18b4fd62e0
should be used by TCP for sure in its cleanup of the IN-PCB (will be coming shortly). Sponsored by: Netflix Inc. Differential Revision: https://reviews.freebsd.org/D4076
1620 lines
46 KiB
C
1620 lines
46 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* From: @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_callout_profiling.h"
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#if defined(__arm__)
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#include "opt_timer.h"
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#endif
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#include "opt_rss.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bus.h>
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#include <sys/callout.h>
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#include <sys/file.h>
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#include <sys/interrupt.h>
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#include <sys/kernel.h>
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#include <sys/ktr.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/sdt.h>
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#include <sys/sleepqueue.h>
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#include <sys/sysctl.h>
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#include <sys/smp.h>
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#ifdef SMP
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#include <machine/cpu.h>
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#endif
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#ifndef NO_EVENTTIMERS
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DPCPU_DECLARE(sbintime_t, hardclocktime);
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#endif
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SDT_PROVIDER_DEFINE(callout_execute);
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SDT_PROBE_DEFINE1(callout_execute, kernel, , callout__start,
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"struct callout *");
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SDT_PROBE_DEFINE1(callout_execute, kernel, , callout__end,
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"struct callout *");
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#ifdef CALLOUT_PROFILING
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static int avg_depth;
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SYSCTL_INT(_debug, OID_AUTO, to_avg_depth, CTLFLAG_RD, &avg_depth, 0,
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"Average number of items examined per softclock call. Units = 1/1000");
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static int avg_gcalls;
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SYSCTL_INT(_debug, OID_AUTO, to_avg_gcalls, CTLFLAG_RD, &avg_gcalls, 0,
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"Average number of Giant callouts made per softclock call. Units = 1/1000");
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static int avg_lockcalls;
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SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls, CTLFLAG_RD, &avg_lockcalls, 0,
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"Average number of lock callouts made per softclock call. Units = 1/1000");
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static int avg_mpcalls;
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SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls, CTLFLAG_RD, &avg_mpcalls, 0,
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"Average number of MP callouts made per softclock call. Units = 1/1000");
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static int avg_depth_dir;
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SYSCTL_INT(_debug, OID_AUTO, to_avg_depth_dir, CTLFLAG_RD, &avg_depth_dir, 0,
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"Average number of direct callouts examined per callout_process call. "
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"Units = 1/1000");
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static int avg_lockcalls_dir;
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SYSCTL_INT(_debug, OID_AUTO, to_avg_lockcalls_dir, CTLFLAG_RD,
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&avg_lockcalls_dir, 0, "Average number of lock direct callouts made per "
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"callout_process call. Units = 1/1000");
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static int avg_mpcalls_dir;
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SYSCTL_INT(_debug, OID_AUTO, to_avg_mpcalls_dir, CTLFLAG_RD, &avg_mpcalls_dir,
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0, "Average number of MP direct callouts made per callout_process call. "
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"Units = 1/1000");
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#endif
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static int ncallout;
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SYSCTL_INT(_kern, OID_AUTO, ncallout, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &ncallout, 0,
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"Number of entries in callwheel and size of timeout() preallocation");
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#ifdef RSS
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static int pin_default_swi = 1;
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static int pin_pcpu_swi = 1;
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#else
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static int pin_default_swi = 0;
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static int pin_pcpu_swi = 0;
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#endif
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SYSCTL_INT(_kern, OID_AUTO, pin_default_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_default_swi,
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0, "Pin the default (non-per-cpu) swi (shared with PCPU 0 swi)");
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SYSCTL_INT(_kern, OID_AUTO, pin_pcpu_swi, CTLFLAG_RDTUN | CTLFLAG_NOFETCH, &pin_pcpu_swi,
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0, "Pin the per-CPU swis (except PCPU 0, which is also default");
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/*
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* TODO:
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* allocate more timeout table slots when table overflows.
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*/
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u_int callwheelsize, callwheelmask;
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/*
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* The callout cpu exec entities represent informations necessary for
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* describing the state of callouts currently running on the CPU and the ones
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* necessary for migrating callouts to the new callout cpu. In particular,
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* the first entry of the array cc_exec_entity holds informations for callout
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* running in SWI thread context, while the second one holds informations
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* for callout running directly from hardware interrupt context.
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* The cached informations are very important for deferring migration when
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* the migrating callout is already running.
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*/
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struct cc_exec {
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struct callout *cc_curr;
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void (*cc_drain)(void *);
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#ifdef SMP
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void (*ce_migration_func)(void *);
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void *ce_migration_arg;
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int ce_migration_cpu;
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sbintime_t ce_migration_time;
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sbintime_t ce_migration_prec;
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#endif
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bool cc_cancel;
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bool cc_waiting;
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};
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/*
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* There is one struct callout_cpu per cpu, holding all relevant
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* state for the callout processing thread on the individual CPU.
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*/
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struct callout_cpu {
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struct mtx_padalign cc_lock;
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struct cc_exec cc_exec_entity[2];
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struct callout *cc_next;
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struct callout *cc_callout;
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struct callout_list *cc_callwheel;
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struct callout_tailq cc_expireq;
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struct callout_slist cc_callfree;
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sbintime_t cc_firstevent;
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sbintime_t cc_lastscan;
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void *cc_cookie;
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u_int cc_bucket;
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u_int cc_inited;
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char cc_ktr_event_name[20];
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};
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#define callout_migrating(c) ((c)->c_iflags & CALLOUT_DFRMIGRATION)
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#define cc_exec_curr(cc, dir) cc->cc_exec_entity[dir].cc_curr
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#define cc_exec_drain(cc, dir) cc->cc_exec_entity[dir].cc_drain
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#define cc_exec_next(cc) cc->cc_next
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#define cc_exec_cancel(cc, dir) cc->cc_exec_entity[dir].cc_cancel
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#define cc_exec_waiting(cc, dir) cc->cc_exec_entity[dir].cc_waiting
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#ifdef SMP
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#define cc_migration_func(cc, dir) cc->cc_exec_entity[dir].ce_migration_func
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#define cc_migration_arg(cc, dir) cc->cc_exec_entity[dir].ce_migration_arg
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#define cc_migration_cpu(cc, dir) cc->cc_exec_entity[dir].ce_migration_cpu
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#define cc_migration_time(cc, dir) cc->cc_exec_entity[dir].ce_migration_time
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#define cc_migration_prec(cc, dir) cc->cc_exec_entity[dir].ce_migration_prec
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struct callout_cpu cc_cpu[MAXCPU];
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#define CPUBLOCK MAXCPU
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#define CC_CPU(cpu) (&cc_cpu[(cpu)])
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#define CC_SELF() CC_CPU(PCPU_GET(cpuid))
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#else
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struct callout_cpu cc_cpu;
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#define CC_CPU(cpu) &cc_cpu
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#define CC_SELF() &cc_cpu
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#endif
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#define CC_LOCK(cc) mtx_lock_spin(&(cc)->cc_lock)
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#define CC_UNLOCK(cc) mtx_unlock_spin(&(cc)->cc_lock)
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#define CC_LOCK_ASSERT(cc) mtx_assert(&(cc)->cc_lock, MA_OWNED)
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static int timeout_cpu;
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static void callout_cpu_init(struct callout_cpu *cc, int cpu);
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static void softclock_call_cc(struct callout *c, struct callout_cpu *cc,
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#ifdef CALLOUT_PROFILING
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int *mpcalls, int *lockcalls, int *gcalls,
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#endif
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int direct);
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static MALLOC_DEFINE(M_CALLOUT, "callout", "Callout datastructures");
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/**
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* Locked by cc_lock:
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* cc_curr - If a callout is in progress, it is cc_curr.
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* If cc_curr is non-NULL, threads waiting in
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* callout_drain() will be woken up as soon as the
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* relevant callout completes.
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* cc_cancel - Changing to 1 with both callout_lock and cc_lock held
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* guarantees that the current callout will not run.
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* The softclock() function sets this to 0 before it
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* drops callout_lock to acquire c_lock, and it calls
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* the handler only if curr_cancelled is still 0 after
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* cc_lock is successfully acquired.
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* cc_waiting - If a thread is waiting in callout_drain(), then
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* callout_wait is nonzero. Set only when
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* cc_curr is non-NULL.
