/*
- * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2016 Apple Computer, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
#include <sys/conf.h>
#include <sys/buf_internal.h>
#include <sys/mount_internal.h>
-#include <sys/namei.h>
#include <sys/vnode_internal.h>
+#include <sys/file_internal.h>
+#include <sys/namei.h>
#include <sys/stat.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#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 int isdisk(dev_t dev, int type);
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, 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 };
static void set_blocksize(vnode_t, dev_t);
+#define LOWPRI_TIER1_WINDOW_MSECS 25
+#define LOWPRI_TIER2_WINDOW_MSECS 100
+#define LOWPRI_TIER3_WINDOW_MSECS 500
+
+#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
+#define LOWPRI_TIER2_IO_PERIOD_SSD_MSECS 15
+#define LOWPRI_TIER3_IO_PERIOD_SSD_MSECS 25
+
+
+int throttle_windows_msecs[THROTTLE_LEVEL_END + 1] = {
+ 0,
+ LOWPRI_TIER1_WINDOW_MSECS,
+ LOWPRI_TIER2_WINDOW_MSECS,
+ LOWPRI_TIER3_WINDOW_MSECS,
+};
+
+int throttle_io_period_msecs[THROTTLE_LEVEL_END + 1] = {
+ 0,
+ LOWPRI_TIER1_IO_PERIOD_MSECS,
+ LOWPRI_TIER2_IO_PERIOD_MSECS,
+ LOWPRI_TIER3_IO_PERIOD_MSECS,
+};
+
+int throttle_io_period_ssd_msecs[THROTTLE_LEVEL_END + 1] = {
+ 0,
+ LOWPRI_TIER1_IO_PERIOD_SSD_MSECS,
+ LOWPRI_TIER2_IO_PERIOD_SSD_MSECS,
+ LOWPRI_TIER3_IO_PERIOD_SSD_MSECS,
+};
+
+
+int throttled_count[THROTTLE_LEVEL_END + 1];
+
+struct _throttle_io_info_t {
+ lck_mtx_t throttle_lock;
+
+ struct timeval throttle_last_write_timestamp;
+ struct timeval throttle_min_timer_deadline;
+ 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;
+
+ thread_call_t throttle_timer_call;
+ int32_t throttle_timer_ref;
+ int32_t throttle_timer_active;
+
+ int32_t throttle_io_count;
+ int32_t throttle_io_count_begin;
+ int *throttle_io_periods;
+ uint32_t throttle_io_period_num;
+
+ 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_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);
}
}
- if (cdevsw[maj].d_type == D_TTY) {
- vnode_lock(vp);
- vp->v_flag |= VISTTY;
- vnode_unlock(vp);
- }
+
+ devsw_lock(dev, S_IFCHR);
error = (*cdevsw[maj].d_open)(dev, ap->a_mode, S_IFCHR, p);
+
+ if (error == 0) {
+ vp->v_specinfo->si_opencount++;
+ }
+
+ devsw_unlock(dev, S_IFCHR);
+
+ if (error == 0 && cdevsw[maj].d_type == D_DISK && !vp->v_un.vu_specinfo->si_initted) {
+ int isssd = 0;
+ uint64_t throttle_mask = 0;
+ uint32_t devbsdunit = 0;
+
+ if (VNOP_IOCTL(vp, DKIOCGETTHROTTLEMASK, (caddr_t)&throttle_mask, 0, NULL) == 0) {
+
+ if (throttle_mask != 0 &&
+ VNOP_IOCTL(vp, DKIOCISSOLIDSTATE, (caddr_t)&isssd, 0, ap->a_context) == 0) {
+ /*
+ * as a reasonable approximation, only use the lowest bit of the mask
+ * to generate a disk unit number
+ */
+ devbsdunit = num_trailing_0(throttle_mask);
+
+ vnode_lock(vp);
+
+ vp->v_un.vu_specinfo->si_isssd = isssd;
+ vp->v_un.vu_specinfo->si_devbsdunit = devbsdunit;
+ vp->v_un.vu_specinfo->si_throttle_mask = throttle_mask;
+ vp->v_un.vu_specinfo->si_throttleable = 1;
+ vp->v_un.vu_specinfo->si_initted = 1;
+
+ vnode_unlock(vp);
+ }
+ }
+ if (vp->v_un.vu_specinfo->si_initted == 0) {
+ vnode_lock(vp);
+ vp->v_un.vu_specinfo->si_initted = 1;
+ vnode_unlock(vp);
+ }
+ }
return (error);
case VBLK:
*/
if ( (error = vfs_mountedon(vp)) )
return (error);
+
+ devsw_lock(dev, S_IFBLK);
error = (*bdevsw[maj].d_open)(dev, ap->a_mode, S_IFBLK, p);
+ if (!error) {
+ vp->v_specinfo->si_opencount++;
+ }
+ devsw_unlock(dev, S_IFBLK);
+
if (!error) {
u_int64_t blkcnt;
u_int32_t blksize;
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) {
+ throttle_info = &_throttle_io_info[vp->v_un.vu_specinfo->si_devbsdunit];
+ 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)
buf_brelse(bp);
return (error);
}
- // LP64todo - fix this!
n = min((unsigned)(n - on), uio_resid(uio));
- error = uiomove((char *)0 + buf_dataptr(bp) + on, n, uio);
+ error = uiomove((char *)buf_dataptr(bp) + on, n, uio);
if (n + on == bsize)
buf_markaged(bp);
buf_brelse(bp);
daddr64_t bn;
int bsize, blkmask, bscale;
int io_sync;
- int io_size;
int devBlockSize=0;
int n, on;
int error = 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) {
+ throttle_info = &_throttle_io_info[vp->v_un.vu_specinfo->si_devbsdunit];
+
+ 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)
return (EINVAL);
io_sync = (ap->a_ioflag & IO_SYNC);
- // LP64todo - fix this!
- io_size = uio_resid(uio);
dev = (vp->v_rdev);
bn = (daddr64_t)((uio->uio_offset / devBlockSize) &~ blkmask);
on = uio->uio_offset % bsize;
- // LP64todo - fix this!
n = min((unsigned)(bsize - on), uio_resid(uio));
/*
}
n = min(n, bsize - buf_resid(bp));
- error = uiomove((char *)0 + buf_dataptr(bp) + on, n, uio);
+ error = uiomove((char *)buf_dataptr(bp) + on, n, uio);
if (error) {
buf_brelse(bp);
return (error);
{
proc_t p = vfs_context_proc(ap->a_context);
dev_t dev = ap->a_vp->v_rdev;
+ int retval = 0;
+
+ KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_IOCTL, 0) | DBG_FUNC_START,
+ dev, ap->a_command, ap->a_fflag, ap->a_vp->v_type, 0);
switch (ap->a_vp->v_type) {
case VCHR:
- return ((*cdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data,
- ap->a_fflag, p));
+ retval = (*cdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data,
+ ap->a_fflag, p);
+ break;
case VBLK:
- if (ap->a_command == 0 && (unsigned int)ap->a_data == B_TAPE) {
- if (bdevsw[major(dev)].d_type == D_TAPE)
- return (0);
- else
- return (1);
- }
- return ((*bdevsw[major(dev)].d_ioctl)(dev, ap->a_command, ap->a_data,
- ap->a_fflag, p));
+ 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:
panic("spec_ioctl");
/* NOTREACHED */
}
- return (0);
+ KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_IOCTL, 0) | DBG_FUNC_END,
+ dev, ap->a_command, ap->a_fflag, retval, 0);
+
+ return (retval);
}
int
}
}
+static int filt_specattach(struct knote *kn, struct kevent_internal_s *kev);
+
+int
+spec_kqfilter(vnode_t vp, struct knote *kn, struct kevent_internal_s *kev)
+{
+ dev_t dev;
+
+ assert(vnode_ischr(vp));
+
+ dev = vnode_specrdev(vp);
+
+#if NETWORKING
+ /*
+ * 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);
+ }
+
+ /* Try to attach to other char special devices */
+ return filt_specattach(kn, kev);
+}
+
/*
* Synch buffers associated with a block device
*/
/*
* Flush all dirty buffers associated with a block device.
