/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2006 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. * * Copyright 2015 Nexenta Systems, Inc. All rights reserved. */ #ifndef _SYS_KSTAT_H #define _SYS_KSTAT_H /* * Definition of general kernel statistics structures and /dev/kstat ioctls */ #include <sys/types.h> #include <sys/time.h> #ifdef __cplusplus extern "C" { #endif typedef int kid_t; /* unique kstat id */ /* * Kernel statistics driver (/dev/kstat) ioctls */ #define KSTAT_IOC_BASE ('K' << 8) #define KSTAT_IOC_CHAIN_ID KSTAT_IOC_BASE | 0x01 #define KSTAT_IOC_READ KSTAT_IOC_BASE | 0x02 #define KSTAT_IOC_WRITE KSTAT_IOC_BASE | 0x03 /* * /dev/kstat ioctl usage (kd denotes /dev/kstat descriptor): * * kcid = ioctl(kd, KSTAT_IOC_CHAIN_ID, NULL); * kcid = ioctl(kd, KSTAT_IOC_READ, kstat_t *); * kcid = ioctl(kd, KSTAT_IOC_WRITE, kstat_t *); */ #define KSTAT_STRLEN 31 /* 30 chars + NULL; must be 16 * n - 1 */ /* * The generic kstat header */ typedef struct kstat { /* * Fields relevant to both kernel and user */ hrtime_t ks_crtime; /* creation time (from gethrtime()) */ struct kstat *ks_next; /* kstat chain linkage */ kid_t ks_kid; /* unique kstat ID */ char ks_module[KSTAT_STRLEN]; /* provider module name */ uchar_t ks_resv; /* reserved, currently just padding */ int ks_instance; /* provider module's instance */ char ks_name[KSTAT_STRLEN]; /* kstat name */ uchar_t ks_type; /* kstat data type */ char ks_class[KSTAT_STRLEN]; /* kstat class */ uchar_t ks_flags; /* kstat flags */ void *ks_data; /* kstat type-specific data */ uint_t ks_ndata; /* # of type-specific data records */ size_t ks_data_size; /* total size of kstat data section */ hrtime_t ks_snaptime; /* time of last data shapshot */ /* * Fields relevant to kernel only */ int (*ks_update)(struct kstat *, int); /* dynamic update */ void *ks_private; /* arbitrary provider-private data */ int (*ks_snapshot)(struct kstat *, void *, int); void *ks_lock; /* protects this kstat's data */ } kstat_t; #ifdef _SYSCALL32 typedef int32_t kid32_t; typedef struct kstat32 { /* * Fields relevant to both kernel and user */ hrtime_t ks_crtime; caddr32_t ks_next; /* struct kstat pointer */ kid32_t ks_kid; char ks_module[KSTAT_STRLEN]; uint8_t ks_resv; int32_t ks_instance; char ks_name[KSTAT_STRLEN]; uint8_t ks_type; char ks_class[KSTAT_STRLEN]; uint8_t ks_flags; caddr32_t ks_data; /* type-specific data */ uint32_t ks_ndata; size32_t ks_data_size; hrtime_t ks_snaptime; /* * Fields relevant to kernel only (only needed here for padding) */ int32_t _ks_update; caddr32_t _ks_private; int32_t _ks_snapshot; caddr32_t _ks_lock; } kstat32_t; #endif /* _SYSCALL32 */ /* * kstat structure and locking strategy * * Each kstat consists of a header section (a kstat_t) and a data section. * The system maintains a set of kstats, protected by kstat_chain_lock. * kstat_chain_lock protects all additions to/deletions from this set, * as well as all changes to kstat headers. kstat data sections are * *optionally* protected by the per-kstat ks_lock. If ks_lock is non-NULL, * kstat clients (e.g. /dev/kstat) will acquire this lock for all of their * operations on that kstat. It is up to the kstat provider to decide whether * guaranteeing consistent data to kstat clients is sufficiently important * to justify the locking cost. Note, however, that most statistic updates * already occur under one of the provider's mutexes, so if the provider sets * ks_lock to point to that mutex, then kstat data locking is free. * * NOTE: variable-size kstats MUST employ kstat data locking, to prevent * data-size races with kstat clients. * * NOTE: ks_lock is really of type (kmutex_t *); it is declared as (void *) * in the