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*/
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/*
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* Resets the execution entity tied to a specific callout cpu.
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*/
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static void
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cc_cce_cleanup(struct callout_cpu *cc, int direct)
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{
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cc_exec_curr(cc, direct) = NULL;
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cc_exec_cancel(cc, direct) = false;
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cc_exec_waiting(cc, direct) = false;
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#ifdef SMP
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cc_migration_cpu(cc, direct) = CPUBLOCK;
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cc_migration_time(cc, direct) = 0;
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cc_migration_prec(cc, direct) = 0;
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cc_migration_func(cc, direct) = NULL;
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cc_migration_arg(cc, direct) = NULL;
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#endif
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}
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/*
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* Checks if migration is requested by a specific callout cpu.
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*/
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static int
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cc_cce_migrating(struct callout_cpu *cc, int direct)
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{
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#ifdef SMP
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return (cc_migration_cpu(cc, direct) != CPUBLOCK);
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#else
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return (0);
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#endif
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}
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/*
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* Kernel low level callwheel initialization
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* called on cpu0 during kernel startup.
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*/
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static void
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callout_callwheel_init(void *dummy)
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{
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struct callout_cpu *cc;
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/*
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* Calculate the size of the callout wheel and the preallocated
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* timeout() structures.
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* XXX: Clip callout to result of previous function of maxusers
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* maximum 384. This is still huge, but acceptable.
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*/
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memset(CC_CPU(0), 0, sizeof(cc_cpu));
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ncallout = imin(16 + maxproc + maxfiles, 18508);
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TUNABLE_INT_FETCH("kern.ncallout", &ncallout);
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/*
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* Calculate callout wheel size, should be next power of two higher
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* than 'ncallout'.
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*/
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callwheelsize = 1 << fls(ncallout);
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callwheelmask = callwheelsize - 1;
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/*
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* Fetch whether we're pinning the swi's or not.
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*/
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TUNABLE_INT_FETCH("kern.pin_default_swi", &pin_default_swi);
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TUNABLE_INT_FETCH("kern.pin_pcpu_swi", &pin_pcpu_swi);
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/*
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* Only cpu0 handles timeout(9) and receives a preallocation.
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*
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* XXX: Once all timeout(9) consumers are converted this can
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* be removed.
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*/
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timeout_cpu = PCPU_GET(cpuid);
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cc = CC_CPU(timeout_cpu);
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cc->cc_callout = malloc(ncallout * sizeof(struct callout),
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M_CALLOUT, M_WAITOK);
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callout_cpu_init(cc, timeout_cpu);
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}
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SYSINIT(callwheel_init, SI_SUB_CPU, SI_ORDER_ANY, callout_callwheel_init, NULL);
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/*
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* Initialize the per-cpu callout structures.
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*/
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static void
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callout_cpu_init(struct callout_cpu *cc, int cpu)
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{
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struct callout *c;
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int i;
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mtx_init(&cc->cc_lock, "callout", NULL, MTX_SPIN | MTX_RECURSE);
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SLIST_INIT(&cc->cc_callfree);
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cc->cc_inited = 1;
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cc->cc_callwheel = malloc(sizeof(struct callout_list) * callwheelsize,
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M_CALLOUT, M_WAITOK);
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for (i = 0; i < callwheelsize; i++)
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LIST_INIT(&cc->cc_callwheel[i]);
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TAILQ_INIT(&cc->cc_expireq);
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cc->cc_firstevent = SBT_MAX;
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for (i = 0; i < 2; i++)
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cc_cce_cleanup(cc, i);
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snprintf(cc->cc_ktr_event_name, sizeof(cc->cc_ktr_event_name),
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"callwheel cpu %d", cpu);
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if (cc->cc_callout == NULL) /* Only cpu0 handles timeout(9) */
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return;
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for (i = 0; i < ncallout; i++) {
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c = &cc->cc_callout[i];
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callout_init(c, 0);
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c->c_iflags = CALLOUT_LOCAL_ALLOC;
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SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle);
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}
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}
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#ifdef SMP
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/*
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* Switches the cpu tied to a specific callout.
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* The function expects a locked incoming callout cpu and returns with
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* locked outcoming callout cpu.
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*/
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static struct callout_cpu *
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callout_cpu_switch(struct callout *c, struct callout_cpu *cc, int new_cpu)
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{
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struct callout_cpu *new_cc;
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MPASS(c != NULL && cc != NULL);
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CC_LOCK_ASSERT(cc);
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/*
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* Avoid interrupts and preemption firing after the callout cpu
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* is blocked in order to avoid deadlocks as the new thread
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* may be willing to acquire the callout cpu lock.
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*/
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c->c_cpu = CPUBLOCK;
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spinlock_enter();
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CC_UNLOCK(cc);
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new_cc = CC_CPU(new_cpu);
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CC_LOCK(new_cc);
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spinlock_exit();
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c->c_cpu = new_cpu;
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return (new_cc);
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}
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#endif
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/*
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* Start standard softclock thread.
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*/
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static void
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start_softclock(void *dummy)
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{
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struct callout_cpu *cc;
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char name[MAXCOMLEN];
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#ifdef SMP
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int cpu;
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struct intr_event *ie;
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#endif
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cc = CC_CPU(timeout_cpu);
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snprintf(name, sizeof(name), "clock (%d)", timeout_cpu);
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if (swi_add(&clk_intr_event, name, softclock, cc, SWI_CLOCK,
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INTR_MPSAFE, &cc->cc_cookie))
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panic("died while creating standard software ithreads");
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if (pin_default_swi &&
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(intr_event_bind(clk_intr_event, timeout_cpu) != 0)) {
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printf("%s: timeout clock couldn't be pinned to cpu %d\n",
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__func__,
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timeout_cpu);
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}
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#ifdef SMP
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CPU_FOREACH(cpu) {
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if (cpu == timeout_cpu)
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continue;
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cc = CC_CPU(cpu);
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cc->cc_callout = NULL; /* Only cpu0 handles timeout(9). */
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callout_cpu_init(cc, cpu);
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snprintf(name, sizeof(name), "clock (%d)", cpu);
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ie = NULL;
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if (swi_add(&ie, name, softclock, cc, SWI_CLOCK,
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INTR_MPSAFE, &cc->cc_cookie))
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panic("died while creating standard software ithreads");
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if (pin_pcpu_swi && (intr_event_bind(ie, cpu) != 0)) {
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printf("%s: per-cpu clock couldn't be pinned to "
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"cpu %d\n",
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__func__,
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cpu);
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}
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}
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#endif
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}
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SYSINIT(start_softclock, SI_SUB_SOFTINTR, SI_ORDER_FIRST, start_softclock, NULL);
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#define CC_HASH_SHIFT 8
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static inline u_int
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callout_hash(sbintime_t sbt)
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{
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return (sbt >> (32 - CC_HASH_SHIFT));
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}
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static inline u_int
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callout_get_bucket(sbintime_t sbt)
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{
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return (callout_hash(sbt) & callwheelmask);
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}
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|
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void
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callout_process(sbintime_t now)
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{
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struct callout *tmp, *tmpn;
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struct callout_cpu *cc;
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struct callout_list *sc;
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sbintime_t first, last, max, tmp_max;
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uint32_t lookahead;
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u_int firstb, lastb, nowb;
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#ifdef CALLOUT_PROFILING
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int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0;
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#endif
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cc = CC_SELF();
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mtx_lock_spin_flags(&cc->cc_lock, MTX_QUIET);
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/* Compute the buckets of the last scan and present times. */
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firstb = callout_hash(cc->cc_lastscan);
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cc->cc_lastscan = now;
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nowb = callout_hash(now);
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/* Compute the last bucket and minimum time of the bucket after it. */
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if (nowb == firstb)
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lookahead = (SBT_1S / 16);
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else if (nowb - firstb == 1)
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lookahead = (SBT_1S / 8);
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else
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lookahead = (SBT_1S / 2);
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first = last = now;
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first += (lookahead / 2);
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last += lookahead;
|
|
last &= (0xffffffffffffffffLLU << (32 - CC_HASH_SHIFT));
|
|
lastb = callout_hash(last) - 1;
|
|
max = last;
|
|
|
|
/*
|
|
* Check if we wrapped around the entire wheel from the last scan.
|
|
* In case, we need to scan entirely the wheel for pending callouts.