*/
- buf_flushdirtyblks(vp, waitfor == MNT_WAIT, 0, "spec_fsync");
+ buf_flushdirtyblks(vp, (waitfor == MNT_WAIT || waitfor == MNT_DWAIT), 0, "spec_fsync");
return (0);
}
return spec_fsync_internal(ap->a_vp, ap->a_waitfor, ap->a_context);
}
+
/*
* Just call the device strategy routine
*/
-extern int hard_throttle_on_root;
-void IOSleep(int);
+void throttle_init(void);
-// the low priority process may wait for at most LOWPRI_MAX_DELAY millisecond
-#define LOWPRI_INITIAL_WINDOW_MSECS 100
-#define LOWPRI_WINDOW_MSECS_INC 50
-#define LOWPRI_MAX_WINDOW_MSECS 200
-#define LOWPRI_MAX_WAITING_MSECS 200
-#define LOWPRI_SLEEP_INTERVAL 5
-struct _throttle_io_info_t {
- struct timeval last_normal_IO_timestamp;
- struct timeval last_IO_timestamp;
- SInt32 numthreads_throttling;
-};
+#if 0
+#define DEBUG_ALLOC_THROTTLE_INFO(format, debug_info, args...) \
+ do { \
+ if ((debug_info)->alloc) \
+ printf("%s: "format, __FUNCTION__, ## args); \
+ } while(0)
-struct _throttle_io_info_t _throttle_io_info[LOWPRI_MAX_NUM_DEV];
-int lowpri_IO_initial_window_msecs = LOWPRI_INITIAL_WINDOW_MSECS;
-int lowpri_IO_window_msecs_inc = LOWPRI_WINDOW_MSECS_INC;
-int lowpri_max_window_msecs = LOWPRI_MAX_WINDOW_MSECS;
-int lowpri_max_waiting_msecs = LOWPRI_MAX_WAITING_MSECS;
+#else
+#define DEBUG_ALLOC_THROTTLE_INFO(format, debug_info, args...)
+#endif
-SYSCTL_INT(_debug, OID_AUTO, lowpri_IO_initial_window_msecs, CTLFLAG_RW, &lowpri_IO_initial_window_msecs, LOWPRI_INITIAL_WINDOW_MSECS, "");
-SYSCTL_INT(_debug, OID_AUTO, lowpri_IO_window_inc, CTLFLAG_RW, &lowpri_IO_window_msecs_inc, LOWPRI_INITIAL_WINDOW_MSECS, "");
-SYSCTL_INT(_debug, OID_AUTO, lowpri_max_window_msecs, CTLFLAG_RW, &lowpri_max_window_msecs, LOWPRI_INITIAL_WINDOW_MSECS, "");
-SYSCTL_INT(_debug, OID_AUTO, lowpri_max_waiting_msecs, CTLFLAG_RW, &lowpri_max_waiting_msecs, LOWPRI_INITIAL_WINDOW_MSECS, "");
-void
-throttle_info_get_last_io_time(mount_t mp, struct timeval *tv)
-{
- size_t devbsdunit;
-
- devbsdunit = mp->mnt_devbsdunit;
+SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier1_window_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_windows_msecs[THROTTLE_LEVEL_TIER1], 0, "");
+SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier2_window_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_windows_msecs[THROTTLE_LEVEL_TIER2], 0, "");
+SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier3_window_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_windows_msecs[THROTTLE_LEVEL_TIER3], 0, "");
- if (devbsdunit < LOWPRI_MAX_NUM_DEV) {
- *tv = _throttle_io_info[devbsdunit].last_IO_timestamp;
- } else {
- memset(tv, 0, sizeof(*tv));
- }
-}
+SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier1_io_period_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_msecs[THROTTLE_LEVEL_TIER1], 0, "");
+SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier2_io_period_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_msecs[THROTTLE_LEVEL_TIER2], 0, "");
+SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier3_io_period_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_msecs[THROTTLE_LEVEL_TIER3], 0, "");
-void
-update_last_io_time(mount_t mp)
-{
- size_t devbsdunit;
-
- devbsdunit = mp->mnt_devbsdunit;
+SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier1_io_period_ssd_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_ssd_msecs[THROTTLE_LEVEL_TIER1], 0, "");
+SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier2_io_period_ssd_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_ssd_msecs[THROTTLE_LEVEL_TIER2], 0, "");
+SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_tier3_io_period_ssd_msecs, CTLFLAG_RW | CTLFLAG_LOCKED, &throttle_io_period_ssd_msecs[THROTTLE_LEVEL_TIER3], 0, "");
- if (devbsdunit < LOWPRI_MAX_NUM_DEV) {
- microuptime(&_throttle_io_info[devbsdunit].last_IO_timestamp);
+SYSCTL_INT(_debug, OID_AUTO, lowpri_throttle_enabled, CTLFLAG_RW | CTLFLAG_LOCKED, &lowpri_throttle_enabled, 0, "");
+
+
+static lck_grp_t *throttle_lock_grp;
+static lck_attr_t *throttle_lock_attr;
+static lck_grp_attr_t *throttle_lock_grp_attr;
+
+
+/*
+ * throttled I/O helper function
+ * convert the index of the lowest set bit to a device index
+ */
+int
+num_trailing_0(uint64_t n)
+{
+ /*
+ * since in most cases the number of trailing 0s is very small,
+ * we simply counting sequentially from the lowest bit
+ */
+ if (n == 0)
+ return sizeof(n) * 8;
+ int count = 0;
+ while (!ISSET(n, 1)) {
+ n >>= 1;
+ ++count;
}
+ return count;
}
-int throttle_io_will_be_throttled(int lowpri_window_msecs, size_t devbsdunit)
+
+/*
+ * Release the reference and if the item was allocated and this is the last
+ * reference then free it.
+ *
+ * This routine always returns the old value.
+ */
+static int
+throttle_info_rel(struct _throttle_io_info_t *info)
{
- struct timeval elapsed;
- int elapsed_msecs;
+ SInt32 oldValue = OSDecrementAtomic(&info->throttle_refcnt);
- microuptime(&elapsed);
- timevalsub(&elapsed, &_throttle_io_info[devbsdunit].last_normal_IO_timestamp);
- elapsed_msecs = elapsed.tv_sec * 1000 + elapsed.tv_usec / 1000;
+ DEBUG_ALLOC_THROTTLE_INFO("refcnt = %d info = %p\n",
+ info, (int)(oldValue -1), info );
- if (lowpri_window_msecs == -1) // use the max waiting time
- lowpri_window_msecs = lowpri_max_waiting_msecs;
+ /* The reference count just went negative, very bad */
+ if (oldValue == 0)
+ panic("throttle info ref cnt went negative!");
- return elapsed_msecs < lowpri_window_msecs;
+ /*
+ * Once reference count is zero, no one else should be able to take a
+ * reference
+ */
+ if ((info->throttle_refcnt == 0) && (info->throttle_alloc)) {
+ DEBUG_ALLOC_THROTTLE_INFO("Freeing info = %p\n", info);
+
+ lck_mtx_destroy(&info->throttle_lock, throttle_lock_grp);
+ FREE(info, M_TEMP);
+ }
+ return oldValue;
}
-void throttle_lowpri_io(boolean_t ok_to_sleep)
+
+/*
+ * Just take a reference on the throttle info structure.
