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McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Anna-Maria Behnsen , Ingo Molnar , Thomas Gleixner , Tejun Heo , Andrew Morton , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Chen Ridong , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Jonathan Corbet , Shuah Khan , Shuah Khan Cc: linux-kernel@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20260413-wujing-dhm-v2-0-06df21caba5d@gmail.com> <20260413-wujing-dhm-v2-1-06df21caba5d@gmail.com> From: Waiman Long In-Reply-To: <20260413-wujing-dhm-v2-1-06df21caba5d@gmail.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-Mimecast-MFC-PROC-ID: mJb2Uk6rX73RYbC7XuHIaUGnya4d1J2f7YXItzkhanI_1776108358 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: EB18220009 X-Stat-Signature: hdanu96q3ei78dcmqjihjdzddtc9ubbd X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1776108367-99548 X-HE-Meta: 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 LbwXzSUU suSkyXzRNyaeWqqEgAyguQQWwvOeIYPd7iZoevjs4DNu7kA4LzNA6eXSqIfQxGayzvpsTzqOU0Iq5/oVTHDcDwy8hjR1smiuZsJgRSNhT21SPeBlX05jGlw6gLwv4N6mu9tNzzeBSGrXXnTMuR3KYc++9gH7IU0NzT7Dn8JHxBhe6/gy8Fhza6zc/35ZESte67w7eO53/dhy8vdE+BwhJt3aj2pyutihqgLC2dyUn5wXyCmy+2voRZqVym6CaAClCTJ3+JuOWI1xbr01eADfY0qe/iNTe07KukpAZH8FZQXH1MHKX1TiN9BbSq+w99RCJl/S3grWparqJArNe2Poi2OrK/In1RMZIcQ36 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/13/26 3:43 AM, Qiliang Yuan wrote: > Most kernel noise types (TICK, TIMER, RCU, etc.) are currently aliased > to a single HK_TYPE_KERNEL_NOISE enum value. This prevents fine-grained > runtime isolation control as all masks are forced to be identical. > > Un-alias service-specific housekeeping types in enum hk_type. This > separation provides the necessary granularity for DHM subsystems to > subscribe to and maintain independent affinity masks. Usually, if we want to run a latency sensitive workload like DPDK, we try to minimize all sorts of kernel noises or interference as much as possible. Do you have a good use case where it is advantageous to remove some types of kernel noises from a given set of CPUs but not the others? Cheers, Longman > Signed-off-by: Qiliang Yuan > --- > include/linux/sched/isolation.h | 20 ++++++++------------ > kernel/sched/isolation.c | 10 +++++++++- > 2 files changed, 17 insertions(+), 13 deletions(-) > > diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h > index dc3975ff1b2e1..b9a041247565c 100644 > --- a/include/linux/sched/isolation.h > +++ b/include/linux/sched/isolation.h > @@ -17,21 +17,17 @@ enum hk_type { > /* Inverse of boot-time isolcpus=managed_irq argument */ > HK_TYPE_MANAGED_IRQ, > /* Inverse of boot-time nohz_full= or isolcpus=nohz arguments */ > - HK_TYPE_KERNEL_NOISE, > + HK_TYPE_TICK, > + HK_TYPE_TIMER, > + HK_TYPE_RCU, > + HK_TYPE_MISC, > + HK_TYPE_WQ, > + HK_TYPE_KTHREAD, > HK_TYPE_MAX, > - > - /* > - * The following housekeeping types are only set by the nohz_full > - * boot commandline option. So they can share the same value. > - */ > - HK_TYPE_TICK = HK_TYPE_KERNEL_NOISE, > - HK_TYPE_TIMER = HK_TYPE_KERNEL_NOISE, > - HK_TYPE_RCU = HK_TYPE_KERNEL_NOISE, > - HK_TYPE_MISC = HK_TYPE_KERNEL_NOISE, > - HK_TYPE_WQ = HK_TYPE_KERNEL_NOISE, > - HK_TYPE_KTHREAD = HK_TYPE_KERNEL_NOISE > }; > > +#define HK_TYPE_KERNEL_NOISE HK_TYPE_TICK > + > #ifdef CONFIG_CPU_ISOLATION > DECLARE_STATIC_KEY_FALSE(housekeeping_overridden); > extern int housekeeping_any_cpu(enum hk_type type); > diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c > index ef152d401fe20..e05ed5118e651 100644 > --- a/kernel/sched/isolation.c > +++ b/kernel/sched/isolation.c > @@ -15,9 +15,17 @@ enum hk_flags { > HK_FLAG_DOMAIN_BOOT = BIT(HK_TYPE_DOMAIN_BOOT), > HK_FLAG_DOMAIN = BIT(HK_TYPE_DOMAIN), > HK_FLAG_MANAGED_IRQ = BIT(HK_TYPE_MANAGED_IRQ), > - HK_FLAG_KERNEL_NOISE = BIT(HK_TYPE_KERNEL_NOISE), > + HK_FLAG_TICK = BIT(HK_TYPE_TICK), > + HK_FLAG_TIMER = BIT(HK_TYPE_TIMER), > + HK_FLAG_RCU = BIT(HK_TYPE_RCU), > + HK_FLAG_MISC = BIT(HK_TYPE_MISC), > + HK_FLAG_WQ = BIT(HK_TYPE_WQ), > + HK_FLAG_KTHREAD = BIT(HK_TYPE_KTHREAD), > }; > > +#define HK_FLAG_KERNEL_NOISE (HK_FLAG_TICK | HK_FLAG_TIMER | HK_FLAG_RCU | \ > + HK_FLAG_MISC | HK_FLAG_WQ | HK_FLAG_KTHREAD) > + > DEFINE_STATIC_KEY_FALSE(housekeeping_overridden); > EXPORT_SYMBOL_GPL(housekeeping_overridden); > >