kstat header so that users don't have to be exposed to all of the * kernel's lock-related data structures. */ #if defined(_KERNEL) #define KSTAT_ENTER(k) \ { kmutex_t *lp = (k)->ks_lock; if (lp) mutex_enter(lp); } #define KSTAT_EXIT(k) \ { kmutex_t *lp = (k)->ks_lock; if (lp) mutex_exit(lp); } #define KSTAT_UPDATE(k, rw) (*(k)->ks_update)((k), (rw)) #define KSTAT_SNAPSHOT(k, buf, rw) (*(k)->ks_snapshot)((k), (buf), (rw)) #endif /* defined(_KERNEL) */ /* * kstat time * * All times associated with kstats (e.g. creation time, snapshot time, * kstat_timer_t and kstat_io_t timestamps, etc.) are 64-bit nanosecond values, * as returned by gethrtime(). The accuracy of these timestamps is machine * dependent, but the precision (units) is the same across all platforms. */ /* * kstat identity (KID) * * Each kstat is assigned a unique KID (kstat ID) when it is added to the * global kstat chain. The KID is used as a cookie by /dev/kstat to * request information about the corresponding kstat. There is also * an identity associated with the entire kstat chain, kstat_chain_id, * which is bumped each time a kstat is added or deleted. /dev/kstat uses * the chain ID to detect changes in the kstat chain (e.g., a new disk * coming online) between ioctl()s. */ /* * kstat module, kstat instance * * ks_module and ks_instance contain the name and instance of the module * that created the kstat. In cases where there can only be one instance, * ks_instance is 0. The kernel proper (/kernel/unix) uses "unix" as its * module name. */ /* * kstat name * * ks_name gives a meaningful name to a kstat. The full kstat namespace * is module.instance.name, so the name only need be unique within a * module. kstat_create() will fail if you try to create a kstat with * an already-used (ks_module, ks_instance, ks_name) triplet. Spaces are * allowed in kstat names, but strongly discouraged, since they hinder * awk-style processing at user level. */ /* * kstat type * * The kstat mechanism provides several flavors of kstat data, defined * below. The "raw" kstat type is just treated as an array of bytes; you * can use this to export any kind of data you want. * * Some kstat types allow multiple data structures per kstat, e.g. * KSTAT_TYPE_NAMED; others do not. This is part of the spec for each * kstat data type. * * User-level tools should *not* rely on the #define KSTAT_NUM_TYPES. To * get this information, read out the standard system kstat "kstat_types". */ #define KSTAT_TYPE_RAW 0 /* can be anything */ /* ks_ndata >= 1 */ #define KSTAT_TYPE_NAMED 1 /* name/value pair */ /* ks_ndata >= 1 */ #define KSTAT_TYPE_INTR 2 /* interrupt statistics */ /* ks_ndata == 1 */ #define KSTAT_TYPE_IO 3 /* I/O statistics */ /* ks_ndata == 1 */ #define KSTAT_TYPE_TIMER 4 /* event timer */ /* ks_ndata >= 1 */ #define KSTAT_NUM_TYPES 5 /* * kstat class * * Each kstat can be characterized as belonging to some broad class * of statistics, e.g. disk, tape, net, vm, streams, etc. This field * can be used as a filter to extract related kstats. The following * values are currently in use: disk, tape, net, controller, vm, kvm, * hat, streams, kstat, and misc. (The kstat class encompasses things * like kstat_types.) */ /* * kstat flags * * Any of the following flags may be passed to kstat_create(). They are * all zero by default. * * KSTAT_FLAG_VIRTUAL: * * Tells kstat_create() not to allocate memory for the * kstat data section; instead, you will set the ks_data * field to point to the data you wish to export. This * provides a convenient way to export existing data * structures. * * KSTAT_FLAG_VAR_SIZE: * * The size of the kstat you are creating will vary over time. * For example, you may