From: Mike Galbraith <efault@gmx.de>
To: K Prateek Nayak <kprateek.nayak@amd.com>,
Peter Zijlstra <peterz@infradead.org>,
mingo@redhat.com, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
bristot@redhat.com, vschneid@redhat.com,
linux-kernel@vger.kernel.org
Cc: wuyun.abel@bytedance.com, tglx@linutronix.de,
Chen Yu <yu.c.chen@intel.com>,
Oliver Sang <oliver.sang@intel.com>
Subject: Re: [RFC][PATCH 08/10] sched/fair: Implement delayed dequeue
Date: Thu, 18 Apr 2024 18:24:59 +0200 [thread overview]
Message-ID: <2b9f7617f2b2130bb6270504ec3858f15d463f1d.camel@gmx.de> (raw)
In-Reply-To: <747627a1414f1f33d0c237f555494149d6937800.camel@gmx.de>
Greetings,
I tossed a couple rocks at it today, and seem to have hit the little
bugger. The root cause seems to be doing the delay dequeue business on
exiting tasks. Hunk #1 of hacklet below seems to quell the explosions.
crash> bt -sx
PID: 21722 TASK: ffff88815710ee40 CPU: 6 COMMAND: "hackbench"
#0 [ffff88822773bb90] machine_kexec+0x156 at ffffffff810642d6
#1 [ffff88822773bbe0] __crash_kexec+0xd7 at ffffffff81152a07
#2 [ffff88822773bc98] crash_kexec+0x23 at ffffffff81152eb3
#3 [ffff88822773bca8] oops_end+0xbe at ffffffff810329be
#4 [ffff88822773bcc8] page_fault_oops+0x81 at ffffffff81071951
#5 [ffff88822773bd28] exc_page_fault+0x62 at ffffffff8194e9e2
#6 [ffff88822773bd50] asm_exc_page_fault+0x22 at ffffffff81a00ba2
[exception RIP: pick_next_task_fair+178]
RIP: ffffffff810d8d12 RSP: ffff88822773be00 RFLAGS: 00010006
RAX: ffff88813cb780b8 RBX: ffff88840edb0e80 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88813cb78080 RDI: ffff88840ec30f00
RBP: ffff88813cb78000 R8: ffff88815710eec0 R9: 0000000000000001
R10: ffff88822773bdc8 R11: 0000000000000013 R12: 0000000000030e80
R13: ffff88815710ee40 R14: ffff88813cb78080 R15: ffff88815710ee40
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#7 [ffff88822773be28] __schedule+0x10d at ffffffff8195865d
#8 [ffff88822773be98] do_task_dead+0x3e at ffffffff810cc00e
#9 [ffff88822773beb0] do_exit+0x770 at ffffffff8108f0e0
#10 [ffff88822773bf00] do_group_exit+0x2c at ffffffff8108f64c
#11 [ffff88822773bf28] __x64_sys_exit_group+0x14 at ffffffff8108f6f4
#12 [ffff88822773bf30] do_syscall_64+0x57 at ffffffff8194ac37
#13 [ffff88822773bf50] entry_SYSCALL_64_after_hwframe+0x76 at ffffffff81a0012b
RIP: 00007f4f2aa76136 RSP: 00007ffcbba84748 RFLAGS: 00000246
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f4f2aa76136
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00007f4f2ab86970 R8: 00000000000000e7 R9: ffffffffffffff80
R10: 0000000000000004 R11: 0000000000000246 R12: 00007f4f2ab86970
R13: 0000000000000001 R14: 00007f4f2ab8a328 R15: 0000000000000000
ORIG_RAX: 00000000000000e7 CS: 0033 SS: 002b
crash> task_struct ffff88815710ee40 | grep sched_delayed
sched_delayed = 1 '\001',
crash>
---
kernel/sched/fair.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5374,6 +5374,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, st
update_curr(cfs_rq);
if (sched_feat(DELAY_DEQUEUE) && sleep &&
+ !(entity_is_task(se) && (task_of(se)->flags & PF_EXITING)) &&
!entity_eligible(cfs_rq, se)) {
if (cfs_rq->next == se)
cfs_rq->next = NULL;