+ *
+ * This routine always returns the old value.
+ */
+static SInt32
+throttle_info_ref(struct _throttle_io_info_t *info)
{
- int i;
- int max_try_num;
- struct uthread *ut;
+ SInt32 oldValue = OSIncrementAtomic(&info->throttle_refcnt);
- ut = get_bsdthread_info(current_thread());
+ DEBUG_ALLOC_THROTTLE_INFO("refcnt = %d info = %p\n",
+ info, (int)(oldValue -1), info );
+ /* Allocated items should never have a reference of zero */
+ if (info->throttle_alloc && (oldValue == 0))
+ panic("Taking a reference without calling create throttle info!\n");
- if (ut->uu_lowpri_window == 0)
- return;
+ return oldValue;
+}
+
+/*
+ * on entry the throttle_lock is held...
+ * this function is responsible for taking
+ * and dropping the reference on the info
+ * structure which will keep it from going
+ * away while the timer is running if it
+ * happens to have been dynamically allocated by
+ * a network fileystem kext which is now trying
+ * to free it
+ */
+static uint32_t
+throttle_timer_start(struct _throttle_io_info_t *info, boolean_t update_io_count, int wakelevel)
+{
+ struct timeval elapsed;
+ struct timeval now;
+ struct timeval period;
+ uint64_t elapsed_msecs;
+ int throttle_level;
+ int level;
+ int msecs;
+ boolean_t throttled = FALSE;
+ boolean_t need_timer = FALSE;
+
+ microuptime(&now);
+
+ if (update_io_count == TRUE) {
+ info->throttle_io_count_begin = info->throttle_io_count;
+ info->throttle_io_period_num++;
+
+ while (wakelevel >= THROTTLE_LEVEL_THROTTLED)
+ info->throttle_start_IO_period_timestamp[wakelevel--] = now;
+
+ info->throttle_min_timer_deadline = now;
+
+ msecs = info->throttle_io_periods[THROTTLE_LEVEL_THROTTLED];
+ period.tv_sec = msecs / 1000;
+ period.tv_usec = (msecs % 1000) * 1000;
+
+ timevaladd(&info->throttle_min_timer_deadline, &period);
+ }
+ for (throttle_level = THROTTLE_LEVEL_START; throttle_level < THROTTLE_LEVEL_END; throttle_level++) {
- max_try_num = lowpri_max_waiting_msecs / LOWPRI_SLEEP_INTERVAL * MAX(1, _throttle_io_info[ut->uu_devbsdunit].numthreads_throttling);
+ 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);
- KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_START,
- ut->uu_lowpri_window, 0, 0, 0, 0);
+ for (level = throttle_level + 1; level <= THROTTLE_LEVEL_END; level++) {
- if (ok_to_sleep == TRUE) {
- for (i=0; i<max_try_num; i++) {
- if (throttle_io_will_be_throttled(ut->uu_lowpri_window, ut->uu_devbsdunit)) {
- IOSleep(LOWPRI_SLEEP_INTERVAL);
- } else {
+ if (!TAILQ_EMPTY(&info->throttle_uthlist[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
+ */
+ throttled = TRUE;
+ }
+ /*
+ * we assume that the windows are the same or longer
+ * as we drop through the throttling tiers... thus
+ * we can stop looking once we run into a tier with
+ * threads to schedule regardless of whether it's
+ * still in its throttling window or not
+ */
break;
}
}
+ if (throttled == TRUE)
+ break;
}
- KERNEL_DEBUG((FSDBG_CODE(DBG_FSRW, 97)) | DBG_FUNC_END,
- ut->uu_lowpri_window, i*5, 0, 0, 0);
- SInt32 oldValue;
- oldValue = OSDecrementAtomic(&_throttle_io_info[ut->uu_devbsdunit].numthreads_throttling);
- ut->uu_lowpri_window = 0;
+ if (throttled == TRUE) {
+ uint64_t deadline = 0;
+ struct timeval target;
+ struct timeval min_target;
+
+ /*
+ * we've got at least one tier still in a throttled window
+ * so we need a timer running... compute the next deadline
+ * and schedule it
+ */
+ for (level = throttle_level+1; level <= THROTTLE_LEVEL_END; level++) {
- if (oldValue <= 0) {
- panic("%s: numthreads negative", __func__);
- }
-}
+ if (TAILQ_EMPTY(&info->throttle_uthlist[level]))
+ continue;
-int throttle_get_io_policy(struct uthread **ut)
-{
- int policy = IOPOL_DEFAULT;
- proc_t p = current_proc();
+ target = info->throttle_start_IO_period_timestamp[level];
- *ut = get_bsdthread_info(current_thread());
-
- if (p != NULL)
- policy = p->p_iopol_disk;
+ msecs = info->throttle_io_periods[level];
+ period.tv_sec = msecs / 1000;
+ period.tv_usec = (msecs % 1000) * 1000;
+
+ timevaladd(&target, &period);
+
+ if (need_timer == FALSE || timevalcmp(&target, &min_target, <)) {
+ min_target = target;
+ need_timer = TRUE;
+ }
+ }
+ if (timevalcmp(&info->throttle_min_timer_deadline, &now, >)) {
+ if (timevalcmp(&info->throttle_min_timer_deadline, &min_target, >))
+ min_target = info->throttle_min_timer_deadline;
+ }
+
+ if (info->throttle_timer_active) {
+ if (thread_call_cancel(info->throttle_timer_call) == FALSE) {
+ /*
+ * couldn't kill the timer because it's already
+ * been dispatched, so don't try to start a new
+ * one... once we drop the lock, the timer will
+ * proceed and eventually re-run this function
+ */
+ need_timer = FALSE;
+ } else
+ info->throttle_timer_active = 0;
+ }
+ if (need_timer == TRUE) {
+ /*
+ * This is defined as an int (32-bit) rather than a 64-bit
+ * value because it would need a really big period in the
+ * order of ~500 days to overflow this. So, we let this be
+ * 32-bit which allows us to use the clock_interval_to_deadline()
+ * routine.