want to use the kstat mechanism to * export a linked list. NOTE: The kstat framework does not * manage the data section, so all variable-size kstats must be * virtual kstats. Moreover, variable-size kstats MUST employ * kstat data locking to prevent data-size races with kstat * clients. See the section on "kstat snapshot" for details. * * KSTAT_FLAG_WRITABLE: * * Makes the kstat's data section writable by root. * The ks_snapshot routine (see below) does not need to check for * this; permission checking is handled in the kstat driver. * * KSTAT_FLAG_PERSISTENT: * * Indicates that this kstat is to be persistent over time. * For persistent kstats, kstat_delete() simply marks the * kstat as dormant; a subsequent kstat_create() reactivates * the kstat. This feature is provided so that statistics * are not lost across driver close/open (e.g., raw disk I/O * on a disk with no mounted partitions.) * NOTE: Persistent kstats cannot be virtual, since ks_data * points to garbage as soon as the driver goes away. * * The following flags are maintained by the kstat framework: * * KSTAT_FLAG_DORMANT: * * For persistent kstats, indicates that the kstat is in the * dormant state (e.g., the corresponding device is closed). * * KSTAT_FLAG_INVALID: * * This flag is set when a kstat is in a transitional state, * e.g. between kstat_create() and kstat_install(). * kstat clients must not attempt to access the kstat's data * if this flag is set. * * KSTAT_FLAG_LONGSTRINGS: * * Indicates that this kstat contains long strings (which * are stored outside of the kstat data section). When copied * out to user space the string data will be held in the data * section provided by the user. */ #define KSTAT_FLAG_VIRTUAL 0x01 #define KSTAT_FLAG_VAR_SIZE 0x02 #define KSTAT_FLAG_WRITABLE 0x04 #define KSTAT_FLAG_PERSISTENT 0x08 #define KSTAT_FLAG_DORMANT 0x10 #define KSTAT_FLAG_INVALID 0x20 #define KSTAT_FLAG_LONGSTRINGS 0x40 /* * Dynamic update support * * The kstat mechanism allows for an optional ks_update function to update * kstat data. This is useful for drivers where the underlying device * keeps cheap hardware stats, but extraction is expensive. Instead of * constantly keeping the kstat data section up to date, you can supply a * ks_update function which updates the kstat's data section on demand. * To take advantage of this feature, simply set the ks_update field before * calling kstat_install(). * * The ks_update function, if supplied, must have the following structure: * * int * foo_kstat_update(kstat_t *ksp, int rw) * { * if (rw == KSTAT_WRITE) { * ... update the native stats from ksp->ks_data; * return EACCES if you don't support this * } else { * ... update ksp->ks_data from the native stats * } * } * * The ks_update return codes are: 0 for success, EACCES if you don't allow * KSTAT_WRITE, and EIO for any other type of error. * * In general, the ks_update function may need to refer to provider-private * data; for example, it may need a pointer to the provider's raw statistics. * The ks_private field is available for this purpose. Its use is entirely * at the provider's discretion. * * All variable-size kstats MUST supply a ks_update routine, which computes * and sets ks_data_size (and ks_ndata if that is meaningful), since these * are needed to perform kstat snapshots (see below). * * No kstat locking should be done inside the ks_update routine. The caller * will already be holding the kstat's ks_lock (to ensure consistent data). */ #define KSTAT_READ 0 #define KSTAT_WRITE 1 /* * Kstat snapshot * * In order to get a consistent view of a kstat's data, clients must obey * the kstat's locking strategy. However, these clients may need to perform * operations on the data which could cause a fault (e.g. copyout()), or * operations which are simply expensive. Doing so could cause deadlock * (e.g. if you're holding a disk's kstat lock which is ultimately required * to resolve a copyout() fault), performance degradation (since the providers' * activity is serialized at the kstat lock), device timing problems, etc. * * To avoid these problems, kstat data is provided via snapshots. Taking * a snapshot is a simple process: allocate a wired-down kernel buffer, * acquire the kstat's data lock, copy the data into the buffer ("take the * snapshot"), and release the lock. This ensures that the kstat's data lock * will be held as briefly as possible, and that no faults will occur while * the lock is held. * * Normally, the snapshot is taken by default_kstat_snapshot(), which * timestamps the data (sets ks_snaptime), copies it, and does a little * massaging to deal with incomplete transactions on i/o kstats. However, * this routine only works for kstats with contiguous data (the typical case). * If you create a kstat whose data is, say, a linked list, you must provide * your own ks_snapshot routine. The routine you supply must have the * following prototype (replace "foo" with something appropriate): * * int foo_kstat_snapshot(kstat_t *ksp, void *buf, int rw); * * The minimal snapshot routine -- one which copies contiguous data that * doesn't need any massaging -- would be this: * * ksp->ks_snaptime = gethrtime(); * if (rw == KSTAT_WRITE) * bcopy(buf, ksp->ks_data, ksp->ks_data_size); * else * bcopy(ksp->ks_data, buf, ksp->ks_data_size); * return (0); * * A more illuminating example is taking a snapshot of a linked list: * * ksp->ks_snaptime = gethrtime(); * if (rw == KSTAT_WRITE) * return (EACCES); ... See below ... * for (foo = first_foo; foo; foo = foo->next) { * bcopy((char *) foo, (char *) buf, sizeof (struct foo)); * buf = ((struct foo *) buf) + 1; * } * return (0); * * In the example above, we have decided that we don't want to allow * KSTAT_WRITE access, so we return EACCES if this is attempted. * * The key points are: * * (1) ks_snaptime must be set (via gethrtime()) to timestamp the data. * (2) Data gets copied from the kstat to the buffer on KSTAT_READ, * and from the buffer to the kstat on KSTAT_WRITE. * (3) ks_snapshot return values are: 0 for success, EACCES if you * don't allow KSTAT_WRITE, and EIO for any other type of error. * * Named kstats (see section on "Named statistics" below) containing long * strings (KSTAT_DATA_STRING) need special handling. The kstat driver * assumes that all strings are copied into the buffer after the array of * named kstats, and the pointers (KSTAT_NAMED_STR_PTR()) are updated to point * into the copy within the buffer. The default snapshot routine does this, * but overriding routines should contain at least the following: * * if (rw == KSTAT_READ) { * kstat_named_t *knp = buf; * char *end = knp + ksp->ks_ndata; * uint_t i; * * ... Do the regular copy ... * bcopy(ksp->ks_data, buf, sizeof (kstat_named_t) * ksp->ks_ndata); * * for (i = 0; i < ksp->ks_ndata; i++, knp++) { * if (knp[i].data_type == KSTAT_DATA_STRING && * KSTAT_NAMED_STR_PTR(knp) != NULL) { * bcopy(KSTAT_NAMED_STR_PTR(knp), end, * KSTAT_NAMED_STR_BUFLEN(knp)); * KSTAT_NAMED_STR_PTR(knp) = end; * end += KSTAT_NAMED_STR_BUFLEN(knp); * } * } */ /* * Named statistics. * * List of arbitrary name=value statistics. */ typedef struct kstat_named { char name[KSTAT_STRLEN]; /* name of counter */ uchar_t data_type; /* data type */ union { char c[16]; /* enough for 128-bit ints */ int32_t i32; uint32_t ui32; struct { union { char *ptr; /* NULL-term string */ #if