@@ -5495,14 +5496,14 @@ pick_next_entity(struct rq *rq, struct c
}
struct sched_entity *se = pick_eevdf(cfs_rq);
- if (se->sched_delayed) {
+ while (se && se->sched_delayed) {
dequeue_entities(rq, se, DEQUEUE_SLEEP | DEQUEUE_DELAYED);
SCHED_WARN_ON(se->sched_delayed);
SCHED_WARN_ON(se->on_rq);
if (sched_feat(DELAY_ZERO) && se->vlag > 0)
se->vlag = 0;
- return NULL;
+ se = pick_eevdf(cfs_rq);
}
return se;
}
next prev parent reply other threads:[~2024-04-18 16:25 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-05 10:27 [RFC][PATCH 00/10] sched/fair: Complete EEVDF Peter Zijlstra
2024-04-05 10:27 ` [RFC][PATCH 01/10] sched/eevdf: Add feature comments Peter Zijlstra
2024-04-05 10:27 ` [RFC][PATCH 02/10] sched/eevdf: Remove min_vruntime_copy Peter Zijlstra
2024-04-05 10:27 ` [RFC][PATCH 03/10] sched/fair: Cleanup pick_task_fair() vs throttle Peter Zijlstra
2024-04-05 21:11 ` Benjamin Segall
2024-04-05 10:27 ` [RFC][PATCH 04/10] sched/fair: Cleanup pick_task_fair()s curr Peter Zijlstra
2024-04-05 10:27 ` [RFC][PATCH 05/10] sched/fair: Unify pick_{,next_}_task_fair() Peter Zijlstra
2024-04-06 2:20 ` Mike Galbraith
2024-04-05 10:28 ` [RFC][PATCH 06/10] sched: Allow sched_class::dequeue_task() to fail Peter Zijlstra
2024-04-05 10:28 ` [RFC][PATCH 07/10] sched/fair: Re-organize dequeue_task_fair() Peter Zijlstra
2024-04-05 10:28 ` [RFC][PATCH 08/10] sched/fair: Implement delayed dequeue Peter Zijlstra
2024-04-06 9:23 ` Chen Yu
2024-04-08 9:06 ` Peter Zijlstra
2024-04-11 1:32 ` Yan-Jie Wang
2024-04-25 10:25 ` Peter Zijlstra
2024-04-12 10:42 ` K Prateek Nayak
2024-04-15 10:56 ` Mike Galbraith
2024-04-16 3:18 ` K Prateek Nayak
2024-04-16 5:36 ` Mike Galbraith
2024-04-18 16:24 ` Mike Galbraith [this message]
2024-04-18 17:08 ` K Prateek Nayak
2024-04-24 15:20 ` Peter Zijlstra
2024-04-25 11:28 ` Peter Zijlstra
2024-04-26 10:56 ` Peter Zijlstra
2024-04-26 11:16 ` Peter Zijlstra
2024-04-26 16:03 ` Mike Galbraith
2024-04-27 6:42 ` Mike Galbraith
2024-04-28 16:32 ` Mike Galbraith
2024-04-29 12:14 ` Peter Zijlstra
2024-04-15 17:07 ` Luis Machado
2024-04-24 15:15 ` Luis Machado
2024-04-25 10:42 ` Peter Zijlstra
2024-04-25 11:49 ` Peter Zijlstra
2024-04-26 9:32 ` Peter Zijlstra
2024-04-26 9:36 ` Peter Zijlstra
2024-04-26 10:16 ` Luis Machado
2024-04-29 14:33 ` Luis Machado
2024-05-02 10:26 ` Luis Machado
2024-05-10 14:49 ` Luis Machado
2024-05-15 9:36 ` Peter Zijlstra
2024-05-15 11:48 ` Peter Zijlstra
2024-05-15 18:03 ` Mike Galbraith
2024-04-26 10:15 ` Luis Machado
2024-04-20 5:57 ` Mike Galbraith
2024-04-22 13:13 ` Tobias Huschle
2024-04-05 10:28 ` [RFC][PATCH 09/10] sched/eevdf: Allow shorter slices to wakeup-preempt Peter Zijlstra
2024-04-05 10:28 ` [RFC][PATCH 10/10] sched/eevdf: Use sched_attr::sched_runtime to set request/slice suggestion Peter Zijlstra
2024-04-06 8:16 ` Hillf Danton
2024-05-07 5:34 ` Mike Galbraith
2024-05-15 10:13 ` Peter Zijlstra
2024-05-07 15:15 ` Chen Yu
2024-05-08 13:52 ` Mike Galbraith
2024-05-09 3:48 ` Chen Yu
2024-05-09 5:00 ` Mike Galbraith
2024-05-13 4:07 ` K Prateek Nayak
2024-05-14 9:18 ` Chen Yu
2024-05-14 15:23 ` K Prateek Nayak
2024-05-14 16:15 ` Chen Yu
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