+ */
+ int target_msecs;
+
+ if (info->throttle_timer_ref == 0) {
+ /*
+ * take a reference for the timer
+ */
+ throttle_info_ref(info);
+
+ info->throttle_timer_ref = 1;
+ }
+ elapsed = min_target;
+ timevalsub(&elapsed, &now);
+ target_msecs = elapsed.tv_sec * 1000 + elapsed.tv_usec / 1000;
+
+ if (target_msecs <= 0) {
+ /*
+ * we may have computed a deadline slightly in the past
+ * due to various factors... if so, just set the timer
+ * to go off in the near future (we don't need to be precise)
+ */
+ target_msecs = 1;
+ }
+ clock_interval_to_deadline(target_msecs, 1000000, &deadline);
- if (*ut != NULL) {
- // the I/O policy of the thread overrides that of the process
- // unless the I/O policy of the thread is default
- if ((*ut)->uu_iopol_disk != IOPOL_DEFAULT)
- policy = (*ut)->uu_iopol_disk;
+ thread_call_enter_delayed(info->throttle_timer_call, deadline);
+ info->throttle_timer_active = 1;
+ }
}
- return policy;
+ return (throttle_level);
}
-int
-spec_strategy(struct vnop_strategy_args *ap)
+
+static void
+throttle_timer(struct _throttle_io_info_t *info)
{
- buf_t bp;
- int bflags;
- dev_t bdev;
+ uthread_t ut, utlist;
+ struct timeval elapsed;
+ struct timeval now;
+ uint64_t elapsed_msecs;
+ int throttle_level;
+ int level;
+ int wake_level;
+ caddr_t wake_address = NULL;
+ boolean_t update_io_count = FALSE;
+ boolean_t need_wakeup = FALSE;
+ boolean_t need_release = FALSE;
- bp = ap->a_bp;
- bdev = buf_device(bp);
- bflags = buf_flags(bp);
+ ut = NULL;
+ lck_mtx_lock(&info->throttle_lock);
- if (kdebug_enable) {
- int code = 0;
+ info->throttle_timer_active = 0;
+ microuptime(&now);
- if (bflags & B_READ)
- code |= DKIO_READ;
- if (bflags & B_ASYNC)
- code |= DKIO_ASYNC;
+ elapsed = now;
+ timevalsub(&elapsed, &info->throttle_start_IO_period_timestamp[THROTTLE_LEVEL_THROTTLED]);
+ elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
- if (bflags & B_META)
- code |= DKIO_META;
- else if (bflags & B_PAGEIO)
- code |= DKIO_PAGING;
+ if (elapsed_msecs >= (uint64_t)info->throttle_io_periods[THROTTLE_LEVEL_THROTTLED]) {
- KERNEL_DEBUG_CONSTANT(FSDBG_CODE(DBG_DKRW, code) | DBG_FUNC_NONE,
- (unsigned int)bp, bdev, (int)buf_blkno(bp), buf_count(bp), 0);
- }
- if (((bflags & (B_PAGEIO | B_READ)) == (B_PAGEIO | B_READ)) &&
- (buf_vnode(bp)->v_mount->mnt_kern_flag & MNTK_ROOTDEV))
- hard_throttle_on_root = 1;
-
- if (lowpri_IO_initial_window_msecs) {
- struct uthread *ut;
- int policy;
- int is_throttleable_io = 0;
- int is_passive_io = 0;
- size_t devbsdunit;
- SInt32 oldValue;
-
- policy = throttle_get_io_policy(&ut);
-
- switch (policy) {
- case IOPOL_DEFAULT:
- case IOPOL_NORMAL:
- break;
- case IOPOL_THROTTLE:
- is_throttleable_io = 1;
- break;
- case IOPOL_PASSIVE:
- is_passive_io = 1;
- break;
- default:
- printf("unknown I/O policy %d", policy);
- break;
- }
+ wake_level = info->throttle_next_wake_level;
- if (!is_throttleable_io && ISSET(bflags, B_PASSIVE))
- is_passive_io |= 1;
+ for (level = THROTTLE_LEVEL_START; level < THROTTLE_LEVEL_END; level++) {
- if (buf_vnode(bp)->v_mount != NULL)
- devbsdunit = buf_vnode(bp)->v_mount->mnt_devbsdunit;
- else
- devbsdunit = LOWPRI_MAX_NUM_DEV - 1;
- if (!is_throttleable_io) {
- if (!is_passive_io){
- microuptime(&_throttle_io_info[devbsdunit].last_normal_IO_timestamp);
- }
- } else {
- /*
- * I'd really like to do the IOSleep here, but
- * we may be holding all kinds of filesystem related locks
- * and the pages for this I/O marked 'busy'...
- * we don't want to cause a normal task to block on
- * one of these locks while we're throttling a task marked
- * for low priority I/O... we'll mark the uthread and
- * do the delay just before we return from the system
- * call that triggered this I/O or from vnode_pagein
- */
- if (ut->uu_lowpri_window == 0) {
- ut->uu_devbsdunit = devbsdunit;
- oldValue = OSIncrementAtomic(&_throttle_io_info[devbsdunit].numthreads_throttling);
- if (oldValue < 0) {
- panic("%s: numthreads negative", __func__);
- }
- ut->uu_lowpri_window = lowpri_IO_initial_window_msecs;
- ut->uu_lowpri_window += lowpri_IO_window_msecs_inc * oldValue;
- } else {
- if (ut->uu_devbsdunit != devbsdunit) { // the thread sends I/Os to different devices within the same system call
- // keep track of the numthreads in the right device
- OSDecrementAtomic(&_throttle_io_info[ut->uu_devbsdunit].numthreads_throttling);
- OSIncrementAtomic(&_throttle_io_info[devbsdunit].numthreads_throttling);
- ut->uu_devbsdunit = devbsdunit;
- }
- int numthreads = MAX(1, _throttle_io_info[devbsdunit].numthreads_throttling);
- ut->uu_lowpri_window += lowpri_IO_window_msecs_inc * numthreads;
- if (ut->uu_lowpri_window > lowpri_max_window_msecs * numthreads)
- ut->uu_lowpri_window = lowpri_max_window_msecs * numthreads;
+ elapsed = now;
+ timevalsub(&elapsed, &info->throttle_start_IO_period_timestamp[wake_level]);
+ elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
+
+ if (elapsed_msecs >= (uint64_t)info->throttle_io_periods[wake_level] && !TAILQ_EMPTY(&info->throttle_uthlist[wake_level])) {
+ /*
+ * we're closing out the current IO period...
+ * if we have a waiting thread, wake it up
+ * after we have reset the I/O window info
+ */
+ need_wakeup = TRUE;
+ update_io_count = TRUE;
+
+ info->throttle_next_wake_level = wake_level - 1;
+
+ if (info->throttle_next_wake_level == THROTTLE_LEVEL_START)
+ info->throttle_next_wake_level = THROTTLE_LEVEL_END;
+
+ break;
}
+ wake_level--;
+
+ if (wake_level == THROTTLE_LEVEL_START)
+ wake_level = THROTTLE_LEVEL_END;
}
}
+ if (need_wakeup == TRUE) {
+ if (!TAILQ_EMPTY(&info->throttle_uthlist[wake_level])) {
- if ((bflags & B_READ) == 0) {
- size_t devbsdunit;
+ 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;
- if (buf_vnode(bp)->v_mount != NULL)
- devbsdunit = buf_vnode(bp)->v_mount->mnt_devbsdunit;
- else
- devbsdunit = LOWPRI_MAX_NUM_DEV - 1;
-
- microuptime(&_throttle_io_info[devbsdunit].last_IO_timestamp);
- }
+ wake_address = (caddr_t)&ut->uu_on_throttlelist;
+ }
+ } else
+ wake_level = THROTTLE_LEVEL_START;
- (*bdevsw[major(bdev)].d_strategy)(bp);
+ throttle_level = throttle_timer_start(info, update_io_count, wake_level);
- return (0);
-}
+ if (wake_address != NULL)
+ wakeup(wake_address);
+ for (level = THROTTLE_LEVEL_THROTTLED; level <= throttle_level; level++) {
-/*
- * This is a noop, simply returning what one has been given.
