/*
- * Copyright (c) 2000-2012 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2016 Apple Computer, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
#include <sys/disk.h>
#include <sys/uio_internal.h>
#include <sys/resource.h>
+#include <machine/machine_routines.h>
#include <miscfs/specfs/specdev.h>
#include <vfs/vfs_support.h>
+#include <vfs/vfs_disk_conditioner.h>
+
#include <kern/assert.h>
#include <kern/task.h>
+#include <kern/sched_prim.h>
+#include <kern/thread.h>
+#include <kern/policy_internal.h>
+#include <kern/timer_call.h>
+#include <kern/waitq.h>
+
#include <pexpert/pexpert.h>
#include <sys/kdebug.h>
+#include <libkern/section_keywords.h>
/* XXX following three prototypes should be in a header file somewhere */
extern dev_t chrtoblk(dev_t dev);
-extern int iskmemdev(dev_t dev);
+extern boolean_t iskmemdev(dev_t dev);
extern int bpfkqfilter(dev_t dev, struct knote *kn);
-extern int ptsd_kqfilter(dev_t dev, struct knote *kn);
-
-extern int ignore_is_ssd;
+extern int ptsd_kqfilter(dev_t, struct knote *);
+extern int ptmx_kqfilter(dev_t, struct knote *);
struct vnode *speclisth[SPECHSZ];
{ &vnop_blktooff_desc, (VOPFUNC)spec_blktooff }, /* blktooff */
{ &vnop_offtoblk_desc, (VOPFUNC)spec_offtoblk }, /* offtoblk */
{ &vnop_blockmap_desc, (VOPFUNC)spec_blockmap }, /* blockmap */
- { (struct vnodeop_desc*)NULL, (int(*)())NULL }
+ { (struct vnodeop_desc*)NULL, (int(*)(void *))NULL }
};
struct vnodeopv_desc spec_vnodeop_opv_desc =
{ &spec_vnodeop_p, spec_vnodeop_entries };
#define LOWPRI_TIER2_WINDOW_MSECS 100
#define LOWPRI_TIER3_WINDOW_MSECS 500
-#define LOWPRI_TIER1_IO_PERIOD_MSECS 15
-#define LOWPRI_TIER2_IO_PERIOD_MSECS 50
+#define LOWPRI_TIER1_IO_PERIOD_MSECS 40
+#define LOWPRI_TIER2_IO_PERIOD_MSECS 85
#define LOWPRI_TIER3_IO_PERIOD_MSECS 200
#define LOWPRI_TIER1_IO_PERIOD_SSD_MSECS 5
struct timeval throttle_last_write_timestamp;
struct timeval throttle_min_timer_deadline;
- struct timeval throttle_window_start_timestamp[THROTTLE_LEVEL_END + 1];
+ struct timeval throttle_window_start_timestamp[THROTTLE_LEVEL_END + 1]; /* window starts at both the beginning and completion of an I/O */
struct timeval throttle_last_IO_timestamp[THROTTLE_LEVEL_END + 1];
pid_t throttle_last_IO_pid[THROTTLE_LEVEL_END + 1];
struct timeval throttle_start_IO_period_timestamp[THROTTLE_LEVEL_END + 1];
+ int32_t throttle_inflight_count[THROTTLE_LEVEL_END + 1];
TAILQ_HEAD( , uthread) throttle_uthlist[THROTTLE_LEVEL_END + 1]; /* Lists of throttled uthreads */
int throttle_next_wake_level;
int32_t throttle_refcnt;
int32_t throttle_alloc;
+ int32_t throttle_disabled;
+ int32_t throttle_is_fusion_with_priority;
};
struct _throttle_io_info_t _throttle_io_info[LOWPRI_MAX_NUM_DEV];
int lowpri_throttle_enabled = 1;
-
-static void throttle_info_update_internal(struct _throttle_io_info_t *info, uthread_t ut, int flags, boolean_t isssd);
+static void throttle_info_end_io_internal(struct _throttle_io_info_t *info, int throttle_level);
+static int throttle_info_update_internal(struct _throttle_io_info_t *info, uthread_t ut, int flags, boolean_t isssd, boolean_t inflight, struct bufattr *bap);
static int throttle_get_thread_throttle_level(uthread_t ut);
+static int throttle_get_thread_throttle_level_internal(uthread_t ut, int io_tier);
+void throttle_info_mount_reset_period(mount_t mp, int isssd);
/*
* Trivial lookup routine that always fails.
*/
if (securelevel >= 2 && isdisk(dev, VCHR))
return (EPERM);
+
+ /* Never allow writing to /dev/mem or /dev/kmem */
+ if (iskmemdev(dev))
+ return (EPERM);
/*
- * When running in secure mode, do not allow opens
- * for writing of /dev/mem, /dev/kmem, or character
- * devices whose corresponding block devices are
- * currently mounted.
+ * When running in secure mode, do not allow opens for
+ * writing of character devices whose corresponding block
+ * devices are currently mounted.
*/
if (securelevel >= 1) {
if ((bdev = chrtoblk(dev)) != NODEV && check_mountedon(bdev, VBLK, &error))
return (error);
- if (iskmemdev(dev))
- return (EPERM);
}
}
switch (vp->v_type) {
case VCHR:
+ {
+ struct _throttle_io_info_t *throttle_info = NULL;
+ int thread_throttle_level;
if (cdevsw[major(vp->v_rdev)].d_type == D_DISK && vp->v_un.vu_specinfo->si_throttleable) {
- struct _throttle_io_info_t *throttle_info;
-
throttle_info = &_throttle_io_info[vp->v_un.vu_specinfo->si_devbsdunit];
-
- throttle_info_update_internal(throttle_info, NULL, 0, vp->v_un.vu_specinfo->si_isssd);
+ thread_throttle_level = throttle_info_update_internal(throttle_info, NULL, 0, vp->v_un.vu_specinfo->si_isssd, TRUE, NULL);
}
error = (*cdevsw[major(vp->v_rdev)].d_read)
(vp->v_rdev, uio, ap->a_ioflag);
+ if (throttle_info) {
+ throttle_info_end_io_internal(throttle_info, thread_throttle_level);
+ }
+
return (error);
+ }
case VBLK:
if (uio->uio_offset < 0)
switch (vp->v_type) {
case VCHR:
+ {
+ struct _throttle_io_info_t *throttle_info = NULL;
+ int thread_throttle_level;
if (cdevsw[major(vp->v_rdev)].d_type == D_DISK && vp->v_un.vu_specinfo->si_throttleable) {
- struct _throttle_io_info_t *throttle_info;
-
throttle_info = &_throttle_io_info[vp->v_un.vu_specinfo->si_devbsdunit];
- throttle_info_update_internal(throttle_info, NULL, 0, vp->v_un.vu_specinfo->si_isssd);
+ thread_throttle_level = throttle_info_update_internal(throttle_info, NULL, 0, vp->v_un.vu_specinfo->si_isssd, TRUE, NULL);
microuptime(&throttle_info->throttle_last_write_timestamp);
}
error = (*cdevsw[major(vp->v_rdev)].d_write)
(vp->v_rdev, uio, ap->a_ioflag);
+ if (throttle_info) {
+ throttle_info_end_io_internal(throttle_info, thread_throttle_level);
+ }
+
return (error);
+ }
case VBLK:
if (uio_resid(uio) == 0)
int retval = 0;
KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_IOCTL, 0) | DBG_FUNC_START,
- (unsigned int)dev, (unsigned int)ap->a_command, (unsigned int)ap->a_fflag, (unsigned int)ap->a_vp->v_type, 0);
+ dev, ap->a_command, ap->a_fflag, ap->a_vp->v_type, 0);
switch (ap->a_vp->v_type) {
break;
case VBLK:
- if (kdebug_enable) {
- if (ap->a_command == DKIOCUNMAP) {
- dk_unmap_t *unmap;
- dk_extent_t *extent;
- uint32_t i;
-
- unmap = (dk_unmap_t *)ap->a_data;
- extent = unmap->extents;
-
- for (i = 0; i < unmap->extentsCount; i++, extent++) {
- KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_IOCTL, 1) | DBG_FUNC_NONE, dev, extent->offset/ap->a_vp->v_specsize, extent->length, 0, 0);
- }
- }
- }
retval = (*bdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data, ap->a_fflag, p);
+ if (!retval && ap->a_command == DKIOCSETBLOCKSIZE)
+ ap->a_vp->v_specsize = *(uint32_t *)ap->a_data;
break;
default:
/* NOTREACHED */
}
KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_IOCTL, 0) | DBG_FUNC_END,
- (unsigned int)dev, (unsigned int)ap->a_command, (unsigned int)ap->a_fflag, retval, 0);
+ dev, ap->a_command, ap->a_fflag, retval, 0);
return (retval);
}
}
}
-static int filt_specattach(struct knote *kn);
+static int filt_specattach(struct knote *kn, struct kevent_internal_s *kev);
int
-spec_kqfilter(vnode_t vp, struct knote *kn)
+spec_kqfilter(vnode_t vp, struct knote *kn, struct kevent_internal_s *kev)
{
dev_t dev;
- int err = EINVAL;
- /*
- * For a few special kinds of devices, we can attach knotes.
