202174606.4074512-6-vincent.guittot@linaro.org |
||
|
Vincent Guittot
|
c2a295bffe |
sched/fair: Add new cfs_rq.h_nr_runnable
With delayed dequeued feature, a sleeping sched_entity remains queued in the rq until its lag has elapsed. As a result, it stays also visible in the statistics that are used to balance the system and in particular the field cfs.h_nr_queued when the sched_entity is associated to a task. Create a new h_nr_runnable that tracks only queued and runnable tasks. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lore.kernel.org/r/20241202174606.4074512-5-vincent.guittot@linaro.org |
||
|
Vincent Guittot
|
7b8a702d94 |
sched/fair: Rename h_nr_running into h_nr_queued
With delayed dequeued feature, a sleeping sched_entity remains queued in the rq until its lag has elapsed but can't run. Rename h_nr_running into h_nr_queued to reflect this new behavior. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lore.kernel.org/r/20241202174606.4074512-4-vincent.guittot@linaro.org |
||
|
Peter Zijlstra
|
40c3b94fbb |
Merge branch 'sched/urgent'
Sync with urgent bits as a base for further work. Signed-off-by: Peter Zijlstra <peterz@infradead.org> |
||
|
Peter Zijlstra
|
76f2f78329 |
sched/eevdf: More PELT vs DELAYED_DEQUEUE
Vincent and Dietmar noted that while
commit fc1892becd56 ("sched/eevdf: Fixup PELT vs DELAYED_DEQUEUE") fixes
the entity runnable stats, it does not adjust the cfs_rq runnable stats,
which are based off of h_nr_running.
Track h_nr_delayed such that we can discount those and adjust the
signal.
Fixes: fc1892becd56 ("sched/eevdf: Fixup PELT vs DELAYED_DEQUEUE")
Closes: https://lore.kernel.org/lkml/a9a45193-d0c6-4ba2-a822-464ad30b550e@arm.com/
Closes: https://lore.kernel.org/lkml/CAKfTPtCNUvWE_GX5LyvTF-WdxUT=ZgvZZv-4t=eWntg5uOFqiQ@mail.gmail.com/
[ Fixes checkpatch warnings and rebased ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reported-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reported-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Link: https://lore.kernel.org/r/20241202174606.4074512-3-vincent.guittot@linaro.org
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||
|
K Prateek Nayak
|
493afbd187 |
sched/fair: Fix NEXT_BUDDY
Adam reports that enabling NEXT_BUDDY insta triggers a WARN in
pick_next_entity().
Moving clear_buddies() up before the delayed dequeue bits ensures
no ->next buddy becomes delayed. Further ensure no new ->next buddy
ever starts as delayed.
Fixes: 152e11f6df29 ("sched/fair: Implement delayed dequeue")
Reported-by: Adam Li <adamli@os.amperecomputing.com>
Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Adam Li <adamli@os.amperecomputing.com>
Link: https://lkml.kernel.org/r/670a0d54-e398-4b1f-8a6e-90784e2fdf89@amd.com
|
||
|
Adrian Huang
|
5f1b64e9a9 |
sched/numa: fix memory leak due to the overwritten vma->numab_state
[Problem Description]
When running the hackbench program of LTP, the following memory leak is
reported by kmemleak.
# /opt/ltp/testcases/bin/hackbench 20 thread 1000
Running with 20*40 (== 800) tasks.
# dmesg | grep kmemleak
...
kmemleak: 480 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
kmemleak: 665 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff888cd8ca2c40 (size 64):
comm "hackbench", pid 17142, jiffies 4299780315
hex dump (first 32 bytes):
ac 74 49 00 01 00 00 00 4c 84 49 00 01 00 00 00 .tI.....L.I.....
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc bff18fd4):
[<ffffffff81419a89>] __kmalloc_cache_noprof+0x2f9/0x3f0
[<ffffffff8113f715>] task_numa_work+0x725/0xa00
[<ffffffff8110f878>] task_work_run+0x58/0x90
[<ffffffff81ddd9f8>] syscall_exit_to_user_mode+0x1c8/0x1e0
[<ffffffff81dd78d5>] do_syscall_64+0x85/0x150
[<ffffffff81e0012b>] entry_SYSCALL_64_after_hwframe+0x76/0x7e
...
This issue can be consistently reproduced on three different servers:
* a 448-core server
* a 256-core server
* a 192-core server
[Root Cause]
Since multiple threads are created by the hackbench program (along with
the command argument 'thread'), a shared vma might be accessed by two or
more cores simultaneously. When two or more cores observe that
vma->numab_state is NULL at the same time, vma->numab_state will be
overwritten.
Although current code ensures that only one thread scans the VMAs in a
single 'numa_scan_period', there might be a chance for another thread
to enter in the next 'numa_scan_period' while we have not gotten till
numab_state allocation [1].
Note that the command `/opt/ltp/testcases/bin/hackbench 50 process 1000`
cannot the reproduce the issue. It is verified with 200+ test runs.
[Solution]
Use the cmpxchg atomic operation to ensure that only one thread executes
the vma->numab_state assignment.
[1] https://lore.kernel.org/lkml/1794be3c-358c-4cdc-a43d-a1f841d91ef7@amd.com/
Link: https://lkml.kernel.org/r/20241113102146.2384-1-ahuang12@lenovo.com
Fixes: ef6a22b70f6d ("sched/numa: apply the scan delay to every new vma")
Signed-off-by: Adrian Huang <ahuang12@lenovo.com>
Reported-by: Jiwei Sun <sunjw10@lenovo.com>
Reviewed-by: Raghavendra K T <raghavendra.kt@amd.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Ben Segall <bsegall@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Waiman Long
|
c907cd44a1 |
sched: Unify HK_TYPE_{TIMER|TICK|MISC} to HK_TYPE_KERNEL_NOISE
As all the non-domain and non-managed_irq housekeeping types have been unified to HK_TYPE_KERNEL_NOISE, replace all these references in the scheduler to use HK_TYPE_KERNEL_NOISE. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20241030175253.125248-5-longman@redhat.com |
||
|
Waiman Long
|
ae5c677729 |
sched/core: Remove HK_TYPE_SCHED
The HK_TYPE_SCHED housekeeping type is defined but not set anywhere. So any code that try to use HK_TYPE_SCHED are essentially dead code. So remove HK_TYPE_SCHED and any code that use it. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Frederic Weisbecker <frederic@kernel.org> Link: https://lore.kernel.org/r/20241030175253.125248-2-longman@redhat.com |
||
|
Valentin Schneider
|
a76328d44c |
sched/fair: Remove CONFIG_CFS_BANDWIDTH=n definition of cfs_bandwidth_used()
Andy reported that clang gets upset with CONFIG_CFS_BANDWIDTH=n: kernel/sched/fair.c:6580:20: error: unused function 'cfs_bandwidth_used' [-Werror,-Wunused-function] 6580 | static inline bool cfs_bandwidth_used(void) | ^~~~~~~~~~~~~~~~~~ Indeed, cfs_bandwidth_used() is only used within functions defined under CONFIG_CFS_BANDWIDTH=y. Remove its CONFIG_CFS_BANDWIDTH=n declaration & definition. Reported-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Valentin Schneider <vschneid@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20241127165501.160004-1-vschneid@redhat.com |
||
|
K Prateek Nayak
|
ff47a0acfc |
sched/fair: Check idle_cpu() before need_resched() to detect ilb CPU turning busy
Commit b2a02fc43a1f ("smp: Optimize send_call_function_single_ipi()")