- */
-int
-spec_blockmap(__unused struct vnop_blockmap_args *ap)
-{
- return (ENOTSUP);
+ TAILQ_FOREACH_SAFE(ut, &info->throttle_uthlist[level], uu_throttlelist, utlist) {
+
+ 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);
+ }
+ }
+ if (info->throttle_timer_active == 0 && info->throttle_timer_ref) {
+ info->throttle_timer_ref = 0;
+ need_release = TRUE;
+ }
+ lck_mtx_unlock(&info->throttle_lock);
+
+ if (need_release == TRUE)
+ throttle_info_rel(info);
}
-/*
- * Device close routine
- */
-int
-spec_close(struct vnop_close_args *ap)
+static int
+throttle_add_to_list(struct _throttle_io_info_t *info, uthread_t ut, int mylevel, boolean_t insert_tail)
{
- struct vnode *vp = ap->a_vp;
- dev_t dev = vp->v_rdev;
- int (*devclose)(dev_t, int, int, struct proc *);
- int mode, error;
- int flags = ap->a_fflag;
- struct proc *p = vfs_context_proc(ap->a_context);
- struct session *sessp;
+ boolean_t start_timer = FALSE;
+ int level = THROTTLE_LEVEL_START;
- switch (vp->v_type) {
+ if (TAILQ_EMPTY(&info->throttle_uthlist[mylevel])) {
+ info->throttle_start_IO_period_timestamp[mylevel] = info->throttle_last_IO_timestamp[mylevel];
+ start_timer = TRUE;
+ }
- case VCHR:
- /*
- * Hack: a tty device that is a controlling terminal
- * has a reference from the session structure.
- * We cannot easily tell that a character device is
- * a controlling terminal, unless it is the closing
- * process' controlling terminal. In that case,
- * if the reference count is 2 (this last descriptor
- * plus the session), release the reference from the session.
- */
- sessp = proc_session(p);
- if (sessp != SESSION_NULL) {
- if ((vcount(vp) == 2) &&
- (vp == sessp->s_ttyvp)) {
- session_lock(sessp);
- sessp->s_ttyvp = NULL;
- sessp->s_ttyvid = 0;
- sessp->s_ttyp = NULL;
- sessp->s_ttypgrpid = NO_PID;
- session_unlock(sessp);
- vnode_rele(vp);
+ if (insert_tail == TRUE)
+ TAILQ_INSERT_TAIL(&info->throttle_uthlist[mylevel], ut, uu_throttlelist);
+ else
+ TAILQ_INSERT_HEAD(&info->throttle_uthlist[mylevel], ut, uu_throttlelist);
+
+ ut->uu_on_throttlelist = mylevel;
+
+ if (start_timer == TRUE) {
+ /* we may need to start or rearm the timer */
+ level = throttle_timer_start(info, FALSE, THROTTLE_LEVEL_START);
+
+ if (level == THROTTLE_LEVEL_END) {
+ if (ut->uu_on_throttlelist >= THROTTLE_LEVEL_THROTTLED) {
+ TAILQ_REMOVE(&info->throttle_uthlist[ut->uu_on_throttlelist], ut, uu_throttlelist);
+
+ ut->uu_on_throttlelist = THROTTLE_LEVEL_NONE;
}
- session_rele(sessp);
}
+ }
+ return (level);
+}
- devclose = cdevsw[major(dev)].d_close;
- mode = S_IFCHR;
- /*
- * close on last reference or on vnode revoke call
- */
- if ((flags & IO_REVOKE) != 0)
- break;
- if (vcount(vp) > 1)
- return (0);
- break;
+static void
+throttle_init_throttle_window(void)
+{
+ int throttle_window_size;
- case VBLK:
-#ifdef DEVFS_IMPLEMENTS_LOCKING
- /*
- * On last close of a block device (that isn't mounted)
- * we must invalidate any in core blocks, so that
- * we can, for instance, change floppy disks.
- */
- if ((error = spec_fsync_internal(vp, MNT_WAIT, ap->a_context)))
- return (error);
+ /*
+ * The hierarchy of throttle window values is as follows:
+ * - Global defaults
+ * - Device tree properties
+ * - Boot-args
+ * All values are specified in msecs.
+ */
- error = buf_invalidateblks(vp, BUF_WRITE_DATA, 0, 0);
- if (error)
- return (error);
- /*
- * Since every use (buffer, vnode, swap, blockmap)
- * holds a reference to the vnode, and because we mark
- * any other vnodes that alias this device, when the
- * sum of the reference counts on all the aliased
- * vnodes descends to one, we are on last close.
- */
- if (vcount(vp) > 0)
- return (0);
-#else /* DEVFS_IMPLEMENTS_LOCKING */
- /*
- * Since every use (buffer, vnode, swap, blockmap)
- * holds a reference to the vnode, and because we mark
- * any other vnodes that alias this device, when the
- * sum of the reference counts on all the aliased
- * vnodes descends to one, we are on last close.
- */
- if (vcount(vp) > 0)
- return (0);
+ /* Override global values with device-tree properties */
+ if (PE_get_default("kern.io_throttle_window_tier1", &throttle_window_size, sizeof(throttle_window_size)))
+ throttle_windows_msecs[THROTTLE_LEVEL_TIER1] = throttle_window_size;
- /*
+ if (PE_get_default("kern.io_throttle_window_tier2", &throttle_window_size, sizeof(throttle_window_size)))
+ throttle_windows_msecs[THROTTLE_LEVEL_TIER2] = throttle_window_size;
+
+ if (PE_get_default("kern.io_throttle_window_tier3", &throttle_window_size, sizeof(throttle_window_size)))
+ throttle_windows_msecs[THROTTLE_LEVEL_TIER3] = throttle_window_size;
+
+ /* Override with boot-args */
+ if (PE_parse_boot_argn("io_throttle_window_tier1", &throttle_window_size, sizeof(throttle_window_size)))
+ throttle_windows_msecs[THROTTLE_LEVEL_TIER1] = throttle_window_size;
+
+ if (PE_parse_boot_argn("io_throttle_window_tier2", &throttle_window_size, sizeof(throttle_window_size)))
+ throttle_windows_msecs[THROTTLE_LEVEL_TIER2] = throttle_window_size;
+
+ if (PE_parse_boot_argn("io_throttle_window_tier3", &throttle_window_size, sizeof(throttle_window_size)))
+ throttle_windows_msecs[THROTTLE_LEVEL_TIER3] = throttle_window_size;
+}
+
+static void
+throttle_init_throttle_period(struct _throttle_io_info_t *info, boolean_t isssd)
+{
+ int throttle_period_size;
+
+ /*
+ * The hierarchy of throttle period values is as follows:
+ * - Global defaults
+ * - Device tree properties
+ * - Boot-args
+ * All values are specified in msecs.
+ */
+
+ /* Assign global defaults */
+ 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];
+
+ /* Override global values with device-tree properties */
+ if (PE_get_default("kern.io_throttle_period_tier1", &throttle_period_size, sizeof(throttle_period_size)))
+ info->throttle_io_periods[THROTTLE_LEVEL_TIER1] = throttle_period_size;
+
+ if (PE_get_default("kern.io_throttle_period_tier2", &throttle_period_size, sizeof(throttle_period_size)))
+ info->throttle_io_periods[THROTTLE_LEVEL_TIER2] = throttle_period_size;
+
+ if (PE_get_default("kern.io_throttle_period_tier3", &throttle_period_size, sizeof(throttle_period_size)))
+ info->throttle_io_periods[THROTTLE_LEVEL_TIER3] = throttle_period_size;
+
+ /* Override with boot-args */
+ if (PE_parse_boot_argn("io_throttle_period_tier1", &throttle_period_size, sizeof(throttle_period_size)))
+ info->throttle_io_periods[THROTTLE_LEVEL_TIER1] = throttle_period_size;
+
+ if (PE_parse_boot_argn("io_throttle_period_tier2", &throttle_period_size, sizeof(throttle_period_size)))
+ info->throttle_io_periods[THROTTLE_LEVEL_TIER2] = throttle_period_size;
+
+ if (PE_parse_boot_argn("io_throttle_period_tier3", &throttle_period_size, sizeof(throttle_period_size)))
+ info->throttle_io_periods[THROTTLE_LEVEL_TIER3] = throttle_period_size;
+
+}
+
+#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_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_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_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
+sys_override_io_throttle(int flag)
+{
+ if (flag == THROTTLE_IO_ENABLE)
+ lowpri_throttle_enabled = 1;
+
+ if (flag == THROTTLE_IO_DISABLE)
+ lowpri_throttle_enabled = 0;
+}
+
+int rethrottle_wakeups = 0;
+
+/*
+ * 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.
