From ec2444530612a886b406e2830d7f314d1a07d4bb Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Wed, 19 Jan 2022 14:39:39 -0800 Subject: psi: Fix "no previous prototype" warnings when CONFIG_CGROUPS=n When CONFIG_CGROUPS is disabled psi code generates the following warnings: kernel/sched/psi.c:1112:21: warning: no previous prototype for 'psi_trigger_create' [-Wmissing-prototypes] 1112 | struct psi_trigger *psi_trigger_create(struct psi_group *group, | ^~~~~~~~~~~~~~~~~~ kernel/sched/psi.c:1182:6: warning: no previous prototype for 'psi_trigger_destroy' [-Wmissing-prototypes] 1182 | void psi_trigger_destroy(struct psi_trigger *t) | ^~~~~~~~~~~~~~~~~~~ kernel/sched/psi.c:1249:10: warning: no previous prototype for 'psi_trigger_poll' [-Wmissing-prototypes] 1249 | __poll_t psi_trigger_poll(void **trigger_ptr, | ^~~~~~~~~~~~~~~~ Change declarations of these functions in the header to provide the prototypes even when they are unused. Fixes: 0e94682b73bf ("psi: introduce psi monitor") Reported-by: kernel test robot Signed-off-by: Suren Baghdasaryan Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220119223940.787748-2-surenb@google.com --- include/linux/psi.h | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/linux/psi.h b/include/linux/psi.h index a70ca833c6d7..827970278d62 100644 --- a/include/linux/psi.h +++ b/include/linux/psi.h @@ -25,18 +25,17 @@ void psi_memstall_enter(unsigned long *flags); void psi_memstall_leave(unsigned long *flags); int psi_show(struct seq_file *s, struct psi_group *group, enum psi_res res); - -#ifdef CONFIG_CGROUPS -int psi_cgroup_alloc(struct cgroup *cgrp); -void psi_cgroup_free(struct cgroup *cgrp); -void cgroup_move_task(struct task_struct *p, struct css_set *to); - struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf, size_t nbytes, enum psi_res res); void psi_trigger_replace(void **trigger_ptr, struct psi_trigger *t); __poll_t psi_trigger_poll(void **trigger_ptr, struct file *file, poll_table *wait); + +#ifdef CONFIG_CGROUPS +int psi_cgroup_alloc(struct cgroup *cgrp); +void psi_cgroup_free(struct cgroup *cgrp); +void cgroup_move_task(struct task_struct *p, struct css_set *to); #endif #else /* CONFIG_PSI */ -- cgit v1.2.3 From bfdf4e6208051ed7165b2e92035b4bf11f43eb63 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Thu, 27 Jan 2022 10:27:20 -0500 Subject: rseq: Remove broken uapi field layout on 32-bit little endian The rseq rseq_cs.ptr.{ptr32,padding} uapi endianness handling is entirely wrong on 32-bit little endian: a preprocessor logic mistake wrongly uses the big endian field layout on 32-bit little endian architectures. Fortunately, those ptr32 accessors were never used within the kernel, and only meant as a convenience for user-space. Remove those and replace the whole rseq_cs union by a __u64 type, as this is the only thing really needed to express the ABI. Document how 32-bit architectures are meant to interact with this field. Fixes: ec9c82e03a74 ("rseq: uapi: Declare rseq_cs field as union, update includes") Signed-off-by: Mathieu Desnoyers Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220127152720.25898-1-mathieu.desnoyers@efficios.com --- include/uapi/linux/rseq.h | 20 ++++---------------- kernel/rseq.c | 8 ++++---- 2 files changed, 8 insertions(+), 20 deletions(-) (limited to 'include') diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h index 9a402fdb60e9..77ee207623a9 100644 --- a/include/uapi/linux/rseq.h +++ b/include/uapi/linux/rseq.h @@ -105,23 +105,11 @@ struct rseq { * Read and set by the kernel. Set by user-space with single-copy * atomicity semantics. This field should only be updated by the * thread which registered this data structure. Aligned on 64-bit. + * + * 32-bit architectures should update the low order bits of the + * rseq_cs field, leaving the high order bits initialized to 0. */ - union { - __u64 ptr64; -#ifdef __LP64__ - __u64 ptr; -#else - struct { -#if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || defined(__BIG_ENDIAN) - __u32 padding; /* Initialized to zero. */ - __u32 ptr32; -#else /* LITTLE */ - __u32 ptr32; - __u32 padding; /* Initialized to zero. */ -#endif /* ENDIAN */ - } ptr; -#endif - } rseq_cs; + __u64 rseq_cs; /* * Restartable sequences flags field. diff --git a/kernel/rseq.c b/kernel/rseq.c index 6d45ac3dae7f..97ac20b4f738 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -128,10 +128,10 @@ static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs) int ret; #ifdef CONFIG_64BIT - if (get_user(ptr, &t->rseq->rseq_cs.ptr64)) + if (get_user(ptr, &t->rseq->rseq_cs)) return -EFAULT; #else - if (copy_from_user(&ptr, &t->rseq->rseq_cs.ptr64, sizeof(ptr))) + if (copy_from_user(&ptr, &t->rseq->rseq_cs, sizeof(ptr))) return -EFAULT; #endif if (!ptr) { @@ -217,9 +217,9 @@ static int clear_rseq_cs(struct task_struct *t) * Set rseq_cs to NULL. */ #ifdef CONFIG_64BIT - return put_user(0UL, &t->rseq->rseq_cs.ptr64); + return put_user(0UL, &t->rseq->rseq_cs); #else - if (clear_user(&t->rseq->rseq_cs.ptr64, sizeof(t->rseq->rseq_cs.ptr64))) + if (clear_user(&t->rseq->rseq_cs, sizeof(t->rseq->rseq_cs))) return -EFAULT; return 0; #endif -- cgit v1.2.3 From c8eaf6ac76f40f6c59fc7d056e2e08c4a57ea9c7 Mon Sep 17 00:00:00 2001 From: Zhen Ni Date: Fri, 28 Jan 2022 17:50:25 +0800 Subject: sched: move autogroup sysctls into its own file move autogroup sysctls to autogroup.c and use the new register_sysctl_init() to register the sysctl interface. Signed-off-by: Zhen Ni Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220128095025.8745-1-nizhen@uniontech.com --- include/linux/sched/sysctl.h | 4 ---- kernel/sched/autogroup.c | 23 +++++++++++++++++++++++ kernel/sched/autogroup.h | 1 + kernel/sysctl.c | 11 ----------- 4 files changed, 24 insertions(+), 15 deletions(-) (limited to 'include') diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h index c19dd5a2c05c..3f2b70f8d32c 100644 --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -45,10 +45,6 @@ extern unsigned int sysctl_sched_uclamp_util_min_rt_default; extern unsigned int sysctl_sched_cfs_bandwidth_slice; #endif -#ifdef CONFIG_SCHED_AUTOGROUP -extern unsigned int sysctl_sched_autogroup_enabled; -#endif - extern int sysctl_sched_rr_timeslice; extern int sched_rr_timeslice; diff --git a/kernel/sched/autogroup.c b/kernel/sched/autogroup.c index 8629b37d118e..31dd2593145e 100644 --- a/kernel/sched/autogroup.c +++ b/kernel/sched/autogroup.c @@ -9,6 +9,28 @@ unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1; static struct autogroup autogroup_default; static atomic_t autogroup_seq_nr; +#ifdef CONFIG_SYSCTL +static struct ctl_table sched_autogroup_sysctls[] = { + { + .procname = "sched_autogroup_enabled", + .data = &sysctl_sched_autogroup_enabled, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = SYSCTL_ONE, + }, + {} +}; + +static void __init sched_autogroup_sysctl_init(void) +{ + register_sysctl_init("kernel", sched_autogroup_sysctls); +} +#else +#define sched_autogroup_sysctl_init() do { } while (0) +#endif + void __init autogroup_init(struct task_struct *init_task) { autogroup_default.tg = &root_task_group; @@ -198,6 +220,7 @@ void sched_autogroup_exit(struct signal_struct *sig) static int __init setup_autogroup(char *str) { sysctl_sched_autogroup_enabled = 0; + sched_autogroup_sysctl_init(); return 1; } diff --git a/kernel/sched/autogroup.h b/kernel/sched/autogroup.h index b96419974a1f..90fcbfdd70c3 100644 --- a/kernel/sched/autogroup.h +++ b/kernel/sched/autogroup.h @@ -27,6 +27,7 @@ extern bool task_wants_autogroup(struct task_struct *p, struct task_group *tg); static inline struct task_group * autogroup_task_group(struct task_struct *p, struct task_group *tg) { + extern unsigned int sysctl_sched_autogroup_enabled; int enabled = READ_ONCE(sysctl_sched_autogroup_enabled); if (enabled && task_wants_autogroup(p, tg)) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 5ae443b2882e..1cb7ca68cd4e 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1750,17 +1750,6 @@ static struct ctl_table kern_table[] = { .proc_handler = sysctl_sched_uclamp_handler, }, #endif -#ifdef CONFIG_SCHED_AUTOGROUP - { - .procname = "sched_autogroup_enabled", - .data = &sysctl_sched_autogroup_enabled, - .maxlen = sizeof(unsigned int), - .mode = 0644, - .proc_handler = proc_dointvec_minmax, - .extra1 = SYSCTL_ZERO, - .extra2 = SYSCTL_ONE, - }, -#endif #ifdef CONFIG_CFS_BANDWIDTH { .procname = "sched_cfs_bandwidth_slice_us", -- cgit v1.2.3 From e496132ebedd870b67f1f6d2428f9bb9d7ae27fd Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 8 Feb 2022 09:43:34 +0000 Subject: sched/fair: Adjust the allowed NUMA imbalance when SD_NUMA spans multiple LLCs Commit 7d2b5dd0bcc4 ("sched/numa: Allow a floating imbalance between NUMA nodes") allowed an imbalance between NUMA nodes such that communicating tasks would not be pulled apart by the load balancer. This works fine when there is a 1:1 relationship between LLC and node but can be suboptimal for multiple LLCs if independent tasks prematurely use CPUs sharing cache. Zen* has multiple LLCs per node with local memory channels and due to the allowed imbalance, it's far harder to tune some workloads to run optimally than it is on hardware that has 1 LLC per node. This patch allows an imbalance to exist up to the point where LLCs should be balanced between nodes. On a Zen3 machine running STREAM parallelised with OMP to have on instance per LLC the results and without binding, the results are 5.17.0-rc0 5.17.0-rc0 vanilla sched-numaimb-v6 MB/sec copy-16 162596.94 ( 0.00%) 580559.74 ( 257.05%) MB/sec scale-16 136901.28 ( 0.00%) 374450.52 ( 173.52%) MB/sec add-16 157300.70 ( 0.00%) 564113.76 ( 258.62%) MB/sec triad-16 151446.88 ( 0.00%) 564304.24 ( 272.61%) STREAM can use directives to force the spread if the OpenMP is new enough but that doesn't help if an application uses threads and it's not known in advance how many threads will be created. Coremark is a CPU and cache intensive benchmark parallelised with threads. When running with 1 thread per core, the vanilla kernel allows threads to contend on cache. With the patch; 5.17.0-rc0 5.17.0-rc0 vanilla sched-numaimb-v5 Min Score-16 368239.36 ( 0.00%) 389816.06 ( 5.86%) Hmean Score-16 388607.33 ( 0.00%) 427877.08 * 10.11%* Max Score-16 408945.69 ( 0.00%) 481022.17 ( 17.62%) Stddev Score-16 15247.04 ( 0.00%) 24966.82 ( -63.75%) CoeffVar Score-16 3.92 ( 0.00%) 5.82 ( -48.48%) It can also make a big difference for semi-realistic workloads like specjbb which can execute arbitrary numbers of threads without advance knowledge of how they should be placed. Even in cases where the average performance is neutral, the results are more stable. 