optimizes IPIs to idle CPUs in TIF_POLLING_NRFLAG mode by setting the
TIF_NEED_RESCHED flag in idle task's thread info and relying on
flush_smp_call_function_queue() in idle exit path to run the
call-function. A softirq raised by the call-function is handled shortly
after in do_softirq_post_smp_call_flush() but the TIF_NEED_RESCHED flag
remains set and is only cleared later when schedule_idle() calls
__schedule().
need_resched() check in _nohz_idle_balance() exists to bail out of load
balancing if another task has woken up on the CPU currently in-charge of
idle load balancing which is being processed in SCHED_SOFTIRQ context.
Since the optimization mentioned above overloads the interpretation of
TIF_NEED_RESCHED, check for idle_cpu() before going with the existing
need_resched() check which can catch a genuine task wakeup on an idle
CPU processing SCHED_SOFTIRQ from do_softirq_post_smp_call_flush(), as
well as the case where ksoftirqd needs to be preempted as a result of
new task wakeup or slice expiry.
In case of PREEMPT_RT or threadirqs, although the idle load balancing
may be inhibited in some cases on the ilb CPU, the fact that ksoftirqd
is the only fair task going back to sleep will trigger a newidle balance
on the CPU which will alleviate some imbalance if it exists if idle
balance fails to do so.
Fixes: b2a02fc43a1f ("smp: Optimize send_call_function_single_ipi()")
Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241119054432.6405-4-kprateek.nayak@amd.com
|
||
|
Linus Torvalds
|
3f020399e4 |
Scheduler changes for v6.13:
- Core facilities:
- Add the "Lazy preemption" model (CONFIG_PREEMPT_LAZY=y), which optimizes
fair-class preemption by delaying preemption requests to the
tick boundary, while working as full preemption for RR/FIFO/DEADLINE
classes. (Peter Zijlstra)
- x86: Enable Lazy preemption (Peter Zijlstra)
- riscv: Enable Lazy preemption (Jisheng Zhang)
- Initialize idle tasks only once (Thomas Gleixner)
- sched/ext: Remove sched_fork() hack (Thomas Gleixner)
- Fair scheduler:
- Optimize the PLACE_LAG when se->vlag is zero (Huang Shijie)
- Idle loop:
Optimize the generic idle loop by removing unnecessary
memory barrier (Zhongqiu Han)
- RSEQ:
- Improve cache locality of RSEQ concurrency IDs for
intermittent workloads (Mathieu Desnoyers)
- Waitqueues:
- Make wake_up_{bit,var} less fragile (Neil Brown)
- PSI:
- Pass enqueue/dequeue flags to psi callbacks directly (Johannes Weiner)
- Preparatory patches for proxy execution:
- core: Add move_queued_task_locked helper (Connor O'Brien)
- core: Consolidate pick_*_task to task_is_pushable helper (Connor O'Brien)
- core: Split out __schedule() deactivate task logic into a helper (John Stultz)
- core: Split scheduler and execution contexts (Peter Zijlstra)
- locking/mutex: Make mutex::wait_lock irq safe (Juri Lelli)
- locking/mutex: Expose __mutex_owner() (Juri Lelli)
- locking/mutex: Remove wakeups from under mutex::wait_lock (Peter Zijlstra)
- Misc fixes and cleanups:
- core: Remove unused __HAVE_THREAD_FUNCTIONS hook support (David Disseldorp)
- core: Update the comment for TIF_NEED_RESCHED_LAZY (Sebastian Andrzej Siewior)
- wait: Remove unused bit_wait_io_timeout (Dr. David Alan Gilbert)
- fair: remove the DOUBLE_TICK feature (Huang Shijie)
- fair: fix the comment for PREEMPT_SHORT (Huang Shijie)
- uclamp: Fix unnused variable warning (Christian Loehle)
- rt: No PREEMPT_RT=y for all{yes,mod}config
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"Core facilities:
- Add the "Lazy preemption" model (CONFIG_PREEMPT_LAZY=y), which
optimizes fair-class preemption by delaying preemption requests to
the tick boundary, while working as full preemption for
RR/FIFO/DEADLINE classes. (Peter Zijlstra)
- x86: Enable Lazy preemption (Peter Zijlstra)
- riscv: Enable Lazy preemption (Jisheng Zhang)
- Initialize idle tasks only once (Thomas Gleixner)
- sched/ext: Remove sched_fork() hack (Thomas Gleixner)
Fair scheduler:
- Optimize the PLACE_LAG when se->vlag is zero (Huang Shijie)
Idle loop:
- Optimize the generic idle loop by removing unnecessary memory
barrier (Zhongqiu Han)
RSEQ:
- Improve cache locality of RSEQ concurrency IDs for intermittent
workloads (Mathieu Desnoyers)
Waitqueues:
- Make wake_up_{bit,var} less fragile (Neil Brown)
PSI:
- Pass enqueue/dequeue flags to psi callbacks directly (Johannes
Weiner)
Preparatory patches for proxy execution:
- Add move_queued_task_locked helper (Connor O'Brien)
- Consolidate pick_*_task to task_is_pushable helper (Connor O'Brien)
- Split out __schedule() deactivate task logic into a helper (John
Stultz)
- Split scheduler and execution contexts (Peter Zijlstra)
- Make mutex::wait_lock irq safe (Juri Lelli)
- Expose __mutex_owner() (Juri Lelli)
- Remove wakeups from under mutex::wait_lock (Peter Zijlstra)
Misc fixes and cleanups:
- Remove unused __HAVE_THREAD_FUNCTIONS hook support (David
Disseldorp)
- Update the comment for TIF_NEED_RESCHED_LAZY (Sebastian Andrzej
Siewior)
- Remove unused bit_wait_io_timeout (Dr. David Alan Gilbert)
- remove the DOUBLE_TICK feature (Huang Shijie)
- fix the comment for PREEMPT_SHORT (Huang Shijie)
- Fix unnused variable warning (Christian Loehle)
- No PREEMPT_RT=y for all{yes,mod}config"
* tag 'sched-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
sched, x86: Update the comment for TIF_NEED_RESCHED_LAZY.