- * Each filter function must check whether the dev type matches it.
- */
+ assert(vnode_ischr(vp));
+
dev = vnode_specrdev(vp);
- if (vnode_istty(vp)) {
- /* We can hook into TTYs... */
- err = filt_specattach(kn);
- } else {
#if NETWORKING
- /* Try a bpf device, as defined in bsd/net/bpf.c */
- err = bpfkqfilter(dev, kn);
+ /*
+ * Try a bpf device, as defined in bsd/net/bpf.c
+ * If it doesn't error out the attach, then it
+ * claimed it. Otherwise, fall through and try
+ * other attaches.
+ */
+ int32_t tmp_flags = kn->kn_flags;
+ int64_t tmp_data = kn->kn_data;
+ int res;
+
+ res = bpfkqfilter(dev, kn);
+ if ((kn->kn_flags & EV_ERROR) == 0) {
+ return res;
+ }
+ kn->kn_flags = tmp_flags;
+ kn->kn_data = tmp_data;
#endif
+
+ if (major(dev) > nchrdev) {
+ knote_set_error(kn, ENXIO);
+ return 0;
+ }
+
+ kn->kn_vnode_kqok = !!(cdevsw_flags[major(dev)] & CDEVSW_SELECT_KQUEUE);
+ kn->kn_vnode_use_ofst = !!(cdevsw_flags[major(dev)] & CDEVSW_USE_OFFSET);
+
+ if (cdevsw_flags[major(dev)] & CDEVSW_IS_PTS) {
+ kn->kn_filtid = EVFILTID_PTSD;
+ return ptsd_kqfilter(dev, kn);
+ } else if (cdevsw_flags[major(dev)] & CDEVSW_IS_PTC) {
+ kn->kn_filtid = EVFILTID_PTMX;
+ return ptmx_kqfilter(dev, kn);
+ } else if (cdevsw[major(dev)].d_type == D_TTY && kn->kn_vnode_kqok) {
+ /*
+ * TTYs from drivers that use struct ttys use their own filter
+ * routines. The PTC driver doesn't use the tty for character
+ * counts, so it must go through the select fallback.
+ */
+ kn->kn_filtid = EVFILTID_TTY;
+ return knote_fops(kn)->f_attach(kn, kev);
}
- return err;
+ /* Try to attach to other char special devices */
+ return filt_specattach(kn, kev);
}
/*
SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_enabled, CTLFLAG_RW | CTLFLAG_LOCKED, &lowpri_throttle_enabled, 0, "");
-static lck_grp_t *throttle_mtx_grp;
-static lck_attr_t *throttle_mtx_attr;
-static lck_grp_attr_t *throttle_mtx_grp_attr;
+static lck_grp_t *throttle_lock_grp;
+static lck_attr_t *throttle_lock_attr;
+static lck_grp_attr_t *throttle_lock_grp_attr;
/*
if ((info->throttle_refcnt == 0) && (info->throttle_alloc)) {
DEBUG_ALLOC_THROTTLE_INFO("Freeing info = %p\n", info);
- lck_mtx_destroy(&info->throttle_lock, throttle_mtx_grp);
+ lck_mtx_destroy(&info->throttle_lock, throttle_lock_grp);
FREE(info, M_TEMP);
}
return oldValue;
if (!TAILQ_EMPTY(&info->throttle_uthlist[level])) {
- if (elapsed_msecs < (uint64_t)throttle_windows_msecs[level]) {
+ if (elapsed_msecs < (uint64_t)throttle_windows_msecs[level] || info->throttle_inflight_count[throttle_level]) {
/*
* we had an I/O occur at a higher priority tier within
* this tier's throttle window
ut = (uthread_t)TAILQ_FIRST(&info->throttle_uthlist[wake_level]);
TAILQ_REMOVE(&info->throttle_uthlist[wake_level], ut, uu_throttlelist);
ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
+ ut->uu_is_throttled = FALSE;
wake_address = (caddr_t)&ut->uu_on_throttlelist;
}
TAILQ_REMOVE(&info->throttle_uthlist[level], ut, uu_throttlelist);
ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
+ ut->uu_is_throttled = FALSE;
wakeup(&ut->uu_on_throttlelist);
}
*/
/* Assign global defaults */
- if (isssd == TRUE)
+ if ((isssd == TRUE) && (info->throttle_is_fusion_with_priority == 0))
info->throttle_io_periods = &throttle_io_period_ssd_msecs[0];
else
info->throttle_io_periods = &throttle_io_period_msecs[0];
}
+#if CONFIG_IOSCHED
+extern void vm_io_reprioritize_init(void);
+int iosched_enabled = 1;
+#endif
+
void
throttle_init(void)
{
struct _throttle_io_info_t *info;
int i;
int level;
-
+#if CONFIG_IOSCHED
+ int iosched;
+#endif
/*
* allocate lock group attribute and group
*/
- throttle_mtx_grp_attr = lck_grp_attr_alloc_init();
- throttle_mtx_grp = lck_grp_alloc_init("throttle I/O", throttle_mtx_grp_attr);
+ throttle_lock_grp_attr = lck_grp_attr_alloc_init();
+ throttle_lock_grp = lck_grp_alloc_init("throttle I/O", throttle_lock_grp_attr);
/* Update throttle parameters based on device tree configuration */
throttle_init_throttle_window();
/*
* allocate the lock attribute
*/
- throttle_mtx_attr = lck_attr_alloc_init();
+ throttle_lock_attr = lck_attr_alloc_init();
for (i = 0; i < LOWPRI_MAX_NUM_DEV; i++) {
info = &_throttle_io_info[i];
- lck_mtx_init(&info->throttle_lock, throttle_mtx_grp, throttle_mtx_attr);
+ lck_mtx_init(&info->throttle_lock, throttle_lock_grp, throttle_lock_attr);
info->throttle_timer_call = thread_call_allocate((thread_call_func_t)throttle_timer, (thread_call_param_t)info);
for (level = 0; level <= THROTTLE_LEVEL_END; level++) {
TAILQ_INIT(&info->throttle_uthlist[level]);
info->throttle_last_IO_pid[level] = 0;
+ info->throttle_inflight_count[level] = 0;
}
info->throttle_next_wake_level = THROTTLE_LEVEL_END;
+ info->throttle_disabled = 0;
+ info->throttle_is_fusion_with_priority = 0;
+ }
+#if CONFIG_IOSCHED
+ if (PE_parse_boot_argn("iosched", &iosched, sizeof(iosched))) {
+ iosched_enabled = iosched;
+ }
+ if (iosched_enabled) {
+ /* Initialize I/O Reprioritization mechanism */
+ vm_io_reprioritize_init();
}
+#endif
}
void
{
if (flag == THROTTLE_IO_ENABLE)
lowpri_throttle_enabled = 1;
+
if (flag == THROTTLE_IO_DISABLE)
lowpri_throttle_enabled = 0;
}
-int rethrottle_removed_from_list = 0;
-int rethrottle_moved_to_new_list = 0;
+int rethrottle_wakeups = 0;
/*
- * move a throttled thread to the appropriate state based
- * on it's new throttle level... throttle_add_to_list will
- * reset the timer deadline if necessary... it may also
- * leave the thread off of the queue if we're already outside
- * the throttle window for the new level
- * takes a valid uthread (which may or may not be on the
- * throttle queue) as input
+ * the uu_rethrottle_lock is used to synchronize this function
+ * with "throttle_lowpri_io" which is where a throttled thread
+ * will block... that function will grab this lock before beginning
+ * it's decision making process concerning the need to block, and
+ * hold it through the assert_wait. When that thread is awakened
+ * for any reason (timer or rethrottle), it will reacquire the
+ * uu_rethrottle_lock before determining if it really is ok for
+ * it to now run. This is the point at which the thread could
+ * enter a different throttling queue and reblock or return from
+ * the throttle w/o having waited out it's entire throttle if
+ * the rethrottle has now moved it out of any currently
+ * active throttle window.