|
|
*/
|
|
if (lastb - firstb >= callwheelsize) {
|
|
lastb = firstb + callwheelsize - 1;
|
|
if (nowb - firstb >= callwheelsize)
|
|
nowb = lastb;
|
|
}
|
|
|
|
/* Iterate callwheel from firstb to nowb and then up to lastb. */
|
|
do {
|
|
sc = &cc->cc_callwheel[firstb & callwheelmask];
|
|
tmp = LIST_FIRST(sc);
|
|
while (tmp != NULL) {
|
|
/* Run the callout if present time within allowed. */
|
|
if (tmp->c_time <= now) {
|
|
/*
|
|
* Consumer told us the callout may be run
|
|
* directly from hardware interrupt context.
|
|
*/
|
|
if (tmp->c_iflags & CALLOUT_DIRECT) {
|
|
#ifdef CALLOUT_PROFILING
|
|
++depth_dir;
|
|
#endif
|
|
cc_exec_next(cc) =
|
|
LIST_NEXT(tmp, c_links.le);
|
|
cc->cc_bucket = firstb & callwheelmask;
|
|
LIST_REMOVE(tmp, c_links.le);
|
|
softclock_call_cc(tmp, cc,
|
|
#ifdef CALLOUT_PROFILING
|
|
&mpcalls_dir, &lockcalls_dir, NULL,
|
|
#endif
|
|
1);
|
|
tmp = cc_exec_next(cc);
|
|
cc_exec_next(cc) = NULL;
|
|
} else {
|
|
tmpn = LIST_NEXT(tmp, c_links.le);
|
|
LIST_REMOVE(tmp, c_links.le);
|
|
TAILQ_INSERT_TAIL(&cc->cc_expireq,
|
|
tmp, c_links.tqe);
|
|
tmp->c_iflags |= CALLOUT_PROCESSED;
|
|
tmp = tmpn;
|
|
}
|
|
continue;
|
|
}
|
|
/* Skip events from distant future. */
|
|
if (tmp->c_time >= max)
|
|
goto next;
|
|
/*
|
|
* Event minimal time is bigger than present maximal
|
|
* time, so it cannot be aggregated.
|
|
*/
|
|
if (tmp->c_time > last) {
|
|
lastb = nowb;
|
|
goto next;
|
|
}
|
|
/* Update first and last time, respecting this event. */
|
|
if (tmp->c_time < first)
|
|
first = tmp->c_time;
|
|
tmp_max = tmp->c_time + tmp->c_precision;
|
|
if (tmp_max < last)
|
|
last = tmp_max;
|
|
next:
|
|
tmp = LIST_NEXT(tmp, c_links.le);
|
|
}
|
|
/* Proceed with the next bucket. */
|
|
firstb++;
|
|
/*
|
|
* Stop if we looked after present time and found
|
|
* some event we can't execute at now.
|
|
* Stop if we looked far enough into the future.
|
|
*/
|
|
} while (((int)(firstb - lastb)) <= 0);
|
|
cc->cc_firstevent = last;
|
|
#ifndef NO_EVENTTIMERS
|
|
cpu_new_callout(curcpu, last, first);
|
|
#endif
|
|
#ifdef CALLOUT_PROFILING
|
|
avg_depth_dir += (depth_dir * 1000 - avg_depth_dir) >> 8;
|
|
avg_mpcalls_dir += (mpcalls_dir * 1000 - avg_mpcalls_dir) >> 8;
|
|
avg_lockcalls_dir += (lockcalls_dir * 1000 - avg_lockcalls_dir) >> 8;
|
|
#endif
|
|
mtx_unlock_spin_flags(&cc->cc_lock, MTX_QUIET);
|
|
/*
|
|
* swi_sched acquires the thread lock, so we don't want to call it
|
|
* with cc_lock held; incorrect locking order.
|
|
*/
|
|
if (!TAILQ_EMPTY(&cc->cc_expireq))
|
|
swi_sched(cc->cc_cookie, 0);
|
|
}
|
|
|
|
static struct callout_cpu *
|
|
callout_lock(struct callout *c)
|
|
{
|
|
struct callout_cpu *cc;
|
|
int cpu;
|
|
|
|
for (;;) {
|
|
cpu = c->c_cpu;
|
|
#ifdef SMP
|
|
if (cpu == CPUBLOCK) {
|
|
while (c->c_cpu == CPUBLOCK)
|
|
cpu_spinwait();
|
|
continue;
|
|
}
|
|
#endif
|
|
cc = CC_CPU(cpu);
|
|
CC_LOCK(cc);
|
|
if (cpu == c->c_cpu)
|
|
break;
|
|
CC_UNLOCK(cc);
|
|
}
|
|
return (cc);
|
|
}
|
|
|
|
static void
|
|
callout_cc_add(struct callout *c, struct callout_cpu *cc,
|
|
sbintime_t sbt, sbintime_t precision, void (*func)(void *),
|
|
void *arg, int cpu, int flags)
|
|
{
|
|
int bucket;
|
|
|
|
CC_LOCK_ASSERT(cc);
|
|
if (sbt < cc->cc_lastscan)
|
|
sbt = cc->cc_lastscan;
|
|
c->c_arg = arg;
|
|
c->c_iflags |= CALLOUT_PENDING;
|
|
c->c_iflags &= ~CALLOUT_PROCESSED;
|
|
c->c_flags |= CALLOUT_ACTIVE;
|
|
if (flags & C_DIRECT_EXEC)
|
|
c->c_iflags |= CALLOUT_DIRECT;
|
|
c->c_func = func;
|
|
c->c_time = sbt;
|
|
c->c_precision = precision;
|
|
bucket = callout_get_bucket(c->c_time);
|
|
CTR3(KTR_CALLOUT, "precision set for %p: %d.%08x",
|
|
c, (int)(c->c_precision >> 32),
|
|
(u_int)(c->c_precision & 0xffffffff));
|
|
LIST_INSERT_HEAD(&cc->cc_callwheel[bucket], c, c_links.le);
|
|
if (cc->cc_bucket == bucket)
|
|
cc_exec_next(cc) = c;
|
|
#ifndef NO_EVENTTIMERS
|
|
/*
|
|
* Inform the eventtimers(4) subsystem there's a new callout
|
|
* that has been inserted, but only if really required.
|
|
*/
|
|
if (SBT_MAX - c->c_time < c->c_precision)
|
|
c->c_precision = SBT_MAX - c->c_time;
|
|
sbt = c->c_time + c->c_precision;
|
|
if (sbt < cc->cc_firstevent) {
|
|
cc->cc_firstevent = sbt;
|
|
cpu_new_callout(cpu, sbt, c->c_time);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
static void
|
|
callout_cc_del(struct callout *c, struct callout_cpu *cc)
|
|
{
|
|
|
|
if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) == 0)
|
|
return;
|
|
c->c_func = NULL;
|
|
SLIST_INSERT_HEAD(&cc->cc_callfree, c, c_links.sle);
|
|
}
|
|
|
|
static void
|
|
softclock_call_cc(struct callout *c, struct callout_cpu *cc,
|
|
#ifdef CALLOUT_PROFILING
|
|
int *mpcalls, int *lockcalls, int *gcalls,
|
|
#endif
|
|
int direct)
|
|
{
|
|
struct rm_priotracker tracker;
|
|
void (*c_func)(void *);
|
|
void *c_arg;
|
|
struct lock_class *class;
|
|
struct lock_object *c_lock;
|
|
uintptr_t lock_status;
|
|
int c_iflags;
|
|
#ifdef SMP
|
|
struct callout_cpu *new_cc;
|
|
void (*new_func)(void *);
|
|
void *new_arg;
|
|
int flags, new_cpu;
|
|
sbintime_t new_prec, new_time;
|
|
#endif
|
|
#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
|
|
sbintime_t sbt1, sbt2;
|
|
struct timespec ts2;
|
|
static sbintime_t maxdt = 2 * SBT_1MS; /* 2 msec */
|
|
static timeout_t *lastfunc;
|
|
#endif
|
|
|
|
KASSERT((c->c_iflags & CALLOUT_PENDING) == CALLOUT_PENDING,
|
|
("softclock_call_cc: pend %p %x", c, c->c_iflags));
|
|
KASSERT((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE,
|
|
("softclock_call_cc: act %p %x", c, c->c_flags));
|
|
class = (c->c_lock != NULL) ? LOCK_CLASS(c->c_lock) : NULL;
|
|
lock_status = 0;
|
|
if (c->c_flags & CALLOUT_SHAREDLOCK) {
|
|
if (class == &lock_class_rm)
|
|
lock_status = (uintptr_t)&tracker;
|
|
else
|
|
lock_status = 1;
|
|
}
|
|
c_lock = c->c_lock;
|
|
c_func = c->c_func;
|
|
c_arg = c->c_arg;
|
|
c_iflags = c->c_iflags;
|
|
if (c->c_iflags & CALLOUT_LOCAL_ALLOC)
|
|
c->c_iflags = CALLOUT_LOCAL_ALLOC;
|
|
else
|
|
c->c_iflags &= ~CALLOUT_PENDING;
|
|
|
|
cc_exec_curr(cc, direct) = c;
|
|
cc_exec_cancel(cc, direct) = false;
|
|
cc_exec_drain(cc, direct) = NULL;
|
|
CC_UNLOCK(cc);
|
|
if (c_lock != NULL) {
|
|
class->lc_lock(c_lock, lock_status);
|
|
/*
|
|
* The callout may have been cancelled
|
|
* while we switched locks.
