freebsd-dev/sys/kern/subr_trap.c
Edward Tomasz Napierala ae34b6ff96 Add four new RCTL resources - readbps, readiops, writebps and writeiops,
for limiting disk (actually filesystem) IO.

Note that in some cases these limits are not quite precise. It's ok,
as long as it's within some reasonable bounds.

Testing - and review of the code, in particular the VFS and VM parts - is
very welcome.

MFC after:	1 month
Relnotes:	yes
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D5080
2016-04-07 04:23:25 +00:00

311 lines
9.0 KiB
C

/*-
* Copyright (C) 1994, David Greenman
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
* Copyright (c) 2007 The FreeBSD Foundation
*
* This code is derived from software contributed to Berkeley by
* the University of Utah, and William Jolitz.
*
* Portions of this software were developed by A. Joseph Koshy under
* sponsorship from the FreeBSD Foundation and Google, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)trap.c 7.4 (Berkeley) 5/13/91
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_hwpmc_hooks.h"
#include "opt_ktrace.h"
#include "opt_sched.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/capsicum.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/pmckern.h>
#include <sys/proc.h>
#include <sys/ktr.h>
#include <sys/pioctl.h>
#include <sys/ptrace.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/syscall.h>
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/vmmeter.h>
#ifdef KTRACE
#include <sys/uio.h>
#include <sys/ktrace.h>
#endif
#include <security/audit/audit.h>
#include <machine/cpu.h>
#ifdef VIMAGE
#include <net/vnet.h>
#endif
#ifdef HWPMC_HOOKS
#include <sys/pmckern.h>
#endif
#include <security/mac/mac_framework.h>
void (*softdep_ast_cleanup)(void);
/*
* Define the code needed before returning to user mode, for trap and
* syscall.
*/
void
userret(struct thread *td, struct trapframe *frame)
{
struct proc *p = td->td_proc;
CTR3(KTR_SYSC, "userret: thread %p (pid %d, %s)", td, p->p_pid,
td->td_name);
KASSERT((p->p_flag & P_WEXIT) == 0,
("Exiting process returns to usermode"));
#if 0
#ifdef DIAGNOSTIC
/* Check that we called signotify() enough. */
PROC_LOCK(p);
thread_lock(td);
if (SIGPENDING(td) && ((td->td_flags & TDF_NEEDSIGCHK) == 0 ||
(td->td_flags & TDF_ASTPENDING) == 0))
printf("failed to set signal flags properly for ast()\n");
thread_unlock(td);
PROC_UNLOCK(p);
#endif
#endif
#ifdef KTRACE
KTRUSERRET(td);
#endif
if (softdep_ast_cleanup != NULL)
softdep_ast_cleanup();
/*
* If this thread tickled GEOM, we need to wait for the giggling to
* stop before we return to userland
*/
if (td->td_pflags & TDP_GEOM)
g_waitidle();
/*
* Charge system time if profiling.
*/
if (p->p_flag & P_PROFIL)
addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio);
/*
* Let the scheduler adjust our priority etc.
*/
sched_userret(td);
/*
* Check for misbehavior.
*
* In case there is a callchain tracing ongoing because of
* hwpmc(4), skip the scheduler pinning check.
* hwpmc(4) subsystem, infact, will collect callchain informations
* at ast() checkpoint, which is past userret().
*/
WITNESS_WARN(WARN_PANIC, NULL, "userret: returning");
KASSERT(td->td_critnest == 0,
("userret: Returning in a critical section"));
KASSERT(td->td_locks == 0,
("userret: Returning with %d locks held", td->td_locks));
KASSERT(td->td_rw_rlocks == 0,
("userret: Returning with %d rwlocks held in read mode",
td->td_rw_rlocks));
KASSERT((td->td_pflags & TDP_NOFAULTING) == 0,
("userret: Returning with pagefaults disabled"));
KASSERT(td->td_no_sleeping == 0,
("userret: Returning with sleep disabled"));
KASSERT(td->td_pinned == 0 || (td->td_pflags & TDP_CALLCHAIN) != 0,
("userret: Returning with with pinned thread"));
KASSERT(td->td_vp_reserv == 0,