*
- * NOTE: This is called with the task lock held.
+ *
+ * NOTES:
+ * 1 - This may be called with the task lock held.
+ * 2 - This may be called with preemption and interrupts disabled
+ * in the kqueue wakeup path so we can't take the throttle_lock which is a mutex
+ * 3 - This cannot safely dereference uu_throttle_info, as it may
+ * get deallocated out from under us
*/
void
rethrottle_thread(uthread_t ut)
{
- struct _throttle_io_info_t *info;
- int my_new_level;
-
- if ((info = ut->uu_throttle_info) == NULL)
+ /*
+ * If uthread doesn't have throttle state, then there's no chance
+ * of it needing a rethrottle.
+ */
+ if (ut->uu_throttle_info == NULL)
return;
- lck_mtx_lock(&info->throttle_lock);
+ boolean_t s = ml_set_interrupts_enabled(FALSE);
+ lck_spin_lock(&ut->uu_rethrottle_lock);
- if (ut->uu_on_throttlelist >= THROTTLE_LEVEL_THROTTLED) {
-
- my_new_level = throttle_get_thread_throttle_level(ut);
+ if (ut->uu_is_throttled == FALSE)
+ ut->uu_was_rethrottled = TRUE;
+ else {
+ int my_new_level = throttle_get_thread_throttle_level(ut);
if (my_new_level != ut->uu_on_throttlelist) {
+ /*
+ * ut is currently blocked (as indicated by
+ * ut->uu_is_throttled == TRUE)
+ * and we're changing it's throttle level, so
+ * we need to wake it up.
+ */
+ ut->uu_is_throttled = FALSE;
+ wakeup(&ut->uu_on_throttlelist);
- TAILQ_REMOVE(&info->throttle_uthlist[ut->uu_on_throttlelist], ut, uu_throttlelist);
- ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
-
- if (my_new_level >= THROTTLE_LEVEL_THROTTLED) {
- throttle_add_to_list(info, ut, my_new_level, TRUE);
- rethrottle_moved_to_new_list++;
- }
-
- /* Thread no longer in window, need to wake it up */
- if (ut->uu_on_throttlelist == THROTTLE_LEVEL_NONE) {
- wakeup(&ut->uu_on_throttlelist);
- rethrottle_removed_from_list++;
- }
+ rethrottle_wakeups++;
+ KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW, 102)), thread_tid(ut->uu_thread), ut->uu_on_throttlelist, my_new_level, 0, 0);
}
}
-
- lck_mtx_unlock(&info->throttle_lock);
+ lck_spin_unlock(&ut->uu_rethrottle_lock);
+ ml_set_interrupts_enabled(s);
}
DEBUG_ALLOC_THROTTLE_INFO("Creating info = %p\n", info, info );
info->throttle_alloc = TRUE;
- lck_mtx_init(&info->throttle_lock, throttle_mtx_grp, throttle_mtx_attr);
+ lck_mtx_init(&info->throttle_lock, throttle_lock_grp, throttle_lock_attr);
info->throttle_timer_call = thread_call_allocate((thread_call_func_t)throttle_timer, (thread_call_param_t)info);
for (level = 0; level <= THROTTLE_LEVEL_END; level++) {
mp->mnt_throttle_info = NULL;
}
+/*
+ * Reset throttling periods for the given mount point
+ *
+ * private interface used by disk conditioner to reset
+ * throttling periods when 'is_ssd' status changes
+ */
+void
+throttle_info_mount_reset_period(mount_t mp, int isssd)
+{
+ struct _throttle_io_info_t *info;
+
+ if (mp == NULL)
+ info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
+ else if (mp->mnt_throttle_info == NULL)
+ info = &_throttle_io_info[mp->mnt_devbsdunit];
+ else
+ info = mp->mnt_throttle_info;
+
+ throttle_init_throttle_period(info, isssd);
+}
+
void
throttle_info_get_last_io_time(mount_t mp, struct timeval *tv)
{
mp->mnt_last_write_completed_timestamp = info->throttle_last_write_timestamp;
}
-
int
throttle_get_io_policy(uthread_t *ut)
{
static int
throttle_get_thread_throttle_level(uthread_t ut)
{
- int thread_throttle_level;
+ uthread_t *ut_p = (ut == NULL) ? &ut : NULL;
+ int io_tier = throttle_get_io_policy(ut_p);
- if (ut == NULL)
- ut = get_bsdthread_info(current_thread());
+ return throttle_get_thread_throttle_level_internal(ut, io_tier);
+}
- thread_throttle_level = proc_get_effective_thread_policy(ut->uu_thread, TASK_POLICY_IO);
+/*
+ * Return a throttle level given an existing I/O tier (such as returned by throttle_get_io_policy)
+ */
+static int
+throttle_get_thread_throttle_level_internal(uthread_t ut, int io_tier) {
+ int thread_throttle_level = io_tier;
+ int user_idle_level;
+
+ assert(ut != NULL);
/* Bootcache misses should always be throttled */
if (ut->uu_throttle_bc == TRUE)
thread_throttle_level = THROTTLE_LEVEL_TIER3;
+ /*
+ * Issue tier3 I/O as tier2 when the user is idle
+ * to allow maintenance tasks to make more progress.
+ *
+ * Assume any positive idle level is enough... for now it's
+ * only ever 0 or 128 but this is not defined anywhere.