sched: No PREEMPT_RT=y for all{yes,mod}config
riscv: add PREEMPT_LAZY support
sched, x86: Enable Lazy preemption
sched: Enable PREEMPT_DYNAMIC for PREEMPT_RT
sched: Add Lazy preemption model
sched: Add TIF_NEED_RESCHED_LAZY infrastructure
sched/ext: Remove sched_fork() hack
sched: Initialize idle tasks only once
sched: psi: pass enqueue/dequeue flags to psi callbacks directly
sched/uclamp: Fix unnused variable warning
sched: Split scheduler and execution contexts
sched: Split out __schedule() deactivate task logic into a helper
sched: Consolidate pick_*_task to task_is_pushable helper
sched: Add move_queued_task_locked helper
locking/mutex: Expose __mutex_owner()
locking/mutex: Make mutex::wait_lock irq safe
locking/mutex: Remove wakeups from under mutex::wait_lock
sched: Improve cache locality of RSEQ concurrency IDs for intermittent workloads
sched: idle: Optimize the generic idle loop by removing needless memory barrier
...
|
||
|
Peter Zijlstra
|
7c70cb94d2 |
sched: Add Lazy preemption model
Change fair to use resched_curr_lazy(), which, when the lazy preemption model is selected, will set TIF_NEED_RESCHED_LAZY. This LAZY bit will be promoted to the full NEED_RESCHED bit on tick. As such, the average delay between setting LAZY and actually rescheduling will be TICK_NSEC/2. In short, Lazy preemption will delay preemption for fair class but will function as Full preemption for all the other classes, most notably the realtime (RR/FIFO/DEADLINE) classes. The goal is to bridge the performance gap with Voluntary, such that we might eventually remove that option entirely. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lkml.kernel.org/r/20241007075055.331243614@infradead.org |
||
|
Shawn Wang
|
9c70b2a33c |
sched/numa: Fix the potential null pointer dereference in task_numa_work()
When running stress-ng-vm-segv test, we found a null pointer dereference
error in task_numa_work(). Here is the backtrace:
[323676.066985] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020
......
[323676.067108] CPU: 35 PID: 2694524 Comm: stress-ng-vm-se
......
[323676.067113] pstate: 23401009 (nzCv daif +PAN -UAO +TCO +DIT +SSBS BTYPE=--)
[323676.067115] pc : vma_migratable+0x1c/0xd0
[323676.067122] lr : task_numa_work+0x1ec/0x4e0
[323676.067127] sp : ffff8000ada73d20
[323676.067128] x29: ffff8000ada73d20 x28: 0000000000000000 x27: 000000003e89f010
[323676.067130] x26: 0000000000080000 x25: ffff800081b5c0d8 x24: ffff800081b27000
[323676.067133] x23: 0000000000010000 x22: 0000000104d18cc0 x21: ffff0009f7158000
[323676.067135] x20: 0000000000000000 x19: 0000000000000000 x18: ffff8000ada73db8
[323676.067138] x17: 0001400000000000 x16: ffff800080df40b0 x15: 0000000000000035
[323676.067140] x14: ffff8000ada73cc8 x13: 1fffe0017cc72001 x12: ffff8000ada73cc8
[323676.067142] x11: ffff80008001160c x10: ffff000be639000c x9 : ffff8000800f4ba4
[323676.067145] x8 : ffff000810375000 x7 : ffff8000ada73974 x6 : 0000000000000001
[323676.067147] x5 : 0068000b33e26707 x4 : 0000000000000001 x3 : ffff0009f7158000
[323676.067149] x2 : 0000000000000041 x1 : 0000000000004400 x0 : 0000000000000000
[323676.067152] Call trace:
[323676.067153] vma_migratable+0x1c/0xd0
[323676.067155] task_numa_work+0x1ec/0x4e0
[323676.067157] task_work_run+0x78/0xd8
[323676.067161] do_notify_resume+0x1ec/0x290
[323676.067163] el0_svc+0x150/0x160
[323676.067167] el0t_64_sync_handler+0xf8/0x128
[323676.067170] el0t_64_sync+0x17c/0x180
[323676.067173] Code: d2888001 910003fd f9000bf3 aa0003f3 (f9401000)
[323676.067177] SMP: stopping secondary CPUs
[323676.070184] Starting crashdump kernel...
stress-ng-vm-segv in stress-ng is used to stress test the SIGSEGV error
handling function of the system, which tries to cause a SIGSEGV error on
return from unmapping the whole address space of the child process.
Normally this program will not cause kernel crashes. But before the
munmap system call returns to user mode, a potential task_numa_work()
for numa balancing could be added and executed. In this scenario, since the
child process has no vma after munmap, the vma_next() in task_numa_work()
will return a null pointer even if the vma iterator restarts from 0.
Recheck the vma pointer before dereferencing it in task_numa_work().
Fixes: 214dbc428137 ("sched: convert to vma iterator")
Signed-off-by: Shawn Wang <shawnwang@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org # v6.2+
Link: https://lkml.kernel.org/r/20241025022208.125527-1-shawnwang@linux.alibaba.com
|
||
|
Peter Zijlstra
|
b55945c500 |
sched: Fix pick_next_task_fair() vs try_to_wake_up() race
Syzkaller robot reported KCSAN tripping over the
ASSERT_EXCLUSIVE_WRITER(p->on_rq) in __block_task().
The report noted that both pick_next_task_fair() and try_to_wake_up()
were concurrently trying to write to the same p->on_rq, violating the
assertion -- even though both paths hold rq->__lock.
The logical consequence is that both code paths end up holding a
different rq->__lock. And looking through ttwu(), this is possible
when the __block_task() 'p->on_rq = 0' store is visible to the ttwu()
'p->on_rq' load, which then assumes the task is not queued and
continues to migrate it.
Rearrange things such that __block_task() releases @p with the store
and no code thereafter will use @p again.
Fixes: 152e11f6df29 ("sched/fair: Implement delayed dequeue")
Reported-by: syzbot+0ec1e96c2cdf5c0e512a@syzkaller.appspotmail.com
Reported-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20241023093641.GE16066@noisy.programming.kicks-ass.net
|
||
|
Peter Zijlstra
|
af0c8b2bf6 |
sched: Split scheduler and execution contexts
Let's define the "scheduling context" as all the scheduler state in task_struct for the task chosen to run, which we'll call the donor task, and the "execution context" as all state required to actually run the task. Currently both are intertwined in task_struct. We want to logically split these such that we can use the scheduling context of the donor task selected to be scheduled, but use the execution context of a different task to actually be run. To this purpose, introduce rq->donor field to point to the task_struct chosen from the runqueue by the scheduler, and will be used for scheduler state, and preserve rq->curr to indicate the execution context of the task that will actually be run. This patch introduces the donor field as a union with curr, so it doesn't cause the contexts to be split yet, but adds the logic to handle everything separately. [add additional comments and update more sched_class code to use rq::proxy] [jstultz: Rebased and resolved minor collisions, reworked to use accessors, tweaked update_curr_common to use rq_proxy fixing rt scheduling issues] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Connor O'Brien <connoro@google.com> Signed-off-by: John Stultz <jstultz@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Metin Kaya <metin.kaya@arm.com> Tested-by: K Prateek Nayak <kprateek.nayak@amd.com> Tested-by: Metin Kaya <metin.kaya@arm.com> Link: https://lore.kernel.org/r/20241009235352.1614323-8-jstultz@google.com |
||
|
Peter Zijlstra
|
3144c83dcc |
Merge branch 'tip/sched/urgent'
Sync with sched/urgent to avoid conflicts. Signed-off-by: Peter Zijlstra <peterz@infradead.org> |
||
|
Peter Zijlstra
|
98442f0ccd |
sched: Fix delayed_dequeue vs switched_from_fair()
Commit 2e0199df252a ("sched/fair: Prepare exit/cleanup paths for delayed_dequeue")
and its follow up fixes try to deal with a rather unfortunate
situation where is task is enqueued in a new class, even though it
shouldn't have been. Mostly because the existing ->switched_to/from()
hooks are in the wrong place for this case.