+ *
+ *
+ * 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)
+{
+ /*
+ * If uthread doesn't have throttle state, then there's no chance
+ * of it needing a rethrottle.
+ */
+ if (ut->uu_throttle_info == NULL)
+ return;
+
+ boolean_t s = ml_set_interrupts_enabled(FALSE);
+ lck_spin_lock(&ut->uu_rethrottle_lock);
+
+ 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);
+
+ 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_spin_unlock(&ut->uu_rethrottle_lock);
+ ml_set_interrupts_enabled(s);
+}
+
+
+/*
+ * KPI routine
+ *
+ * Create and take a reference on a throttle info structure and return a
+ * pointer for the file system to use when calling throttle_info_update.
+ * Calling file system must have a matching release for every create.
+ */
+void *
+throttle_info_create(void)
+{
+ struct _throttle_io_info_t *info;
+ int level;
+
+ MALLOC(info, struct _throttle_io_info_t *, sizeof(*info), M_TEMP, M_ZERO | M_WAITOK);
+ /* Should never happen but just in case */
+ if (info == NULL)
+ return NULL;
+ /* Mark that this one was allocated and needs to be freed */
+ DEBUG_ALLOC_THROTTLE_INFO("Creating info = %p\n", info, info );
+ info->throttle_alloc = TRUE;
+
+ 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_next_wake_level = THROTTLE_LEVEL_END;
+
+ /* Take a reference */
+ OSIncrementAtomic(&info->throttle_refcnt);
+ return info;
+}
+
+/*
+ * KPI routine
+ *
+ * Release the throttle info pointer if all the reference are gone. Should be
+ * called to release reference taken by throttle_info_create
+ */
+void
+throttle_info_release(void *throttle_info)
+{
+ DEBUG_ALLOC_THROTTLE_INFO("Releaseing info = %p\n",
+ (struct _throttle_io_info_t *)throttle_info,
+ (struct _throttle_io_info_t *)throttle_info);
+ if (throttle_info) /* Just to be careful */
+ throttle_info_rel(throttle_info);
+}
+
+/*
+ * KPI routine
+ *
+ * File Systems that create an info structure, need to call this routine in
+ * their mount routine (used by cluster code). File Systems that call this in
+ * their mount routines must call throttle_info_mount_rel in their unmount
+ * routines.
+ */
+void
+throttle_info_mount_ref(mount_t mp, void *throttle_info)
+{
+ if ((throttle_info == NULL) || (mp == NULL))
+ return;
+ throttle_info_ref(throttle_info);
+
+ /*
+ * We already have a reference release it before adding the new one
+ */
+ if (mp->mnt_throttle_info)
+ throttle_info_rel(mp->mnt_throttle_info);
+ mp->mnt_throttle_info = throttle_info;
+}
+
+/*
+ * Private KPI routine
+ *
+ * return a handle for accessing throttle_info given a throttle_mask. The
+ * handle must be released by throttle_info_rel_by_mask
+ */
+int
+throttle_info_ref_by_mask(uint64_t throttle_mask, throttle_info_handle_t *throttle_info_handle)
+{
+ int dev_index;
+ struct _throttle_io_info_t *info;
+
+ if (throttle_info_handle == NULL)
+ return EINVAL;
+
+ dev_index = num_trailing_0(throttle_mask);
+ info = &_throttle_io_info[dev_index];
+ throttle_info_ref(info);
+ *(struct _throttle_io_info_t**)throttle_info_handle = info;
+
+ return 0;
+}
+
+/*
+ * Private KPI routine
+ *
+ * release the handle obtained by throttle_info_ref_by_mask
+ */
+void
+throttle_info_rel_by_mask(throttle_info_handle_t throttle_info_handle)
+{
+ /*
+ * for now the handle is just a pointer to _throttle_io_info_t
+ */
+ throttle_info_rel((struct _throttle_io_info_t*)throttle_info_handle);
+}
+
+/*
+ * KPI routine
+ *
+ * File Systems that throttle_info_mount_ref, must call this routine in their
+ * umount routine.
+ */
+void
+throttle_info_mount_rel(mount_t mp)
+{
+ if (mp->mnt_throttle_info)
+ throttle_info_rel(mp->mnt_throttle_info);
+ 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)
+{
+ 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;
+
+ *tv = info->throttle_last_write_timestamp;
+}
+
+void
+update_last_io_time(mount_t mp)
+{
+ 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;
+
+ microuptime(&info->throttle_last_write_timestamp);
+ if (mp != NULL)
+ mp->mnt_last_write_completed_timestamp = info->throttle_last_write_timestamp;
+}
+
+int
+throttle_get_io_policy(uthread_t *ut)
+{
+ if (ut != NULL)
+ *ut = get_bsdthread_info(current_thread());
+
+ return (proc_get_effective_thread_policy(current_thread(), TASK_POLICY_IO));
+}
+
+int
+throttle_get_passive_io_policy(uthread_t *ut)
+{
+ if (ut != NULL)
+ *ut = get_bsdthread_info(current_thread());
+
+ return (proc_get_effective_thread_policy(current_thread(), TASK_POLICY_PASSIVE_IO));
+}
+
+
+static int
+throttle_get_thread_throttle_level(uthread_t ut)
+{
+ uthread_t *ut_p = (ut == NULL) ? &ut : NULL;
+ int io_tier = throttle_get_io_policy(ut_p);
+
+ return throttle_get_thread_throttle_level_internal(ut, io_tier);
+}
+
+/*
+ * 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);
+
+ microuptime(&now);
+
+ 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);
+
+ if (elapsed_msecs < (uint64_t)throttle_windows_msecs[thread_throttle_level])
+ break;
+ }
+ if (throttle_level >= thread_throttle_level) {
+ /*
+ * we're beyond all of the throttle windows
+ * that affect the throttle level of this thread,
+ * so go ahead and treat as normal I/O
+ */
+ return (THROTTLE_DISENGAGED);
+ }
+ if (mylevel)
+ *mylevel = thread_throttle_level;
+ if (throttling_level)
+ *throttling_level = throttle_level;
+
+ if (info->throttle_io_count != info->throttle_io_count_begin) {
+ /*
+ * we've already issued at least one throttleable I/O
+ * in the current I/O window, so avoid issuing another one
+ */
+ return (THROTTLE_NOW);
+ }
+ /*
+ * we're in the throttle window, so
+ * cut the I/O size back
+ */
+ return (THROTTLE_ENGAGED);
+}
+
+/*
+ * If we have a mount point and it has a throttle info pointer then
+ * use it to do the check, otherwise use the device unit number to find
+ * the correct throttle info array element.