+ */
+ if (thread_throttle_level >= THROTTLE_LEVEL_TIER3) {
+ user_idle_level = timer_get_user_idle_level();
+ if (user_idle_level > 0) {
+ thread_throttle_level--;
+ }
+ }
+
return (thread_throttle_level);
}
-
+/*
+ * I/O will be throttled if either of the following are true:
+ * - Higher tiers have in-flight I/O
+ * - The time delta since the last start/completion of a higher tier is within the throttle window interval
+ *
+ * In-flight I/O is bookended by throttle_info_update_internal/throttle_info_end_io_internal
+ */
static int
throttle_io_will_be_throttled_internal(void * throttle_info, int * mylevel, int * throttling_level)
{
struct _throttle_io_info_t *info = throttle_info;
struct timeval elapsed;
+ struct timeval now;
uint64_t elapsed_msecs;
int thread_throttle_level;
int throttle_level;
if ((thread_throttle_level = throttle_get_thread_throttle_level(NULL)) < THROTTLE_LEVEL_THROTTLED)
return (THROTTLE_DISENGAGED);
- for (throttle_level = THROTTLE_LEVEL_START; throttle_level < thread_throttle_level; throttle_level++) {
+ microuptime(&now);
- microuptime(&elapsed);
+ for (throttle_level = THROTTLE_LEVEL_START; throttle_level < thread_throttle_level; throttle_level++) {
+ if (info->throttle_inflight_count[throttle_level]) {
+ break;
+ }
+ elapsed = now;
timevalsub(&elapsed, &info->throttle_window_start_timestamp[throttle_level]);
elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
int
throttle_io_will_be_throttled(__unused int lowpri_window_msecs, mount_t mp)
{
- void *info;
+ struct _throttle_io_info_t *info;
/*
* Should we just return zero if no mount point
else
info = mp->mnt_throttle_info;
- return throttle_io_will_be_throttled_internal(info, NULL, NULL);
+ if (info->throttle_is_fusion_with_priority) {
+ uthread_t ut = get_bsdthread_info(current_thread());
+ if (ut->uu_lowpri_window == 0)
+ return (THROTTLE_DISENGAGED);
+ }
+
+ if (info->throttle_disabled)
+ return (THROTTLE_DISENGAGED);
+ else
+ return throttle_io_will_be_throttled_internal(info, NULL, NULL);
}
/*
*/
static void
-throttle_update_proc_stats(pid_t throttling_pid)
+throttle_update_proc_stats(pid_t throttling_pid, int count)
{
proc_t throttling_proc;
proc_t throttled_proc = current_proc();
/* The throttled_proc is always the current proc; so we are not concerned with refs */
- OSAddAtomic64(1, &(throttled_proc->was_throttled));
+ OSAddAtomic64(count, &(throttled_proc->was_throttled));
/* The throttling pid might have exited by now */
throttling_proc = proc_find(throttling_pid);
if (throttling_proc != PROC_NULL) {
- OSAddAtomic64(1, &(throttling_proc->did_throttle));
+ OSAddAtomic64(count, &(throttling_proc->did_throttle));
proc_rele(throttling_proc);
}
}
int sleep_cnt = 0;
uint32_t throttle_io_period_num = 0;
boolean_t insert_tail = TRUE;
+ boolean_t s;
ut = get_bsdthread_info(current_thread());
ut->uu_lowpri_window = 0;
return (0);
}
-
lck_mtx_lock(&info->throttle_lock);
+ assert(ut->uu_on_throttlelist < THROTTLE_LEVEL_THROTTLED);
if (sleep_amount == 0)
goto done;
throttle_io_period_num = info->throttle_io_period_num;
+ ut->uu_was_rethrottled = FALSE;
+
while ( (throttle_type = throttle_io_will_be_throttled_internal(info, &mylevel, &throttling_level)) ) {
if (throttle_type == THROTTLE_ENGAGED) {
if ((info->throttle_io_period_num - throttle_io_period_num) >= (uint32_t)sleep_amount)
break;
}
+ /*
+ * keep the same position in the list if "rethrottle_thread" changes our throttle level and
+ * then puts us back to the original level before we get a chance to run
+ */
+ if (ut->uu_on_throttlelist >= THROTTLE_LEVEL_THROTTLED && ut->uu_on_throttlelist != mylevel) {
+ /*
+ * must have been awakened via "rethrottle_thread" (the timer pulls us off the list)
+ * and we've changed our throttling level, so pull ourselves off of the appropriate list
+ * and make sure we get put on the tail of the new list since we're starting anew w/r to
+ * the throttling engine
+ */
+ TAILQ_REMOVE(&info->throttle_uthlist[ut->uu_on_throttlelist], ut, uu_throttlelist);
+ ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
+ insert_tail = TRUE;
+ }
if (ut->uu_on_throttlelist < THROTTLE_LEVEL_THROTTLED) {
if (throttle_add_to_list(info, ut, mylevel, insert_tail) == THROTTLE_LEVEL_END)
goto done;
}
assert(throttling_level >= THROTTLE_LEVEL_START && throttling_level <= THROTTLE_LEVEL_END);
- throttle_update_proc_stats(info->throttle_last_IO_pid[throttling_level]);
+
+ s = ml_set_interrupts_enabled(FALSE);
+ lck_spin_lock(&ut->uu_rethrottle_lock);
+
+ /*
+ * this is the critical section w/r to our interaction
+ * with "rethrottle_thread"
+ */
+ if (ut->uu_was_rethrottled == TRUE) {
+
+ lck_spin_unlock(&ut->uu_rethrottle_lock);
+ ml_set_interrupts_enabled(s);
+ lck_mtx_yield(&info->throttle_lock);
+
+ KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW, 103)), thread_tid(ut->uu_thread), ut->uu_on_throttlelist, 0, 0, 0);
+
+ ut->uu_was_rethrottled = FALSE;
+ continue;
+ }
KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_THROTTLE, PROCESS_THROTTLED)) | DBG_FUNC_NONE,
info->throttle_last_IO_pid[throttling_level], throttling_level, proc_selfpid(), mylevel, 0);
-
if (sleep_cnt == 0) {
KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_START,
throttle_windows_msecs[mylevel], info->throttle_io_periods[mylevel], info->throttle_io_count, 0, 0);
throttled_count[mylevel]++;
}
- msleep((caddr_t)&ut->uu_on_throttlelist, &info->throttle_lock, PRIBIO + 1, "throttle_lowpri_io", NULL);
+ ut->uu_wmesg = "throttle_lowpri_io";
+
+ assert_wait((caddr_t)&ut->uu_on_throttlelist, THREAD_UNINT);
+
+ ut->uu_is_throttled = TRUE;
+ lck_spin_unlock(&ut->uu_rethrottle_lock);
+ ml_set_interrupts_enabled(s);
+
+ lck_mtx_unlock(&info->throttle_lock);
+
+ thread_block(THREAD_CONTINUE_NULL);
+
+ ut->uu_wmesg = NULL;
+
+ ut->uu_is_throttled = FALSE;
+ ut->uu_was_rethrottled = FALSE;
+
+ lck_mtx_lock(&info->throttle_lock);
sleep_cnt++;
TAILQ_REMOVE(&info->throttle_uthlist[ut->uu_on_throttlelist], ut, uu_throttlelist);
ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
}
-
lck_mtx_unlock(&info->throttle_lock);
if (sleep_cnt) {
KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_END,
throttle_windows_msecs[mylevel], info->throttle_io_periods[mylevel], info->throttle_io_count, 0, 0);
+ /*
+ * We update the stats for the last pid which opened a throttle window for the throttled thread.
+ * This might not be completely accurate since the multiple throttles seen by the lower tier pid
+ * might have been caused by various higher prio pids. However, updating these stats accurately
+ * means doing a proc_find while holding the throttle lock which leads to deadlock.