This all led to Paul being able to trigger failures at something like
once per 10k CPU hours of RCU torture.
For now, do the ugly thing and move the code to the right place by
ignoring the switch hooks.
Note: Clean up the whole sched_class::switch*_{to,from}() thing.
Fixes: 2e0199df252a ("sched/fair: Prepare exit/cleanup paths for delayed_dequeue")
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20241003185037.GA5594@noisy.programming.kicks-ass.net
|
||
|
Huang Shijie
|
4423af84b2 |
sched/fair: optimize the PLACE_LAG when se->vlag is zero
When PLACE_LAG is enabled, from the relationship:
vl_i = (W + w_i)*vl'_i / W
we know that if vl'_i(se->vlag) is zero, the vl_i is zero too.
So if se->vlag is zero, there is no need to waste cycles to
do the calculation.
Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Christoph Lameter (Ampere) <cl@linux.com>
Link: https://lkml.kernel.org/r/20241001070021.10626-1-shijie@os.amperecomputing.com
|
||
|
Huang Shijie
|
e31488c9df |
sched/fair: remove the DOUBLE_TICK feature
The patch "5e963f2bd46 sched/fair: Commit to EEVDF" removed the code following the DOUBLE_TICK: - - if (!sched_feat(EEVDF) && cfs_rq->nr_running > 1) - check_preempt_tick(cfs_rq, curr); The DOUBLE_TICK feature becomes dead code now, so remove it. Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: "Christoph Lameter (Ampere)" <cl@linux.com> Reviewed-by: Vishal Chourasia <vishalc@linux.ibm.com> Link: https://lore.kernel.org/r/20241001065451.10356-1-shijie@os.amperecomputing.com |
||
|
Chen Yu
|
d4ac164bde |
sched/eevdf: Fix wakeup-preempt by checking cfs_rq->nr_running
Commit 85e511df3cec ("sched/eevdf: Allow shorter slices to wakeup-preempt")
introduced a mechanism that a wakee with shorter slice could preempt
the current running task. It also lower the bar for the current task
to be preempted, by checking the rq->nr_running instead of cfs_rq->nr_running
when the current task has ran out of time slice. But there is a scenario
that is problematic. Say, if there is 1 cfs task and 1 rt task, before
85e511df3cec, update_deadline() will not trigger a reschedule, and after
85e511df3cec, since rq->nr_running is 2 and resched is true, a resched_curr()
would happen.
Some workloads (like the hackbench reported by lkp) do not like
over-scheduling. We can see that the preemption rate has been
increased by 2.2%:
1.654e+08 +2.2% 1.69e+08 hackbench.time.involuntary_context_switches
Restore its previous check criterion.
Fixes: 85e511df3cec ("sched/eevdf: Allow shorter slices to wakeup-preempt")
Closes: https://lore.kernel.org/oe-lkp/202409231416.9403c2e9-oliver.sang@intel.com
Reported-by: kernel test robot <oliver.sang@intel.com>
Suggested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Honglei Wang <jameshongleiwang@126.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Link: https://lore.kernel.org/r/20240925085440.358138-1-yu.c.chen@intel.com
|
||
|
Mike Galbraith
|
9b5ce1a37e |
sched: Fix sched_delayed vs cfs_bandwidth
Meeting an unfinished DELAY_DEQUEUE treated entity in unthrottle_cfs_rq()
leads to a couple terminal scenarios. Finish it first, so ENQUEUE_WAKEUP
can proceed as it would have sans DELAY_DEQUEUE treatment.
Fixes: 152e11f6df29 ("sched/fair: Implement delayed dequeue")
Reported-by: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/7515d2e64c989b9e3b828a9e21bcd959b99df06a.camel@gmx.de
|
||
|
Linus Torvalds
|
88264981f2 |
sched_ext: Initial pull request for v6.12
This is the initial pull request of sched_ext. The v7 patchset
(https://lkml.kernel.org/r/20240618212056.2833381-1-tj@kernel.org) is
applied on top of tip/sched/core + bpf/master as of Jun 18th.
tip/sched/core 793a62823d1c ("sched/core: Drop spinlocks on contention iff kernel is preempti
ble")
bpf/master f6afdaf72af7 ("Merge branch 'bpf-support-resilient-split-btf'")
Since then, the following pulls were made:
- v6.11-rc1 is pulled to keep up with the mainline.
- tip/sched/core was pulled several times:
- 7b9f6c864a34, 0df340ceae2e, 5ac998574f93, 0b1777f0fa04: To resolve
conflicts. See each commit for details on conflicts and their
resolutions.
- d7b01aef9dbd: To receive fd03c5b85855 ("sched: Rework pick_next_task()")
and related commits. @prev in added to sched_class->put_prev_task() and
put_prev_task() is reordered after ->pick_task(), which makes
sched_class->switch_class() unnecessary. The follow-up commits update
sched_ext accordingly and drop sched_class->switch_class().
- bpf/master was pulled to receive baebe9aaba1e ("bpf: allow passing struct
bpf_iter_<type> as kfunc arguments") and related changes in preparation
for the DSQ iterator patchset
To obtain the net sched_ext changes, diff against:
git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext.git for-6.12-base
which is the merge of:
tip/sched/core bc9057da1a22 ("sched/cpufreq: Use NSEC_PER_MSEC for deadline task")
bpf/master 2ad6d23f465 ("selftests/bpf: Do not update vmlinux.h unnecessarily")
Since the v7 patchset, the following changes were made:
- cpuperf support which was a part of the v6 patchset was posted separately
and then applied after reviews.
- cgroup support which was a part of the v6 patchset was posted seprately,
iterated and then applied.
- Improve integration with sched core.
- Double locking usage in migration paths dropped. Depend on
TASK_ON_RQ_MIGRATING synchronization instead.
- The BPF scheduler couldn't directly dispatch to the local DSQ of another
CPU using a SCX_DSQ_LOCAL_ON verdict. This caused difficulties around
handling non-wakeup enqueues. Updated so that SCX_DSQ_LOCAL_ON can be used
in the enqueue path too.
- DSQ iterator which was a part of the v6 patchset was posted separately.
The iterator itself was applied after a couple revisions. The associated
selective consumption kfunc can use further improvements and is still
being worked on.
- scx_bpf_dispatch[_vtime]_from_dsq() added to increase flexibility. A task
can now be transferred between two DSQs from almost any context. This
involved significant refactoring of migration code.
- Various fixes and improvements.
As the branch is based on top of tip/sched/core + bpf/master, please merge
after both are applied.
