From 22b63e6173746a6e967b6ce430f1f0bfd6a9db13 Mon Sep 17 00:00:00 2001 From: dlg Date: Mon, 7 Nov 2022 12:56:38 +0000 Subject: [PATCH] move pf_purge out from under the kernel lock and avoid the hogging cpu this also avoids holding NET_LOCK too long. the main change is done by running the purge tasks in systqmp instead of systq. the pf state list was recently reworked so iteration over the state can be done without blocking insertions. however, scanning a lot of states can still take a lot of time, so this also makes the state list scanner yield if it has spent too much time running. the other purge tasks for source nodes, rules, and fragments have been moved to their own timeout/task pair to simplify the time accounting. in my environment, before this change pf purges often took 10 to 50ms. the softclock thread runs next to it often took a similar amount of time, presumably because they ended up spinning waiting for each other. after this change the pf_purges are more like 6 to 12ms, and dont block softclock. most of the variability in the runs now seems to come from contention on the net lock. tested by me sthen@ chris@ ok sashan@ kn@ claudio@ --- sys/net/pf.c | 144 ++++++++++++++++++++++++++++++++----------- sys/net/pf_ioctl.c | 8 ++- sys/net/pfvar.h | 3 +- sys/net/pfvar_priv.h | 5 +- 4 files changed, 116 insertions(+), 44 deletions(-) diff --git a/sys/net/pf.c b/sys/net/pf.c index 62108ab25c9..2c6124e74f2 100644 --- a/sys/net/pf.c +++ b/sys/net/pf.c @@ -1,4 +1,4 @@ -/* $OpenBSD: pf.c,v 1.1142 2022/11/06 18:05:05 dlg Exp $ */ +/* $OpenBSD: pf.c,v 1.1143 2022/11/07 12:56:38 dlg Exp $ */ /* * Copyright (c) 2001 Daniel Hartmeier @@ -120,10 +120,6 @@ u_char pf_tcp_secret[16]; int pf_tcp_secret_init; int pf_tcp_iss_off; -int pf_npurge; -struct task pf_purge_task = TASK_INITIALIZER(pf_purge, &pf_npurge); -struct timeout pf_purge_to = TIMEOUT_INITIALIZER(pf_purge_timeout, NULL); - enum pf_test_status { PF_TEST_FAIL = -1, PF_TEST_OK, @@ -1499,49 +1495,111 @@ pf_purge_expired_rules(void) } } -void -pf_purge_timeout(void *unused) -{ - /* XXX move to systqmp to avoid KERNEL_LOCK */ - task_add(systq, &pf_purge_task); -} +void pf_purge_states(void *); +struct task pf_purge_states_task = + TASK_INITIALIZER(pf_purge_states, NULL); + +void pf_purge_states_tick(void *); +struct timeout pf_purge_states_to = + TIMEOUT_INITIALIZER(pf_purge_states_tick, NULL); + +unsigned int pf_purge_expired_states(unsigned int, unsigned int); + +/* + * how many states to scan this interval. + * + * this is set when the timeout fires, and reduced by the task. the + * task will reschedule itself until the limit is reduced to zero, + * and then it adds the timeout again. + */ +unsigned int pf_purge_states_limit; + +/* + * limit how many states are processed with locks held per run of + * the state purge task. + */ +unsigned int pf_purge_states_collect = 64; void -pf_purge(void *xnloops) +pf_purge_states_tick(void *null) { - int *nloops = xnloops; + unsigned int limit = pf_status.states; + unsigned int interval = pf_default_rule.timeout[PFTM_INTERVAL]; + + if (limit == 0) { + timeout_add_sec(&pf_purge_states_to, 1); + return; + } /* * process