5.17.0-rc0 5.17.0-rc0 vanilla sched-numaimb-v6 Hmean tput-1 71631.55 ( 0.00%) 73065.57 ( 2.00%) Hmean tput-8 582758.78 ( 0.00%) 556777.23 ( -4.46%) Hmean tput-16 1020372.75 ( 0.00%) 1009995.26 ( -1.02%) Hmean tput-24 1416430.67 ( 0.00%) 1398700.11 ( -1.25%) Hmean tput-32 1687702.72 ( 0.00%) 1671357.04 ( -0.97%) Hmean tput-40 1798094.90 ( 0.00%) 2015616.46 * 12.10%* Hmean tput-48 1972731.77 ( 0.00%) 2333233.72 ( 18.27%) Hmean tput-56 2386872.38 ( 0.00%) 2759483.38 ( 15.61%) Hmean tput-64 2909475.33 ( 0.00%) 2925074.69 ( 0.54%) Hmean tput-72 2585071.36 ( 0.00%) 2962443.97 ( 14.60%) Hmean tput-80 2994387.24 ( 0.00%) 3015980.59 ( 0.72%) Hmean tput-88 3061408.57 ( 0.00%) 3010296.16 ( -1.67%) Hmean tput-96 3052394.82 ( 0.00%) 2784743.41 ( -8.77%) Hmean tput-104 2997814.76 ( 0.00%) 2758184.50 ( -7.99%) Hmean tput-112 2955353.29 ( 0.00%) 2859705.09 ( -3.24%) Hmean tput-120 2889770.71 ( 0.00%) 2764478.46 ( -4.34%) Hmean tput-128 2871713.84 ( 0.00%) 2750136.73 ( -4.23%) Stddev tput-1 5325.93 ( 0.00%) 2002.53 ( 62.40%) Stddev tput-8 6630.54 ( 0.00%) 10905.00 ( -64.47%) Stddev tput-16 25608.58 ( 0.00%) 6851.16 ( 73.25%) Stddev tput-24 12117.69 ( 0.00%) 4227.79 ( 65.11%) Stddev tput-32 27577.16 ( 0.00%) 8761.05 ( 68.23%) Stddev tput-40 59505.86 ( 0.00%) 2048.49 ( 96.56%) Stddev tput-48 168330.30 ( 0.00%) 93058.08 ( 44.72%) Stddev tput-56 219540.39 ( 0.00%) 30687.02 ( 86.02%) Stddev tput-64 121750.35 ( 0.00%) 9617.36 ( 92.10%) Stddev tput-72 223387.05 ( 0.00%) 34081.13 ( 84.74%) Stddev tput-80 128198.46 ( 0.00%) 22565.19 ( 82.40%) Stddev tput-88 136665.36 ( 0.00%) 27905.97 ( 79.58%) Stddev tput-96 111925.81 ( 0.00%) 99615.79 ( 11.00%) Stddev tput-104 146455.96 ( 0.00%) 28861.98 ( 80.29%) Stddev tput-112 88740.49 ( 0.00%) 58288.23 ( 34.32%) Stddev tput-120 186384.86 ( 0.00%) 45812.03 ( 75.42%) Stddev tput-128 78761.09 ( 0.00%) 57418.48 ( 27.10%) Similarly, for embarassingly parallel problems like NPB-ep, there are improvements due to better spreading across LLC when the machine is not fully utilised. vanilla sched-numaimb-v6 Min ep.D 31.79 ( 0.00%) 26.11 ( 17.87%) Amean ep.D 31.86 ( 0.00%) 26.17 * 17.86%* Stddev ep.D 0.07 ( 0.00%) 0.05 ( 24.41%) CoeffVar ep.D 0.22 ( 0.00%) 0.20 ( 7.97%) Max ep.D 31.93 ( 0.00%) 26.21 ( 17.91%) Signed-off-by: Mel Gorman Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Gautham R. Shenoy Tested-by: K Prateek Nayak Link: https://lore.kernel.org/r/20220208094334.16379-3-mgorman@techsingularity.net --- include/linux/sched/topology.h | 1 + kernel/sched/fair.c | 22 ++++++++++-------- kernel/sched/topology.c | 53 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 66 insertions(+), 10 deletions(-) (limited to 'include') diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h index 8054641c0a7b..56cffe42abbc 100644 --- a/include/linux/sched/topology.h +++ b/include/linux/sched/topology.h @@ -93,6 +93,7 @@ struct sched_domain { unsigned int busy_factor; /* less balancing by factor if busy */ unsigned int imbalance_pct; /* No balance until over watermark */ unsigned int cache_nice_tries; /* Leave cache hot tasks for # tries */ + unsigned int imb_numa_nr; /* Nr running tasks that allows a NUMA imbalance */ int nohz_idle; /* NOHZ IDLE status */ int flags; /* See SD_* */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ea710168ae91..5c4bfffe8c2c 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1489,6 +1489,7 @@ struct task_numa_env { int src_cpu, src_nid; int dst_cpu, dst_nid; + int imb_numa_nr; struct numa_stats src_stats, dst_stats; @@ -1503,7 +1504,7 @@ struct task_numa_env { static unsigned long cpu_load(struct rq *rq); static unsigned long cpu_runnable(struct rq *rq); static inline long adjust_numa_imbalance(int imbalance, - int dst_running, int dst_weight); + int dst_running, int imb_numa_nr); static inline enum numa_type numa_classify(unsigned int imbalance_pct, @@ -1884,7 +1885,7 @@ static void task_numa_find_cpu(struct task_numa_env *env, dst_running = env->dst_stats.nr_running + 1; imbalance = max(0, dst_running - src_running); imbalance = adjust_numa_imbalance(imbalance, dst_running, - env->dst_stats.weight); + env->imb_numa_nr); /* Use idle CPU if there is no imbalance */ if (!imbalance) { @@ -1949,8 +1950,10 @@ static int task_numa_migrate(struct task_struct *p) */ rcu_read_lock(); sd = rcu_dereference(per_cpu(sd_numa, env.src_cpu)); - if (sd) + if (sd) { env.imbalance_pct = 100 + (sd->imbalance_pct - 100) / 2; + env.imb_numa_nr = sd->imb_numa_nr; + } rcu_read_unlock(); /* @@ -9005,10 +9008,9 @@ static bool update_pick_idlest(struct sched_group *idlest, * This is an approximation as the number of running tasks may not be * related to the number of busy CPUs due to sched_setaffinity. */ -static inline bool -allow_numa_imbalance(unsigned int running, unsigned int weight) +static inline bool allow_numa_imbalance(int running, int imb_numa_nr) { - return (running < (weight >> 2)); + return running <= imb_numa_nr; } /* @@ -9148,7 +9150,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) * allowed. If there is a real need of migration, * periodic load balance will take care of it. */ - if (allow_numa_imbalance(local_sgs.sum_nr_running + 1, local_sgs.group_weight)) + if (allow_numa_imbalance(local_sgs.sum_nr_running + 1, sd->imb_numa_nr)) return NULL; } @@ -9240,9 +9242,9 @@ next_group: #define NUMA_IMBALANCE_MIN 2 static inline long adjust_numa_imbalance(int imbalance, - int dst_running, int dst_weight) + int dst_running, int imb_numa_nr) { - if (!allow_numa_imbalance(dst_running, dst_weight)) + if (!allow_numa_imbalance(dst_running, imb_numa_nr)) return imbalance; /* @@ -9354,7 +9356,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s /* Consider allowing a small imbalance between NUMA groups */ if (env->sd->flags & SD_NUMA) { env->imbalance = adjust_numa_imbalance(env->imbalance, - local->sum_nr_running + 1, local->group_weight); + local->sum_nr_running + 1, env->sd->imb_numa_nr); } return; diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index d201a7052a29..e6cd55951304 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -2242,6 +2242,59 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att } } + /* + * Calculate an allowed NUMA imbalance such that LLCs do not get + * imbalanced. + */ + for_each_cpu(i, cpu_map) { + unsigned int imb = 0; + unsigned int imb_span = 1; + + for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { + struct sched_domain *child = sd->child; + + if (!(sd->flags & SD_SHARE_PKG_RESOURCES) && child && + (child->flags & SD_SHARE_PKG_RESOURCES)) { + struct sched_domain *top, *top_p; + unsigned int nr_llcs; + + /* + * For a single LLC per node, allow an + * imbalance up to 25% of the node. This is an + * arbitrary cutoff based on SMT-2 to balance + * between memory bandwidth and avoiding + * premature sharing of HT resources and SMT-4 + * or SMT-8 *may* benefit from a different + * cutoff. + * + * For multiple LLCs, allow an imbalance + * until multiple tasks would share an LLC + * on one node while LLCs on another node + * remain idle. + */ + nr_llcs = sd->span_weight / child->span_weight; + if (nr_llcs == 1) + imb = sd->span_weight >> 2; + else + imb = nr_llcs; + sd->imb_numa_nr = imb; + + /* Set span based on the first NUMA domain. */ + top = sd; + top_p = top->parent; + while (top_p && !(top_p->flags & SD_NUMA)) { + top = top->parent; + top_p = top->parent; + } + imb_span = top_p ? top_p->span_weight : sd->span_weight; + } else { + int factor = max(1U, (sd->span_weight / imb_span)); + + sd->imb_numa_nr = imb * factor; + } + } + } + /* Calculate CPU capacity for physical packages and nodes */ for (i = nr_cpumask_bits-1; i >= 0; i--) { if (!cpumask_test_cpu(i, cpu_map)) -- cgit v1.2.3 From e6df4ead85d9da1b07dd40bd4c6d2182f3e210c4 Mon Sep 17 00:00:00 2001 From: Zhaoyang Huang Date: Tue, 25 Jan 2022 14:56:58 +0800 Subject: psi: fix possible trigger missing in the window When a new threshold breaching stall happens after a psi event was generated and within the window duration, the new event is not generated because the events are rate-limited to one per window. If after that no new stall is recorded then the event will not be generated even after rate-limiting duration has passed. This is happening because with no new stall, window_update will not be called even though threshold was previously breached. To fix this, record threshold breaching occurrence and generate the event once window duration is passed. Suggested-by: Suren Baghdasaryan Signed-off-by: Zhaoyang Huang Signed-off-by: Peter Zijlstra (Intel) Acked-by: Johannes Weiner Acked-by: Suren Baghdasaryan Link: https://lore.kernel.org/r/1643093818-19835-1-git-send-email-huangzhaoyang@gmail.com --- include/linux/psi_types.h | 3 +++ kernel/sched/psi.c | 46 ++++++++++++++++++++++++++++++---------------- 2 files changed, 33 insertions(+), 16 deletions(-) (limited to 'include') diff --git a/include/linux/psi_types.h b/include/linux/psi_types.h index 516c0fe836fd..dc3ec5e4b9ee 100644 --- a/include/linux/psi_types.h +++ b/include/linux/psi_types.h @@ -144,6 +144,9 @@ struct psi_trigger { /* Refcounting to prevent premature destruction */ struct kref refcount; + + /* Deferred event(s) from previous ratelimit window */ + bool pending_event; }; struct psi_group { diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index cfe76f704d8a..e9d623cb8d1b 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -523,7 +523,7 @@ static void init_triggers(struct psi_group *group, u64 now) static u64 update_triggers(struct psi_group *group, u64 now) { struct psi_trigger *t; - bool new_stall = false; + bool update_total = false; u64 *total = group->total[PSI_POLL]; /* @@ -532,24 +532,35 @@ static u64 update_triggers(struct psi_group *group, u64 now) */ list_for_each_entry(t, &group->triggers, node) { u64 growth; + bool new_stall; - /* Check for stall activity */ - if (group->polling_total[t->state] == total[t->state]) - continue; + new_stall = group->polling_total[t->state] != total[t->state]; + /* Check for stall activity or a previous threshold breach */ + if (!new_stall && !t->pending_event) + continue; /* - * Multiple triggers might be looking at the same state, - * remember to update group->polling_total[] once we've - * been through all of them. Also remember to extend the - * polling time if we see new stall activity. + * Check for new stall activity, as well as deferred + * events that occurred in the last window after the + * trigger had already fired (we want to ratelimit + * events without dropping any). */ - new_stall = true; - - /* Calculate growth since last update */ - growth = window_update(&t->win, now, total[t->state]); - if (growth < t->threshold) - continue; - + if (new_stall) { + /* + * Multiple triggers might be looking at the same state, + * remember to update group->polling_total[] once we've + * been through all of them. Also remember to extend the + * polling time if we see new stall activity. + */ + update_total = true; + + /* Calculate growth since last update */ + growth = window_update(&t->win, now, total[t->state]); + if (growth < t->threshold) + continue; + + t->pending_event = true; + } /* Limit event signaling to once per window */ if (now < t->last_event_time + t->win.size) continue; @@ -558,9 +569,11 @@ static u64 update_triggers(struct psi_group *group, u64 now) if (cmpxchg(&t->event, 0, 1) == 0) wake_up_interruptible(&t->event_wait); t->last_event_time = now; + /* Reset threshold breach flag once event got generated */ + t->pending_event = false; } - if (new_stall) + if (update_total) memcpy(group->polling_total, total, sizeof(group->polling_total)); @@ -1125,6 +1138,7 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, t->last_event_time = 0; init_waitqueue_head(&t->event_wait); kref_init(&t->refcount); + t->pending_event = false; mutex_lock(&group->trigger_lock); -- cgit v1.2.3 From 04d4e665a60902cf36e7ad39af1179cb5df542ad Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 7 Feb 2022 16:59:06 +0100 Subject: sched/isolation: Use single feature type while referring to housekeeping cpumask Refer to housekeeping APIs using single feature types instead of flags. This prevents from passing multiple isolation features at once to housekeeping interfaces, which soon won't be possible anymore as each isolation features will have their own cpumask. Signed-off-by: Frederic Weisbecker Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Juri Lelli Reviewed-by: Phil Auld Link: https://lore.kernel.org/r/20220207155910.527133-5-frederic@kernel.org --- arch/x86/kernel/cpu/aperfmperf.c | 6 +++--- arch/x86/kvm/x86.c | 2 +- drivers/base/cpu.c | 2 +- drivers/pci/pci-driver.c | 4 ++-- include/linux/sched/isolation.h | 43 ++++++++++++++++++++-------------------- kernel/cgroup/cpuset.c | 6 +++--- kernel/cpu.c | 4 ++-- kernel/irq/cpuhotplug.c | 4 ++-- kernel/irq/manage.c | 4 ++-- kernel/kthread.c | 4 ++-- kernel/rcu/tasks.h | 2 +- kernel/rcu/tree_plugin.h | 6 +++--- kernel/sched/core.c | 12 +++++------ kernel/sched/fair.c | 10 +++++----- kernel/sched/isolation.c | 32 ++++++++++++++++++++---------- kernel/sched/topology.c | 8 ++++---- kernel/watchdog.c | 2 +- kernel/workqueue.c | 4 ++-- net/core/net-sysfs.c | 4 ++-- 19 files changed, 86 insertions(+), 73 deletions(-) (limited to 'include') diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c index 22911deacb6e..9ca008f9e9b1 100644 --- a/arch/x86/kernel/cpu/aperfmperf.c +++ b/arch/x86/kernel/cpu/aperfmperf.c @@ -91,7 +91,7 @@ unsigned int aperfmperf_get_khz(int cpu) if (!boot_cpu_has(X86_FEATURE_APERFMPERF)) return 0; - if (!housekeeping_cpu(cpu, HK_FLAG_MISC)) + if (!housekeeping_cpu(cpu, HK_TYPE_MISC)) return 0; if (rcu_is_idle_cpu(cpu)) @@ -114,7 +114,7 @@ void arch_freq_prepare_all(void) return; for_each_online_cpu(cpu) { - if (!housekeeping_cpu(cpu, HK_FLAG_MISC)) + if (!housekeeping_cpu(cpu, HK_TYPE_MISC)) continue; if (rcu_is_idle_cpu(cpu)) continue; /* Idle CPUs are completely uninteresting. */ @@ -136,7 +136,7 @@ unsigned int arch_freq_get_on_cpu(int cpu) if (!boot_cpu_has(X86_FEATURE_APERFMPERF)) return 0; - if (!housekeeping_cpu(cpu, HK_FLAG_MISC)) + if (!housekeeping_cpu(cpu, HK_TYPE_MISC)) return 0; if (aperfmperf_snapshot_cpu(cpu, ktime_get(), true)) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9e43d756312f..02a7ac1b6bb2 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8769,7 +8769,7 @@ int kvm_arch_init(void *opaque) } if (pi_inject_timer == -1) - pi_inject_timer = housekeeping_enabled(HK_FLAG_TIMER); + pi_inject_timer = housekeeping_enabled(HK_TYPE_TIMER); #ifdef CONFIG_X86_64 pvclock_gtod_register_notifier(&pvclock_gtod_notifier); diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 5fc258073bc7..2ef23fce0860 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -275,7 +275,7 @@ static ssize_t print_cpus_isolated(struct device *dev, return -ENOMEM; cpumask_andnot(isolated, cpu_possible_mask, - housekeeping_cpumask(HK_FLAG_DOMAIN)); + housekeeping_cpumask(HK_TYPE_DOMAIN)); len = sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(isolated)); free_cpumask_var(isolated); diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c index 4a5792c82d08..f61c40a47891 100644 --- a/drivers/pci/pci-driver.c +++ b/drivers/pci/pci-driver.c @@ -377,8 +377,8 @@ static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev, goto out; } cpumask_and(wq_domain_mask, - housekeeping_cpumask(HK_FLAG_WQ), - housekeeping_cpumask(HK_FLAG_DOMAIN)); + housekeeping_cpumask(HK_TYPE_WQ), + housekeeping_cpumask(HK_TYPE_DOMAIN)); cpu = cpumask_any_and(cpumask_of_node(node), wq_domain_mask); diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h index cc9f393e2a70..8c15abd67aed 100644 --- a/include/linux/sched/isolation.h +++ b/include/linux/sched/isolation.h @@ -5,54 +5,55 @@ #include #include -enum hk_flags { - HK_FLAG_TIMER = 1, - HK_FLAG_RCU = (1 << 1), - HK_FLAG_MISC = (1 << 2), - HK_FLAG_SCHED = (1 << 3), - HK_FLAG_TICK = (1 << 4), - HK_FLAG_DOMAIN = (1 << 5), - HK_FLAG_WQ = (1 << 6), - HK_FLAG_MANAGED_IRQ = (1 << 7), - HK_FLAG_KTHREAD = (1 << 8), +enum hk_type { + HK_TYPE_TIMER, + HK_TYPE_RCU, + HK_TYPE_MISC, + HK_TYPE_SCHED, + HK_TYPE_TICK, + HK_TYPE_DOMAIN, + HK_TYPE_WQ, + HK_TYPE_MANAGED_IRQ, + HK_TYPE_KTHREAD, + HK_TYPE_MAX }; #ifdef CONFIG_CPU_ISOLATION DECLARE_STATIC_KEY_FALSE(housekeeping_overridden); -extern int housekeeping_any_cpu(enum hk_flags flags); -extern const struct cpumask *housekeeping_cpumask(enum hk_flags flags); -extern bool housekeeping_enabled(enum hk_flags flags); -extern void housekeeping_affine(struct task_struct *t, enum hk_flags flags); -extern bool housekeeping_test_cpu(int cpu, enum hk_flags flags); +extern int housekeeping_any_cpu(enum hk_type type); +extern const struct cpumask *housekeeping_cpumask(enum hk_type type); +extern bool housekeeping_enabled(enum hk_type type); +extern void housekeeping_affine(struct task_struct *t, enum hk_type type); +extern bool housekeeping_test_cpu(int cpu, enum hk_type type); extern void __init housekeeping_init(void); #else -static inline int housekeeping_any_cpu(enum hk_flags flags) +static inline int housekeeping_any_cpu(enum hk_type type) { return smp_processor_id(); } -static inline const struct cpumask *housekeeping_cpumask(enum hk_flags flags) +static inline const struct cpumask *housekeeping_cpumask(enum hk_type type) { return cpu_possible_mask; } -static inline bool housekeeping_enabled(enum hk_flags flags) +static inline bool housekeeping_enabled(enum hk_type type) { return false; } static inline void housekeeping_affine(struct task_struct *t, - enum hk_flags flags) { } + enum hk_type type) { } static inline void housekeeping_init(void) { } #endif /* CONFIG_CPU_ISOLATION */ -static inline bool housekeeping_cpu(int cpu, enum hk_flags flags) +static inline bool housekeeping_cpu(int cpu, enum hk_type type) { #ifdef CONFIG_CPU_ISOLATION if (static_branch_unlikely(&housekeeping_overridden)) - return housekeeping_test_cpu(cpu, flags); + return housekeeping_test_cpu(cpu, type); #endif return true; } diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index dc653ab26e50..e4e18a2cb404 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -803,7 +803,7 @@ static int generate_sched_domains(cpumask_var_t **domains, update_domain_attr_tree(dattr, &top_cpuset); } cpumask_and(doms[0], top_cpuset.effective_cpus, - housekeeping_cpumask(HK_FLAG_DOMAIN)); + housekeeping_cpumask(HK_TYPE_DOMAIN)); goto done; } @@ -833,7 +833,7 @@ static int generate_sched_domains(cpumask_var_t **domains, if (!cpumask_empty(cp->cpus_allowed) && !(is_sched_load_balance(cp) && cpumask_intersects(cp->cpus_allowed, - housekeeping_cpumask(HK_FLAG_DOMAIN)))) + housekeeping_cpumask(HK_TYPE_DOMAIN)))) continue; if (root_load_balance && @@ -922,7 +922,7 @@ restart: if (apn == b->pn) { cpumask_or(dp, dp, b->effective_cpus); - cpumask_and(dp, dp, housekeeping_cpumask(HK_FLAG_DOMAIN)); + cpumask_and(dp, dp, housekeeping_cpumask(HK_TYPE_DOMAIN)); if (dattr) update_domain_attr_tree(dattr + nslot, b); diff --git a/kernel/cpu.c b/kernel/cpu.c index 407a2568f35e..f39eb0b52dfe 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1488,8 +1488,8 @@ int freeze_secondary_cpus(int primary) cpu_maps_update_begin(); if (primary == -1) { primary = cpumask_first(cpu_online_mask); - if (!housekeeping_cpu(primary, HK_FLAG_TIMER)) - primary = housekeeping_any_cpu(HK_FLAG_TIMER); + if (!housekeeping_cpu(primary, HK_TYPE_TIMER)) + primary = housekeeping_any_cpu(HK_TYPE_TIMER); } else { if (!cpu_online(primary)) primary = cpumask_first(cpu_online_mask); diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c index 39a41c56ad4f..1ed2b1739363 100644 --- a/kernel/irq/cpuhotplug.c +++ b/kernel/irq/cpuhotplug.c @@ -176,10 +176,10 @@ static bool hk_should_isolate(struct irq_data *data, unsigned int cpu) { const struct cpumask *hk_mask; - if (!housekeeping_enabled(HK_FLAG_MANAGED_IRQ)) + if (!housekeeping_enabled(HK_TYPE_MANAGED_IRQ)) return false; - hk_mask = housekeeping_cpumask(HK_FLAG_MANAGED_IRQ); + hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ); if (cpumask_subset(irq_data_get_effective_affinity_mask(data), hk_mask)) return false; diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index f23ffd30385b..c03f71d5ec10 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -247,13 +247,13 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask, * online. */ if (irqd_affinity_is_managed(data) && - housekeeping_enabled(HK_FLAG_MANAGED_IRQ)) { + housekeeping_enabled(HK_TYPE_MANAGED_IRQ)) { const struct cpumask *hk_mask, *prog_mask; static DEFINE_RAW_SPINLOCK(tmp_mask_lock); static struct cpumask tmp_mask; - hk_mask = housekeeping_cpumask(HK_FLAG_MANAGED_IRQ); + hk_mask = housekeeping_cpumask(HK_TYPE_MANAGED_IRQ); raw_spin_lock(&tmp_mask_lock); cpumask_and(&tmp_mask, mask, hk_mask); diff --git a/kernel/kthread.c b/kernel/kthread.c index 38c6dd822da8..d100d5a15b38 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -356,7 +356,7 @@ static int kthread(void *_create) * back to default in case they have been changed. */ sched_setscheduler_nocheck(current, SCHED_NORMAL, ¶m); - set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_KTHREAD)); + set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_TYPE_KTHREAD)); /* OK, tell user we're spawned, wait for stop or wakeup */ __set_current_state(TASK_UNINTERRUPTIBLE); @@ -722,7 +722,7 @@ int kthreadd(void *unused) /* Setup a clean context for our children to inherit. */ set_task_comm(tsk, "kthreadd"); ignore_signals(tsk); - set_cpus_allowed_ptr(tsk, housekeeping_cpumask(HK_FLAG_KTHREAD)); + set_cpus_allowed_ptr(tsk, housekeeping_cpumask(HK_TYPE_KTHREAD)); set_mems_allowed(node_states[N_MEMORY]); current->flags |= PF_NOFREEZE; diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 84f1d91604cc..6093b200dff7 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -492,7 +492,7 @@ static int __noreturn rcu_tasks_kthread(void *arg) struct rcu_tasks *rtp = arg; /* Run on housekeeping CPUs by default. Sysadm can move if desired. */ - housekeeping_affine(current, HK_FLAG_RCU); + housekeeping_affine(current, HK_TYPE_RCU); WRITE_ONCE(rtp->kthread_ptr, current); // Let GPs start! /* diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index c5b45c2f68a1..65f25a32f6d7 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1214,9 +1214,9 @@ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu) if ((mask & leaf_node_cpu_bit(rnp, cpu)) && cpu != outgoingcpu) cpumask_set_cpu(cpu, cm); - cpumask_and(cm, cm, housekeeping_cpumask(HK_FLAG_RCU)); + cpumask_and(cm, cm, housekeeping_cpumask(HK_TYPE_RCU)); if (cpumask_weight(cm) == 0) - cpumask_copy(cm, housekeeping_cpumask(HK_FLAG_RCU)); + cpumask_copy(cm, housekeeping_cpumask(HK_TYPE_RCU)); set_cpus_allowed_ptr(t, cm); free_cpumask_var(cm); } @@ -1291,7 +1291,7 @@ static void rcu_bind_gp_kthread(void) { if (!tick_nohz_full_enabled()) return; - housekeeping_affine(current, HK_FLAG_RCU); + housekeeping_affine(current, HK_TYPE_RCU); } /* Record the current task on dyntick-idle entry. */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index b2226922206d..1e08b02e0cd5 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1025,13 +1025,13 @@ int get_nohz_timer_target(void) struct sched_domain *sd; const struct cpumask *hk_mask; - if (housekeeping_cpu(cpu, HK_FLAG_TIMER)) { + if (housekeeping_cpu(cpu, HK_TYPE_TIMER)) { if (!idle_cpu(cpu)) return cpu; default_cpu = cpu; } - hk_mask = housekeeping_cpumask(HK_FLAG_TIMER); + hk_mask = housekeeping_cpumask(HK_TYPE_TIMER); rcu_read_lock(); for_each_domain(cpu, sd) { @@ -1047,7 +1047,7 @@ int get_nohz_timer_target(void) } if (default_cpu == -1) - default_cpu = housekeeping_any_cpu(HK_FLAG_TIMER); + default_cpu = housekeeping_any_cpu(HK_TYPE_TIMER); cpu = default_cpu; unlock: rcu_read_unlock(); @@ -5371,7 +5371,7 @@ static void sched_tick_start(int cpu) int os; struct tick_work *twork; - if (housekeeping_cpu(cpu, HK_FLAG_TICK)) + if (housekeeping_cpu(cpu, HK_TYPE_TICK)) return; WARN_ON_ONCE(!tick_work_cpu); @@ -5392,7 +5392,7 @@ static void sched_tick_stop(int cpu) struct tick_work *twork; int os; - if (housekeeping_cpu(cpu, HK_FLAG_TICK)) + if (housekeeping_cpu(cpu, HK_TYPE_TICK)) return; WARN_ON_ONCE(!tick_work_cpu); @@ -9251,7 +9251,7 @@ void __init sched_init_smp(void) mutex_unlock(&sched_domains_mutex); /* Move init over to a non-isolated CPU */ - if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0) + if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_TYPE_DOMAIN)) < 0) BUG(); current->flags &= ~PF_NO_SETAFFINITY; sched_init_granularity(); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 11a72e1b3b2c..dcbd3110c687 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10337,7 +10337,7 @@ static inline int on_null_domain(struct rq *rq) * - When one of the busy CPUs notice that there may be an idle rebalancing * needed, they will kick the idle load balancer, which then does idle * load balancing for all the idle CPUs. - * - HK_FLAG_MISC CPUs are used for this task, because HK_FLAG_SCHED not set + * - HK_TYPE_MISC CPUs are used for this task, because HK_TYPE_SCHED not set * anywhere yet. */ @@ -10346,7 +10346,7 @@ static inline int find_new_ilb(void) int ilb; const struct cpumask *hk_mask; - hk_mask = housekeeping_cpumask(HK_FLAG_MISC); + hk_mask = housekeeping_cpumask(HK_TYPE_MISC); for_each_cpu_and(ilb, nohz.idle_cpus_mask, hk_mask) { @@ -10362,7 +10362,7 @@ static inline int find_new_ilb(void) /* * Kick a CPU to do the nohz balancing, if it is time for it. We pick any - * idle CPU in the HK_FLAG_MISC housekeeping set (if there is one). + * idle CPU in the HK_TYPE_MISC housekeeping set (if there is one). */ static void kick_ilb(unsigned int flags) { @@ -10575,7 +10575,7 @@ void nohz_balance_enter_idle(int cpu) return; /* Spare idle load balancing on CPUs that don't want to be disturbed: */ - if (!housekeeping_cpu(cpu, HK_FLAG_SCHED)) + if (!housekeeping_cpu(cpu, HK_TYPE_SCHED)) return; /* @@ -10791,7 +10791,7 @@ static void nohz_newidle_balance(struct rq *this_rq) * This CPU doesn't want to be disturbed by scheduler * housekeeping */ - if (!housekeeping_cpu(this_cpu, HK_FLAG_SCHED)) + if (!housekeeping_cpu(this_cpu, HK_TYPE_SCHED)) return; /* Will wake up very soon. No time for doing anything else*/ diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index 7f06eaf12818..a735d9e229dd 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -9,23 +9,35 @@ */ #include "sched.h" +enum hk_flags { + HK_FLAG_TIMER = BIT(HK_TYPE_TIMER), + HK_FLAG_RCU = BIT(HK_TYPE_RCU), + HK_FLAG_MISC = BIT(HK_TYPE_MISC), + HK_FLAG_SCHED = BIT(HK_TYPE_SCHED), + HK_FLAG_TICK = BIT(HK_TYPE_TICK), + HK_FLAG_DOMAIN = BIT(HK_TYPE_DOMAIN), + HK_FLAG_WQ = BIT(HK_TYPE_WQ), + HK_FLAG_MANAGED_IRQ = BIT(HK_TYPE_MANAGED_IRQ), + HK_FLAG_KTHREAD = BIT(HK_TYPE_KTHREAD), +}; + DEFINE_STATIC_KEY_FALSE(housekeeping_overridden); EXPORT_SYMBOL_GPL(housekeeping_overridden); static cpumask_var_t housekeeping_mask; static unsigned int housekeeping_flags; -bool housekeeping_enabled(enum hk_flags flags) +bool housekeeping_enabled(enum hk_type type) { - return !!(housekeeping_flags & flags); + return !!(housekeeping_flags & BIT(type)); } EXPORT_SYMBOL_GPL(housekeeping_enabled); -int housekeeping_any_cpu(enum hk_flags flags) +int housekeeping_any_cpu(enum hk_type type) { int cpu; if (static_branch_unlikely(&housekeeping_overridden)) { - if (housekeeping_flags & flags) { + if (housekeeping_flags & BIT(type)) { cpu = sched_numa_find_closest(housekeeping_mask, smp_processor_id()); if (cpu < nr_cpu_ids) return cpu; @@ -37,27 +49,27 @@ int housekeeping_any_cpu(enum hk_flags flags) } EXPORT_SYMBOL_GPL(housekeeping_any_cpu); -const struct cpumask *housekeeping_cpumask(enum hk_flags flags) +const struct cpumask *housekeeping_cpumask(enum hk_type type) { if (static_branch_unlikely(&housekeeping_overridden)) - if (housekeeping_flags & flags) + if (housekeeping_flags & BIT(type)) return housekeeping_mask; return cpu_possible_mask; } EXPORT_SYMBOL_GPL(housekeeping_cpumask); -void housekeeping_affine(struct task_struct *t, enum hk_flags flags) +void housekeeping_affine(struct task_struct *t, enum hk_type type) { if (static_branch_unlikely(&housekeeping_overridden)) - if (housekeeping_flags & flags) + if (housekeeping_flags & BIT(type)) set_cpus_allowed_ptr(t, housekeeping_mask); } EXPORT_SYMBOL_GPL(housekeeping_affine); -bool housekeeping_test_cpu(int cpu, enum hk_flags flags) +bool housekeeping_test_cpu(int cpu, enum hk_type type) { if (static_branch_unlikely(&housekeeping_overridden)) - if (housekeeping_flags & flags) + if (housekeeping_flags & BIT(type)) return cpumask_test_cpu(cpu, housekeeping_mask); return true; } diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 5db322c9cb3f..32841c6741d1 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -1366,7 +1366,7 @@ static void asym_cpu_capacity_scan(void) list_for_each_entry(entry, &asym_cap_list, link) cpumask_clear(cpu_capacity_span(entry)); - for_each_cpu_and(cpu, cpu_possible_mask, housekeeping_cpumask(HK_FLAG_DOMAIN)) + for_each_cpu_and(cpu, cpu_possible_mask, housekeeping_cpumask(HK_TYPE_DOMAIN)) asym_cpu_capacity_update_data(cpu); list_for_each_entry_safe(entry, next, &asym_cap_list, link) { @@ -2440,7 +2440,7 @@ int sched_init_domains(const struct cpumask *cpu_map) doms_cur = alloc_sched_domains(ndoms_cur); if (!doms_cur) doms_cur = &fallback_doms; - cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_FLAG_DOMAIN)); + cpumask_and(doms_cur[0], cpu_map, housekeeping_cpumask(HK_TYPE_DOMAIN)); err = build_sched_domains(doms_cur[0], NULL); return err; @@ -2529,7 +2529,7 @@ void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[], if (doms_new) { n = 1; cpumask_and(doms_new[0], cpu_active_mask, - housekeeping_cpumask(HK_FLAG_DOMAIN)); + housekeeping_cpumask(HK_TYPE_DOMAIN)); } } else { n = ndoms_new; @@ -2564,7 +2564,7 @@ match1: n = 0; doms_new = &fallback_doms; cpumask_and(doms_new[0], cpu_active_mask, - housekeeping_cpumask(HK_FLAG_DOMAIN)); + housekeeping_cpumask(HK_TYPE_DOMAIN)); } /* Build new domains: */ diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 99afb88d2e85..9166220457bc 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -848,7 +848,7 @@ void __init lockup_detector_init(void) pr_info("Disabling watchdog on nohz_full cores by default\n"); cpumask_copy(&watchdog_cpumask, - housekeeping_cpumask(HK_FLAG_TIMER)); + housekeeping_cpumask(HK_TYPE_TIMER)); if (!watchdog_nmi_probe()) nmi_watchdog_available = true; diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 61ed310621ea..52e9abbb7759 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -6011,8 +6011,8 @@ void __init workqueue_init_early(void) BUILD_BUG_ON(__alignof__(struct pool_workqueue) < __alignof__(long long)); BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL)); - cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_FLAG_WQ)); - cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, housekeeping_cpumask(HK_FLAG_DOMAIN)); + cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_WQ)); + cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_DOMAIN)); pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC); diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index ed8da7b8d35b..7ceb3460161b 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -839,8 +839,8 @@ static ssize_t store_rps_map(struct netdev_rx_queue *queue, } if (!cpumask_empty(mask)) { - cpumask_and(mask, mask, housekeeping_cpumask(HK_FLAG_DOMAIN)); - cpumask_and(mask, mask, housekeeping_cpumask(HK_FLAG_WQ)); + cpumask_and(mask, mask, housekeeping_cpumask(HK_TYPE_DOMAIN)); + cpumask_and(mask, mask, housekeeping_cpumask(HK_TYPE_WQ)); if (cpumask_empty(mask)) { free_cpumask_var(mask); return -EINVAL; -- cgit v1.2.3 From 8a69fe0be143b0a1af829f85f0e9a1ae7d6a04db Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 14 Feb 2022 16:52:11 +0000 Subject: sched/preempt: Refactor sched_dynamic_update() Currently sched_dynamic_update needs to open-code the enabled/disabled function names for each preemption model it supports, when in practice this is a boolean enabled/disabled state for each function. Make this clearer and avoid repetition by defining the enabled/disabled states at the function definition, and using helper macros to perform the static_call_update(). Where x86 currently overrides the enabled function, it is made to provide both the enabled and disabled states for consistency, with defaults provided by the core code otherwise. In subsequent patches this will allow us to support PREEMPT_DYNAMIC without static calls. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Acked-by: Ard Biesheuvel Acked-by: Frederic Weisbecker Link: https://lore.kernel.org/r/20220214165216.2231574-3-mark.rutland@arm.com --- arch/x86/include/asm/preempt.h | 10 ++++--- include/linux/entry-common.h | 2 ++ kernel/sched/core.c | 59 ++++++++++++++++++++++++++---------------- 3 files changed, 45 insertions(+), 26 deletions(-) (limited to 'include') diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h index fe5efbcba824..5f6daea1ee24 100644 --- a/arch/x86/include/asm/preempt.h +++ b/arch/x86/include/asm/preempt.h @@ -108,16 +108,18 @@ static __always_inline bool should_resched(int preempt_offset) extern asmlinkage void preempt_schedule(void); extern asmlinkage void preempt_schedule_thunk(void); -#define __preempt_schedule_func preempt_schedule_thunk +#define preempt_schedule_dynamic_enabled preempt_schedule_thunk +#define preempt_schedule_dynamic_disabled NULL extern asmlinkage void preempt_schedule_notrace(void); extern asmlinkage void preempt_schedule_notrace_thunk(void); -#define __preempt_schedule_notrace_func preempt_schedule_notrace_thunk +#define preempt_schedule_notrace_dynamic_enabled preempt_schedule_notrace_thunk +#define preempt_schedule_notrace_dynamic_disabled NULL #ifdef CONFIG_PREEMPT_DYNAMIC -DECLARE_STATIC_CALL(preempt_schedule, __preempt_schedule_func); +DECLARE_STATIC_CALL(preempt_schedule, preempt_schedule_dynamic_enabled); #define __preempt_schedule() \ do { \ @@ -125,7 +127,7 @@ do { \ asm volatile ("call " STATIC_CALL_TRAMP_STR(preempt_schedule) : ASM_CALL_CONSTRAINT); \ } while (0) -DECLARE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func); +DECLARE_STATIC_CALL(preempt_schedule_notrace, preempt_schedule_notrace_dynamic_enabled); #define __preempt_schedule_notrace() \ do { \ diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index 2e2b8d6140ed..a01ac1a0a292 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -456,6 +456,8 @@ irqentry_state_t noinstr irqentry_enter(struct pt_regs *regs); */ void irqentry_exit_cond_resched(void); #ifdef CONFIG_PREEMPT_DYNAMIC +#define irqentry_exit_cond_resched_dynamic_enabled irqentry_exit_cond_resched +#define irqentry_exit_cond_resched_dynamic_disabled NULL DECLARE_STATIC_CALL(irqentry_exit_cond_resched, irqentry_exit_cond_resched); #endif diff --git a/kernel/sched/core.c b/kernel/sched/core.c index a123ffa8e21c..bf3a97f48c1d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6491,7 +6491,11 @@ NOKPROBE_SYMBOL(preempt_schedule); EXPORT_SYMBOL(preempt_schedule); #ifdef CONFIG_PREEMPT_DYNAMIC -DEFINE_STATIC_CALL(preempt_schedule, __preempt_schedule_func); +#ifndef preempt_schedule_dynamic_enabled +#define preempt_schedule_dynamic_enabled preempt_schedule +#define preempt_schedule_dynamic_disabled NULL +#endif +DEFINE_STATIC_CALL(preempt_schedule, preempt_schedule_dynamic_enabled); EXPORT_STATIC_CALL_TRAMP(preempt_schedule); #endif @@ -6549,7 +6553,11 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void) EXPORT_SYMBOL_GPL(preempt_schedule_notrace); #ifdef CONFIG_PREEMPT_DYNAMIC -DEFINE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func); +#ifndef preempt_schedule_notrace_dynamic_enabled +#define preempt_schedule_notrace_dynamic_enabled preempt_schedule_notrace +#define preempt_schedule_notrace_dynamic_disabled NULL +#endif +DEFINE_STATIC_CALL(preempt_schedule_notrace, preempt_schedule_notrace_dynamic_enabled); EXPORT_STATIC_CALL_TRAMP(preempt_schedule_notrace); #endif @@ -8060,9 +8068,13 @@ EXPORT_SYMBOL(__cond_resched); #endif #ifdef CONFIG_PREEMPT_DYNAMIC +#define cond_resched_dynamic_enabled __cond_resched +#define cond_resched_dynamic_disabled ((void *)&__static_call_return0) DEFINE_STATIC_CALL_RET0(cond_resched, __cond_resched); EXPORT_STATIC_CALL_TRAMP(cond_resched); +#define might_resched_dynamic_enabled __cond_resched +#define might_resched_dynamic_disabled ((void *)&__static_call_return0) DEFINE_STATIC_CALL_RET0(might_resched, __cond_resched); EXPORT_STATIC_CALL_TRAMP(might_resched); #endif @@ -8192,43 +8204,46 @@ int sched_dynamic_mode(const char *str) return -EINVAL; } +#define preempt_dynamic_enable(f) static_call_update(f, f##_dynamic_enabled) +#define preempt_dynamic_disable(f) static_call_update(f, f##_dynamic_disabled) + void sched_dynamic_update(int mode) { /* * Avoid {NONE,VOLUNTARY} -> FULL transitions from ever ending up in * the ZERO state, which is invalid. */ - static_call_update(cond_resched, __cond_resched); - static_call_update(might_resched, __cond_resched); - static_call_update(preempt_schedule, __preempt_schedule_func); - static_call_update(preempt_schedule_notrace, __preempt_schedule_notrace_func); - static_call_update(irqentry_exit_cond_resched, irqentry_exit_cond_resched); + preempt_dynamic_enable(cond_resched); + preempt_dynamic_enable(might_resched); + preempt_dynamic_enable(preempt_schedule); + preempt_dynamic_enable(preempt_schedule_notrace); + preempt_dynamic_enable(irqentry_exit_cond_resched); switch (mode) { case preempt_dynamic_none: - static_call_update(cond_resched, __cond_resched); - static_call_update(might_resched, (void *)&__static_call_return0); - static_call_update(preempt_schedule, NULL); - static_call_update(preempt_schedule_notrace, NULL); - static_call_update(irqentry_exit_cond_resched, NULL); + preempt_dynamic_enable(cond_resched); + preempt_dynamic_disable(might_resched); + preempt_dynamic_disable(preempt_schedule); + preempt_dynamic_disable(preempt_schedule_notrace); + preempt_dynamic_disable(irqentry_exit_cond_resched); pr_info("Dynamic Preempt: none\n"); break; case preempt_dynamic_voluntary: - static_call_update(cond_resched, __cond_resched); - static_call_update(might_resched, __cond_resched); - static_call_update(preempt_schedule, NULL); - static_call_update(preempt_schedule_notrace, NULL); - static_call_update(irqentry_exit_cond_resched, NULL); + preempt_dynamic_enable(cond_resched); + preempt_dynamic_enable(might_resched); + preempt_dynamic_disable(preempt_schedule); + preempt_dynamic_disable(preempt_schedule_notrace); + preempt_dynamic_disable(irqentry_exit_cond_resched); pr_info("Dynamic Preempt: voluntary\n"); break; case preempt_dynamic_full: - static_call_update(cond_resched, (void *)&__static_call_return0); - static_call_update(might_resched, (void *)&__static_call_return0); - static_call_update(preempt_schedule, __preempt_schedule_func); - static_call_update(preempt_schedule_notrace, __preempt_schedule_notrace_func); - static_call_update(irqentry_exit_cond_resched, irqentry_exit_cond_resched); + preempt_dynamic_disable(cond_resched); + preempt_dynamic_disable(might_resched); + preempt_dynamic_enable(preempt_schedule); + preempt_dynamic_enable(preempt_schedule_notrace); + preempt_dynamic_enable(irqentry_exit_cond_resched); pr_info("Dynamic Preempt: full\n"); break; } -- cgit v1.2.3 From 4624a14f4daa8ab4578d274555fd8847254ce339 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 14 Feb 2022 16:52:12 +0000 Subject: sched/preempt: Simplify irqentry_exit_cond_resched() callers Currently callers of irqentry_exit_cond_resched() need to be aware of whether the function should be indirected via a static call, leading to ugly ifdeffery in callers. Save them the hassle with a static inline wrapper that does the right thing. The raw_irqentry_exit_cond_resched() will also be useful in subsequent patches which will add conditional wrappers for preemption functions. Note: in arch/x86/entry/common.c, xen_pv_evtchn_do_upcall() always calls irqentry_exit_cond_resched() directly, even when PREEMPT_DYNAMIC is in use. I believe this is a latent bug (which this patch corrects), but I'm not entirely certain this wasn't deliberate. Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Acked-by: Ard Biesheuvel Acked-by: Frederic Weisbecker Link: https://lore.kernel.org/r/20220214165216.2231574-4-mark.rutland@arm.com --- include/linux/entry-common.h | 9 ++++++--- kernel/entry/common.c | 12 ++++-------- 2 files changed, 10 insertions(+), 11 deletions(-) (limited to 'include') diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index a01ac1a0a292..dfd84c59b144 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -454,11 +454,14 @@ irqentry_state_t noinstr irqentry_enter(struct pt_regs *regs); * * Conditional reschedule with additional sanity checks. */ -void irqentry_exit_cond_resched(void); +void raw_irqentry_exit_cond_resched(void); #ifdef CONFIG_PREEMPT_DYNAMIC -#define irqentry_exit_cond_resched_dynamic_enabled irqentry_exit_cond_resched +#define irqentry_exit_cond_resched_dynamic_enabled raw_irqentry_exit_cond_resched #define irqentry_exit_cond_resched_dynamic_disabled NULL -DECLARE_STATIC_CALL(irqentry_exit_cond_resched, irqentry_exit_cond_resched); +DECLARE_STATIC_CALL(irqentry_exit_cond_resched, raw_irqentry_exit_cond_resched); +#define irqentry_exit_cond_resched() static_call(irqentry_exit_cond_resched)() +#else +#define irqentry_exit_cond_resched() raw_irqentry_exit_cond_resched() #endif /** diff --git a/kernel/entry/common.c b/kernel/entry/common.c index bad713684c2e..1739ca79613b 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -380,7 +380,7 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs) return ret; } -void irqentry_exit_cond_resched(void) +void raw_irqentry_exit_cond_resched(void) { if (!preempt_count()) { /* Sanity check RCU and thread stack */ @@ -392,7 +392,7 @@ void irqentry_exit_cond_resched(void) } } #ifdef CONFIG_PREEMPT_DYNAMIC -DEFINE_STATIC_CALL(irqentry_exit_cond_resched, irqentry_exit_cond_resched); +DEFINE_STATIC_CALL(irqentry_exit_cond_resched, raw_irqentry_exit_cond_resched); #endif noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state) @@ -420,13 +420,9 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state) } instrumentation_begin(); - if (IS_ENABLED(CONFIG_PREEMPTION)) { -#ifdef CONFIG_PREEMPT_DYNAMIC - static_call(irqentry_exit_cond_resched)(); -#else + if (IS_ENABLED(CONFIG_PREEMPTION)) irqentry_exit_cond_resched(); -#endif - } + /* Covers both tracing and lockdep */ trace_hardirqs_on(); instrumentation_end(); -- cgit v1.2.3 From 99cf983cc8bca4adb461b519664c939a565cfd4d Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 14 Feb 2022 16:52:14 +0000 Subject: sched/preempt: Add PREEMPT_DYNAMIC using static keys Where an architecture selects HAVE_STATIC_CALL but not HAVE_STATIC_CALL_INLINE, each static call has an out-of-line trampoline which will either branch to a callee or return to the caller. On such architectures, a number of constraints can conspire to make those trampolines more complicated and potentially less useful than we'd like. For example: * Hardware and software control flow integrity schemes can require the addition of "landing pad" instructions (e.g. `BTI` for arm64), which will also be present at the "real" callee. * Limited branch ranges can require that trampolines generate or load an address into a register and perform an indirect branch (or at least have a slow path that does so). This loses some of the benefits of having a direct branch. * Interaction with SW CFI schemes can be complicated and fragile, e.g. requiring that we can recognise idiomatic codegen and remove indirections understand, at least until clang proves more helpful mechanisms for dealing with this. For PREEMPT_DYNAMIC, we don't need the full power of static calls, as we really only need to enable/disable specific preemption functions. We can achieve the same effect without a number of the pain points above by using static keys to fold early returns into the preemption functions themselves rather than in an out-of-line trampoline, effectively inlining the trampoline into the start of the function. For arm64, this results in good code generation. For example, the dynamic_cond_resched() wrapper looks as follows when enabled. When disabled, the first `B` is replaced with a `NOP`, resulting in an early return. | : | bti c | b // or `nop` | mov w0, #0x0 | ret | mrs x0, sp_el0 | ldr x0, [x0, #8] | cbnz x0, | paciasp | stp x29, x30, [sp, #-16]! | mov x29, sp | bl | mov w0, #0x1 | ldp x29, x30, [sp], #16 | autiasp | ret ... compared to the regular form of the function: | <__cond_resched>: | bti c | mrs x0, sp_el0 | ldr x1, [x0, #8] | cbz x1, <__cond_resched+0x18> | mov w0, #0x0 | ret | paciasp | stp x29, x30, [sp, #-16]! | mov x29, sp | bl | mov w0, #0x1 | ldp x29, x30, [sp], #16 | autiasp | ret Any architecture which implements static keys should be able to use this to implement PREEMPT_DYNAMIC with similar cost to non-inlined static calls. Since this is likely to have greater overhead than (inlined) static calls, PREEMPT_DYNAMIC is only defaulted to enabled when HAVE_PREEMPT_DYNAMIC_CALL is selected. Signed-off-by: Mark Rutland Signed-off-by: Peter Zijlstra (Intel) Acked-by: Ard Biesheuvel Acked-by: Frederic Weisbecker Link: https://lore.kernel.org/r/20220214165216.2231574-6-mark.rutland@arm.com --- arch/Kconfig | 36 ++++++++++++++++++++++++++--- arch/x86/Kconfig | 2 +- include/linux/entry-common.h | 10 ++++++-- include/linux/kernel.h | 7 +++++- include/linux/sched.h | 10 +++++++- kernel/Kconfig.preempt | 3 ++- kernel/entry/common.c | 11 +++++++++ kernel/sched/core.c | 54 ++++++++++++++++++++++++++++++++++++++++++-- 8 files changed, 122 insertions(+), 11 deletions(-) (limited to 'include') diff --git a/arch/Kconfig b/arch/Kconfig index 601691f1570f..d544abd14c01 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -1278,11 +1278,41 @@ config HAVE_STATIC_CALL_INLINE config HAVE_PREEMPT_DYNAMIC bool + +config HAVE_PREEMPT_DYNAMIC_CALL + bool depends on HAVE_STATIC_CALL + select HAVE_PREEMPT_DYNAMIC + help + An architecture should select this if it can handle the preemption + model being selected at boot time using static calls. + + Where an architecture selects HAVE_STATIC_CALL_INLINE, any call to a + preemption function will be patched directly. + + Where an architecture does not select HAVE_STATIC_CALL_INLINE, any + call to a preemption function will go through a trampoline, and the + trampoline will be patched. + + It is strongly advised to support inline static call to avoid any + overhead. + +config HAVE_PREEMPT_DYNAMIC_KEY + bool + depends on HAVE_ARCH_JUMP_LABEL && CC_HAS_ASM_GOTO + select HAVE_PREEMPT_DYNAMIC help - Select this if the architecture support boot time preempt setting - on top of static calls. It is strongly advised to support inline - static call to avoid any overhead. + An architecture should select this if it can handle the preemption + model being selected at boot time using static keys. + + Each preemption function will be given an early return based on a + static key. This should have slightly lower overhead than non-inline + static calls, as this effectively inlines each trampoline into the + start of its callee. This may avoid redundant work, and may + integrate better with CFI schemes. + + This will have greater overhead than using inline static calls as + the call to the preemption function cannot be entirely elided. config ARCH_WANT_LD_ORPHAN_WARN bool diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index ebe8fc76949a..f13cfdfb30ce 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -245,7 +245,7 @@ config X86 select HAVE_STACK_VALIDATION if