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Merge tag 'sched_ext-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Pull sched_ext support from Tejun Heo:
"This implements a new scheduler class called ‘ext_sched_class’, or
sched_ext, which allows scheduling policies to be implemented as BPF
programs.
The goals of this are:
- Ease of experimentation and exploration: Enabling rapid iteration
of new scheduling policies.
- Customization: Building application-specific schedulers which
implement policies that are not applicable to general-purpose
schedulers.
- Rapid scheduler deployments: Non-disruptive swap outs of scheduling
policies in production environments"
See individual commits for more documentation, but also the cover letter
for the latest series:
Link: https://lore.kernel.org/all/20240618212056.2833381-1-tj@kernel.org/
* tag 'sched_ext-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: (110 commits)
sched: Move update_other_load_avgs() to kernel/sched/pelt.c
sched_ext: Don't trigger ops.quiescent/runnable() on migrations
sched_ext: Synchronize bypass state changes with rq lock
scx_qmap: Implement highpri boosting
sched_ext: Implement scx_bpf_dispatch[_vtime]_from_dsq()
sched_ext: Compact struct bpf_iter_scx_dsq_kern
sched_ext: Replace consume_local_task() with move_local_task_to_local_dsq()
sched_ext: Move consume_local_task() upward
sched_ext: Move sanity check and dsq_mod_nr() into task_unlink_from_dsq()
sched_ext: Reorder args for consume_local/remote_task()
sched_ext: Restructure dispatch_to_local_dsq()
sched_ext: Fix processs_ddsp_deferred_locals() by unifying DTL_INVALID handling
sched_ext: Make find_dsq_for_dispatch() handle SCX_DSQ_LOCAL_ON
sched_ext: Refactor consume_remote_task()
sched_ext: Rename scx_kfunc_set_sleepable to unlocked and relocate
sched_ext: Add missing static to scx_dump_data
sched_ext: Add missing static to scx_has_op[]
sched_ext: Temporarily work around pick_task_scx() being called without balance_scx()
sched_ext: Add a cgroup scheduler which uses flattened hierarchy
sched_ext: Add cgroup support
...
|
||
|
Linus Torvalds
|
617a814f14 |
ALong with the usual shower of singleton patches, notable patch series in
this pull request are:
"Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
consistency to the APIs and behaviour of these two core allocation
functions. This also simplifies/enables Rustification.
"Some cleanups for shmem" from Baolin Wang. No functional changes - mode
code reuse, better function naming, logic simplifications.
"mm: some small page fault cleanups" from Josef Bacik. No functional
changes - code cleanups only.
"Various memory tiering fixes" from Zi Yan. A small fix and a little
cleanup.
"mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
simplifications and .text shrinkage.
"Kernel stack usage histogram" from Pasha Tatashin and Shakeel Butt. This
is a feature, it adds new feilds to /proc/vmstat such as
$ grep kstack /proc/vmstat
kstack_1k 3
kstack_2k 188
kstack_4k 11391
kstack_8k 243
kstack_16k 0
which tells us that 11391 processes used 4k of stack while none at all
used 16k. Useful for some system tuning things, but partivularly useful
for "the dynamic kernel stack project".
"kmemleak: support for percpu memory leak detect" from Pavel Tikhomirov.
Teaches kmemleak to detect leaksage of percpu memory.
"mm: memcg: page counters optimizations" from Roman Gushchin. "3
independent small optimizations of page counters".
"mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from David
Hildenbrand. Improves PTE/PMD splitlock detection, makes powerpc/8xx work
correctly by design rather than by accident.
"mm: remove arch_make_page_accessible()" from David Hildenbrand. Some
folio conversions which make arch_make_page_accessible() unneeded.
"mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David Finkel.
Cleans up and fixes our handling of the resetting of the cgroup/process
peak-memory-use detector.
"Make core VMA operations internal and testable" from Lorenzo Stoakes.
Rationalizaion and encapsulation of the VMA manipulation APIs. With a
view to better enable testing of the VMA functions, even from a
userspace-only harness.
"mm: zswap: fixes for global shrinker" from Takero Funaki. Fix issues in
the zswap global shrinker, resulting in improved performance.
"mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill in
some missing info in /proc/zoneinfo.
"mm: replace follow_page() by folio_walk" from David Hildenbrand. Code
cleanups and rationalizations (conversion to folio_walk()) resulting in
the removal of follow_page().
"improving dynamic zswap shrinker protection scheme" from Nhat Pham. Some
tuning to improve zswap's dynamic shrinker. Significant reductions in
swapin and improvements in performance are shown.
"mm: Fix several issues with unaccepted memory" from Kirill Shutemov.
Improvements to the new unaccepted memory feature,
"mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on DAX
PUDs. This was missing, although nobody seems to have notied yet.
"Introduce a store type enum for the Maple tree" from Sidhartha Kumar.
Cleanups and modest performance improvements for the maple tree library
code.
"memcg: further decouple v1 code from v2" from Shakeel Butt. Move more
cgroup v1 remnants away from the v2 memcg code.
"memcg: initiate deprecation of v1 features" from Shakeel Butt. Adds
various warnings telling users that memcg v1 features are deprecated.
"mm: swap: mTHP swap allocator base on swap cluster order" from Chris Li.
Greatly improves the success rate of the mTHP swap allocation.
"mm: introduce numa_memblks" from Mike Rapoport. Moves various disparate
per-arch implementations of numa_memblk code into generic code.
"mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
improves the performance of munmap() of swap-filled ptes.
"support large folio swap-out and swap-in for shmem" from Baolin Wang.
With this series we no longer split shmem large folios into simgle-page
folios when swapping out shmem.
"mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice performance
improvements and code reductions for gigantic folios.
"support shmem mTHP collapse" from Baolin Wang. Adds support for
khugepaged's collapsing of shmem mTHP folios.
"mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
performance regression due to the addition of mseal().
"Increase the number of bits available in page_type" from Matthew Wilcox.
Increases the number of bits available in page_type!
"Simplify the page flags a little" from Matthew Wilcox. Many legacy page
flags are now folio flags, so the page-based flags and their
accessors/mutators can be removed.
"mm: store zero pages to be swapped out in a bitmap" from Usama Arif. An
optimization which permits us to avoid writing/reading zero-filled zswap
pages to backing store.
"Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race window
which occurs when a MAP_FIXED operqtion is occurring during an unrelated
vma tree walk.
"mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of the
vma_merge() functionality, making ot cleaner, more testable and better
tested.
"misc fixups for DAMON {self,kunit} tests" from SeongJae Park. Minor
fixups of DAMON selftests and kunit tests.
"mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang. Code
cleanups and folio conversions.
"Shmem mTHP controls and stats improvements" from Ryan Roberts. Cleanups
for shmem controls and stats.
"mm: count the number of anonymous THPs per size" from Barry Song. Expose
additional anon THP stats to userspace for improved tuning.
"mm: finish isolate/putback_lru_page()" from Kefeng Wang: more folio
conversions and removal of now-unused page-based APIs.
