Messages in this thread Patch in this message | | | From | Tim Chen <> | Subject | Re: [RFC PATCH v4 00/19] Core scheduling v4 | Date | Wed, 15 Jan 2020 11:33:06 -0800 |
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On 1/14/20 7:43 PM, Li, Aubrey wrote: > On 2020/1/14 23:40, Vineeth Remanan Pillai wrote: >> On Mon, Jan 13, 2020 at 8:12 PM Tim Chen <tim.c.chen@linux.intel.com> wrote: >> >>> I also encountered kernel panic with the v4 code when taking cpu offline or online >>> when core scheduler is running. I've refreshed the previous patch, along >>> with 3 other patches to fix problems related to CPU online/offline. >>> >>> As a side effect of the fix, each core can now operate in core-scheduling >>> mode or non core-scheduling mode, depending on how many online SMT threads it has. >>> >>> Vineet, are you guys planning to refresh v4 and update it to v5? Aubrey posted >>> a port to the latest kernel earlier. >>> >> Thanks for the updated patch Tim. >> >> We have been testing with v4 rebased on 5.4.8 as RC kernels had given us >> trouble in the past. v5 is due soon and we are planning to release v5 when >> 5.5 comes out. As of now, v5 has your crash fixes and Aubrey's changes >> related to load balancing. > > It turns out my load balancing related changes need to be refined. > For example, we don't migrate task if the task's core cookie does not match > with CPU's core cookie, but if the entire core is idle, we should allow task > migration, something like the following: > > I plan to do this after my Chinese New Year holiday(Feb 3rd). > > Thanks, > -Aubrey >
Aubrey's attached patch should replace his previous patch sched/fair: don't migrate task if cookie not match
I've also added a fix below for Aubrey's patch sched/fair: find cookie matched idlest CPU.
Aubrey, can you merge this fix into that patch when you update your patches?
Tim
---->8---- From 06c09a9c86db6a7c30e5ebca7a635005ac2df37b Mon Sep 17 00:00:00 2001 From: Tim Chen <tim.c.chen@linux.intel.com> Date: Thu, 12 Dec 2019 09:08:18 -0800 Subject: [PATCH] sched: Check core scheduler in use when comparing cookie
When scanning scheduler groups to find the idlest cpu for a task waking up, cookie matching should not be considered if a target cpu doesn't use core scheduling. Code introduced by patch
sched/fair: find cookie matched idlest CPU
matches cookie regardless of cpu's core scheduler state. Fix this.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> --- kernel/sched/fair.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a90179937f63..55e7b22522db 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5656,8 +5656,15 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, for_each_cpu(i, sched_group_span(group)) { struct rq *rq = cpu_rq(i); - if (p->core_cookie == rq->core->core_cookie) + if (!sched_core_enabled(rq)) { cookie_match = true; + break; + } + + if (p->core_cookie == rq->core->core_cookie) { + cookie_match = true; + break; + } } /* Skip over this group if no cookie matched */ if (!cookie_match) -- 2.20.1
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