|
|
*/
|
|
if (cc_exec_cancel(cc, direct)) {
|
|
class->lc_unlock(c_lock);
|
|
goto skip;
|
|
}
|
|
/* The callout cannot be stopped now. */
|
|
cc_exec_cancel(cc, direct) = true;
|
|
if (c_lock == &Giant.lock_object) {
|
|
#ifdef CALLOUT_PROFILING
|
|
(*gcalls)++;
|
|
#endif
|
|
CTR3(KTR_CALLOUT, "callout giant %p func %p arg %p",
|
|
c, c_func, c_arg);
|
|
} else {
|
|
#ifdef CALLOUT_PROFILING
|
|
(*lockcalls)++;
|
|
#endif
|
|
CTR3(KTR_CALLOUT, "callout lock %p func %p arg %p",
|
|
c, c_func, c_arg);
|
|
}
|
|
} else {
|
|
#ifdef CALLOUT_PROFILING
|
|
(*mpcalls)++;
|
|
#endif
|
|
CTR3(KTR_CALLOUT, "callout %p func %p arg %p",
|
|
c, c_func, c_arg);
|
|
}
|
|
KTR_STATE3(KTR_SCHED, "callout", cc->cc_ktr_event_name, "running",
|
|
"func:%p", c_func, "arg:%p", c_arg, "direct:%d", direct);
|
|
#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
|
|
sbt1 = sbinuptime();
|
|
#endif
|
|
THREAD_NO_SLEEPING();
|
|
SDT_PROBE1(callout_execute, kernel, , callout__start, c);
|
|
c_func(c_arg);
|
|
SDT_PROBE1(callout_execute, kernel, , callout__end, c);
|
|
THREAD_SLEEPING_OK();
|
|
#if defined(DIAGNOSTIC) || defined(CALLOUT_PROFILING)
|
|
sbt2 = sbinuptime();
|
|
sbt2 -= sbt1;
|
|
if (sbt2 > maxdt) {
|
|
if (lastfunc != c_func || sbt2 > maxdt * 2) {
|
|
ts2 = sbttots(sbt2);
|
|
printf(
|
|
"Expensive timeout(9) function: %p(%p) %jd.%09ld s\n",
|
|
c_func, c_arg, (intmax_t)ts2.tv_sec, ts2.tv_nsec);
|
|
}
|
|
maxdt = sbt2;
|
|
lastfunc = c_func;
|
|
}
|
|
#endif
|
|
KTR_STATE0(KTR_SCHED, "callout", cc->cc_ktr_event_name, "idle");
|
|
CTR1(KTR_CALLOUT, "callout %p finished", c);
|
|
if ((c_iflags & CALLOUT_RETURNUNLOCKED) == 0)
|
|
class->lc_unlock(c_lock);
|
|
skip:
|
|
CC_LOCK(cc);
|
|
KASSERT(cc_exec_curr(cc, direct) == c, ("mishandled cc_curr"));
|
|
cc_exec_curr(cc, direct) = NULL;
|
|
if (cc_exec_drain(cc, direct)) {
|
|
void (*drain)(void *);
|
|
|
|
drain = cc_exec_drain(cc, direct);
|
|
cc_exec_drain(cc, direct) = NULL;
|
|
CC_UNLOCK(cc);
|
|
drain(c_arg);
|
|
CC_LOCK(cc);
|
|
}
|
|
if (cc_exec_waiting(cc, direct)) {
|
|
/*
|
|
* There is someone waiting for the
|
|
* callout to complete.
|
|
* If the callout was scheduled for
|
|
* migration just cancel it.
|
|
*/
|
|
if (cc_cce_migrating(cc, direct)) {
|
|
cc_cce_cleanup(cc, direct);
|
|
|
|
/*
|
|
* It should be assert here that the callout is not
|
|
* destroyed but that is not easy.
|
|
*/
|
|
c->c_iflags &= ~CALLOUT_DFRMIGRATION;
|
|
}
|
|
cc_exec_waiting(cc, direct) = false;
|
|
CC_UNLOCK(cc);
|
|
wakeup(&cc_exec_waiting(cc, direct));
|
|
CC_LOCK(cc);
|
|
} else if (cc_cce_migrating(cc, direct)) {
|
|
KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0,
|
|
("Migrating legacy callout %p", c));
|
|
#ifdef SMP
|
|
/*
|
|
* If the callout was scheduled for
|
|
* migration just perform it now.
|
|
*/
|
|
new_cpu = cc_migration_cpu(cc, direct);
|
|
new_time = cc_migration_time(cc, direct);
|
|
new_prec = cc_migration_prec(cc, direct);
|
|
new_func = cc_migration_func(cc, direct);
|
|
new_arg = cc_migration_arg(cc, direct);
|
|
cc_cce_cleanup(cc, direct);
|
|
|
|
/*
|
|
* It should be assert here that the callout is not destroyed
|
|
* but that is not easy.
|
|
*
|
|
* As first thing, handle deferred callout stops.
|
|
*/
|
|
if (!callout_migrating(c)) {
|
|
CTR3(KTR_CALLOUT,
|
|
"deferred cancelled %p func %p arg %p",
|
|
c, new_func, new_arg);
|
|
callout_cc_del(c, cc);
|
|
return;
|
|
}
|
|
c->c_iflags &= ~CALLOUT_DFRMIGRATION;
|
|
|
|
new_cc = callout_cpu_switch(c, cc, new_cpu);
|
|
flags = (direct) ? C_DIRECT_EXEC : 0;
|
|
callout_cc_add(c, new_cc, new_time, new_prec, new_func,
|
|
new_arg, new_cpu, flags);
|
|
CC_UNLOCK(new_cc);
|
|
CC_LOCK(cc);
|
|
#else
|
|
panic("migration should not happen");
|
|
#endif
|
|
}
|
|
/*
|
|
* If the current callout is locally allocated (from
|
|
* timeout(9)) then put it on the freelist.
|
|
*
|
|
* Note: we need to check the cached copy of c_iflags because
|
|
* if it was not local, then it's not safe to deref the
|
|
* callout pointer.
|
|
*/
|
|
KASSERT((c_iflags & CALLOUT_LOCAL_ALLOC) == 0 ||
|
|
c->c_iflags == CALLOUT_LOCAL_ALLOC,
|
|
("corrupted callout"));
|
|
if (c_iflags & CALLOUT_LOCAL_ALLOC)
|
|
callout_cc_del(c, cc);
|
|
}
|
|
|
|
/*
|
|
* The callout mechanism is based on the work of Adam M. Costello and
|
|
* George Varghese, published in a technical report entitled "Redesigning
|
|
* the BSD Callout and Timer Facilities" and modified slightly for inclusion
|
|
* in FreeBSD by Justin T. Gibbs. The original work on the data structures
|
|
* used in this implementation was published by G. Varghese and T. Lauck in
|
|
* the paper "Hashed and Hierarchical Timing Wheels: Data Structures for
|
|
* the Efficient Implementation of a Timer Facility" in the Proceedings of
|
|
* the 11th ACM Annual Symposium on Operating Systems Principles,
|
|
* Austin, Texas Nov 1987.