"replace per-quota region priorities histogram buffer with per-context
one" from SeongJae Park. DAMON histogram rationalization.
"Docs/damon: update GitHub repo URLs and maintainer-profile" from SeongJae
Park. DAMON documentation updates.
"mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and improve
related doc and warn" from Jason Wang: fixes usage of page allocator
__GFP_NOFAIL and GFP_ATOMIC flags.
"mm: split underused THPs" from Yu Zhao. Improve THP=always policy - this
was overprovisioning THPs in sparsely accessed memory areas.
"zram: introduce custom comp backends API" frm Sergey Senozhatsky. Add
support for zram run-time compression algorithm tuning.
"mm: Care about shadow stack guard gap when getting an unmapped area" from
Mark Brown. Fix up the various arch_get_unmapped_area() implementations
to better respect guard areas.
"Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability of
mem_cgroup_iter() and various code cleanups.
"mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
pfnmap support.
"resource: Fix region_intersects() vs add_memory_driver_managed()" from
Huang Ying. Fix a bug in region_intersects() for systems with CXL memory.
"mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches a
couple more code paths to correctly recover from the encountering of
poisoned memry.
"mm: enable large folios swap-in support" from Barry Song. Support the
swapin of mTHP memory into appropriately-sized folios, rather than into
single-page folios.
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Merge tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Along with the usual shower of singleton patches, notable patch series
in this pull request are:
- "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
consistency to the APIs and behaviour of these two core allocation
functions. This also simplifies/enables Rustification.
- "Some cleanups for shmem" from Baolin Wang. No functional changes -
mode code reuse, better function naming, logic simplifications.
- "mm: some small page fault cleanups" from Josef Bacik. No
functional changes - code cleanups only.
- "Various memory tiering fixes" from Zi Yan. A small fix and a
little cleanup.
- "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
simplifications and .text shrinkage.
- "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
Butt. This is a feature, it adds new feilds to /proc/vmstat such as
$ grep kstack /proc/vmstat
kstack_1k 3
kstack_2k 188
kstack_4k 11391
kstack_8k 243
kstack_16k 0
which tells us that 11391 processes used 4k of stack while none at
all used 16k. Useful for some system tuning things, but
partivularly useful for "the dynamic kernel stack project".
- "kmemleak: support for percpu memory leak detect" from Pavel
Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.
- "mm: memcg: page counters optimizations" from Roman Gushchin. "3
independent small optimizations of page counters".
- "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
David Hildenbrand. Improves PTE/PMD splitlock detection, makes
powerpc/8xx work correctly by design rather than by accident.
- "mm: remove arch_make_page_accessible()" from David Hildenbrand.
Some folio conversions which make arch_make_page_accessible()
unneeded.
- "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
Finkel. Cleans up and fixes our handling of the resetting of the
cgroup/process peak-memory-use detector.
- "Make core VMA operations internal and testable" from Lorenzo
Stoakes. Rationalizaion and encapsulation of the VMA manipulation
APIs. With a view to better enable testing of the VMA functions,
even from a userspace-only harness.
- "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
issues in the zswap global shrinker, resulting in improved
performance.
- "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
in some missing info in /proc/zoneinfo.
- "mm: replace follow_page() by folio_walk" from David Hildenbrand.
Code cleanups and rationalizations (conversion to folio_walk())
resulting in the removal of follow_page().
- "improving dynamic zswap shrinker protection scheme" from Nhat
Pham. Some tuning to improve zswap's dynamic shrinker. Significant
reductions in swapin and improvements in performance are shown.
- "mm: Fix several issues with unaccepted memory" from Kirill
Shutemov. Improvements to the new unaccepted memory feature,
- "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
DAX PUDs. This was missing, although nobody seems to have notied
yet.
- "Introduce a store type enum for the Maple tree" from Sidhartha
Kumar. Cleanups and modest performance improvements for the maple
tree library code.
- "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
more cgroup v1 remnants away from the v2 memcg code.
- "memcg: initiate deprecation of v1 features" from Shakeel Butt.
Adds various warnings telling users that memcg v1 features are
deprecated.
- "mm: swap: mTHP swap allocator base on swap cluster order" from
Chris Li. Greatly improves the success rate of the mTHP swap
allocation.
- "mm: introduce numa_memblks" from Mike Rapoport. Moves various
disparate per-arch implementations of numa_memblk code into generic
code.
- "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
improves the performance of munmap() of swap-filled ptes.
- "support large folio swap-out and swap-in for shmem" from Baolin
Wang. With this series we no longer split shmem large folios into
simgle-page folios when swapping out shmem.
- "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
performance improvements and code reductions for gigantic folios.
- "support shmem mTHP collapse" from Baolin Wang. Adds support for
khugepaged's collapsing of shmem mTHP folios.
- "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
performance regression due to the addition of mseal().
- "Increase the number of bits available in page_type" from Matthew
Wilcox. Increases the number of bits available in page_type!
- "Simplify the page flags a little" from Matthew Wilcox. Many legacy
page flags are now folio flags, so the page-based flags and their
accessors/mutators can be removed.
- "mm: store zero pages to be swapped out in a bitmap" from Usama
Arif. An optimization which permits us to avoid writing/reading
zero-filled zswap pages to backing store.
- "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
window which occurs when a MAP_FIXED operqtion is occurring during
an unrelated vma tree walk.
- "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
the vma_merge() functionality, making ot cleaner, more testable and
better tested.
- "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
Minor fixups of DAMON selftests and kunit tests.
- "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
Code cleanups and folio conversions.
- "Shmem mTHP controls and stats improvements" from Ryan Roberts.
Cleanups for shmem controls and stats.
- "mm: count the number of anonymous THPs per size" from Barry Song.
Expose additional anon THP stats to userspace for improved tuning.
- "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
folio conversions and removal of now-unused page-based APIs.
- "replace per-quota region priorities histogram buffer with
per-context one" from SeongJae Park. DAMON histogram
rationalization.
- "Docs/damon: update GitHub repo URLs and maintainer-profile" from
SeongJae Park. DAMON documentation updates.
- "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
improve related doc and warn" from Jason Wang: fixes usage of page
allocator __GFP_NOFAIL and GFP_ATOMIC flags.
- "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
This was overprovisioning THPs in sparsely accessed memory areas.
- "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
Add support for zram run-time compression algorithm tuning.
- "mm: Care about shadow stack guard gap when getting an unmapped
area" from Mark Brown. Fix up the various arch_get_unmapped_area()
implementations to better respect guard areas.
- "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
of mem_cgroup_iter() and various code cleanups.
- "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
pfnmap support.
- "resource: Fix region_intersects() vs add_memory_driver_managed()"
from Huang Ying. Fix a bug in region_intersects() for systems with
CXL memory.
- "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
a couple more code paths to correctly recover from the encountering
of poisoned memry.
