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From: Delyan Kratunov <delyank@fb.com>
To: "peterz@infradead.org" <peterz@infradead.org>
Cc: "bigeasy@linutronix.de" <bigeasy@linutronix.de>,
	"dietmar.eggemann@arm.com" <dietmar.eggemann@arm.com>,
	"keescook@chromium.org" <keescook@chromium.org>,
	"x86@kernel.org" <x86@kernel.org>,
	"andrii@kernel.org" <andrii@kernel.org>,
	"u.kleine-koenig@pengutronix.de" <u.kleine-koenig@pengutronix.de>,
	"vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"mingo@kernel.org" <mingo@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"rdunlap@infradead.org" <rdunlap@infradead.org>,
	"rostedt@goodmis.org" <rostedt@goodmis.org>,
	"Kenta.Tada@sony.com" <Kenta.Tada@sony.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"bristot@redhat.com" <bristot@redhat.com>,
	"ebiederm@xmission.com" <ebiederm@xmission.com>,
	"ast@kernel.org" <ast@kernel.org>,
	"legion@kernel.org" <legion@kernel.org>,
	"adharmap@quicinc.com" <adharmap@quicinc.com>,
	"valentin.schneider@arm.com" <valentin.schneider@arm.com>,
	"ed.tsai@mediatek.com" <ed.tsai@mediatek.com>,
	"juri.lelli@redhat.com" <juri.lelli@redhat.com>
Subject: Re: [PATCH] sched/tracing: append prev_state to tp args instead
Date: Fri, 22 Apr 2022 17:22:20 +0000	[thread overview]
Message-ID: <056e9bb0d0e3fc20572d42db7386face1d0665d6.camel@fb.com> (raw)
In-Reply-To: <20220422110903.GW2731@worktop.programming.kicks-ass.net>

On Fri, 2022-04-22 at 13:09 +0200, Peter Zijlstra wrote:
> And on the other hand; those users need to be fixed anyway, right?
> Accessing prev->__state is equally broken.

The users that access prev->__state would most likely have to be fixed, for sure.

However, not all users access prev->__state. `offcputime` for example just takes a
stack trace and associates it with the switched out task. This kind of user
would continue working with the proposed patch.

> If bpf wants to ride on them, it needs to suffer the pain of doing so.

Sure, I'm just advocating for a fairly trivial patch to avoid some of the suffering,
hopefully without being a burden to development. If that's not the case, then it's a
clear no-go.


  parent reply	other threads:[~2022-04-22 18:06 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-20 16:25 [PATCH v3 0/2] sched/tracing: sched_switch prev_state reported as TASK_RUNNING when it's not Valentin Schneider
2022-01-20 16:25 ` [PATCH v3 1/2] sched/tracing: Don't re-read p->state when emitting sched_switch event Valentin Schneider
2022-03-01 15:24   ` [tip: sched/core] " tip-bot2 for Valentin Schneider
2022-03-04 16:13     ` Valentin Schneider
2022-03-08 18:02     ` Qais Yousef
2022-03-08 18:10       ` Greg KH
2022-03-08 18:51         ` Qais Yousef
2022-04-09 23:38           ` Qais Yousef
2022-04-10 22:06             ` Qais Yousef
2022-04-10 23:22               ` Holger Hoffstätte
2022-04-11  7:18                 ` Holger Hoffstätte
2022-04-11  7:28                   ` Greg KH
2022-04-11  8:05                     ` Holger Hoffstätte
2022-04-11 13:23                       ` Greg KH
2022-04-11 13:22             ` Greg KH
2022-04-11 21:06               ` Qais Yousef
2022-01-20 16:25 ` [PATCH v3 2/2] sched/tracing: Report TASK_RTLOCK_WAIT tasks as TASK_UNINTERRUPTIBLE Valentin Schneider
2022-03-01 15:24   ` [tip: sched/core] " tip-bot2 for Valentin Schneider
2022-04-09 23:42   ` [PATCH v3 2/2] " Qais Yousef
2022-04-10  6:14     ` Greg KH
2022-04-10 22:13       ` Qais Yousef
2022-04-11 13:20         ` Greg KH
2022-04-11 20:18           ` Qais Yousef
2022-01-21 17:15 ` [PATCH v3 0/2] sched/tracing: sched_switch prev_state reported as TASK_RUNNING when it's not Steven Rostedt
2022-02-27 15:33   ` Peter Zijlstra
2022-04-21 22:12 ` [PATCH] sched/tracing: append prev_state to tp args instead Delyan Kratunov
2022-04-22 10:13   ` Valentin Schneider
2022-04-22 11:09   ` Peter Zijlstra
2022-04-22 15:55     ` Steven Rostedt
2022-04-22 16:54       ` Andrii Nakryiko
2022-04-22 16:37     ` Andrii Nakryiko
2022-04-22 17:22     ` Delyan Kratunov [this message]
2022-04-22 18:30       ` Alexei Starovoitov
2022-04-26 12:28         ` Peter Zijlstra
2022-04-26 14:09           ` Qais Yousef
2022-04-26 15:54             ` Andrii Nakryiko
2022-04-27 10:34               ` Qais Yousef
2022-04-27 18:17                 ` Andrii Nakryiko
2022-04-27 20:32                   ` Alexei Starovoitov
2022-04-28 10:02                   ` Qais Yousef
2022-05-09 19:32                     ` Andrii Nakryiko
2022-05-10  7:01                       ` Peter Zijlstra
2022-05-10  8:29                         ` Peter Zijlstra
2022-05-10 14:31                           ` Steven Rostedt
2022-05-11 18:28                           ` [PATCH v2] " Delyan Kratunov
2022-05-11 19:10                             ` Steven Rostedt
2022-05-11 22:45                             ` [tip: sched/urgent] sched/tracing: Append " tip-bot2 for Delyan Kratunov
2022-05-11 23:40                             ` [PATCH v2] sched/tracing: append " Thomas Gleixner
2022-04-26 15:51           ` [PATCH] " Andrii Nakryiko

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