+ */
+int
+throttle_io_will_be_throttled(__unused int lowpri_window_msecs, mount_t mp)
+{
+ struct _throttle_io_info_t *info;
+
+ /*
+ * Should we just return zero if no mount point
+ */
+ 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;
+
+ 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);
+}
+
+/*
+ * Routine to increment I/O throttling counters maintained in the proc
+ */
+
+static void
+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(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(count, &(throttling_proc->did_throttle));
+ proc_rele(throttling_proc);
+ }
+}
+
+/*
+ * Block until woken up by the throttle timer or by a rethrottle call.
+ * As long as we hold the throttle_lock while querying the throttle tier, we're
+ * safe against seeing an old throttle tier after a rethrottle.
+ */
+uint32_t
+throttle_lowpri_io(int sleep_amount)
+{
+ uthread_t ut;
+ struct _throttle_io_info_t *info;
+ int throttle_type = 0;
+ int mylevel = 0;
+ int throttling_level = THROTTLE_LEVEL_NONE;
+ 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());
+
+ if (ut->uu_lowpri_window == 0)
+ return (0);
+
+ info = ut->uu_throttle_info;
+
+ if (info == NULL) {
+ ut->uu_throttle_bc = FALSE;
+ 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;
+
+ if (sleep_amount == 1 && ut->uu_throttle_bc == FALSE)
+ sleep_amount = 0;
+
+ 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 (sleep_amount == 0)
+ break;
+ if (info->throttle_io_period_num < throttle_io_period_num)
+ break;
+ 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);
+
+ 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]++;
+ }
+ 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++;
+
+ if (sleep_amount == 0)
+ insert_tail = FALSE;
+ else if (info->throttle_io_period_num < throttle_io_period_num ||
+ (info->throttle_io_period_num - throttle_io_period_num) >= (uint32_t)sleep_amount) {
+ insert_tail = FALSE;
+ sleep_amount = 0;
+ }
+ }
+done:
+ if (ut->uu_on_throttlelist >= THROTTLE_LEVEL_THROTTLED) {
+ 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);
+ }
+
+ ut->uu_throttle_info = NULL;
+ ut->uu_throttle_bc = FALSE;
+ ut->uu_lowpri_window = 0;
+
+ throttle_info_rel(info);
+
+ return (sleep_cnt);
+}
+
+/*
+ * KPI routine
+ *
+ * set a kernel thread's IO policy. policy can be:
+ * IOPOL_NORMAL, IOPOL_THROTTLE, IOPOL_PASSIVE, IOPOL_UTILITY, IOPOL_STANDARD
+ *
+ * explanations about these policies are in the man page of setiopolicy_np
+ */
+void throttle_set_thread_io_policy(int 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);
+}
+
+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);
+
+ ut->uu_throttle_info = NULL;
+ ut->uu_lowpri_window = 0;
+ ut->uu_throttle_bc = FALSE;
+ }
+}
+
+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 || info->throttle_disabled)
+ return;
+
+ if (info->throttle_io_periods == 0) {
+ throttle_init_throttle_period(info, isssd);
+ }
+ if (ut->uu_throttle_info == NULL) {
+
+ ut->uu_throttle_info = info;
+ throttle_info_ref(info);
+ DEBUG_ALLOC_THROTTLE_INFO("updating info = %p\n", info, info );
+
+ ut->uu_lowpri_window = 1;
+ ut->uu_throttle_bc = BC_throttle;
+ }
+}
+
+/*
+ * 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
+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 || info->throttle_disabled)
+ return THROTTLE_LEVEL_NONE;
+
+ if (ut == NULL)
+ ut = get_bsdthread_info(current_thread());
+
+ 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)) {
+ 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);
+ }
+ microuptime(&info->throttle_last_IO_timestamp[thread_throttle_level]);
+ }
+
+
+ if (thread_throttle_level >= THROTTLE_LEVEL_THROTTLED) {
+ /*
+ * I'd really like to do the IOSleep here, but
+ * we may be holding all kinds of filesystem related locks
+ * and the pages for this I/O marked 'busy'...
+ * we don't want to cause a normal task to block on
+ * one of these locks while we're throttling a task marked
+ * for low priority I/O... we'll mark the uthread and
+ * do the delay just before we return from the system
+ * call that triggered this I/O or from vnode_pagein
+ */
+ OSAddAtomic(1, &info->throttle_io_count);
+
+ throttle_info_set_initial_window(ut, info, FALSE, isssd);
+ }
+
+ return thread_throttle_level;
+}
+
+void *throttle_info_update_by_mount(mount_t mp)
+{
+ struct _throttle_io_info_t *info;
+ uthread_t ut;
+ boolean_t isssd = FALSE;
+
+ ut = get_bsdthread_info(current_thread());
+
+ if (mp != NULL) {
+ if (disk_conditioner_mount_is_ssd(mp))
+ isssd = TRUE;
+ info = &_throttle_io_info[mp->mnt_devbsdunit];
+ } else
+ info = &_throttle_io_info[LOWPRI_MAX_NUM_DEV - 1];
+
+ if (!ut->uu_lowpri_window)
+ throttle_info_set_initial_window(ut, info, FALSE, isssd);
+
+ return info;
+}
+
+
+/*
+ * KPI routine
+ *
+ * this is usually called before every I/O, used for throttled I/O
+ * book keeping. This routine has low overhead and does not sleep
+ */
+void throttle_info_update(void *throttle_info, int flags)
+{
+ if (throttle_info)
+ throttle_info_update_internal(throttle_info, NULL, flags, FALSE, FALSE, NULL);
+}
+
+/*
+ * KPI routine
+ *
+ * this is usually called before every I/O, used for throttled I/O
+ * book keeping. This routine has low overhead and does not sleep
+ */
+void throttle_info_update_by_mask(void *throttle_info_handle, int flags)
+{
+ void *throttle_info = throttle_info_handle;
+
+ /*
+ * for now we only use the lowest bit of the throttle mask, so the
+ * handle is the same as the throttle_info. Later if we store a
+ * set of throttle infos in the handle, we will want to loop through
+ * them and call throttle_info_update in a loop
+ */
+ 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)
+ * Called to determine if this IO is being throttled to this level so that it can be treated specially
+ */
+int throttle_info_io_will_be_throttled(void * throttle_info, int policy)
+{
+ struct _throttle_io_info_t *info = throttle_info;
+ struct timeval elapsed;
+ uint64_t elapsed_msecs;
+ int throttle_level;
+ int thread_throttle_level;
+
+ switch (policy) {
+
+ case IOPOL_THROTTLE:
+ thread_throttle_level = THROTTLE_LEVEL_TIER3;
+ break;
+ case IOPOL_UTILITY:
+ thread_throttle_level = THROTTLE_LEVEL_TIER2;
+ break;
+ case IOPOL_STANDARD:
+ thread_throttle_level = THROTTLE_LEVEL_TIER1;
+ break;
+ default:
+ thread_throttle_level = THROTTLE_LEVEL_TIER0;
+ 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]);
+ elapsed_msecs = (uint64_t)elapsed.tv_sec * (uint64_t)1000 + (elapsed.tv_usec / 1000);
+
+ if (elapsed_msecs < (uint64_t)throttle_windows_msecs[thread_throttle_level])
+ break;
+ }
+ if (throttle_level >= thread_throttle_level) {
+ /*
+ * we're beyond all of the throttle windows
+ * so go ahead and treat as normal I/O
+ */
+ return (THROTTLE_DISENGAGED);
+ }
+ /*
+ * we're in the throttle window
+ */
+ 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)
+{
+ buf_t bp;
+ int bflags;
+ int io_tier;
+ int passive;
+ dev_t bdev;
+ uthread_t ut;
+ mount_t mp;
+ struct bufattr *bap;
+ 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) {
+ 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 (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 (io_tier != 0)
+ code |= DKIO_THROTTLE;
+
+ code |= ((io_tier << DKIO_TIER_SHIFT) & DKIO_TIER_MASK);
+
+ if (bflags & B_PASSIVE)
+ code |= DKIO_PASSIVE;
+
+ 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 (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, inflight, bap);
+
+ if ((bflags & B_READ) == 0) {
+ microuptime(&throttle_info->throttle_last_write_timestamp);
+
+ if (mp) {
+ mp->mnt_last_write_issued_timestamp = throttle_info->throttle_last_write_timestamp;
+ INCR_PENDING_IO(buf_count(bp), mp->mnt_pending_write_size);
+ }
+ } else if (mp) {
+ INCR_PENDING_IO(buf_count(bp), mp->mnt_pending_read_size);
+ }
+ /*
+ * The BootCache may give us special information about
+ * the IO, so it returns special values that we check
+ * for here.