|
|
*/
|
|
|
|
/*
|
|
* Software (low priority) clock interrupt.
|
|
* Run periodic events from timeout queue.
|
|
*/
|
|
void
|
|
softclock(void *arg)
|
|
{
|
|
struct callout_cpu *cc;
|
|
struct callout *c;
|
|
#ifdef CALLOUT_PROFILING
|
|
int depth = 0, gcalls = 0, lockcalls = 0, mpcalls = 0;
|
|
#endif
|
|
|
|
cc = (struct callout_cpu *)arg;
|
|
CC_LOCK(cc);
|
|
while ((c = TAILQ_FIRST(&cc->cc_expireq)) != NULL) {
|
|
TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
|
|
softclock_call_cc(c, cc,
|
|
#ifdef CALLOUT_PROFILING
|
|
&mpcalls, &lockcalls, &gcalls,
|
|
#endif
|
|
0);
|
|
#ifdef CALLOUT_PROFILING
|
|
++depth;
|
|
#endif
|
|
}
|
|
#ifdef CALLOUT_PROFILING
|
|
avg_depth += (depth * 1000 - avg_depth) >> 8;
|
|
avg_mpcalls += (mpcalls * 1000 - avg_mpcalls) >> 8;
|
|
avg_lockcalls += (lockcalls * 1000 - avg_lockcalls) >> 8;
|
|
avg_gcalls += (gcalls * 1000 - avg_gcalls) >> 8;
|
|
#endif
|
|
CC_UNLOCK(cc);
|
|
}
|
|
|
|
/*
|
|
* timeout --
|
|
* Execute a function after a specified length of time.
|
|
*
|
|
* untimeout --
|
|
* Cancel previous timeout function call.
|
|
*
|
|
* callout_handle_init --
|
|
* Initialize a handle so that using it with untimeout is benign.
|
|
*
|
|
* See AT&T BCI Driver Reference Manual for specification. This
|
|
* implementation differs from that one in that although an
|
|
* identification value is returned from timeout, the original
|
|
* arguments to timeout as well as the identifier are used to
|
|
* identify entries for untimeout.
|
|
*/
|
|
struct callout_handle
|
|
timeout(timeout_t *ftn, void *arg, int to_ticks)
|
|
{
|
|
struct callout_cpu *cc;
|
|
struct callout *new;
|
|
struct callout_handle handle;
|
|
|
|
cc = CC_CPU(timeout_cpu);
|
|
CC_LOCK(cc);
|
|
/* Fill in the next free callout structure. */
|
|
new = SLIST_FIRST(&cc->cc_callfree);
|
|
if (new == NULL)
|
|
/* XXX Attempt to malloc first */
|
|
panic("timeout table full");
|
|
SLIST_REMOVE_HEAD(&cc->cc_callfree, c_links.sle);
|
|
callout_reset(new, to_ticks, ftn, arg);
|
|
handle.callout = new;
|
|
CC_UNLOCK(cc);
|
|
|
|
return (handle);
|
|
}
|
|
|
|
void
|
|
untimeout(timeout_t *ftn, void *arg, struct callout_handle handle)
|
|
{
|
|
struct callout_cpu *cc;
|
|
|
|
/*
|
|
* Check for a handle that was initialized
|
|
* by callout_handle_init, but never used
|
|
* for a real timeout.
|
|
*/
|
|
if (handle.callout == NULL)
|
|
return;
|
|
|
|
cc = callout_lock(handle.callout);
|
|
if (handle.callout->c_func == ftn && handle.callout->c_arg == arg)
|
|
callout_stop(handle.callout);
|
|
CC_UNLOCK(cc);
|
|
}
|
|
|
|
void
|
|
callout_handle_init(struct callout_handle *handle)
|
|
{
|
|
handle->callout = NULL;
|
|
}
|
|
|
|
/*
|
|
* New interface; clients allocate their own callout structures.
|
|
*
|
|
* callout_reset() - establish or change a timeout
|
|
* callout_stop() - disestablish a timeout
|
|
* callout_init() - initialize a callout structure so that it can
|
|
* safely be passed to callout_reset() and callout_stop()
|
|
*
|
|
* <sys/callout.h> defines three convenience macros:
|
|
*
|
|
* callout_active() - returns truth if callout has not been stopped,
|
|
* drained, or deactivated since the last time the callout was
|
|
* reset.
|
|
* callout_pending() - returns truth if callout is still waiting for timeout
|
|
* callout_deactivate() - marks the callout as having been serviced
|
|
*/
|
|
int
|
|
callout_reset_sbt_on(struct callout *c, sbintime_t sbt, sbintime_t precision,
|
|
void (*ftn)(void *), void *arg, int cpu, int flags)
|
|
{
|
|
sbintime_t to_sbt, pr;
|
|
struct callout_cpu *cc;
|
|
int cancelled, direct;
|
|
int ignore_cpu=0;
|
|
|
|
cancelled = 0;
|
|
if (cpu == -1) {
|
|
ignore_cpu = 1;
|
|
} else if ((cpu >= MAXCPU) ||
|
|
((CC_CPU(cpu))->cc_inited == 0)) {
|
|
/* Invalid CPU spec */
|
|
panic("Invalid CPU in callout %d", cpu);
|
|
}
|
|
if (flags & C_ABSOLUTE) {
|
|
to_sbt = sbt;
|
|
} else {
|
|
if ((flags & C_HARDCLOCK) && (sbt < tick_sbt))
|
|
sbt = tick_sbt;
|
|
if ((flags & C_HARDCLOCK) ||
|
|
#ifdef NO_EVENTTIMERS
|
|
sbt >= sbt_timethreshold) {
|
|
to_sbt = getsbinuptime();
|
|
|
|
/* Add safety belt for the case of hz > 1000. */
|
|
to_sbt += tc_tick_sbt - tick_sbt;
|
|
#else
|
|
sbt >= sbt_tickthreshold) {
|
|
/*
|
|
* Obtain the time of the last hardclock() call on
|
|
* this CPU directly from the kern_clocksource.c.
|
|
* This value is per-CPU, but it is equal for all
|
|
* active ones.
|
|
*/
|
|
#ifdef __LP64__
|
|
to_sbt = DPCPU_GET(hardclocktime);
|
|
#else
|
|
spinlock_enter();
|
|
to_sbt = DPCPU_GET(hardclocktime);
|
|
spinlock_exit();
|
|
#endif
|
|
#endif
|
|
if ((flags & C_HARDCLOCK) == 0)
|
|
to_sbt += tick_sbt;
|
|
} else
|
|
to_sbt = sbinuptime();
|
|
if (SBT_MAX - to_sbt < sbt)
|
|
to_sbt = SBT_MAX;
|
|
else
|
|
to_sbt += sbt;
|
|
pr = ((C_PRELGET(flags) < 0) ? sbt >> tc_precexp :
|
|
sbt >> C_PRELGET(flags));
|
|
if (pr > precision)
|
|
precision = pr;
|
|
}
|
|
/*
|
|
* This flag used to be added by callout_cc_add, but the
|
|
* first time you call this we could end up with the
|
|
* wrong direct flag if we don't do it before we add.
|
|
*/
|
|
if (flags & C_DIRECT_EXEC) {
|
|
direct = 1;
|
|
} else {
|
|
direct = 0;
|
|
}
|
|
KASSERT(!direct || c->c_lock == NULL,
|
|
("%s: direct callout %p has lock", __func__, c));
|
|
cc = callout_lock(c);
|
|
/*
|
|
* Don't allow migration of pre-allocated callouts lest they
|
|
* become unbalanced or handle the case where the user does
|
|
* not care.
|
|
*/
|
|
if ((c->c_iflags & CALLOUT_LOCAL_ALLOC) ||
|
|
ignore_cpu) {
|
|
cpu = c->c_cpu;
|
|
}
|
|
|
|
if (cc_exec_curr(cc, direct) == c) {
|
|
/*
|
|
* We're being asked to reschedule a callout which is
|
|
* currently in progress. If there is a lock then we
|
|
* can cancel the callout if it has not really started.
|
|
*/
|
|
if (c->c_lock != NULL && !cc_exec_cancel(cc, direct))
|
|
cancelled = cc_exec_cancel(cc, direct) = true;
|
|
if (cc_exec_waiting(cc, direct)) {
|
|
/*
|
|
* Someone has called callout_drain to kill this
|
|
* callout. Don't reschedule.