a fraction of the state table every second - * Note: - * we no longer need PF_LOCK() here, because - * pf_purge_expired_states() uses pf_state_lock to maintain - * consistency. */ - if (pf_default_rule.timeout[PFTM_INTERVAL] > 0) - pf_purge_expired_states(1 + (pf_status.states - / pf_default_rule.timeout[PFTM_INTERVAL])); + if (interval > 1) + limit /= interval; + + pf_purge_states_limit = limit; + task_add(systqmp, &pf_purge_states_task); +} + +void +pf_purge_states(void *null) +{ + unsigned int limit; + unsigned int scanned; + + limit = pf_purge_states_limit; + if (limit < pf_purge_states_collect) + limit = pf_purge_states_collect; + + scanned = pf_purge_expired_states(limit, pf_purge_states_collect); + if (scanned >= pf_purge_states_limit) { + /* we've run out of states to scan this "interval" */ + timeout_add_sec(&pf_purge_states_to, 1); + return; + } + + pf_purge_states_limit -= scanned; + task_add(systqmp, &pf_purge_states_task); +} + +void pf_purge_tick(void *); +struct timeout pf_purge_to = + TIMEOUT_INITIALIZER(pf_purge_tick, NULL); + +void pf_purge(void *); +struct task pf_purge_task = + TASK_INITIALIZER(pf_purge, NULL); + +void +pf_purge_tick(void *null) +{ + task_add(systqmp, &pf_purge_task); +} + +void +pf_purge(void *null) +{ + unsigned int interval = max(1, pf_default_rule.timeout[PFTM_INTERVAL]); + + /* XXX is NET_LOCK necessary? */ NET_LOCK(); PF_LOCK(); - /* purge other expired types every PFTM_INTERVAL seconds */ - if (++(*nloops) >= pf_default_rule.timeout[PFTM_INTERVAL]) { - pf_purge_expired_src_nodes(); - pf_purge_expired_rules(); - } + + pf_purge_expired_src_nodes(); + pf_purge_expired_rules(); + PF_UNLOCK(); /* * Fragments don't require PF_LOCK(), they use their own lock. */ - if ((*nloops) >= pf_default_rule.timeout[PFTM_INTERVAL]) { - pf_purge_expired_fragments(); - *nloops = 0; - } + pf_purge_expired_fragments(); NET_UNLOCK(); - timeout_add_sec(&pf_purge_to, 1); + /* interpret the interval as idle time between runs */ + timeout_add_sec(&pf_purge_to, interval); } int32_t @@ -1741,8 +1799,8 @@ pf_free_state(struct pf_state *cur) pf_status.states--; } -void -pf_purge_expired_states(u_int32_t maxcheck) +unsigned int +pf_purge_expired_states(const unsigned int limit, const unsigned int collect) { /* * this task/thread/context/whatever is the only thing that @@ -1756,6 +1814,8 @@ pf_purge_expired_states(u_int32_t maxcheck) struct pf_state *st; SLIST_HEAD(pf_state_gcl, pf_state) gcl = SLIST_HEAD_INITIALIZER(gcl); time_t now; + unsigned int scanned; + unsigned int collected = 0; PF_ASSERT_UNLOCKED(); @@ -1769,7 +1829,7 @@ pf_purge_expired_states(u_int32_t maxcheck) if (head == NULL) { /* the list is empty */ rw_exit_read(&pf_state_list.pfs_rwl); - return; + return (limit); } /* (re)start at the front of the list */ @@ -1778,28 +1838,38 @@ pf_purge_expired_states(u_int32_t maxcheck) now = getuptime(); - do { + for (scanned = 0; scanned < limit; scanned++) { uint8_t stimeout = cur->timeout; + unsigned int limited = 0; if ((stimeout == PFTM_UNLINKED) || (pf_state_expires(cur, stimeout) <= now)) { st = pf_state_ref(cur); SLIST_INSERT_HEAD(&gcl, st, gc_list); + + if (++collected >= collect) + limited = 1; } /* don't iterate past the end of our view of the list */ if (cur == tail) { + scanned = limit; cur = NULL; break; } cur = TAILQ_NEXT(cur, entry_list); - } while (maxcheck--); + + /* don't spend too much time here. */ + if (ISSET(READ_ONCE(curcpu()->ci_schedstate.spc_schedflags), + SPCF_SHOULDYIELD) || limited) + break; + } rw_exit_read(&pf_state_list.pfs_rwl); if (SLIST_EMPTY(&gcl)) - return; + return (scanned); NET_LOCK(); rw_enter_write(&pf_state_list.pfs_rwl); @@ -1820,6 +1890,8 @@ pf_purge_expired_states(u_int32_t maxcheck) SLIST_REMOVE_HEAD(&gcl, gc_list); pf_state_unref(st); } + + return (scanned); } int diff --git a/sys/net/pf_ioctl.c b/sys/net/pf_ioctl.c index 60b11cb0630..b5d3261f8d1 100644 --- a/sys/net/pf_ioctl.c +++ b/sys/net/pf_ioctl.c @@ -1,4 +1,4 @@ -/* $OpenBSD: pf_ioctl.c,v 1.387 2022/11/06 18:05:05 dlg Exp $ */ +/* $OpenBSD: pf_ioctl.c,v 1.388 2022/11/07 12:56:38 dlg Exp $ */ /* * Copyright (c) 2001 Daniel Hartmeier @@ -1169,6 +1169,7 @@ pfioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p) pf_status.stateid = gettime(); pf_status.stateid = pf_status.stateid << 32; } + timeout_add_sec(&pf_purge_states_to, 1); timeout_add_sec(&pf_purge_to, 1); pf_create_queues(); DPFPRINTF(LOG_NOTICE, "pf: started"); @@ -2768,8 +2769,9 @@ pfioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p) pf_default_rule.timeout[i] = pf_default_rule_new.timeout[i]; if (pf_default_rule.timeout[i] == PFTM_INTERVAL && - pf_default_rule.timeout[i] < old) - task_add(net_tq(0), &pf_purge_task); + pf_default_rule.timeout[i] < old && + timeout_del(&pf_purge_to)) + task_add(systqmp, &pf_purge_task); } pfi_xcommit(); pf_trans_set_commit(); diff --git a/sys/net/pfvar.h b/sys/net/pfvar.h index 8d972897bcb..91b309ab729 100644 --- a/sys/net/pfvar.h +++ b/sys/net/pfvar.h @@ -1,4 +1,4 @@ -/* $OpenBSD: pfvar.h,v 1.512 2022/11/06 18:05:05 dlg Exp $ */ +/* $OpenBSD: pfvar.h,v 1.513 2022/11/07 12:56:38 dlg Exp $ */ /* * Copyright (c) 2001 Daniel Hartmeier @@ -1716,7 +1716,6 @@ extern void pf_tbladdr_remove(struct pf_addr_wrap *); extern void pf_tbladdr_copyout(struct pf_addr_wrap *); extern void pf_calc_skip_steps(struct pf_rulequeue *); extern void pf_purge_expired_src_nodes(void); -extern void pf_purge_expired_states(u_int32_t); extern void pf_purge_expired_rules(void); extern void pf_remove_state(struct pf_state *); extern void pf_remove_divert_state(struct pf_state_key *); diff --git a/sys/net/pfvar_priv.h b/sys/net/pfvar_priv.h index ec8f61a800d..70d135b269d 100644 --- a/sys/net/pfvar_priv.h +++ b/sys/net/pfvar_priv.h @@ -1,4 +1,4 @@ -/* $OpenBSD: pfvar_priv.h,v 1.10 2022/04/29 08:58:49 bluhm Exp $ */ +/* $OpenBSD: pfvar_priv.h,v 1.11 2022/11/07 12:56:38 dlg Exp $ */ /* * Copyright (c) 2001 Daniel Hartmeier @@ -209,6 +209,7 @@ struct pf_pdesc { } hdr; }; +extern struct timeout pf_purge_states_to; extern struct task pf_purge_task; extern struct timeout pf_purge_to; @@ -262,8 +263,6 @@ extern struct rwlock pf_state_lock; rw_status(&pf_state_lock), __func__);\ } while (0) -extern void pf_purge_timeout(void *); -extern void pf_purge(void *); #endif /* _KERNEL */ #endif /* _NET_PFVAR_PRIV_H_ */ -- 2.20.1