X86_64 select HAVE_STATIC_CALL select HAVE_STATIC_CALL_INLINE if HAVE_STACK_VALIDATION - select HAVE_PREEMPT_DYNAMIC + select HAVE_PREEMPT_DYNAMIC_CALL select HAVE_RSEQ select HAVE_SYSCALL_TRACEPOINTS select HAVE_UNSTABLE_SCHED_CLOCK diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h index dfd84c59b144..141952f4fee8 100644 --- a/include/linux/entry-common.h +++ b/include/linux/entry-common.h @@ -456,13 +456,19 @@ irqentry_state_t noinstr irqentry_enter(struct pt_regs *regs); */ void raw_irqentry_exit_cond_resched(void); #ifdef CONFIG_PREEMPT_DYNAMIC +#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) #define irqentry_exit_cond_resched_dynamic_enabled raw_irqentry_exit_cond_resched #define irqentry_exit_cond_resched_dynamic_disabled NULL DECLARE_STATIC_CALL(irqentry_exit_cond_resched, raw_irqentry_exit_cond_resched); #define irqentry_exit_cond_resched() static_call(irqentry_exit_cond_resched)() -#else -#define irqentry_exit_cond_resched() raw_irqentry_exit_cond_resched() +#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) +DECLARE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched); +void dynamic_irqentry_exit_cond_resched(void); +#define irqentry_exit_cond_resched() dynamic_irqentry_exit_cond_resched() #endif +#else /* CONFIG_PREEMPT_DYNAMIC */ +#define irqentry_exit_cond_resched() raw_irqentry_exit_cond_resched() +#endif /* CONFIG_PREEMPT_DYNAMIC */ /** * irqentry_exit - Handle return from exception that used irqentry_enter() diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 33f47a996513..a890428bcc1a 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -99,7 +99,7 @@ struct user; extern int __cond_resched(void); # define might_resched() __cond_resched() -#elif defined(CONFIG_PREEMPT_DYNAMIC) +#elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) extern int __cond_resched(void); @@ -110,6 +110,11 @@ static __always_inline void might_resched(void) static_call_mod(might_resched)(); } +#elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) + +extern int dynamic_might_resched(void); +# define might_resched() dynamic_might_resched() + #else # define might_resched() do { } while (0) diff --git a/include/linux/sched.h b/include/linux/sched.h index 508b91d57470..de03ddeb064b 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2020,7 +2020,7 @@ static inline int test_tsk_need_resched(struct task_struct *tsk) #if !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC) extern int __cond_resched(void); -#ifdef CONFIG_PREEMPT_DYNAMIC +#if defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) DECLARE_STATIC_CALL(cond_resched, __cond_resched); @@ -2029,6 +2029,14 @@ static __always_inline int _cond_resched(void) return static_call_mod(cond_resched)(); } +#elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) +extern int dynamic_cond_resched(void); + +static __always_inline int _cond_resched(void) +{ + return dynamic_cond_resched(); +} + #else static inline int _cond_resched(void) diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt index ce77f0265660..c2f1fd95a821 100644 --- a/kernel/Kconfig.preempt +++ b/kernel/Kconfig.preempt @@ -96,8 +96,9 @@ config PREEMPTION config PREEMPT_DYNAMIC bool "Preemption behaviour defined on boot" depends on HAVE_PREEMPT_DYNAMIC && !PREEMPT_RT + select JUMP_LABEL if HAVE_PREEMPT_DYNAMIC_KEY select PREEMPT_BUILD - default y + default y if HAVE_PREEMPT_DYNAMIC_CALL help This option allows to define the preemption model on the kernel command line parameter and thus override the default preemption diff --git a/kernel/entry/common.c b/kernel/entry/common.c index 1739ca79613b..b145249ad91a 100644 --- a/kernel/entry/common.c +++ b/kernel/entry/common.c @@ -3,6 +3,7 @@ #include #include #include +#include #include #include #include @@ -392,7 +393,17 @@ void raw_irqentry_exit_cond_resched(void) } } #ifdef CONFIG_PREEMPT_DYNAMIC +#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) DEFINE_STATIC_CALL(irqentry_exit_cond_resched, raw_irqentry_exit_cond_resched); +#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) +DEFINE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched); +void dynamic_irqentry_exit_cond_resched(void) +{ + if (!static_key_unlikely(&sk_dynamic_irqentry_exit_cond_resched)) + return; + raw_irqentry_exit_cond_resched(); +} +#endif #endif noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 300c0454a2b8..9e65028189f4 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -14,6 +14,7 @@ #include #include +#include #include #include @@ -6484,21 +6485,31 @@ asmlinkage __visible void __sched notrace preempt_schedule(void) */ if (likely(!preemptible())) return; - preempt_schedule_common(); } NOKPROBE_SYMBOL(preempt_schedule); EXPORT_SYMBOL(preempt_schedule); #ifdef CONFIG_PREEMPT_DYNAMIC +#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) #ifndef preempt_schedule_dynamic_enabled #define preempt_schedule_dynamic_enabled preempt_schedule #define preempt_schedule_dynamic_disabled NULL #endif DEFINE_STATIC_CALL(preempt_schedule, preempt_schedule_dynamic_enabled); EXPORT_STATIC_CALL_TRAMP(preempt_schedule); +#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) +static DEFINE_STATIC_KEY_TRUE(sk_dynamic_preempt_schedule); +void __sched notrace dynamic_preempt_schedule(void) +{ + if (!static_branch_unlikely(&sk_dynamic_preempt_schedule)) + return; + preempt_schedule(); +} +NOKPROBE_SYMBOL(dynamic_preempt_schedule); +EXPORT_SYMBOL(dynamic_preempt_schedule); +#endif #endif - /** * preempt_schedule_notrace - preempt_schedule called by tracing @@ -6553,12 +6564,24 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void) EXPORT_SYMBOL_GPL(preempt_schedule_notrace); #ifdef CONFIG_PREEMPT_DYNAMIC +#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) #ifndef preempt_schedule_notrace_dynamic_enabled #define preempt_schedule_notrace_dynamic_enabled preempt_schedule_notrace #define preempt_schedule_notrace_dynamic_disabled NULL #endif DEFINE_STATIC_CALL(preempt_schedule_notrace, preempt_schedule_notrace_dynamic_enabled); EXPORT_STATIC_CALL_TRAMP(preempt_schedule_notrace); +#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) +static DEFINE_STATIC_KEY_TRUE(sk_dynamic_preempt_schedule_notrace); +void __sched notrace dynamic_preempt_schedule_notrace(void) +{ + if (!static_branch_unlikely(&sk_dynamic_preempt_schedule_notrace)) + return; + preempt_schedule_notrace(); +} +NOKPROBE_SYMBOL(dynamic_preempt_schedule_notrace); +EXPORT_SYMBOL(dynamic_preempt_schedule_notrace); +#endif #endif #endif /* CONFIG_PREEMPTION */ @@ -8068,6 +8091,7 @@ EXPORT_SYMBOL(__cond_resched); #endif #ifdef CONFIG_PREEMPT_DYNAMIC +#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) #define cond_resched_dynamic_enabled __cond_resched #define cond_resched_dynamic_disabled ((void *)&__static_call_return0) DEFINE_STATIC_CALL_RET0(cond_resched, __cond_resched); @@ -8077,6 +8101,25 @@ EXPORT_STATIC_CALL_TRAMP(cond_resched); #define might_resched_dynamic_disabled ((void *)&__static_call_return0) DEFINE_STATIC_CALL_RET0(might_resched, __cond_resched); EXPORT_STATIC_CALL_TRAMP(might_resched); +#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) +static DEFINE_STATIC_KEY_FALSE(sk_dynamic_cond_resched); +int __sched dynamic_cond_resched(void) +{ + if (!static_branch_unlikely(&sk_dynamic_cond_resched)) + return 0; + return __cond_resched(); +} +EXPORT_SYMBOL(dynamic_cond_resched); + +static DEFINE_STATIC_KEY_FALSE(sk_dynamic_might_resched); +int __sched dynamic_might_resched(void) +{ + if (!static_branch_unlikely(&sk_dynamic_might_resched)) + return 0; + return __cond_resched(); +} +EXPORT_SYMBOL(dynamic_might_resched); +#endif #endif /* @@ -8206,8 +8249,15 @@ int sched_dynamic_mode(const char *str) return -EINVAL; } +#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) #define preempt_dynamic_enable(f) static_call_update(f, f##_dynamic_enabled) #define preempt_dynamic_disable(f) static_call_update(f, f##_dynamic_disabled) +#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) +#define preempt_dynamic_enable(f) static_key_enable(&sk_dynamic_##f.key) +#define preempt_dynamic_disable(f) static_key_disable(&sk_dynamic_##f.key) +#else +#error "Unsupported PREEMPT_DYNAMIC mechanism" +#endif void sched_dynamic_update(int mode) { -- cgit v1.2.3 From d0b9d6dcaa5ac480c272683919f387cc6d82b638 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 23 Sep 2021 20:42:44 +0200 Subject: sched/headers: Fix header to build standalone: Uses various kernel types that don't build standalone. Signed-off-by: Ingo Molnar Reviewed-by: Peter Zijlstra --- include/linux/sched_clock.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/sched_clock.h b/include/linux/sched_clock.h index 835ee87ed792..cb41c5edb4d4 100644 --- a/include/linux/sched_clock.h +++ b/include/linux/sched_clock.h @@ -5,6 +5,8 @@ #ifndef LINUX_SCHED_CLOCK #define LINUX_SCHED_CLOCK +#include + #ifdef CONFIG_GENERIC_SCHED_CLOCK /** * struct clock_read_data - data required to read from sched_clock() -- cgit v1.2.3 From 669f45f19cf7feea7066dce86a0ce89dfc8a2065 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 22 Feb 2022 13:23:59 +0100 Subject: sched/headers: Add initial new headers as identity mappings This allows code sharing between fast-headers tree and the vanilla scheduler tree. Signed-off-by: Ingo Molnar Reviewed-by: Peter Zijlstra --- arch/arm64/include/asm/paravirt_api_clock.h | 1 + arch/x86/include/asm/paravirt_api_clock.h | 1 + include/linux/cgroup_api.h | 1 + include/linux/cpumask_api.h | 1 + include/linux/fs_api.h | 1 + include/linux/gfp_api.h | 1 + include/linux/hashtable_api.h | 1 + include/linux/hrtimer_api.h | 1 + include/linux/kobject_api.h | 1 + include/linux/kref_api.h | 1 + include/linux/ktime_api.h | 1 + include/linux/llist_api.h | 1 + include/linux/lockdep_api.h | 1 + include/linux/mm_api.h | 1 + include/linux/mutex_api.h | 1 + include/linux/perf_event_api.h | 1 + include/linux/pgtable_api.h | 1 + include/linux/ptrace_api.h | 1 + include/linux/rcuwait_api.h | 1 + include/linux/refcount_api.h | 1 + include/linux/sched/affinity.h | 1 + include/linux/sched/cond_resched.h | 1 + include/linux/sched/posix-timers.h | 1 + include/linux/sched/rseq_api.h | 1 + include/linux/sched/task_flags.h | 1 + include/linux/sched/thread_info_api.h | 1 + include/linux/seqlock_api.h | 1 + include/linux/softirq.h | 1 + include/linux/spinlock_api.h | 1 + include/linux/swait_api.h | 1 + include/linux/syscalls_api.h | 1 + include/linux/u64_stats_sync_api.h | 1 + include/linux/wait_api.h | 1 + include/linux/workqueue_api.h | 1 + 34 files changed, 34 insertions(+) create mode 100644 arch/arm64/include/asm/paravirt_api_clock.h create mode 100644 arch/x86/include/asm/paravirt_api_clock.h create mode 100644 include/linux/cgroup_api.h create mode 100644 include/linux/cpumask_api.h create mode 100644 include/linux/fs_api.h create mode 100644 include/linux/gfp_api.h create mode 100644 include/linux/hashtable_api.h create mode 100644 include/linux/hrtimer_api.h create mode 100644 include/linux/kobject_api.h create mode 100644 include/linux/kref_api.h create mode 100644 include/linux/ktime_api.h create mode 100644 include/linux/llist_api.h create mode 100644 include/linux/lockdep_api.h create mode 100644 include/linux/mm_api.h create mode 100644 include/linux/mutex_api.h create mode 100644 include/linux/perf_event_api.h create mode 100644 include/linux/pgtable_api.h create mode 100644 include/linux/ptrace_api.h create mode 100644 include/linux/rcuwait_api.h create mode 100644 include/linux/refcount_api.h create mode 100644 include/linux/sched/affinity.h create mode 100644 include/linux/sched/cond_resched.h create mode 100644 include/linux/sched/posix-timers.h create mode 100644 include/linux/sched/rseq_api.h create mode 100644 include/linux/sched/task_flags.h create mode 100644 include/linux/sched/thread_info_api.h create mode 100644 include/linux/seqlock_api.h create mode 100644 include/linux/softirq.h create mode 100644 include/linux/spinlock_api.h create mode 100644 include/linux/swait_api.h create mode 100644 include/linux/syscalls_api.h create mode 100644 include/linux/u64_stats_sync_api.h create mode 100644 include/linux/wait_api.h create mode 100644 include/linux/workqueue_api.h (limited to 'include') diff --git a/arch/arm64/include/asm/paravirt_api_clock.h b/arch/arm64/include/asm/paravirt_api_clock.h new file mode 100644 index 000000000000..65ac7cee0dad --- /dev/null +++ b/arch/arm64/include/asm/paravirt_api_clock.h @@ -0,0 +1 @@ +#include diff --git a/arch/x86/include/asm/paravirt_api_clock.h b/arch/x86/include/asm/paravirt_api_clock.h new file mode 100644 index 000000000000..65ac7cee0dad --- /dev/null +++ b/arch/x86/include/asm/paravirt_api_clock.