|
|
*/
|
|
CTR4(KTR_CALLOUT, "%s %p func %p arg %p",
|
|
cancelled ? "cancelled" : "failed to cancel",
|
|
c, c->c_func, c->c_arg);
|
|
CC_UNLOCK(cc);
|
|
return (cancelled);
|
|
}
|
|
#ifdef SMP
|
|
if (callout_migrating(c)) {
|
|
/*
|
|
* This only occurs when a second callout_reset_sbt_on
|
|
* is made after a previous one moved it into
|
|
* deferred migration (below). Note we do *not* change
|
|
* the prev_cpu even though the previous target may
|
|
* be different.
|
|
*/
|
|
cc_migration_cpu(cc, direct) = cpu;
|
|
cc_migration_time(cc, direct) = to_sbt;
|
|
cc_migration_prec(cc, direct) = precision;
|
|
cc_migration_func(cc, direct) = ftn;
|
|
cc_migration_arg(cc, direct) = arg;
|
|
cancelled = 1;
|
|
CC_UNLOCK(cc);
|
|
return (cancelled);
|
|
}
|
|
#endif
|
|
}
|
|
if (c->c_iflags & CALLOUT_PENDING) {
|
|
if ((c->c_iflags & CALLOUT_PROCESSED) == 0) {
|
|
if (cc_exec_next(cc) == c)
|
|
cc_exec_next(cc) = LIST_NEXT(c, c_links.le);
|
|
LIST_REMOVE(c, c_links.le);
|
|
} else {
|
|
TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
|
|
}
|
|
cancelled = 1;
|
|
c->c_iflags &= ~ CALLOUT_PENDING;
|
|
c->c_flags &= ~ CALLOUT_ACTIVE;
|
|
}
|
|
|
|
#ifdef SMP
|
|
/*
|
|
* If the callout must migrate try to perform it immediately.
|
|
* If the callout is currently running, just defer the migration
|
|
* to a more appropriate moment.
|
|
*/
|
|
if (c->c_cpu != cpu) {
|
|
if (cc_exec_curr(cc, direct) == c) {
|
|
/*
|
|
* Pending will have been removed since we are
|
|
* actually executing the callout on another
|
|
* CPU. That callout should be waiting on the
|
|
* lock the caller holds. If we set both
|
|
* active/and/pending after we return and the
|
|
* lock on the executing callout proceeds, it
|
|
* will then see pending is true and return.
|
|
* At the return from the actual callout execution
|
|
* the migration will occur in softclock_call_cc
|
|
* and this new callout will be placed on the
|
|
* new CPU via a call to callout_cpu_switch() which
|
|
* will get the lock on the right CPU followed
|
|
* by a call callout_cc_add() which will add it there.
|
|
* (see above in softclock_call_cc()).
|
|
*/
|
|
cc_migration_cpu(cc, direct) = cpu;
|
|
cc_migration_time(cc, direct) = to_sbt;
|
|
cc_migration_prec(cc, direct) = precision;
|
|
cc_migration_func(cc, direct) = ftn;
|
|
cc_migration_arg(cc, direct) = arg;
|
|
c->c_iflags |= (CALLOUT_DFRMIGRATION | CALLOUT_PENDING);
|
|
c->c_flags |= CALLOUT_ACTIVE;
|
|
CTR6(KTR_CALLOUT,
|
|
"migration of %p func %p arg %p in %d.%08x to %u deferred",
|
|
c, c->c_func, c->c_arg, (int)(to_sbt >> 32),
|
|
(u_int)(to_sbt & 0xffffffff), cpu);
|
|
CC_UNLOCK(cc);
|
|
return (cancelled);
|
|
}
|
|
cc = callout_cpu_switch(c, cc, cpu);
|
|
}
|
|
#endif
|
|
|
|
callout_cc_add(c, cc, to_sbt, precision, ftn, arg, cpu, flags);
|
|
CTR6(KTR_CALLOUT, "%sscheduled %p func %p arg %p in %d.%08x",
|
|
cancelled ? "re" : "", c, c->c_func, c->c_arg, (int)(to_sbt >> 32),
|
|
(u_int)(to_sbt & 0xffffffff));
|
|
CC_UNLOCK(cc);
|
|
|
|
return (cancelled);
|
|
}
|
|
|
|
/*
|
|
* Common idioms that can be optimized in the future.
|
|
*/
|
|
int
|
|
callout_schedule_on(struct callout *c, int to_ticks, int cpu)
|
|
{
|
|
return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, cpu);
|
|
}
|
|
|
|
int
|
|
callout_schedule(struct callout *c, int to_ticks)
|
|
{
|
|
return callout_reset_on(c, to_ticks, c->c_func, c->c_arg, c->c_cpu);
|
|
}
|
|
|
|
int
|
|
_callout_stop_safe(struct callout *c, int safe, void (*drain)(void *))
|
|
{
|
|
struct callout_cpu *cc, *old_cc;
|
|
struct lock_class *class;
|
|
int direct, sq_locked, use_lock;
|
|
int not_on_a_list;
|
|
|
|
if (safe)
|
|
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, c->c_lock,
|
|
"calling %s", __func__);
|
|
|
|
/*
|
|
* Some old subsystems don't hold Giant while running a callout_stop(),
|
|
* so just discard this check for the moment.
|
|
*/
|
|
if (!safe && c->c_lock != NULL) {
|
|
if (c->c_lock == &Giant.lock_object)
|
|
use_lock = mtx_owned(&Giant);
|
|
else {
|
|
use_lock = 1;
|
|
class = LOCK_CLASS(c->c_lock);
|
|
class->lc_assert(c->c_lock, LA_XLOCKED);
|
|
}
|
|
} else
|
|
use_lock = 0;
|
|
if (c->c_iflags & CALLOUT_DIRECT) {
|
|
direct = 1;
|
|
} else {
|
|
direct = 0;
|
|
}
|
|
sq_locked = 0;
|
|
old_cc = NULL;
|
|
again:
|
|
cc = callout_lock(c);
|
|
|
|
if ((c->c_iflags & (CALLOUT_DFRMIGRATION | CALLOUT_PENDING)) ==
|
|
(CALLOUT_DFRMIGRATION | CALLOUT_PENDING) &&
|
|
((c->c_flags & CALLOUT_ACTIVE) == CALLOUT_ACTIVE)) {
|
|
/*
|
|
* Special case where this slipped in while we
|
|
* were migrating *as* the callout is about to
|
|
* execute. The caller probably holds the lock
|
|
* the callout wants.
|
|
*
|
|
* Get rid of the migration first. Then set
|
|
* the flag that tells this code *not* to
|
|
* try to remove it from any lists (its not
|
|
* on one yet). When the callout wheel runs,
|
|
* it will ignore this callout.
|
|
*/
|
|
c->c_iflags &= ~CALLOUT_PENDING;
|
|
c->c_flags &= ~CALLOUT_ACTIVE;
|
|
not_on_a_list = 1;
|
|
} else {
|
|
not_on_a_list = 0;
|
|
}
|
|
|
|
/*
|
|
* If the callout was migrating while the callout cpu lock was
|
|
* dropped, just drop the sleepqueue lock and check the states
|
|
* again.
|
|
*/
|
|
if (sq_locked != 0 && cc != old_cc) {
|
|
#ifdef SMP
|
|
CC_UNLOCK(cc);
|
|
sleepq_release(&cc_exec_waiting(old_cc, direct));
|
|
sq_locked = 0;
|
|
old_cc = NULL;
|
|
goto again;
|
|
#else
|
|
panic("migration should not happen");
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* If the callout isn't pending, it's not on the queue, so
|
|
* don't attempt to remove it from the queue. We can try to
|
|
* stop it by other means however.
|
|
*/
|
|
if (!(c->c_iflags & CALLOUT_PENDING)) {
|
|
/*
|
|
* If it wasn't on the queue and it isn't the current
|
|
* callout, then we can't stop it, so just bail.
|
|
* It probably has already been run (if locking
|
|
* is properly done). You could get here if the caller
|
|
* calls stop twice in a row for example. The second
|
|
* call would fall here without CALLOUT_ACTIVE set.