+ *
+ * IO_SATISFIED_BY_CACHE
+ * The read has been satisfied by the boot cache. Don't
+ * throttle the thread unnecessarily.
+ *
+ * IO_SHOULD_BE_THROTTLED
+ * The boot cache is playing back a playlist and this IO
+ * cut through. Throttle it so we're not cutting through
+ * the boot cache too often.
+ *
+ * Note that typical strategy routines are defined with
+ * a void return so we'll get garbage here. In the
+ * unlikely case the garbage matches our special return
+ * value, it's not a big deal since we're only adjusting
+ * the throttling delay.
+ */
+#define IO_SATISFIED_BY_CACHE ((int)0xcafefeed)
+#define IO_SHOULD_BE_THROTTLED ((int)0xcafebeef)
+ 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) {
+ /*
+ * If this was a throttled IO satisfied by the boot cache,
+ * don't delay the thread.
+ */
+ throttle_info_reset_window(ut);
+
+ } else if (IO_SHOULD_BE_THROTTLED == strategy_ret) {
+ /*
+ * If the boot cache indicates this IO should be throttled,
+ * delay the thread.
+ */
+ throttle_info_set_initial_window(ut, throttle_info, TRUE, isssd);
+ }
+ return (0);
+}
+
+
+/*
+ * This is a noop, simply returning what one has been given.
+ */
+int
+spec_blockmap(__unused struct vnop_blockmap_args *ap)
+{
+ return (ENOTSUP);
+}
+
+
+/*
+ * Device close routine
+ */
+int
+spec_close(struct vnop_close_args *ap)
+{
+ struct vnode *vp = ap->a_vp;
+ dev_t dev = vp->v_rdev;
+ int error = 0;
+ int flags = ap->a_fflag;
+ struct proc *p = vfs_context_proc(ap->a_context);
+ struct session *sessp;
+
+ switch (vp->v_type) {
+
+ case VCHR:
+ /*
+ * Hack: a tty device that is a controlling terminal
+ * has a reference from the session structure.
+ * We cannot easily tell that a character device is
+ * a controlling terminal, unless it is the closing
+ * process' controlling terminal. In that case,
+ * if the reference count is 1 (this is the very
+ * last close)
+ */
+ sessp = proc_session(p);
+ devsw_lock(dev, S_IFCHR);
+ if (sessp != SESSION_NULL) {
+ if (vp == sessp->s_ttyvp && vcount(vp) == 1) {
+ struct tty *tp = TTY_NULL;
+
+ devsw_unlock(dev, S_IFCHR);
+ session_lock(sessp);
+ if (vp == sessp->s_ttyvp) {
+ tp = SESSION_TP(sessp);
+ sessp->s_ttyvp = NULL;
+ sessp->s_ttyvid = 0;
+ sessp->s_ttyp = TTY_NULL;
+ sessp->s_ttypgrpid = NO_PID;
+ }
+ session_unlock(sessp);
+
+ 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);
+ }
+ session_rele(sessp);
+ }
+
+ if (--vp->v_specinfo->si_opencount < 0)
+ panic("negative open count (c, %u, %u)", major(dev), minor(dev));
+
+ /*
+ * close on last reference or on vnode revoke call
+ */
+ if (vcount(vp) == 0 || (flags & IO_REVOKE) != 0)
+ error = cdevsw[major(dev)].d_close(dev, flags, S_IFCHR, p);
+
+ devsw_unlock(dev, S_IFCHR);
+ break;
+
+ case VBLK:
+ /*
+ * If there is more than one outstanding open, don't
+ * send the close to the device.
+ */
+ devsw_lock(dev, S_IFBLK);
+ if (vcount(vp) > 1) {
+ vp->v_specinfo->si_opencount--;
+ devsw_unlock(dev, S_IFBLK);
+ return (0);
+ }
+ devsw_unlock(dev, S_IFBLK);
+
+ /*
* On last close of a block device (that isn't mounted)
* we must invalidate any in core blocks, so that
* we can, for instance, change floppy disks.
error = buf_invalidateblks(vp, BUF_WRITE_DATA, 0, 0);
if (error)
return (error);
-#endif /* DEVFS_IMPLEMENTS_LOCKING */
- devclose = bdevsw[major(dev)].d_close;
- mode = S_IFBLK;
+
+ devsw_lock(dev, S_IFBLK);
+
+ if (--vp->v_specinfo->si_opencount < 0)
+ panic("negative open count (b, %u, %u)", major(dev), minor(dev));
+
+ if (vcount(vp) == 0)
+ error = bdevsw[major(dev)].d_close(dev, flags, S_IFBLK, p);
+
+ devsw_unlock(dev, S_IFBLK);
break;
default:
return(EBADF);
}
- return ((*devclose)(dev, flags, mode, p));
+ return error;
}
/*
return (0);
}
+
+static void filt_specdetach(struct knote *kn);
+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);
+
+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
+spec_knote_select_and_link(struct knote *kn)
+{
+ 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, __unused struct kevent_internal_s *kev)
+{
+ vnode_t vp;
+ dev_t dev;
+
+ vp = (vnode_t)kn->kn_fp->f_fglob->fg_data; /* Already have iocount, and vnode is alive */
+
+ assert(vnode_ischr(vp));
+
+ dev = vnode_specrdev(vp);
+
+ /*
+ * 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;
+ }
+
+ /*
+ * 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_filtid = EVFILTID_SPEC;
+ kn->kn_hook_data = 0;
+ kn->kn_hookid = vnode_vid(vp);
+
+ knote_markstayactive(kn);
+ return spec_knote_select_and_link(kn);
+}
+
+static void
+filt_specdetach(struct knote *kn)
+{
+ knote_clearstayactive(kn);
+
+ /*
+ * 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.
+ */
+ 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);
+ }
+
+ return 0;
+}
+
+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;
+ vfs_context_t ctx;
+ int res;
+ int selres;
+ int error;
+
+ 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;
+ }
+
+ selres = spec_knote_select_and_link(kn);
+ filt_spec_common(kn, 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;
+ }
+ }
+
+ return res;
+}
+
+static unsigned
+filt_specpeek(struct knote *kn)
+{
+ int selres = 0;
+
+ selres = spec_knote_select_and_link(kn);
+ filt_spec_common(kn, selres);
+
+ return kn->kn_data;
+}
+
projects / apple / xnu.git / blobdiff