+ */
+ throttle_update_proc_stats(info->throttle_last_IO_pid[throttling_level], sleep_cnt);
}
- throttle_info_rel(info);
-
ut->uu_throttle_info = NULL;
ut->uu_throttle_bc = FALSE;
ut->uu_lowpri_window = 0;
+ throttle_info_rel(info);
+
return (sleep_cnt);
}
*/
void throttle_set_thread_io_policy(int policy)
{
- proc_set_task_policy(current_task(), current_thread(),
- TASK_POLICY_INTERNAL, TASK_POLICY_IOPOL,
- policy);
+ proc_set_thread_policy(current_thread(), TASK_POLICY_INTERNAL, TASK_POLICY_IOPOL, policy);
}
+int throttle_get_thread_effective_io_policy()
+{
+ return proc_get_effective_thread_policy(current_thread(), TASK_POLICY_IO);
+}
-static
void throttle_info_reset_window(uthread_t ut)
{
struct _throttle_io_info_t *info;
+ if (ut == NULL)
+ ut = get_bsdthread_info(current_thread());
+
if ( (info = ut->uu_throttle_info) ) {
throttle_info_rel(info);
static
void throttle_info_set_initial_window(uthread_t ut, struct _throttle_io_info_t *info, boolean_t BC_throttle, boolean_t isssd)
{
- if (lowpri_throttle_enabled == 0)
+ if (lowpri_throttle_enabled == 0 || info->throttle_disabled)
return;
if (info->throttle_io_periods == 0) {
}
}
+/*
+ * Update inflight IO count and throttling window
+ * Should be called when an IO is done
+ *
+ * Only affects IO that was sent through spec_strategy
+ */
+void throttle_info_end_io(buf_t bp) {
+ mount_t mp;
+ struct bufattr *bap;
+ struct _throttle_io_info_t *info;
+ int io_tier;
+
+ bap = &bp->b_attr;
+ if (!ISSET(bap->ba_flags, BA_STRATEGY_TRACKED_IO)) {
+ return;
+ }
+ CLR(bap->ba_flags, BA_STRATEGY_TRACKED_IO);
+
+ mp = buf_vnode(bp)->v_mount;
+ if (mp != NULL) {
+ info = &_throttle_io_info[mp->mnt_devbsdunit];
+ } else {
+ info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
+ }
+
+ io_tier = GET_BUFATTR_IO_TIER(bap);
+ if (ISSET(bap->ba_flags, BA_IO_TIER_UPGRADE)) {
+ io_tier--;
+ }
+
+ throttle_info_end_io_internal(info, io_tier);
+}
+
+/*
+ * Decrement inflight count initially incremented by throttle_info_update_internal
+ */
+static
+void throttle_info_end_io_internal(struct _throttle_io_info_t *info, int throttle_level) {
+ if (throttle_level == THROTTLE_LEVEL_NONE) {
+ return;
+ }
+ microuptime(&info->throttle_window_start_timestamp[throttle_level]);
+ OSDecrementAtomic(&info->throttle_inflight_count[throttle_level]);
+ assert(info->throttle_inflight_count[throttle_level] >= 0);
+}
+
+/*
+ * If inflight is TRUE and bap is NULL then the caller is responsible for calling
+ * throttle_info_end_io_internal to avoid leaking in-flight I/O.
+ */
static
-void throttle_info_update_internal(struct _throttle_io_info_t *info, uthread_t ut, int flags, boolean_t isssd)
+int throttle_info_update_internal(struct _throttle_io_info_t *info, uthread_t ut, int flags, boolean_t isssd, boolean_t inflight, struct bufattr *bap)
{
int thread_throttle_level;
- if (lowpri_throttle_enabled == 0)
- return;
+ if (lowpri_throttle_enabled == 0 || info->throttle_disabled)
+ return THROTTLE_LEVEL_NONE;
if (ut == NULL)
ut = get_bsdthread_info(current_thread());
- thread_throttle_level = throttle_get_thread_throttle_level(ut);
+ if (bap && inflight && !ut->uu_throttle_bc) {
+ thread_throttle_level = GET_BUFATTR_IO_TIER(bap);
+ if (ISSET(bap->ba_flags, BA_IO_TIER_UPGRADE)) {
+ thread_throttle_level--;
+ }
+ } else {
+ thread_throttle_level = throttle_get_thread_throttle_level(ut);
+ }
if (thread_throttle_level != THROTTLE_LEVEL_NONE) {
- if(!ISSET(flags, B_PASSIVE)) {
- microuptime(&info->throttle_window_start_timestamp[thread_throttle_level]);
+ if(!ISSET(flags, B_PASSIVE)) {
info->throttle_last_IO_pid[thread_throttle_level] = proc_selfpid();
+ if (inflight && !ut->uu_throttle_bc) {
+ if (NULL != bap) {
+ SET(bap->ba_flags, BA_STRATEGY_TRACKED_IO);
+ }
+ OSIncrementAtomic(&info->throttle_inflight_count[thread_throttle_level]);
+ } else {
+ microuptime(&info->throttle_window_start_timestamp[thread_throttle_level]);
+ }
KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_THROTTLE, OPEN_THROTTLE_WINDOW)) | DBG_FUNC_NONE,
current_proc()->p_pid, thread_throttle_level, 0, 0, 0);
}
throttle_info_set_initial_window(ut, info, FALSE, isssd);
}
+
+ return thread_throttle_level;
}
void *throttle_info_update_by_mount(mount_t mp)
ut = get_bsdthread_info(current_thread());
if (mp != NULL) {
- if ((mp->mnt_kern_flag & MNTK_SSD) && !ignore_is_ssd)
+ if (disk_conditioner_mount_is_ssd(mp))
isssd = TRUE;
info = &_throttle_io_info[mp->mnt_devbsdunit];
} else
void throttle_info_update(void *throttle_info, int flags)
{
if (throttle_info)
- throttle_info_update_internal(throttle_info, NULL, flags, FALSE);
+ throttle_info_update_internal(throttle_info, NULL, flags, FALSE, FALSE, NULL);
}
/*
*/
throttle_info_update(throttle_info, flags);
}
+/*
+ * KPI routine
+ *
+ * This routine marks the throttle info as disabled. Used for mount points which
+ * support I/O scheduling.