|
|
*/
|
|
c->c_flags &= ~CALLOUT_ACTIVE;
|
|
if (cc_exec_curr(cc, direct) != c) {
|
|
CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
|
|
c, c->c_func, c->c_arg);
|
|
CC_UNLOCK(cc);
|
|
if (sq_locked)
|
|
sleepq_release(&cc_exec_waiting(cc, direct));
|
|
return (-1);
|
|
}
|
|
|
|
if (safe) {
|
|
/*
|
|
* The current callout is running (or just
|
|
* about to run) and blocking is allowed, so
|
|
* just wait for the current invocation to
|
|
* finish.
|
|
*/
|
|
while (cc_exec_curr(cc, direct) == c) {
|
|
/*
|
|
* Use direct calls to sleepqueue interface
|
|
* instead of cv/msleep in order to avoid
|
|
* a LOR between cc_lock and sleepqueue
|
|
* chain spinlocks. This piece of code
|
|
* emulates a msleep_spin() call actually.
|
|
*
|
|
* If we already have the sleepqueue chain
|
|
* locked, then we can safely block. If we
|
|
* don't already have it locked, however,
|
|
* we have to drop the cc_lock to lock
|
|
* it. This opens several races, so we
|
|
* restart at the beginning once we have
|
|
* both locks. If nothing has changed, then
|
|
* we will end up back here with sq_locked
|
|
* set.
|
|
*/
|
|
if (!sq_locked) {
|
|
CC_UNLOCK(cc);
|
|
sleepq_lock(
|
|
&cc_exec_waiting(cc, direct));
|
|
sq_locked = 1;
|
|
old_cc = cc;
|
|
goto again;
|
|
}
|
|
|
|
/*
|
|
* Migration could be cancelled here, but
|
|
* as long as it is still not sure when it
|
|
* will be packed up, just let softclock()
|
|
* take care of it.
|
|
*/
|
|
cc_exec_waiting(cc, direct) = true;
|
|
DROP_GIANT();
|
|
CC_UNLOCK(cc);
|
|
sleepq_add(
|
|
&cc_exec_waiting(cc, direct),
|
|
&cc->cc_lock.lock_object, "codrain",
|
|
SLEEPQ_SLEEP, 0);
|
|
sleepq_wait(
|
|
&cc_exec_waiting(cc, direct),
|
|
0);
|
|
sq_locked = 0;
|
|
old_cc = NULL;
|
|
|
|
/* Reacquire locks previously released. */
|
|
PICKUP_GIANT();
|
|
CC_LOCK(cc);
|
|
}
|
|
} else if (use_lock &&
|
|
!cc_exec_cancel(cc, direct) && (drain == NULL)) {
|
|
|
|
/*
|
|
* The current callout is waiting for its
|
|
* lock which we hold. Cancel the callout
|
|
* and return. After our caller drops the
|
|
* lock, the callout will be skipped in
|
|
* softclock(). This *only* works with a
|
|
* callout_stop() *not* callout_drain() or
|
|
* callout_async_drain().
|
|
*/
|
|
cc_exec_cancel(cc, direct) = true;
|
|
CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
|
|
c, c->c_func, c->c_arg);
|
|
KASSERT(!cc_cce_migrating(cc, direct),
|
|
("callout wrongly scheduled for migration"));
|
|
if (callout_migrating(c)) {
|
|
c->c_iflags &= ~CALLOUT_DFRMIGRATION;
|
|
#ifdef SMP
|
|
cc_migration_cpu(cc, direct) = CPUBLOCK;
|
|
cc_migration_time(cc, direct) = 0;
|
|
cc_migration_prec(cc, direct) = 0;
|
|
cc_migration_func(cc, direct) = NULL;
|
|
cc_migration_arg(cc, direct) = NULL;
|
|
#endif
|
|
}
|
|
CC_UNLOCK(cc);
|
|
KASSERT(!sq_locked, ("sleepqueue chain locked"));
|
|
return (1);
|
|
} else if (callout_migrating(c)) {
|
|
/*
|
|
* The callout is currently being serviced
|
|
* and the "next" callout is scheduled at
|
|
* its completion with a migration. We remove
|
|
* the migration flag so it *won't* get rescheduled,
|
|
* but we can't stop the one thats running so
|
|
* we return 0.
|
|
*/
|
|
c->c_iflags &= ~CALLOUT_DFRMIGRATION;
|
|
#ifdef SMP
|
|
/*
|
|
* We can't call cc_cce_cleanup here since
|
|
* if we do it will remove .ce_curr and
|
|
* its still running. This will prevent a
|
|
* reschedule of the callout when the
|
|
* execution completes.
|
|
*/
|
|
cc_migration_cpu(cc, direct) = CPUBLOCK;
|
|
cc_migration_time(cc, direct) = 0;
|
|
cc_migration_prec(cc, direct) = 0;
|
|
cc_migration_func(cc, direct) = NULL;
|
|
cc_migration_arg(cc, direct) = NULL;
|
|
#endif
|
|
CTR3(KTR_CALLOUT, "postponing stop %p func %p arg %p",
|
|
c, c->c_func, c->c_arg);
|
|
if (drain) {
|
|
cc_exec_drain(cc, direct) = drain;
|
|
}
|
|
CC_UNLOCK(cc);
|
|
return (0);
|
|
}
|
|
CTR3(KTR_CALLOUT, "failed to stop %p func %p arg %p",
|
|
c, c->c_func, c->c_arg);
|
|
if (drain) {
|
|
cc_exec_drain(cc, direct) = drain;
|
|
}
|
|
CC_UNLOCK(cc);
|
|
KASSERT(!sq_locked, ("sleepqueue chain still locked"));
|
|
return (0);
|
|
}
|
|
if (sq_locked)
|
|
sleepq_release(&cc_exec_waiting(cc, direct));
|
|
|
|
c->c_iflags &= ~CALLOUT_PENDING;
|
|
c->c_flags &= ~CALLOUT_ACTIVE;
|
|
|
|
CTR3(KTR_CALLOUT, "cancelled %p func %p arg %p",
|
|
c, c->c_func, c->c_arg);
|
|
if (not_on_a_list == 0) {
|
|
if ((c->c_iflags & CALLOUT_PROCESSED) == 0) {
|
|
if (cc_exec_next(cc) == c)
|
|
cc_exec_next(cc) = LIST_NEXT(c, c_links.le);
|
|
LIST_REMOVE(c, c_links.le);
|
|
} else {
|
|
TAILQ_REMOVE(&cc->cc_expireq, c, c_links.tqe);
|
|
}
|
|
}
|
|
callout_cc_del(c, cc);
|
|
CC_UNLOCK(cc);
|
|
return (1);
|
|
}
|
|
|
|
void
|
|
callout_init(struct callout *c, int mpsafe)
|
|
{
|
|
bzero(c, sizeof *c);
|
|
if (mpsafe) {
|
|
c->c_lock = NULL;
|
|
c->c_iflags = CALLOUT_RETURNUNLOCKED;
|
|
} else {
|
|
c->c_lock = &Giant.lock_object;
|
|
c->c_iflags = 0;
|
|
}
|
|
c->c_cpu = timeout_cpu;
|
|
}
|
|
|
|
void
|
|
_callout_init_lock(struct callout *c, struct lock_object *lock, int flags)
|
|
{
|
|
bzero(c, sizeof *c);
|
|
c->c_lock = lock;
|
|
KASSERT((flags & ~(CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK)) == 0,
|
|
("callout_init_lock: bad flags %d", flags));
|
|
KASSERT(lock != NULL || (flags & CALLOUT_RETURNUNLOCKED) == 0,
|
|
("callout_init_lock: CALLOUT_RETURNUNLOCKED with no lock"));
|
|
KASSERT(lock == NULL || !(LOCK_CLASS(lock)->lc_flags &
|
|
(LC_SPINLOCK | LC_SLEEPABLE)), ("%s: invalid lock class",
|
|
__func__));
|
|
c->c_iflags = flags & (CALLOUT_RETURNUNLOCKED | CALLOUT_SHAREDLOCK);
|
|
c->c_cpu = timeout_cpu;
|
|
}
|
|
|
|
#ifdef APM_FIXUP_CALLTODO
|
|
/*
|
|
* Adjust the kernel calltodo timeout list. This routine is used after
|
|
* an APM resume to recalculate the calltodo timer list values with the
|
|
* number of hz's we have been sleeping. The next hardclock() will detect
|
|
* that there are fired timers and run softclock() to execute them.
