// SPDX-License-Identifier: GPL-2.0-or-later /* * ip_vs_est.c: simple rate estimator for IPVS * * Authors: Wensong Zhang <[email protected]> * * Changes: Hans Schillstrom <[email protected]> * Network name space (netns) aware. * Global data moved to netns i.e struct netns_ipvs * Affected data: est_list and est_lock. * estimation_timer() runs with timer per netns. * get_stats()) do the per cpu summing. */ #define KMSG_COMPONENT … #define pr_fmt(fmt) … #include <linux/kernel.h> #include <linux/jiffies.h> #include <linux/types.h> #include <linux/interrupt.h> #include <linux/sysctl.h> #include <linux/list.h> #include <linux/rcupdate_wait.h> #include <net/ip_vs.h> /* This code is to estimate rate in a shorter interval (such as 8 seconds) for virtual services and real servers. For measure rate in a long interval, it is easy to implement a user level daemon which periodically reads those statistical counters and measure rate. We measure rate during the last 8 seconds every 2 seconds: avgrate = avgrate*(1-W) + rate*W where W = 2^(-2) NOTES. * Average bps is scaled by 2^5, while average pps and cps are scaled by 2^10. * Netlink users can see 64-bit values but sockopt users are restricted to 32-bit values for conns, packets, bps, cps and pps. * A lot of code is taken from net/core/gen_estimator.c KEY POINTS: - cpustats counters are updated per-cpu in SoftIRQ context with BH disabled - kthreads read the cpustats to update the estimators (svcs, dests, total) - the states of estimators can be read (get stats) or modified (zero stats) from processes KTHREADS: - estimators are added initially to est_temp_list and later kthread 0 distributes them to one or many kthreads for estimation - kthread contexts are created and attached to array - the kthread tasks are started when first service is added, before that the total stats are not estimated - when configuration (cpulist/nice) is changed, the tasks are restarted by work (est_reload_work) - kthread tasks are stopped while the cpulist is empty - the kthread context holds lists with estimators (chains) which are processed every 2 seconds - as estimators can be added dynamically and in bursts, we try to spread them to multiple chains which are estimated at different time - on start, kthread 0 enters calculation phase to determine the chain limits and the limit of estimators per kthread - est_add_ktid: ktid where to add new ests, can point to empty slot where we should add kt data */ static struct lock_class_key __ipvs_est_key; static void ip_vs_est_calc_phase(struct netns_ipvs *ipvs); static void ip_vs_est_drain_temp_list(struct netns_ipvs *ipvs); static void ip_vs_chain_estimation(struct hlist_head *chain) { … } static void ip_vs_tick_estimation(struct ip_vs_est_kt_data *kd, int row) { … } static int ip_vs_estimation_kthread(void *data) { … } /* Schedule stop/start for kthread tasks */ void ip_vs_est_reload_start(struct netns_ipvs *ipvs) { … } /* Start kthread task with current configuration */ int ip_vs_est_kthread_start(struct netns_ipvs *ipvs, struct ip_vs_est_kt_data *kd) { … } void ip_vs_est_kthread_stop(struct ip_vs_est_kt_data *kd) { … } /* Apply parameters to kthread */ static void ip_vs_est_set_params(struct netns_ipvs *ipvs, struct ip_vs_est_kt_data *kd) { … } /* Create and start estimation kthread in a free or new array slot */ static int ip_vs_est_add_kthread(struct netns_ipvs *ipvs) { … } /* Select ktid where to add new ests: available, unused or new slot */ static void ip_vs_est_update_ktid(struct netns_ipvs *ipvs) { … } /* Add estimator to current kthread (est_add_ktid) */ static int ip_vs_enqueue_estimator(struct netns_ipvs *ipvs, struct ip_vs_estimator *est) { … } /* Start estimation for stats */ int ip_vs_start_estimator(struct netns_ipvs *ipvs, struct ip_vs_stats *stats) { … } static void ip_vs_est_kthread_destroy(struct ip_vs_est_kt_data *kd) { … } /* Unlink estimator from chain */ void ip_vs_stop_estimator(struct netns_ipvs *ipvs, struct ip_vs_stats *stats) { … } /* Register all ests from est_temp_list to kthreads */ static void ip_vs_est_drain_temp_list(struct netns_ipvs *ipvs) { … } /* Calculate limits for all kthreads */ static int ip_vs_est_calc_limits(struct netns_ipvs *ipvs, int *chain_max) { … } /* Calculate the parameters and apply them in context of kt #0 * ECP: est_calc_phase * ECM: est_chain_max * ECP ECM Insert Chain enable Description * --------------------------------------------------------------------------- * 0 0 est_temp_list 0 create kt #0 context * 0 0 est_temp_list 0->1 service added, start kthread #0 task * 0->1 0 est_temp_list 1 kt task #0 started, enters calc phase * 1 0 est_temp_list 1 kt #0: determine est_chain_max, * stop tasks, move ests to est_temp_list * and free kd for kthreads 1..last * 1->0 0->N kt chains 1 ests can go to kthreads * 0 N kt chains 1 drain est_temp_list, create new kthread * contexts, start tasks, estimate */ static void ip_vs_est_calc_phase(struct netns_ipvs *ipvs) { … } void ip_vs_zero_estimator(struct ip_vs_stats *stats) { … } /* Get decoded rates */ void ip_vs_read_estimator(struct ip_vs_kstats *dst, struct ip_vs_stats *stats) { … } int __net_init ip_vs_estimator_net_init(struct netns_ipvs *ipvs) { … } void __net_exit ip_vs_estimator_net_cleanup(struct netns_ipvs *ipvs) { … }
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