("userret: Returning while holding vnode reservation"));
KASSERT((td->td_flags & TDF_SBDRY) == 0,
("userret: Returning with stop signals deferred"));
KASSERT(td->td_su == NULL,
("userret: Returning with SU cleanup request not handled"));
#ifdef VIMAGE
/* Unfortunately td_vnet_lpush needs VNET_DEBUG. */
VNET_ASSERT(curvnet == NULL,
("%s: Returning on td %p (pid %d, %s) with vnet %p set in %s",
__func__, td, p->p_pid, td->td_name, curvnet,
(td->td_vnet_lpush != NULL) ? td->td_vnet_lpush : "N/A"));
#endif
#ifdef RACCT
if (racct_enable && p->p_throttled != 0) {
PROC_LOCK(p);
while (p->p_throttled != 0) {
msleep(p->p_racct, &p->p_mtx, 0, "racct",
p->p_throttled < 0 ? 0 : p->p_throttled);
if (p->p_throttled > 0)
p->p_throttled = 0;
}
PROC_UNLOCK(p);
}
#endif
}
/*
* Process an asynchronous software trap.
* This is relatively easy.
* This function will return with preemption disabled.
*/
void
ast(struct trapframe *framep)
{
struct thread *td;
struct proc *p;
int flags;
int sig;
td = curthread;
p = td->td_proc;
CTR3(KTR_SYSC, "ast: thread %p (pid %d, %s)", td, p->p_pid,
p->p_comm);
KASSERT(TRAPF_USERMODE(framep), ("ast in kernel mode"));
WITNESS_WARN(WARN_PANIC, NULL, "Returning to user mode");
mtx_assert(&Giant, MA_NOTOWNED);
THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
td->td_frame = framep;
td->td_pticks = 0;
/*
* This updates the td_flag's for the checks below in one
* "atomic" operation with turning off the astpending flag.
* If another AST is triggered while we are handling the
* AST's saved in flags, the astpending flag will be set and
* ast() will be called again.
*/
thread_lock(td);
flags = td->td_flags;
td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK |
TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND);
thread_unlock(td);
PCPU_INC(cnt.v_trap);
if (td->td_cowgen != p->p_cowgen)
thread_cow_update(td);
if (td->td_pflags & TDP_OWEUPC && p->p_flag & P_PROFIL) {
addupc_task(td, td->td_profil_addr, td->td_profil_ticks);
td->td_profil_ticks = 0;
td->td_pflags &= ~TDP_OWEUPC;
}
#ifdef HWPMC_HOOKS
/* Handle Software PMC callchain capture. */
if (PMC_IS_PENDING_CALLCHAIN(td))
PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_USER_CALLCHAIN_SOFT, (void *) framep);
#endif
if (flags & TDF_ALRMPEND) {
PROC_LOCK(p);
kern_psignal(p, SIGVTALRM);
PROC_UNLOCK(p);
}
if (flags & TDF_PROFPEND) {
PROC_LOCK(p);
kern_psignal(p, SIGPROF);
PROC_UNLOCK(p);
}
#ifdef MAC
if (flags & TDF_MACPEND)
mac_thread_userret(td);
#endif
if (flags & TDF_NEEDRESCHED) {
#ifdef KTRACE
if (KTRPOINT(td, KTR_CSW))
ktrcsw(1, 1, __func__);
#endif
thread_lock(td);
sched_prio(td, td->td_user_pri);
mi_switch(SW_INVOL | SWT_NEEDRESCHED, NULL);
thread_unlock(td);
#ifdef KTRACE
if (KTRPOINT(td, KTR_CSW))
ktrcsw(0, 1, __func__);
#endif
}
/*
* Check for signals. Unlocked reads of p_pendingcnt or
* p_siglist might cause process-directed signal to be handled
* later.
*/
if (flags & TDF_NEEDSIGCHK || p->p_pendingcnt > 0 ||
!SIGISEMPTY(p->p_siglist)) {
PROC_LOCK(p);
mtx_lock(&p->p_sigacts->ps_mtx);
while ((sig = cursig(td)) != 0)
postsig(sig);
mtx_unlock(&p->p_sigacts->ps_mtx);
PROC_UNLOCK(p);
}
/*
* We need to check to see if we have to exit or wait due to a
* single threading requirement or some other STOP condition.
*/
if (flags & TDF_NEEDSUSPCHK) {
PROC_LOCK(p);
thread_suspend_check(0);
PROC_UNLOCK(p);
}
if (td->td_pflags & TDP_OLDMASK) {
td->td_pflags &= ~TDP_OLDMASK;
kern_sigprocmask(td, SIG_SETMASK, &td->td_oldsigmask, NULL, 0);
}
userret(td, framep);
}
const char *
syscallname(struct proc *p, u_int code)
{
static const char unknown[] = "unknown";
struct sysentvec *sv;
sv = p->p_sysent;
if (sv->sv_syscallnames == NULL || code >= sv->sv_size)
return (unknown);
return (sv->sv_syscallnames[code]);
}