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Shenoy" References: <0664be8a3e805ed93eb930131951b1a84cebed66.1750268218.git.tim.c.chen@linux.intel.com> From: Shrikanth Hegde Content-Language: en-US In-Reply-To: <0664be8a3e805ed93eb930131951b1a84cebed66.1750268218.git.tim.c.chen@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 2HcFZvKoMkHp9_eXx-DeuPdfvB4_2lLr X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNzAzMDE2MCBTYWx0ZWRfXw6xiKNTT7F1G oezLRP4BRyghdQqnQlyhrXcW31idU8g78AP04wF8XLaiyI2BMP1S2OpkHRVvZoDnGNLPpAx4jwU mtdxMyNYs48gFjyrcFCALr7ef7wpE/RCaJuBquhnJITJV/G1bbkeT8HyDtDebN6d90nQg7Gw2N3 kArsfSJapA0v20egTsTk1Gn9cysESchj96yvLQ5jjtHEkBidbKqSZHBZi05zvdIAamBQxRz2gsj IcwhrKXAVpZyS0jmdYyrnGlZ/9tuWgy1piQw9YT/BUCT1Bp88bQn8lcpAIufpYi0RA3fktlvlU3 eh4GHRPU5ycx4uFVi/oUizSeHVm++jcLyuXgRWBs/g3MNpVRTXgEBF5dkHt2LJdqMN5boacgyPG 1y33A05VUnui/J4ojd5KIwKWhTdmev/hzRs+J/mKw/ZcEGkFmgnYvDz9zpQESdGYTT+IMCCy X-Authority-Analysis: v=2.4 cv=LpeSymdc c=1 sm=1 tr=0 ts=6866dde7 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=AynvelB-xCFbiBmI:21 a=IkcTkHD0fZMA:10 a=Wb1JkmetP80A:10 a=QyXUC8HyAAAA:8 a=5GvQ3MoFtB6bETeWhTMA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: RgmI-_NB8avJwRTlIqeycByMNIiQvxER X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.7,FMLib:17.12.80.40 definitions=2025-07-03_04,2025-07-02_04,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 spamscore=0 bulkscore=0 lowpriorityscore=0 adultscore=0 clxscore=1015 impostorscore=0 mlxscore=0 mlxlogscore=999 phishscore=0 suspectscore=0 malwarescore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505280000 definitions=main-2507030160 On 6/18/25 23:57, Tim Chen wrote: > Track for each run queue, the number of tasks that have a LLC preference > and how many of those tasks are running in its preferred LLC. This is > similar to nr_numa_running and nr_preferred_running for NUMA balance, > and will be used by the cache-aware load balancing in subsequent patches. > > Signed-off-by: Tim Chen > --- > kernel/sched/core.c | 12 ++++++++++++ > kernel/sched/fair.c | 42 +++++++++++++++++++++++++++++++++++++++++- > kernel/sched/sched.h | 7 +++++++ > 3 files changed, 60 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index d9c3e75f79d1..34056eb79ef2 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -498,6 +498,18 @@ void __trace_set_current_state(int state_value) > } > EXPORT_SYMBOL(__trace_set_current_state); > > +#ifdef CONFIG_SMP CONFIG_SMP is true unconditionally now. Else may need to go. > +int task_llc(const struct task_struct *p) > +{ > + return per_cpu(sd_llc_id, task_cpu(p)); > +} > +#else > +int task_llc(const struct task_struct *p) > +{ > + return 0; > +} > +#endif > + > /* > * Serialization rules: > * > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index cc804a8c7061..88ff47194faa 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -1195,6 +1195,18 @@ static inline int llc_idx(int cpu) > return per_cpu(sd_llc_idx, cpu); > } > > +static void account_llc_enqueue(struct rq *rq, struct task_struct *p) > +{ > + rq->nr_llc_running += (p->preferred_llc != -1); > + rq->nr_pref_llc_running += (p->preferred_llc == task_llc(p)); > +} > + > +static void account_llc_dequeue(struct rq *rq, struct task_struct *p) > +{ > + rq->nr_llc_running -= (p->preferred_llc != -1); > + rq->nr_pref_llc_running -= (p->preferred_llc == task_llc(p)); > +} > + > void mm_init_sched(struct mm_struct *mm, struct mm_sched __percpu *_pcpu_sched) > { > unsigned long epoch; > @@ -1298,8 +1310,11 @@ void account_mm_sched(struct rq *rq, struct task_struct *p, s64 delta_exec) > if (mm->mm_sched_cpu != -1) > mm_sched_llc = per_cpu(sd_llc_id, mm->mm_sched_cpu); > > - if (p->preferred_llc != mm_sched_llc) > + if (p->preferred_llc != mm_sched_llc) { > + account_llc_dequeue(rq, p); > p->preferred_llc = mm_sched_llc; > + account_llc_enqueue(rq, p); > + } > } > > static void task_tick_cache(struct rq *rq, struct task_struct *p) > @@ -1400,6 +1415,14 @@ void init_sched_mm(struct task_struct *p) > work->next = work; > } > > +void reset_llc_stats(struct rq *rq) > +{ > + if (rq->nr_llc_running) > + rq->nr_llc_running = 0; > + > + rq->nr_pref_llc_running = 0; > +} > + > #else > > static inline void account_mm_sched(struct rq *rq, struct task_struct *p, > @@ -1410,6 +1433,17 @@ void init_sched_mm(struct task_struct *p) { } > > static void task_tick_cache(struct rq *rq, struct task_struct *p) { } > > +static void account_llc_enqueue(struct rq *rq, struct task_struct *p) > +{ > +} > + > +static void account_llc_dequeue(struct rq *rq, struct task_struct *p) > +{ > +} > + > +void reset_llc_stats(struct rq *rq) > +{ > +} > #endif > > static inline > @@ -3939,6 +3973,7 @@ account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) > struct rq *rq = rq_of(cfs_rq); > > account_numa_enqueue(rq, task_of(se)); > + account_llc_enqueue(rq, task_of(se)); > list_add(&se->group_node, &rq->cfs_tasks); > } > #endif > @@ -3952,10 +3987,15 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) > #ifdef CONFIG_SMP > if (entity_is_task(se)) { > account_numa_dequeue(rq_of(cfs_rq), task_of(se)); > + account_llc_dequeue(rq_of(cfs_rq), task_of(se)); > list_del_init(&se->group_node); > } > #endif > cfs_rq->nr_queued--; > + > + /* safeguard? */ > + if (!parent_entity(se) && !cfs_rq->nr_queued) > + reset_llc_stats(rq_of(cfs_rq)); > } > > /* > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index 74eb2f3615aa..6c83a71ac8ca 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -1104,6 +1104,10 @@ struct rq { > unsigned int nr_preferred_running; > unsigned int numa_migrate_on; > #endif > +#ifdef CONFIG_SCHED_CACHE > + unsigned int nr_pref_llc_running; > + unsigned int nr_llc_running; > +#endif > #ifdef CONFIG_NO_HZ_COMMON > #ifdef CONFIG_SMP > unsigned long last_blocked_load_update_tick; > @@ -1948,6 +1952,9 @@ init_numa_balancing(unsigned long clone_flags, struct task_struct *p) > > #endif /* !CONFIG_NUMA_BALANCING */ > > +extern void reset_llc_stats(struct rq *rq); > +extern int task_llc(const struct task_struct *p); > + > #ifdef CONFIG_SMP > > static inline void