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/cgroup_api.h b/include/linux/cgroup_api.h new file mode 100644 index 000000000000..d0cfe8025111 --- /dev/null +++ b/include/linux/cgroup_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/cpumask_api.h b/include/linux/cpumask_api.h new file mode 100644 index 000000000000..83bd3ebe82b0 --- /dev/null +++ b/include/linux/cpumask_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/fs_api.h b/include/linux/fs_api.h new file mode 100644 index 000000000000..83be38d6d413 --- /dev/null +++ b/include/linux/fs_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/gfp_api.h b/include/linux/gfp_api.h new file mode 100644 index 000000000000..5a05a2764a86 --- /dev/null +++ b/include/linux/gfp_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/hashtable_api.h b/include/linux/hashtable_api.h new file mode 100644 index 000000000000..c268ac2c5c0e --- /dev/null +++ b/include/linux/hashtable_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/hrtimer_api.h b/include/linux/hrtimer_api.h new file mode 100644 index 000000000000..8d9700894468 --- /dev/null +++ b/include/linux/hrtimer_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/kobject_api.h b/include/linux/kobject_api.h new file mode 100644 index 000000000000..6e36a054c2d6 --- /dev/null +++ b/include/linux/kobject_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/kref_api.h b/include/linux/kref_api.h new file mode 100644 index 000000000000..d67e554721d2 --- /dev/null +++ b/include/linux/kref_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/ktime_api.h b/include/linux/ktime_api.h new file mode 100644 index 000000000000..f697d493960f --- /dev/null +++ b/include/linux/ktime_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/llist_api.h b/include/linux/llist_api.h new file mode 100644 index 000000000000..625bec0393a1 --- /dev/null +++ b/include/linux/llist_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/lockdep_api.h b/include/linux/lockdep_api.h new file mode 100644 index 000000000000..907e66979ab2 --- /dev/null +++ b/include/linux/lockdep_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/mm_api.h b/include/linux/mm_api.h new file mode 100644 index 000000000000..a5ace2b198b8 --- /dev/null +++ b/include/linux/mm_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/mutex_api.h b/include/linux/mutex_api.h new file mode 100644 index 000000000000..85ab9491e13e --- /dev/null +++ b/include/linux/mutex_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/perf_event_api.h b/include/linux/perf_event_api.h new file mode 100644 index 000000000000..c2fd6048b790 --- /dev/null +++ b/include/linux/perf_event_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/pgtable_api.h b/include/linux/pgtable_api.h new file mode 100644 index 000000000000..ff367a4ba8c4 --- /dev/null +++ b/include/linux/pgtable_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/ptrace_api.h b/include/linux/ptrace_api.h new file mode 100644 index 000000000000..26e7d275ad8d --- /dev/null +++ b/include/linux/ptrace_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/rcuwait_api.h b/include/linux/rcuwait_api.h new file mode 100644 index 000000000000..f962e28544dd --- /dev/null +++ b/include/linux/rcuwait_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/refcount_api.h b/include/linux/refcount_api.h new file mode 100644 index 000000000000..5f032589f568 --- /dev/null +++ b/include/linux/refcount_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/sched/affinity.h b/include/linux/sched/affinity.h new file mode 100644 index 000000000000..227f5be81bcd --- /dev/null +++ b/include/linux/sched/affinity.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/sched/cond_resched.h b/include/linux/sched/cond_resched.h new file mode 100644 index 000000000000..227f5be81bcd --- /dev/null +++ b/include/linux/sched/cond_resched.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/sched/posix-timers.h b/include/linux/sched/posix-timers.h new file mode 100644 index 000000000000..523a381d6c88 --- /dev/null +++ b/include/linux/sched/posix-timers.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/sched/rseq_api.h b/include/linux/sched/rseq_api.h new file mode 100644 index 000000000000..cf2af72693e1 --- /dev/null +++ b/include/linux/sched/rseq_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/sched/task_flags.h b/include/linux/sched/task_flags.h new file mode 100644 index 000000000000..227f5be81bcd --- /dev/null +++ b/include/linux/sched/task_flags.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/sched/thread_info_api.h b/include/linux/sched/thread_info_api.h new file mode 100644 index 000000000000..2c60fbc16c08 --- /dev/null +++ b/include/linux/sched/thread_info_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/seqlock_api.h b/include/linux/seqlock_api.h new file mode 100644 index 000000000000..be91e7d3b826 --- /dev/null +++ b/include/linux/seqlock_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/softirq.h b/include/linux/softirq.h new file mode 100644 index 000000000000..c73d7dcb4cb5 --- /dev/null +++ b/include/linux/softirq.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/spinlock_api.h b/include/linux/spinlock_api.h new file mode 100644 index 000000000000..6338b27f98df --- /dev/null +++ b/include/linux/spinlock_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/swait_api.h b/include/linux/swait_api.h new file mode 100644 index 000000000000..1eeaaaaa5ea7 --- /dev/null +++ b/include/linux/swait_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/syscalls_api.h b/include/linux/syscalls_api.h new file mode 100644 index 000000000000..23e012b04db4 --- /dev/null +++ b/include/linux/syscalls_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/u64_stats_sync_api.h b/include/linux/u64_stats_sync_api.h new file mode 100644 index 000000000000..c72ca63da44b --- /dev/null +++ b/include/linux/u64_stats_sync_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/wait_api.h b/include/linux/wait_api.h new file mode 100644 index 000000000000..4e930548935a --- /dev/null +++ b/include/linux/wait_api.h @@ -0,0 +1 @@ +#include diff --git a/include/linux/workqueue_api.h b/include/linux/workqueue_api.h new file mode 100644 index 000000000000..77debb5d2760 --- /dev/null +++ b/include/linux/workqueue_api.h @@ -0,0 +1 @@ +#include -- cgit v1.2.3 From fbed5664b73830dcb1a19af4f7f1f1b424f54609 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 22 Feb 2022 13:28:20 +0100 Subject: sched/headers: Make the header build standalone This header depends on various scheduler definitions. Signed-off-by: Ingo Molnar Reviewed-by: Peter Zijlstra --- include/linux/sched/deadline.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/sched/deadline.h b/include/linux/sched/deadline.h index 1aff00b65f3c..7c83d4d5a971 100644 --- a/include/linux/sched/deadline.h +++ b/include/linux/sched/deadline.h @@ -6,6 +6,8 @@ * NORMAL/BATCH tasks. */ +#include + #define MAX_DL_PRIO 0 static inline int dl_prio(int prio) -- cgit v1.2.3 From dc6e0818bc9a0336d9accf3ea35d146d72aa7a18 Mon Sep 17 00:00:00 2001 From: Chengming Zhou Date: Sun, 20 Feb 2022 13:14:25 +0800 Subject: sched/cpuacct: Optimize away RCU read lock Since cpuacct_charge() is called from the scheduler update_curr(), we must already have rq lock held, then the RCU read lock can be optimized away. And do the same thing in it's wrapper cgroup_account_cputime(), but we can't use lockdep_assert_rq_held() there, which defined in kernel/sched/sched.h. Suggested-by: Peter Zijlstra (Intel) Signed-off-by: Chengming Zhou Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20220220051426.5274-2-zhouchengming@bytedance.com --- include/linux/cgroup.h | 2 -- kernel/sched/cpuacct.c | 4 +--- 2 files changed, 1 insertion(+), 5 deletions(-) (limited to 'include') diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 75c151413fda..9a109c6ac0e0 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -791,11 +791,9 @@ static inline void cgroup_account_cputime(struct task_struct *task, cpuacct_charge(task, delta_exec); - rcu_read_lock(); cgrp = task_dfl_cgroup(task); if (cgroup_parent(cgrp)) __cgroup_account_cputime(cgrp, delta_exec); - rcu_read_unlock(); } static inline void cgroup_account_cputime_field(struct task_struct *task, diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c index 307800586ac8..f79f88456d72 100644 --- a/kernel/sched/cpuacct.c +++ b/kernel/sched/cpuacct.c @@ -337,12 +337,10 @@ void cpuacct_charge(struct task_struct *tsk, u64 cputime) unsigned int cpu = task_cpu(tsk); struct cpuacct *ca; - rcu_read_lock(); + lockdep_assert_rq_held(cpu_rq(cpu)); for (ca = task_ca(tsk); ca; ca = parent_ca(ca)) *per_cpu_ptr(ca->cpuusage, cpu) += cputime; - - rcu_read_unlock(); } /* -- cgit v1.2.3 From 3eba0505d03a9c1eb30d40c2330c0880b22d1b3a Mon Sep 17 00:00:00 2001 From: Chengming Zhou Date: Sun, 20 Feb 2022 13:14:26 +0800 Subject: sched/cpuacct: Remove redundant RCU read lock The cpuacct_account_field() and it's cgroup v2 wrapper cgroup_account_cputime_field() is only called from cputime in task_group_account_field(), which is already in RCU read-side critical section. So remove these redundant RCU read lock. Suggested-by: Tejun Heo Signed-off-by: Chengming Zhou Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20220220051426.5274-3-zhouchengming@bytedance.com --- include/linux/cgroup.h | 2 -- kernel/sched/cpuacct.c | 2 -- 2 files changed, 4 deletions(-) (limited to 'include') diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 9a109c6ac0e0..1e356c222756 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -804,11 +804,9 @@ static inline void cgroup_account_cputime_field(struct task_struct *task, cpuacct_account_field(task, index, delta_exec); - rcu_read_lock(); cgrp = task_dfl_cgroup(task); if (cgroup_parent(cgrp)) __cgroup_account_cputime_field(cgrp, index, delta_exec); - rcu_read_unlock(); } #else /* CONFIG_CGROUPS */ diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c index f79f88456d72..d269ede84e85 100644 --- a/kernel/sched/cpuacct.c +++ b/kernel/sched/cpuacct.c @@ -352,10 +352,8 @@ void cpuacct_account_field(struct task_struct *tsk, int index, u64 val) { struct cpuacct *ca; - rcu_read_lock(); for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca)) __this_cpu_add(ca->cpustat->cpustat[index], val); - rcu_read_unlock(); } struct cgroup_subsys cpuacct_cgrp_subsys = { -- cgit v1.2.3 From fa2c3254d7cfff5f7a916ab928a562d1165f17bb Mon Sep 17 00:00:00 2001 From: Valentin Schneider Date: Thu, 20 Jan 2022 16:25:19 +0000 Subject: sched/tracing: Don't re-read p->state when emitting sched_switch event As of commit c6e7bd7afaeb ("sched/core: Optimize ttwu() spinning on p->on_cpu") the