- "mm: enable large folios swap-in support" from Barry Song. Support
the swapin of mTHP memory into appropriately-sized folios, rather
than into single-page folios"
* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
zram: free secondary algorithms names
uprobes: turn xol_area->pages[2] into xol_area->page
uprobes: introduce the global struct vm_special_mapping xol_mapping
Revert "uprobes: use vm_special_mapping close() functionality"
mm: support large folios swap-in for sync io devices
mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
set_memory: add __must_check to generic stubs
mm/vma: return the exact errno in vms_gather_munmap_vmas()
memcg: cleanup with !CONFIG_MEMCG_V1
mm/show_mem.c: report alloc tags in human readable units
mm: support poison recovery from copy_present_page()
mm: support poison recovery from do_cow_fault()
resource, kunit: add test case for region_intersects()
resource: make alloc_free_mem_region() works for iomem_resource
mm: z3fold: deprecate CONFIG_Z3FOLD
vfio/pci: implement huge_fault support
mm/arm64: support large pfn mappings
mm/x86: support large pfn mappings
...
|
||
|
Linus Torvalds
|
2004cef11e |
In the v6.12 scheduler development cycle we had 63 commits from 18 contributors:
- Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot de Oliveira's
last major contribution to the kernel:
"SCHED_DEADLINE servers can help fixing starvation issues of low priority
tasks (e.g., SCHED_OTHER) when higher priority tasks monopolize CPU
cycles. Today we have RT Throttling; DEADLINE servers should be able to
replace and improve that."
(Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes,
Youssef Esmat, Huang Shijie)
- Preparatory changes for sched_ext integration:
- Use set_next_task(.first) where required
- Fix up set_next_task() implementations
- Clean up DL server vs. core sched
- Split up put_prev_task_balance()
- Rework pick_next_task()
- Combine the last put_prev_task() and the first set_next_task()
- Rework dl_server
- Add put_prev_task(.next)
(Peter Zijlstra, with a fix by Tejun Heo)
- Complete the EEVDF transition and refine EEVDF scheduling:
- Implement delayed dequeue
- Allow shorter slices to wakeup-preempt
- Use sched_attr::sched_runtime to set request/slice suggestion
- Document the new feature flags
- Remove unused and duplicate-functionality fields
- Simplify & unify pick_next_task_fair()
- Misc debuggability enhancements
(Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann,
Valentin Schneider and Chuyi Zhou)
- Initialize the vruntime of a new task when it is first enqueued,
resulting in significant decrease in latency of newly woken tasks.
(Zhang Qiao)
- Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
(K Prateek Nayak, Peter Zijlstra)
- Clean up and clarify the usage of Clean up usage of rt_task()
(Qais Yousef)
- Preempt SCHED_IDLE entities in strict cgroup hierarchies
(Tianchen Ding)
- Clarify the documentation of time units for deadline scheduler
parameters. (Christian Loehle)
- Remove the HZ_BW chicken-bit feature flag introduced a year ago,
the original change seems to be working fine.
(Phil Auld)
- Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
Peilin He, Qais Yousefm and Vincent Guittot)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
- Implement the SCHED_DEADLINE server infrastructure - Daniel Bristot
de Oliveira's last major contribution to the kernel:
"SCHED_DEADLINE servers can help fixing starvation issues of low
priority tasks (e.g., SCHED_OTHER) when higher priority tasks
monopolize CPU cycles. Today we have RT Throttling; DEADLINE
servers should be able to replace and improve that."
(Daniel Bristot de Oliveira, Peter Zijlstra, Joel Fernandes, Youssef
Esmat, Huang Shijie)
- Preparatory changes for sched_ext integration:
- Use set_next_task(.first) where required
- Fix up set_next_task() implementations
- Clean up DL server vs. core sched
- Split up put_prev_task_balance()
- Rework pick_next_task()
- Combine the last put_prev_task() and the first set_next_task()
- Rework dl_server
- Add put_prev_task(.next)
(Peter Zijlstra, with a fix by Tejun Heo)
- Complete the EEVDF transition and refine EEVDF scheduling:
- Implement delayed dequeue
- Allow shorter slices to wakeup-preempt
- Use sched_attr::sched_runtime to set request/slice suggestion
- Document the new feature flags
- Remove unused and duplicate-functionality fields
- Simplify & unify pick_next_task_fair()
- Misc debuggability enhancements
(Peter Zijlstra, with fixes/cleanups by Dietmar Eggemann, Valentin
Schneider and Chuyi Zhou)
- Initialize the vruntime of a new task when it is first enqueued,
resulting in significant decrease in latency of newly woken tasks
(Zhang Qiao)
- Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
(K Prateek Nayak, Peter Zijlstra)
- Clean up and clarify the usage of Clean up usage of rt_task()
(Qais Yousef)
- Preempt SCHED_IDLE entities in strict cgroup hierarchies
(Tianchen Ding)
- Clarify the documentation of time units for deadline scheduler
parameters (Christian Loehle)
- Remove the HZ_BW chicken-bit feature flag introduced a year ago,
the original change seems to be working fine (Phil Auld)
- Misc fixes and cleanups (Chen Yu, Dan Carpenter, Huang Shijie,
Peilin He, Qais Yousefm and Vincent Guittot)
* tag 'sched-core-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
sched/cpufreq: Use NSEC_PER_MSEC for deadline task
cpufreq/cppc: Use NSEC_PER_MSEC for deadline task
sched/deadline: Clarify nanoseconds in uapi
sched/deadline: Convert schedtool example to chrt
sched/debug: Fix the runnable tasks output
sched: Fix sched_delayed vs sched_core
kernel/sched: Fix util_est accounting for DELAY_DEQUEUE
kthread: Fix task state in kthread worker if being frozen
sched/pelt: Use rq_clock_task() for hw_pressure
sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c
sched/core: Introduce SM_IDLE and an idle re-entry fast-path in __schedule()
sched: Add put_prev_task(.next)
sched: Rework dl_server
sched: Combine the last put_prev_task() and the first set_next_task()
sched: Rework pick_next_task()
sched: Split up put_prev_task_balance()
sched: Clean up DL server vs core sched
sched: Fixup set_next_task() implementations
sched: Use set_next_task(.first) where required
sched/fair: Properly deactivate sched_delayed task upon class change
...
|
||
|
Tejun Heo
|
0b1777f0fa |
Merge branch 'tip/sched/core' into sched_ext/for-6.12
Pull in tip/sched/core to resolve two merge conflicts:
- 96fd6c65efc6 ("sched: Factor out update_other_load_avgs() from __update_blocked_others()")
5d871a63997f ("sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c")
A simple context conflict. The former added __update_blocked_others() in
the same #ifdef CONFIG_SMP block that effective_cpu_util() and
sched_cpu_util() are in and the latter moved those functions to fair.c.
This makes __update_blocked_others() more out of place. Will follow up
with a patch to relocate.