+ */
+
+void throttle_info_disable_throttle(int devno, boolean_t isfusion)
+{
+ struct _throttle_io_info_t *info;
+
+ if (devno < 0 || devno >= LOWPRI_MAX_NUM_DEV)
+ panic("Illegal devno (%d) passed into throttle_info_disable_throttle()", devno);
+
+ info = &_throttle_io_info[devno];
+ // don't disable software throttling on devices that are part of a fusion device
+ // and override the software throttle periods to use HDD periods
+ if (isfusion) {
+ info->throttle_is_fusion_with_priority = isfusion;
+ throttle_init_throttle_period(info, FALSE);
+ }
+ info->throttle_disabled = !info->throttle_is_fusion_with_priority;
+ return;
+}
+
/*
* KPI routine (private)
break;
}
for (throttle_level = THROTTLE_LEVEL_START; throttle_level < thread_throttle_level; throttle_level++) {
+ if (info->throttle_inflight_count[throttle_level]) {
+ break;
+ }
microuptime(&elapsed);
timevalsub(&elapsed, &info->throttle_window_start_timestamp[throttle_level]);
return (THROTTLE_ENGAGED);
}
+int throttle_lowpri_window(void)
+{
+ struct uthread *ut = get_bsdthread_info(current_thread());
+ return ut->uu_lowpri_window;
+}
+
+
+#if CONFIG_IOSCHED
+int upl_get_cached_tier(void *);
+#endif
+
int
spec_strategy(struct vnop_strategy_args *ap)
{
int strategy_ret;
struct _throttle_io_info_t *throttle_info;
boolean_t isssd = FALSE;
+ boolean_t inflight = FALSE;
+ boolean_t upgrade = FALSE;
+ int code = 0;
+
+#if !CONFIG_EMBEDDED
proc_t curproc = current_proc();
+#endif /* !CONFIG_EMBEDDED */
bp = ap->a_bp;
bdev = buf_device(bp);
mp = buf_vnode(bp)->v_mount;
bap = &bp->b_attr;
+#if CONFIG_IOSCHED
+ if (bp->b_flags & B_CLUSTER) {
+
+ io_tier = upl_get_cached_tier(bp->b_upl);
+
+ if (io_tier == -1)
+ io_tier = throttle_get_io_policy(&ut);
+#if DEVELOPMENT || DEBUG
+ else {
+ int my_io_tier = throttle_get_io_policy(&ut);
+
+ if (io_tier != my_io_tier)
+ KERNEL_DEBUG_CONSTANT((FSDBG_CODE(DBG_THROTTLE, IO_TIER_UPL_MISMATCH)) | DBG_FUNC_NONE, buf_kernel_addrperm_addr(bp), my_io_tier, io_tier, 0, 0);
+ }
+#endif
+ } else
+ io_tier = throttle_get_io_policy(&ut);
+#else
io_tier = throttle_get_io_policy(&ut);
+#endif
passive = throttle_get_passive_io_policy(&ut);
+ /*
+ * Mark if the I/O was upgraded by throttle_get_thread_throttle_level
+ * while preserving the original issued tier (throttle_get_io_policy
+ * does not return upgraded tiers)
+ */
+ if (mp && io_tier > throttle_get_thread_throttle_level_internal(ut, io_tier)) {
+#if CONFIG_IOSCHED
+ if (!(mp->mnt_ioflags & MNT_IOFLAGS_IOSCHED_SUPPORTED)) {
+ upgrade = TRUE;
+ }
+#else /* CONFIG_IOSCHED */
+ upgrade = TRUE;
+#endif /* CONFIG_IOSCHED */
+ }
+
if (bp->b_flags & B_META)
bap->ba_flags |= BA_META;
+#if CONFIG_IOSCHED
+ /*
+ * For I/O Scheduling, we currently do not have a way to track and expedite metadata I/Os.
+ * To ensure we dont get into priority inversions due to metadata I/Os, we use the following rules:
+ * For metadata reads, ceil all I/Os to IOSCHED_METADATA_TIER & mark them passive if the I/O tier was upgraded
+ * For metadata writes, unconditionally mark them as IOSCHED_METADATA_TIER and passive
+ */
+ if (bap->ba_flags & BA_META) {
+ if (mp && (mp->mnt_ioflags & MNT_IOFLAGS_IOSCHED_SUPPORTED)) {
+ if (bp->b_flags & B_READ) {
+ if (io_tier > IOSCHED_METADATA_TIER) {
+ io_tier = IOSCHED_METADATA_TIER;
+ passive = 1;
+ }
+ } else {
+ io_tier = IOSCHED_METADATA_TIER;
+ passive = 1;
+ }
+ }
+ }
+#endif /* CONFIG_IOSCHED */
+
SET_BUFATTR_IO_TIER(bap, io_tier);
- if (passive)
+ if (passive) {
bp->b_flags |= B_PASSIVE;
+ bap->ba_flags |= BA_PASSIVE;
+ }
+#if !CONFIG_EMBEDDED
if ((curproc != NULL) && ((curproc->p_flag & P_DELAYIDLESLEEP) == P_DELAYIDLESLEEP))
bap->ba_flags |= BA_DELAYIDLESLEEP;
+#endif /* !CONFIG_EMBEDDED */
bflags = bp->b_flags;
if (((bflags & B_READ) == 0) && ((bflags & B_ASYNC) == 0))
bufattr_markquickcomplete(bap);
- if (kdebug_enable) {
- int code = 0;
+ if (bflags & B_READ)
+ code |= DKIO_READ;
+ if (bflags & B_ASYNC)
+ code |= DKIO_ASYNC;
- if (bflags & B_READ)
- code |= DKIO_READ;
- if (bflags & B_ASYNC)
- code |= DKIO_ASYNC;
+ if (bap->ba_flags & BA_META)
+ code |= DKIO_META;
+ else if (bflags & B_PAGEIO)
+ code |= DKIO_PAGING;
- if (bflags & B_META)
- code |= DKIO_META;
- else if (bflags & B_PAGEIO)
- code |= DKIO_PAGING;
+ if (io_tier != 0)
+ code |= DKIO_THROTTLE;
- if (io_tier != 0)
- code |= DKIO_THROTTLE;
+ code |= ((io_tier << DKIO_TIER_SHIFT) & DKIO_TIER_MASK);
- code |= ((io_tier << DKIO_TIER_SHIFT) & DKIO_TIER_MASK);
+ if (bflags & B_PASSIVE)
+ code |= DKIO_PASSIVE;
- if (bflags & B_PASSIVE)
- code |= DKIO_PASSIVE;
+ if (bap->ba_flags & BA_NOCACHE)
+ code |= DKIO_NOCACHE;
- if (bap->ba_flags & BA_NOCACHE)
- code |= DKIO_NOCACHE;
+ if (upgrade) {
+ code |= DKIO_TIER_UPGRADE;
+ SET(bap->ba_flags, BA_IO_TIER_UPGRADE);
+ }
+ if (kdebug_enable) {
KERNEL_DEBUG_CONSTANT_IST(KDEBUG_COMMON, FSDBG_CODE(DBG_DKRW, code) | DBG_FUNC_NONE,
buf_kernel_addrperm_addr(bp), bdev, (int)buf_blkno(bp), buf_count(bp), 0);
}
+
+ thread_update_io_stats(current_thread(), buf_count(bp), code);
+
if (mp != NULL) {
- if ((mp->mnt_kern_flag & MNTK_SSD) && !ignore_is_ssd)
+ if (disk_conditioner_mount_is_ssd(mp))
isssd = TRUE;
+ /*
+ * Partially initialized mounts don't have a final devbsdunit and should not be tracked.