following sequence becomes possible: p->__state = TASK_INTERRUPTIBLE; __schedule() deactivate_task(p); ttwu() READ !p->on_rq p->__state=TASK_WAKING trace_sched_switch() __trace_sched_switch_state() task_state_index() return 0; TASK_WAKING isn't in TASK_REPORT, so the task appears as TASK_RUNNING in the trace event. Prevent this by pushing the value read from __schedule() down the trace event. Reported-by: Abhijeet Dharmapurikar Signed-off-by: Valentin Schneider Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt (Google) Link: https://lore.kernel.org/r/20220120162520.570782-2-valentin.schneider@arm.com --- include/linux/sched.h | 11 ++++++++--- include/trace/events/sched.h | 11 +++++++---- kernel/sched/core.c | 4 ++-- kernel/trace/fgraph.c | 4 +++- kernel/trace/ftrace.c | 4 +++- kernel/trace/trace_events.c | 8 ++++++-- kernel/trace/trace_osnoise.c | 4 +++- kernel/trace/trace_sched_switch.c | 1 + kernel/trace/trace_sched_wakeup.c | 1 + 9 files changed, 34 insertions(+), 14 deletions(-) (limited to 'include') diff --git a/include/linux/sched.h b/include/linux/sched.h index f00132e7ef6e..457c8a058b77 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1620,10 +1620,10 @@ static inline pid_t task_pgrp_nr(struct task_struct *tsk) #define TASK_REPORT_IDLE (TASK_REPORT + 1) #define TASK_REPORT_MAX (TASK_REPORT_IDLE << 1) -static inline unsigned int task_state_index(struct task_struct *tsk) +static inline unsigned int __task_state_index(unsigned int tsk_state, + unsigned int tsk_exit_state) { - unsigned int tsk_state = READ_ONCE(tsk->__state); - unsigned int state = (tsk_state | tsk->exit_state) & TASK_REPORT; + unsigned int state = (tsk_state | tsk_exit_state) & TASK_REPORT; BUILD_BUG_ON_NOT_POWER_OF_2(TASK_REPORT_MAX); @@ -1633,6 +1633,11 @@ static inline unsigned int task_state_index(struct task_struct *tsk) return fls(state); } +static inline unsigned int task_state_index(struct task_struct *tsk) +{ + return __task_state_index(READ_ONCE(tsk->__state), tsk->exit_state); +} + static inline char task_index_to_char(unsigned int state) { static const char state_char[] = "RSDTtXZPI"; diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index 94640482cfe7..65e786756321 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -187,7 +187,9 @@ DEFINE_EVENT(sched_wakeup_template, sched_wakeup_new, TP_ARGS(p)); #ifdef CREATE_TRACE_POINTS -static inline long __trace_sched_switch_state(bool preempt, struct task_struct *p) +static inline long __trace_sched_switch_state(bool preempt, + unsigned int prev_state, + struct task_struct *p) { unsigned int state; @@ -208,7 +210,7 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct * * it for left shift operation to get the correct task->state * mapping. */ - state = task_state_index(p); + state = __task_state_index(prev_state, p->exit_state); return state ? (1 << (state - 1)) : state; } @@ -220,10 +222,11 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct * TRACE_EVENT(sched_switch, TP_PROTO(bool preempt, + unsigned int prev_state, struct task_struct *prev, struct task_struct *next), - TP_ARGS(preempt, prev, next), + TP_ARGS(preempt, prev_state, prev, next), TP_STRUCT__entry( __array( char, prev_comm, TASK_COMM_LEN ) @@ -239,7 +242,7 @@ TRACE_EVENT(sched_switch, memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); __entry->prev_pid = prev->pid; __entry->prev_prio = prev->prio; - __entry->prev_state = __trace_sched_switch_state(preempt, prev); + __entry->prev_state = __trace_sched_switch_state(preempt, prev_state, prev); memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); __entry->next_pid = next->pid; __entry->next_prio = next->prio; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ef946123e9af..3aafc15da24a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4836,7 +4836,7 @@ static struct rq *finish_task_switch(struct task_struct *prev) { struct rq *rq = this_rq(); struct mm_struct *mm = rq->prev_mm; - long prev_state; + unsigned int prev_state; /* * The previous task will have left us with a preempt_count of 2 @@ -6300,7 +6300,7 @@ static void __sched notrace __schedule(unsigned int sched_mode) migrate_disable_switch(rq, prev); psi_sched_switch(prev, next, !task_on_rq_queued(prev)); - trace_sched_switch(sched_mode & SM_MASK_PREEMPT, prev, next); + trace_sched_switch(sched_mode & SM_MASK_PREEMPT, prev_state, prev, next); /* Also unlocks the rq: */ rq = context_switch(rq, prev, next, &rf); diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 22061d38fc00..19028e072cdb 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -415,7 +415,9 @@ free: static void ftrace_graph_probe_sched_switch(void *ignore, bool preempt, - struct task_struct *prev, struct task_struct *next) + unsigned int prev_state, + struct task_struct *prev, + struct task_struct *next) { unsigned long long timestamp; int index; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index f9feb197b2da..6762ae029fdd 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -7347,7 +7347,9 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops) static void ftrace_filter_pid_sched_switch_probe(void *data, bool preempt, - struct task_struct *prev, struct task_struct *next) + unsigned int prev_state, + struct task_struct *prev, + struct task_struct *next) { struct trace_array *tr = data; struct trace_pid_list *pid_list; diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 3147614c1812..2a19ea747ff4 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -759,7 +759,9 @@ void trace_event_follow_fork(struct trace_array *tr, bool enable) static void event_filter_pid_sched_switch_probe_pre(void *data, bool preempt, - struct task_struct *prev, struct task_struct *next) + unsigned int prev_state, + struct task_struct *prev, + struct task_struct *next) { struct trace_array *tr = data; struct trace_pid_list *no_pid_list; @@ -783,7 +785,9 @@ event_filter_pid_sched_switch_probe_pre(void *data, bool preempt, static void event_filter_pid_sched_switch_probe_post(void *data, bool preempt, - struct task_struct *prev, struct task_struct *next) + unsigned int prev_state, + struct task_struct *prev, + struct task_struct *next) { struct trace_array *tr = data; struct trace_pid_list *no_pid_list; diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index 870a08da5b48..1829b4cb8cc1 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -1167,7 +1167,9 @@ thread_exit(struct osnoise_variables *osn_var, struct task_struct *t) * used to record the beginning and to report the end of a thread noise window. */ static void -trace_sched_switch_callback(void *data, bool preempt, struct task_struct *p, +trace_sched_switch_callback(void *data, bool preempt, + unsigned int prev_state, + struct task_struct *p, struct task_struct *n) { struct osnoise_variables *osn_var = this_cpu_osn_var(); diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index e304196d7c28..993b0ed10d8c 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -22,6 +22,7 @@ static DEFINE_MUTEX(sched_register_mutex); static void probe_sched_switch(void *ignore, bool preempt, + unsigned int prev_state, struct task_struct *prev, struct task_struct *next) { int flags; diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 2402de520eca..46429f9a96fa 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -426,6 +426,7 @@ tracing_sched_wakeup_trace(struct trace_array *tr, static void notrace probe_wakeup_sched_switch(void *ignore, bool preempt, + unsigned int prev_state, struct task_struct *prev, struct task_struct *next) { struct trace_array_cpu *data; -- cgit v1.2.3 From 25795ef6299f07ce3838f3253a9cb34f64efcfae Mon Sep 17 00:00:00 2001 From: Valentin Schneider Date: Thu, 20 Jan 2022 16:25:20 +0000 Subject: sched/tracing: Report TASK_RTLOCK_WAIT tasks as TASK_UNINTERRUPTIBLE MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit TASK_RTLOCK_WAIT currently isn't part of TASK_REPORT, thus a task blocking on an rtlock will appear as having a task state == 0, IOW TASK_RUNNING. The actual state is saved in p->saved_state, but reading it after reading p->__state has a few issues: o that could still be TASK_RUNNING in the case of e.g. rt_spin_lock o ttwu_state_match() might have changed that to TASK_RUNNING As pointed out by Eric, adding TASK_RTLOCK_WAIT to TASK_REPORT implies exposing a new state to userspace tools which way not know what to do with them. The only information that needs to be conveyed here is that a task is waiting on an rt_mutex, which matches TASK_UNINTERRUPTIBLE - there's no need for a new state. Reported-by: Uwe Kleine-König Signed-off-by: Valentin Schneider Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Steven Rostedt (Google) Link: https://lore.kernel.org/r/20220120162520.570782-3-valentin.schneider@arm.com --- include/linux/sched.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include') diff --git a/include/linux/sched.h b/include/linux/sched.h index 457c8a058b77..78b606c9ab38 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1630,6 +1630,14 @@ static inline unsigned int __task_state_index(unsigned int tsk_state, if (tsk_state == TASK_IDLE) state = TASK_REPORT_IDLE; + /* + * We're lying here, but rather than expose a completely new task state + * to userspace, we can make this appear as if the task has gone through + * a regular rt_mutex_lock() call. + */ + if (tsk_state == TASK_RTLOCK_WAIT) + state = TASK_UNINTERRUPTIBLE; + return fls(state); } -- cgit v1.2.3 From f2aa197e4794bf4c2c0c9570684f86e6fa103e8b Mon Sep 17 00:00:00 2001 From: Chengming Zhou Date: Sat, 5 Mar 2022 11:41:03 +0800 Subject: cgroup: Fix suspicious rcu_dereference_check() usage warning task_css_set_check() will use rcu_dereference_check() to check for rcu_read_lock_held() on the read-side, which is not true after commit dc6e0818bc9a ("sched/cpuacct: Optimize away RCU read lock"). This commit drop explicit rcu_read_lock(), change to RCU-sched read-side critical section. So fix the RCU warning by adding check for rcu_read_lock_sched_held(). Fixes: dc6e0818bc9a ("sched/cpuacct: Optimize away RCU read lock") Reported-by: Linux Kernel Functional Testing Reported-by: syzbot+16e3f2c77e7c5a0113f9@syzkaller.appspotmail.com Signed-off-by: Chengming Zhou Signed-off-by: Peter Zijlstra (Intel) Acked-by: Tejun Heo Tested-by: Zhouyi Zhou Tested-by: Marek Szyprowski Link: https://lore.kernel.org/r/20220305034103.57123-1-zhouchengming@bytedance.com --- include/linux/cgroup.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 1e356c222756..0d1ada8968d7 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -450,6 +450,7 @@ extern struct mutex cgroup_mutex; extern spinlock_t css_set_lock; #define task_css_set_check(task, __c) \ rcu_dereference_check((task)->cgroups, \ + rcu_read_lock_sched_held() || \ lockdep_is_held(&cgroup_mutex) || \ lockdep_is_held(&css_set_lock) || \ ((task)->flags & PF_EXITING) || (__c)) -- cgit v1.2.3 From 3387ce4d8a5f2956fab827edf499fe6780e83faa Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 21 Mar 2022 11:05:50 +0100 Subject: headers/prep: Fix header to build standalone: Add the dependency to , because cgroup_move_task() will dereference 'struct css_set'. ( Only older toolchains are affected, due to variations in the implementation of rcu_assign_pointer() et al. ) Cc: Peter Zijlstra Cc: Linus Torvalds Reported-by: Sachin Sant Reported-by: Andrew Morton Reported-by: Borislav Petkov Signed-off-by: Ingo Molnar --- include/linux/psi.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/psi.h b/include/linux/psi.h index 7f7d1d88c3bb..89784763d19e 100644 --- a/include/linux/psi.h +++ b/include/linux/psi.h @@ -6,6 +6,7 @@ #include #include #include +#include struct seq_file; struct css_set; -- cgit v1.2.3