- 96fd6c65efc6 ("sched: Factor out update_other_load_avgs() from __update_blocked_others()")
84d265281d6c ("sched/pelt: Use rq_clock_task() for hw_pressure")
The former factored out the body of __update_blocked_others() into
update_other_load_avgs(). The latter changed how update_hw_load_avg() is
called in the body. Resolved by applying the change to
update_other_load_avgs() instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
||
|
Dietmar Eggemann
|
729288bc68 |
kernel/sched: Fix util_est accounting for DELAY_DEQUEUE
Remove delayed tasks from util_est even they are runnable. Exclude delayed task which are (a) migrating between rq's or (b) in a SAVE/RESTORE dequeue/enqueue. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/c49ef5fe-a909-43f1-b02f-a765ab9cedbf@arm.com |
||
|
Chen Yu
|
84d265281d |
sched/pelt: Use rq_clock_task() for hw_pressure
commit 97450eb90965 ("sched/pelt: Remove shift of thermal clock")
removed the decay_shift for hw_pressure. This commit uses the
sched_clock_task() in sched_tick() while it replaces the
sched_clock_task() with rq_clock_pelt() in __update_blocked_others().
This could bring inconsistence. One possible scenario I can think of
is in ___update_load_sum():
u64 delta = now - sa->last_update_time
'now' could be calculated by rq_clock_pelt() from
__update_blocked_others(), and last_update_time was calculated by
rq_clock_task() previously from sched_tick(). Usually the former
chases after the latter, it cause a very large 'delta' and brings
unexpected behavior.
Fixes: 97450eb90965 ("sched/pelt: Remove shift of thermal clock")
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Hongyan Xia <hongyan.xia2@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20240827112607.181206-1-yu.c.chen@intel.com
|
||
|
Vincent Guittot
|
5d871a6399 |
sched/fair: Move effective_cpu_util() and effective_cpu_util() in fair.c
Move effective_cpu_util() and sched_cpu_util() functions in fair.c file with others utilization related functions. No functional change. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20240904092417.20660-1-vincent.guittot@linaro.org |
||
|
Yujie Liu
|
f22cde4371 |
sched/numa: Fix the vma scan starving issue
Problem statement:
Since commit fc137c0ddab2 ("sched/numa: enhance vma scanning logic"), the
Numa vma scan overhead has been reduced a lot. Meanwhile, the reducing of
the vma scan might create less Numa page fault information. The
insufficient information makes it harder for the Numa balancer to make
decision. Later, commit b7a5b537c55c08 ("sched/numa: Complete scanning of
partial VMAs regardless of PID activity") and commit 84db47ca7146d7
("sched/numa: Fix mm numa_scan_seq based unconditional scan") are found to
bring back part of the performance.
Recently when running SPECcpu omnetpp_r on a 320 CPUs/2 Sockets system, a
long duration of remote Numa node read was observed by PMU events: A few
cores having ~500MB/s remote memory access for ~20 seconds. It causes
high core-to-core variance and performance penalty. After the
investigation, it is found that many vmas are skipped due to the active
PID check. According to the trace events, in most cases,
vma_is_accessed() returns false because the history access info stored in
pids_active array has been cleared.
Proposal:
The main idea is to adjust vma_is_accessed() to let it return true easier.
Thus compare the diff between mm->numa_scan_seq and
vma->numab_state->prev_scan_seq. If the diff has exceeded the threshold,
scan the vma.
This patch especially helps the cases where there are small number of
threads, like the process-based SPECcpu. Without this patch, if the
SPECcpu process access the vma at the beginning, then sleeps for a long
time, the pid_active array will be cleared. A a result, if this process
is woken up again, it never has a chance to set prot_none anymore.
Because only the first 2 times of access is granted for vma scan:
(current->mm->numa_scan_seq) - vma->numab_state->start_scan_seq) < 2 to be
worse, no other threads within the task can help set the prot_none. This
causes information lost.
Raghavendra helped test current patch and got the positive result
on the AMD platform:
autonumabench NUMA01
base patched
Amean syst-NUMA01 194.05 ( 0.00%) 165.11 * 14.92%*
Amean elsp-NUMA01 324.86 ( 0.00%) 315.58 * 2.86%*
Duration User 380345.36 368252.04
Duration System 1358.89 1156.23
Duration Elapsed 2277.45 2213.25
autonumabench NUMA02
Amean syst-NUMA02 1.12 ( 0.00%) 1.09 * 2.93%*
Amean elsp-NUMA02 3.50 ( 0.00%) 3.56 * -1.84%*
Duration User 1513.23 1575.48
Duration System 8.33 8.13
Duration Elapsed 28.59 29.71
kernbench
Amean user-256 22935.42 ( 0.00%) 22535.19 * 1.75%*
Amean syst-256 7284.16 ( 0.00%) 7608.72 * -4.46%*
Amean elsp-256 159.01 ( 0.00%) 158.17 * 0.53%*
Duration User 68816.41 67615.74
Duration System 21873.94 22848.08
Duration Elapsed 506.66 504.55
Intel 256 CPUs/2 Sockets:
autonuma benchmark also shows improvements:
v6.10-rc5 v6.10-rc5
+patch
Amean syst-NUMA01 245.85 ( 0.00%) 230.84 * 6.11%*
Amean syst-NUMA01_THREADLOCAL 205.27 ( 0.00%) 191.86 * 6.53%*
Amean syst-NUMA02 18.57 ( 0.00%) 18.09 * 2.58%*
Amean syst-NUMA02_SMT 2.63 ( 0.00%) 2.54 * 3.47%*
Amean elsp-NUMA01 517.17 ( 0.00%) 526.34 * -1.77%*
Amean elsp-NUMA01_THREADLOCAL 99.92 ( 0.00%) 100.59 * -0.67%*
Amean elsp-NUMA02 15.81 ( 0.00%) 15.72 * 0.59%*
Amean elsp-NUMA02_SMT 13.23 ( 0.00%) 12.89 * 2.53%*
v6.10-rc5 v6.10-rc5
+patch
Duration User 1064010.16 1075416.23
Duration System 3307.64 3104.66
Duration Elapsed 4537.54 4604.73
The SPECcpu remote node access issue disappears with the patch applied.
Link: https://lkml.kernel.org/r/20240827112958.181388-1-yu.c.chen@intel.com
Fixes: fc137c0ddab2 ("sched/numa: enhance vma scanning logic")
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Co-developed-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Yujie Liu <yujie.liu@intel.com>
Reported-by: Xiaoping Zhou <xiaoping.zhou@intel.com>
Reviewed-and-tested-by: Raghavendra K T <raghavendra.kt@amd.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: "Chen, Tim C" <tim.c.chen@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Raghavendra K T <raghavendra.kt@amd.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Tejun Heo
|
d7b01aef9d |
Merge branch 'tip/sched/core' into for-6.12
- Resolve trivial context conflicts from dl_server clearing being moved around. - Add @next to put_prev_task_scx() and @prev to pick_next_task_scx() to match sched/core. - Merge sched_class->switch_class() addition from sched_ext with tip/sched/core changes in __pick_next_task(). - Make pick_next_task_scx() call put_prev_task_scx() to emulate the previous behavior where sched_class->put_prev_task() was called before sched_class->pick_next_task(). While this makes sched_ext build and function, the behavior is not in line with other sched classes. The follow-up patches will address the discrepancies and remove sched_class->switch_class(). Signed-off-by: Tejun Heo <tj@kernel.org> |