|
|
*
|
|
* Please note, I have not done an exhaustive analysis of what code this
|
|
* might break. I am motivated to have my select()'s and alarm()'s that
|
|
* have expired during suspend firing upon resume so that the applications
|
|
* which set the timer can do the maintanence the timer was for as close
|
|
* as possible to the originally intended time. Testing this code for a
|
|
* week showed that resuming from a suspend resulted in 22 to 25 timers
|
|
* firing, which seemed independant on whether the suspend was 2 hours or
|
|
* 2 days. Your milage may vary. - Ken Key <key@cs.utk.edu>
|
|
*/
|
|
void
|
|
adjust_timeout_calltodo(struct timeval *time_change)
|
|
{
|
|
register struct callout *p;
|
|
unsigned long delta_ticks;
|
|
|
|
/*
|
|
* How many ticks were we asleep?
|
|
* (stolen from tvtohz()).
|
|
*/
|
|
|
|
/* Don't do anything */
|
|
if (time_change->tv_sec < 0)
|
|
return;
|
|
else if (time_change->tv_sec <= LONG_MAX / 1000000)
|
|
delta_ticks = (time_change->tv_sec * 1000000 +
|
|
time_change->tv_usec + (tick - 1)) / tick + 1;
|
|
else if (time_change->tv_sec <= LONG_MAX / hz)
|
|
delta_ticks = time_change->tv_sec * hz +
|
|
(time_change->tv_usec + (tick - 1)) / tick + 1;
|
|
else
|
|
delta_ticks = LONG_MAX;
|
|
|
|
if (delta_ticks > INT_MAX)
|
|
delta_ticks = INT_MAX;
|
|
|
|
/*
|
|
* Now rip through the timer calltodo list looking for timers
|
|
* to expire.
|
|
*/
|
|
|
|
/* don't collide with softclock() */
|
|
CC_LOCK(cc);
|
|
for (p = calltodo.c_next; p != NULL; p = p->c_next) {
|
|
p->c_time -= delta_ticks;
|
|
|
|
/* Break if the timer had more time on it than delta_ticks */
|
|
if (p->c_time > 0)
|
|
break;
|
|
|
|
/* take back the ticks the timer didn't use (p->c_time <= 0) */
|
|
delta_ticks = -p->c_time;
|
|
}
|
|
CC_UNLOCK(cc);
|
|
|
|
return;
|
|
}
|
|
#endif /* APM_FIXUP_CALLTODO */
|
|
|
|
static int
|
|
flssbt(sbintime_t sbt)
|
|
{
|
|
|
|
sbt += (uint64_t)sbt >> 1;
|
|
if (sizeof(long) >= sizeof(sbintime_t))
|
|
return (flsl(sbt));
|
|
if (sbt >= SBT_1S)
|
|
return (flsl(((uint64_t)sbt) >> 32) + 32);
|
|
return (flsl(sbt));
|
|
}
|
|
|
|
/*
|
|
* Dump immediate statistic snapshot of the scheduled callouts.
|
|
*/
|
|
static int
|
|
sysctl_kern_callout_stat(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
struct callout *tmp;
|
|
struct callout_cpu *cc;
|
|
struct callout_list *sc;
|
|
sbintime_t maxpr, maxt, medpr, medt, now, spr, st, t;
|
|
int ct[64], cpr[64], ccpbk[32];
|
|
int error, val, i, count, tcum, pcum, maxc, c, medc;
|
|
#ifdef SMP
|
|
int cpu;
|
|
#endif
|
|
|
|
val = 0;
|
|
error = sysctl_handle_int(oidp, &val, 0, req);
|
|
if (error != 0 || req->newptr == NULL)
|
|
return (error);
|
|
count = maxc = 0;
|
|
st = spr = maxt = maxpr = 0;
|
|
bzero(ccpbk, sizeof(ccpbk));
|
|
bzero(ct, sizeof(ct));
|
|
bzero(cpr, sizeof(cpr));
|
|
now = sbinuptime();
|
|
#ifdef SMP
|
|
CPU_FOREACH(cpu) {
|
|
cc = CC_CPU(cpu);
|
|
#else
|
|
cc = CC_CPU(timeout_cpu);
|
|
#endif
|
|
CC_LOCK(cc);
|
|
for (i = 0; i < callwheelsize; i++) {
|
|
sc = &cc->cc_callwheel[i];
|
|
c = 0;
|
|
LIST_FOREACH(tmp, sc, c_links.le) {
|
|
c++;
|
|
t = tmp->c_time - now;
|
|
if (t < 0)
|
|
t = 0;
|
|
st += t / SBT_1US;
|
|
spr += tmp->c_precision / SBT_1US;
|
|
if (t > maxt)
|
|
maxt = t;
|
|
if (tmp->c_precision > maxpr)
|
|
maxpr = tmp->c_precision;
|
|
ct[flssbt(t)]++;
|
|
cpr[flssbt(tmp->c_precision)]++;
|
|
}
|
|
if (c > maxc)
|
|
maxc = c;
|
|
ccpbk[fls(c + c / 2)]++;
|
|
count += c;
|
|
}
|
|
CC_UNLOCK(cc);
|
|
#ifdef SMP
|
|
}
|
|
#endif
|
|
|
|
for (i = 0, tcum = 0; i < 64 && tcum < count / 2; i++)
|
|
tcum += ct[i];
|
|
medt = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0;
|
|
for (i = 0, pcum = 0; i < 64 && pcum < count / 2; i++)
|
|
pcum += cpr[i];
|
|
medpr = (i >= 2) ? (((sbintime_t)1) << (i - 2)) : 0;
|
|
for (i = 0, c = 0; i < 32 && c < count / 2; i++)
|
|
c += ccpbk[i];
|
|
medc = (i >= 2) ? (1 << (i - 2)) : 0;
|
|
|
|
printf("Scheduled callouts statistic snapshot:\n");
|
|
printf(" Callouts: %6d Buckets: %6d*%-3d Bucket size: 0.%06ds\n",
|
|
count, callwheelsize, mp_ncpus, 1000000 >> CC_HASH_SHIFT);
|
|
printf(" C/Bk: med %5d avg %6d.%06jd max %6d\n",
|
|
medc,
|
|
count / callwheelsize / mp_ncpus,
|
|
(uint64_t)count * 1000000 / callwheelsize / mp_ncpus % 1000000,
|
|
maxc);
|
|
printf(" Time: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n",
|
|
medt / SBT_1S, (medt & 0xffffffff) * 1000000 >> 32,
|
|
(st / count) / 1000000, (st / count) % 1000000,
|
|
maxt / SBT_1S, (maxt & 0xffffffff) * 1000000 >> 32);
|
|
printf(" Prec: med %5jd.%06jds avg %6jd.%06jds max %6jd.%06jds\n",
|
|
medpr / SBT_1S, (medpr & 0xffffffff) * 1000000 >> 32,
|
|
(spr / count) / 1000000, (spr / count) % 1000000,
|
|
maxpr / SBT_1S, (maxpr & 0xffffffff) * 1000000 >> 32);
|
|
printf(" Distribution: \tbuckets\t time\t tcum\t"
|
|
" prec\t pcum\n");
|
|
for (i = 0, tcum = pcum = 0; i < 64; i++) {
|
|
if (ct[i] == 0 && cpr[i] == 0)
|
|
continue;
|
|
t = (i != 0) ? (((sbintime_t)1) << (i - 1)) : 0;
|
|
tcum += ct[i];
|
|
pcum += cpr[i];
|
|
printf(" %10jd.%06jds\t 2**%d\t%7d\t%7d\t%7d\t%7d\n",
|
|
t / SBT_1S, (t & 0xffffffff) * 1000000 >> 32,
|
|
i - 1 - (32 - CC_HASH_SHIFT),
|
|
ct[i], tcum, cpr[i], pcum);
|
|
}
|
|
return (error);
|
|
}
|
|
SYSCTL_PROC(_kern, OID_AUTO, callout_stat,
|
|
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
|
|
0, 0, sysctl_kern_callout_stat, "I",
|
|
"Dump immediate statistic snapshot of the scheduled callouts");
|