+ * Verify that devbsdunit is initialized (non-zero) or that 0 is the correct initialized value
+ * (mnt_throttle_mask is initialized and num_trailing_0 would be 0)
+ */
+ if (mp->mnt_devbsdunit || (mp->mnt_throttle_mask != LOWPRI_MAX_NUM_DEV - 1 && mp->mnt_throttle_mask & 0x1)) {
+ inflight = TRUE;
+ }
throttle_info = &_throttle_io_info[mp->mnt_devbsdunit];
+
} else
throttle_info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
- throttle_info_update_internal(throttle_info, ut, bflags, isssd);
+ throttle_info_update_internal(throttle_info, ut, bflags, isssd, inflight, bap);
if ((bflags & B_READ) == 0) {
microuptime(&throttle_info->throttle_last_write_timestamp);
typedef int strategy_fcn_ret_t(struct buf *bp);
strategy_ret = (*(strategy_fcn_ret_t*)bdevsw[major(bdev)].d_strategy)(bp);
+
+ // disk conditioner needs to track when this I/O actually starts
+ // which means track it after `strategy` which may include delays
+ // from inflight I/Os
+ microuptime(&bp->b_timestamp_tv);
if (IO_SATISFIED_BY_CACHE == strategy_ret) {
/*
int flags = ap->a_fflag;
struct proc *p = vfs_context_proc(ap->a_context);
struct session *sessp;
- int do_rele = 0;
switch (vp->v_type) {
devsw_lock(dev, S_IFCHR);
if (sessp != SESSION_NULL) {
if (vp == sessp->s_ttyvp && vcount(vp) == 1) {
- struct tty *tp;
+ struct tty *tp = TTY_NULL;
devsw_unlock(dev, S_IFCHR);
session_lock(sessp);
sessp->s_ttyvid = 0;
sessp->s_ttyp = TTY_NULL;
sessp->s_ttypgrpid = NO_PID;
- do_rele = 1;
}
session_unlock(sessp);
- if (do_rele) {
- vnode_rele(vp);
- if (NULL != tp)
- ttyfree(tp);
+ if (tp != TTY_NULL) {
+ /*
+ * We may have won a race with a proc_exit
+ * of the session leader, the winner
+ * clears the flag (even if not set)
+ */
+ tty_lock(tp);
+ ttyclrpgrphup(tp);
+ tty_unlock(tp);
+
+ ttyfree(tp);
}
devsw_lock(dev, S_IFCHR);
}
}
static void filt_specdetach(struct knote *kn);
-static int filt_spec(struct knote *kn, long hint);
+static int filt_specevent(struct knote *kn, long hint);
+static int filt_spectouch(struct knote *kn, struct kevent_internal_s *kev);
+static int filt_specprocess(struct knote *kn, struct filt_process_s *data, struct kevent_internal_s *kev);
static unsigned filt_specpeek(struct knote *kn);
-struct filterops spec_filtops = {
- .f_isfd = 1,
- .f_attach = filt_specattach,
- .f_detach = filt_specdetach,
- .f_event = filt_spec,
- .f_peek = filt_specpeek
+SECURITY_READ_ONLY_EARLY(struct filterops) spec_filtops = {
+ .f_isfd = 1,
+ .f_attach = filt_specattach,
+ .f_detach = filt_specdetach,
+ .f_event = filt_specevent,
+ .f_touch = filt_spectouch,
+ .f_process = filt_specprocess,
+ .f_peek = filt_specpeek
};
+
+/*
+ * Given a waitq that is assumed to be embedded within a selinfo structure,
+ * return the containing selinfo structure. While 'wq' is not really a queue
+ * element, this macro simply does the offset_of calculation to get back to a
+ * containing struct given the struct type and member name.
+ */
+#define selinfo_from_waitq(wq) \
+ qe_element((wq), struct selinfo, si_waitq)
+
static int
-filter_to_seltype(int16_t filter)
+spec_knote_select_and_link(struct knote *kn)
{
- switch (filter) {
- case EVFILT_READ:
- return FREAD;
- case EVFILT_WRITE:
- return FWRITE;
- break;
- default:
- panic("filt_to_seltype(): invalid filter %d\n", filter);
+ uthread_t uth;
+ vfs_context_t ctx;
+ vnode_t vp;
+ struct waitq_set *old_wqs;
+ uint64_t rsvd, rsvd_arg;
+ uint64_t *rlptr = NULL;
+ struct selinfo *si = NULL;
+ int selres = 0;
+
+ uth = get_bsdthread_info(current_thread());
+
+ ctx = vfs_context_current();
+ vp = (vnode_t)kn->kn_fp->f_fglob->fg_data;
+
+ int error = vnode_getwithvid(vp, kn->kn_hookid);
+ if (error != 0) {
+ knote_set_error(kn, ENOENT);
return 0;
}
+
+ /*
+ * This function may be called many times to link or re-link the
+ * underlying vnode to the kqueue. If we've already linked the two,
+ * we will have a valid kn_hook_data which ties us to the underlying
+ * device's waitq via a the waitq's prepost table object. However,
+ * devices can abort any select action by calling selthreadclear().
+ * This is OK because the table object will be invalidated by the
+ * driver (through a call to selthreadclear), so any attempt to access
+ * the associated waitq will fail because the table object is invalid.
+ *
+ * Even if we've already registered, we need to pass a pointer
+ * to a reserved link structure. Otherwise, selrecord() will
+ * infer that we're in the second pass of select() and won't
+ * actually do anything!
+ */
+ rsvd = rsvd_arg = waitq_link_reserve(NULL);
+ rlptr = (void *)&rsvd_arg;
+
+ /*
+ * Trick selrecord() into hooking kqueue's wait queue set into the device's
+ * selinfo wait queue.
+ */
+ old_wqs = uth->uu_wqset;
+ uth->uu_wqset = &(knote_get_kq(kn)->kq_wqs);
+ /*
+ * Now these are the laws of VNOP_SELECT, as old and as true as the sky,
+ * And the device that shall keep it may prosper, but the device that shall
+ * break it must receive ENODEV:
+ *
+ * 1. Take a lock to protect against other selects on the same vnode.
+ * 2. Return 1 if data is ready to be read.
+ * 3. Return 0 and call `selrecord` on a handy `selinfo` structure if there
+ * is no data.
+ * 4. Call `selwakeup` when the vnode has an active `selrecord` and data
+ * can be read or written (depending on the seltype).
+ * 5. If there's a `selrecord` and no corresponding `selwakeup`, but the
+ * vnode is going away, call `selthreadclear`.
+ */
+ selres = VNOP_SELECT(vp, knote_get_seltype(kn), 0, rlptr, ctx);
+ uth->uu_wqset = old_wqs;
+
+ /*
+ * Make sure to cleanup the reserved link - this guards against
+ * drivers that may not actually call selrecord().
+ */
+ waitq_link_release(rsvd);
+ if (rsvd != rsvd_arg) {
+ /* The driver / handler called selrecord() */
+ struct waitq *wq;
+ memcpy(&wq, rlptr, sizeof(void *));
+
+ /*
+ * The waitq is part of the selinfo structure managed by the
+ * driver. For certain drivers, we want to hook the knote into
+ * the selinfo structure's si_note field so selwakeup can call
+ * KNOTE.
+ */
+ si = selinfo_from_waitq(wq);
+
+ /*
+ * The waitq_get_prepost_id() function will (potentially)
+ * allocate a prepost table object for the waitq and return
+ * the table object's ID to us. It will also set the
+ * waitq_prepost_id field within the waitq structure.
+ *
+ * We can just overwrite kn_hook_data because it's simply a
+ * table ID used to grab a reference when needed.
+ *
+ * We have a reference on the vnode, so we know that the
+ * device won't go away while we get this ID.
+ */
+ kn->kn_hook_data = waitq_get_prepost_id(wq);
+ } else if (selres == 0) {
+ /*
+ * The device indicated that there's no data to read, but didn't call
+ * `selrecord`. Nothing will be notified of changes to this vnode, so
+ * return an error back to user space, to make it clear that the knote
+ * is not attached.
+ */
+ knote_set_error(kn, ENODEV);
+ }
+
+ vnode_put(vp);
+
+ return selres;
+}
+
+static void filt_spec_common(struct knote *kn, int selres)
+{
+ if (kn->kn_vnode_use_ofst) {
+ if (kn->kn_fp->f_fglob->fg_offset >= (uint32_t)selres) {
+ kn->kn_data = 0;
+ } else {
+ kn->kn_data = ((uint32_t)selres) - kn->kn_fp->f_fglob->fg_offset;
+ }
+ } else {
+ kn->kn_data = selres;
+ }
}
-static int
-filt_specattach(struct knote *kn)
+static int
+filt_specattach(struct knote *kn, __unused struct kevent_internal_s *kev)
{
vnode_t vp;
dev_t dev;
dev = vnode_specrdev(vp);
- if (major(dev) > nchrdev) {
- return ENXIO;
- }
-
- if ((cdevsw_flags[major(dev)] & CDEVSW_SELECT_KQUEUE) == 0) {
- return EINVAL;
+ /*
+ * For a few special kinds of devices, we can attach knotes with
+ * no restrictions because their "select" vectors return the amount
+ * of data available. Others require an explicit NOTE_LOWAT with
+ * data of 1, indicating that the caller doesn't care about actual
+ * data counts, just an indication that the device has data.
