From: Peter Zijlstra <peterz@infradead.org>
To: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc: Nishanth Aravamudan <naravamudan@digitalocean.com>,
Julien Desfossez <jdesfossez@digitalocean.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Vineeth Pillai <viremana@linux.microsoft.com>,
Aaron Lu <aaron.lwe@gmail.com>,
Aubrey Li <aubrey.intel@gmail.com>,
tglx@linutronix.de, linux-kernel@vger.kernel.org,
mingo@kernel.org, torvalds@linux-foundation.org,
fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com,
Phil Auld <pauld@redhat.com>,
Valentin Schneider <valentin.schneider@arm.com>,
Mel Gorman <mgorman@techsingularity.net>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
vineeth@bitbyteword.org, Chen Yu <yu.c.chen@intel.com>,
Christian Brauner <christian.brauner@ubuntu.com>,
Agata Gruza <agata.gruza@intel.com>,
Antonio Gomez Iglesias <antonio.gomez.iglesias@intel.com>,
graf@amazon.com, konrad.wilk@oracle.com, dfaggioli@suse.com,
pjt@google.com, rostedt@goodmis.org, derkling@google.com,
benbjiang@tencent.com,
Alexandre Chartre <alexandre.chartre@oracle.com>,
James.Bottomley@hansenpartnership.com, OWeisse@umich.edu,
Dhaval Giani <dhaval.giani@oracle.com>,
Junaid Shahid <junaids@google.com>,
jsbarnes@google.com, chris.hyser@oracle.com,
Ben Segall <bsegall@google.com>, Josh Don <joshdon@google.com>,
Hao Luo <haoluo@google.com>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [PATCH v10 2/5] sched: CGroup tagging interface for core scheduling
Date: Thu, 4 Feb 2021 15:35:50 +0100 [thread overview]
Message-ID: <YBwGRpnISmwkJ2i8@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210123011704.1901835-3-joel@joelfernandes.org>
On Fri, Jan 22, 2021 at 08:17:01PM -0500, Joel Fernandes (Google) wrote:
> +static inline void __sched_core_erase_cookie(struct sched_core_cookie *cookie)
> +{
> + lockdep_assert_held(&sched_core_cookies_lock);
> +
> + /* Already removed */
> + if (RB_EMPTY_NODE(&cookie->node))
> + return;
> +
> + rb_erase(&cookie->node, &sched_core_cookies);
> + RB_CLEAR_NODE(&cookie->node);
> +}
> +
> +/* Called when a task no longer points to the cookie in question */
> +static void sched_core_put_cookie(struct sched_core_cookie *cookie)
> +{
> + unsigned long flags;
> +
> + if (!cookie)
> + return;
> +
> + if (refcount_dec_and_test(&cookie->refcnt)) {
> + raw_spin_lock_irqsave(&sched_core_cookies_lock, flags);
> + __sched_core_erase_cookie(cookie);
> + raw_spin_unlock_irqrestore(&sched_core_cookies_lock, flags);
> + kfree(cookie);
> + }
> +}
> +static void __sched_core_update_cookie(struct task_struct *p)
> +{
> + raw_spin_lock(&sched_core_cookies_lock);
> + /*
> + * Cookie exists, increment refcnt. If refcnt is currently 0,
> + * we're racing with a put() (refcnt decremented but cookie not
> + * yet removed from the tree). In this case, we can simply
> + * perform the removal ourselves and retry.
> + * sched_core_put_cookie() will still function correctly.
> + */
> + if (unlikely(!refcount_inc_not_zero(&match->refcnt))) {
> + __sched_core_erase_cookie(match);
> + goto retry;
> + }
refcount_dec_and_lock() avoids that complication.
next prev parent reply other threads:[~2021-02-04 14:40 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-23 1:16 [PATCH v10 0/5] Core scheduling remaining patches Joel Fernandes (Google)
2021-01-23 1:17 ` [PATCH v10 1/5] sched: migration changes for core scheduling Joel Fernandes (Google)
2021-01-23 1:17 ` [PATCH v10 2/5] sched: CGroup tagging interface " Joel Fernandes (Google)
2021-02-03 16:51 ` Peter Zijlstra
2021-02-04 13:59 ` Peter Zijlstra
2021-02-05 16:42 ` Joel Fernandes
2021-02-04 13:54 ` Peter Zijlstra
2021-02-05 3:45 ` Josh Don
2021-02-04 13:57 ` Peter Zijlstra
2021-02-04 20:52 ` Chris Hyser
2021-02-05 10:43 ` Peter Zijlstra
2021-02-05 22:19 ` Chris Hyser
2021-02-04 14:01 ` Peter Zijlstra
2021-02-05 3:55 ` Josh Don
2021-02-04 14:35 ` Peter Zijlstra [this message]
2021-02-05 4:07 ` Josh Don
2021-02-04 14:52 ` Peter Zijlstra
2021-02-05 16:37 ` Joel Fernandes
2021-02-05 11:41 ` Peter Zijlstra
2021-02-05 11:52 ` Peter Zijlstra
2021-02-06 1:15 ` Josh Don
2021-02-05 12:00 ` Peter Zijlstra
2021-02-23 4:00 ` Chris Hyser
2021-02-23 9:05 ` Peter Zijlstra
2021-02-23 19:25 ` Chris Hyser
2021-02-24 5:15 ` Josh Don
2021-02-24 13:02 ` Chris Hyser
2021-02-24 13:52 ` chris hyser
2021-02-24 15:47 ` chris hyser
2021-02-26 20:07 ` Chris Hyser
2021-03-01 21:01 ` Josh Don
2021-01-23 1:17 ` [PATCH v10 3/5] kselftest: Add tests for core-sched interface Joel Fernandes (Google)
2021-01-23 1:17 ` [PATCH v10 4/5] Documentation: Add core scheduling documentation Joel Fernandes (Google)
2021-01-23 1:17 ` [PATCH v10 5/5] sched: Debug bits Joel Fernandes (Google)
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