+ */
+ if (!kn->kn_vnode_kqok &&
+ ((kn->kn_sfflags & NOTE_LOWAT) == 0 || kn->kn_sdata != 1)) {
+ knote_set_error(kn, EINVAL);
+ return 0;
}
- /* Resulting wql is safe to unlink even if it has never been linked */
- kn->kn_hook = wait_queue_link_allocate();
- if (kn->kn_hook == NULL) {
- return EAGAIN;
+ /*
+ * This forces the select fallback to call through VNOP_SELECT and hook
+ * up selinfo on every filter routine.
+ *
+ * Pseudo-terminal controllers are opted out of native kevent support --
+ * remove this when they get their own EVFILTID.
+ */
+ if (cdevsw_flags[major(dev)] & CDEVSW_IS_PTC) {
+ kn->kn_vnode_kqok = 0;
}
- kn->kn_fop = &spec_filtops;
+ kn->kn_filtid = EVFILTID_SPEC;
+ kn->kn_hook_data = 0;
kn->kn_hookid = vnode_vid(vp);
- knote_markstayqueued(kn);
-
- return 0;
+ knote_markstayactive(kn);
+ return spec_knote_select_and_link(kn);
}
-static void
+static void
filt_specdetach(struct knote *kn)
{
- kern_return_t ret;
+ knote_clearstayactive(kn);
- /*
- * Given wait queue link and wait queue set, unlink. This is subtle.
- * If the device has been revoked from under us, selclearthread() will
- * have removed our link from the kqueue's wait queue set, which
- * wait_queue_set_unlink_one() will detect and handle.
+ /*
+ * This is potentially tricky: the device's selinfo waitq that was
+ * tricked into being part of this knote's waitq set may not be a part
+ * of any other set, and the device itself may have revoked the memory
+ * in which the waitq was held. We use the knote's kn_hook_data field
+ * to keep the ID of the waitq's prepost table object. This
+ * object keeps a pointer back to the waitq, and gives us a safe way
+ * to decouple the dereferencing of driver allocated memory: if the
+ * driver goes away (taking the waitq with it) then the prepost table
+ * object will be invalidated. The waitq details are handled in the
+ * waitq API invoked here.
+ */
+ if (kn->kn_hook_data) {
+ waitq_unlink_by_prepost_id(kn->kn_hook_data, &(knote_get_kq(kn)->kq_wqs));
+ kn->kn_hook_data = 0;
+ }
+}
+
+static int
+filt_specevent(struct knote *kn, __unused long hint)
+{
+ /*
+ * Nothing should call knote or knote_vanish on this knote.
*/
- ret = wait_queue_set_unlink_one(kn->kn_kq->kq_wqs, kn->kn_hook);
- if (ret != KERN_SUCCESS) {
- panic("filt_specdetach(): failed to unlink wait queue link.");
+ panic("filt_specevent(%p)", kn);
+ return 0;
+}
+
+static int
+filt_spectouch(struct knote *kn, struct kevent_internal_s *kev)
+{
+ kn->kn_sdata = kev->data;
+ kn->kn_sfflags = kev->fflags;
+ if ((kn->kn_status & KN_UDATA_SPECIFIC) == 0)
+ kn->kn_udata = kev->udata;
+
+ if (kev->flags & EV_ENABLE) {
+ return spec_knote_select_and_link(kn);
}
- (void)wait_queue_link_free(kn->kn_hook);
- kn->kn_hook = NULL;
- kn->kn_status &= ~KN_STAYQUEUED;
+ return 0;
}
-static int
-filt_spec(struct knote *kn, long hint)
+static int
+filt_specprocess(struct knote *kn, struct filt_process_s *data, struct kevent_internal_s *kev)
{
+#pragma unused(data)
vnode_t vp;
uthread_t uth;
- wait_queue_set_t old_wqs;
vfs_context_t ctx;
+ int res;
int selres;
int error;
- int use_offset;
- dev_t dev;
- uint64_t flags;
-
- assert(kn->kn_hook != NULL);
-
- if (hint != 0) {
- panic("filt_spec(): nonzero hint?");
- }
uth = get_bsdthread_info(current_thread());
ctx = vfs_context_current();
vp = (vnode_t)kn->kn_fp->f_fglob->fg_data;
+ /* FIXME JMM - locking against touches? */
+
error = vnode_getwithvid(vp, kn->kn_hookid);
if (error != 0) {
kn->kn_flags |= (EV_EOF | EV_ONESHOT);
+ *kev = kn->kn_kevent;
return 1;
}
-
- dev = vnode_specrdev(vp);
- flags = cdevsw_flags[major(dev)];
- use_offset = ((flags & CDEVSW_USE_OFFSET) != 0);
- assert((flags & CDEVSW_SELECT_KQUEUE) != 0);
- /* Trick selrecord() into hooking kqueue's wait queue set into device wait queue */
- old_wqs = uth->uu_wqset;
- uth->uu_wqset = kn->kn_kq->kq_wqs;
- selres = VNOP_SELECT(vp, filter_to_seltype(kn->kn_filter), 0, kn->kn_hook, ctx);
- uth->uu_wqset = old_wqs;
+ selres = spec_knote_select_and_link(kn);
+ filt_spec_common(kn, selres);
- if (use_offset) {
- if (kn->kn_fp->f_fglob->fg_offset >= (uint32_t)selres) {
+ vnode_put(vp);
+
+ res = ((kn->kn_sfflags & NOTE_LOWAT) != 0) ?
+ (kn->kn_data >= kn->kn_sdata) : kn->kn_data;
+
+ if (res) {
+ *kev = kn->kn_kevent;
+ if (kn->kn_flags & EV_CLEAR) {
+ kn->kn_fflags = 0;
kn->kn_data = 0;
- } else {
- kn->kn_data = ((uint32_t)selres) - kn->kn_fp->f_fglob->fg_offset;
}
- } else {
- kn->kn_data = selres;
}
- vnode_put(vp);
-
- return (kn->kn_data != 0);
+ return res;
}
static unsigned
filt_specpeek(struct knote *kn)
{
- vnode_t vp;
- uthread_t uth;
- wait_queue_set_t old_wqs;
- vfs_context_t ctx;
- int error, selres;
-
- uth = get_bsdthread_info(current_thread());
- ctx = vfs_context_current();
- vp = (vnode_t)kn->kn_fp->f_fglob->fg_data;
+ int selres = 0;
- error = vnode_getwithvid(vp, kn->kn_hookid);
- if (error != 0) {
- return 1; /* Just like VNOP_SELECT() on recycled vnode */
- }
+ selres = spec_knote_select_and_link(kn);
+ filt_spec_common(kn, selres);
- /*
- * Why pass the link here? Because we may not have registered in the past...
- */
- old_wqs = uth->uu_wqset;
- uth->uu_wqset = kn->kn_kq->kq_wqs;
- selres = VNOP_SELECT(vp, filter_to_seltype(kn->kn_filter), 0, kn->kn_hook, ctx);
- uth->uu_wqset = old_wqs;
-
- vnode_put(vp);
- return selres;
+ return kn->kn_data;
}
projects / apple / xnu.git / blobdiff