defined(_KERNEL) && defined(_MULTI_DATAMODEL) caddr32_t ptr32; #endif char __pad[8]; /* 64-bit padding */ } addr; uint32_t len; /* # bytes for strlen + '\0' */ } str; /* * The int64_t and uint64_t types are not valid for a maximally conformant * 32-bit compilation environment (cc -Xc) using compilers prior to the * introduction of C99 conforming compiler (reference ISO/IEC 9899:1990). * In these cases, the visibility of i64 and ui64 is only permitted for * 64-bit compilation environments or 32-bit non-maximally conformant * C89 or C90 ANSI C compilation environments (cc -Xt and cc -Xa). In the * C99 ANSI C compilation environment, the long long type is supported. * The _INT64_TYPE is defined by the implementation (see sys/int_types.h). */ #if defined(_INT64_TYPE) int64_t i64; uint64_t ui64; #endif long l; ulong_t ul; /* These structure members are obsolete */ longlong_t ll; u_longlong_t ull; float f; double d; } value; /* value of counter */ } kstat_named_t; #define KSTAT_DATA_CHAR 0 #define KSTAT_DATA_INT32 1 #define KSTAT_DATA_UINT32 2 #define KSTAT_DATA_INT64 3 #define KSTAT_DATA_UINT64 4 #if !defined(_LP64) #define KSTAT_DATA_LONG KSTAT_DATA_INT32 #define KSTAT_DATA_ULONG KSTAT_DATA_UINT32 #else #if !defined(_KERNEL) #define KSTAT_DATA_LONG KSTAT_DATA_INT64 #define KSTAT_DATA_ULONG KSTAT_DATA_UINT64 #else #define KSTAT_DATA_LONG 7 /* only visible to the kernel */ #define KSTAT_DATA_ULONG 8 /* only visible to the kernel */ #endif /* !_KERNEL */ #endif /* !_LP64 */ /* * Statistics exporting named kstats with long strings (KSTAT_DATA_STRING) * may not make the assumption that ks_data_size is equal to (ks_ndata * sizeof * (kstat_named_t)). ks_data_size in these cases is equal to the sum of the * amount of space required to store the strings (ie, the sum of * KSTAT_NAMED_STR_BUFLEN() for all KSTAT_DATA_STRING statistics) plus the * space required to store the kstat_named_t's. * * The default update routine will update ks_data_size automatically for * variable-length kstats containing long strings (using the default update * routine only makes sense if the string is the only thing that is changing * in size, and ks_ndata is constant). Fixed-length kstats containing long * strings must explicitly change ks_data_size (after creation but before * initialization) to reflect the correct amount of space required for the * long strings and the kstat_named_t's. */ #define KSTAT_DATA_STRING 9 /* These types are obsolete */ #define KSTAT_DATA_LONGLONG KSTAT_DATA_INT64 #define KSTAT_DATA_ULONGLONG KSTAT_DATA_UINT64 #define KSTAT_DATA_FLOAT 5 #define KSTAT_DATA_DOUBLE 6 #define KSTAT_NAMED_PTR(kptr) ((kstat_named_t *)(kptr)->ks_data) /* * Retrieve the pointer of the string contained in the given named kstat. */ #define KSTAT_NAMED_STR_PTR(knptr) ((knptr)->value.str.addr.ptr) /* * Retrieve the length of the buffer required to store the string in the given * named kstat. */ #define KSTAT_NAMED_STR_BUFLEN(knptr) ((knptr)->value.str.len) /* * Interrupt statistics. * * An interrupt is a hard interrupt (sourced from the hardware device * itself), a soft interrupt (induced by the system via the use of * some system interrupt source), a watchdog interrupt (induced by * a periodic timer call), spurious (an interrupt entry point was * entered but there was no interrupt condition to service), * or multiple service (an interrupt condition was detected and * serviced just prior to returning from any of the other types). * * Measurement of the spurious class of interrupts is useful for * autovectored devices in order to pinpoint any interrupt latency * problems in a particular system configuration. * * Devices that have more than one interrupt of the same * type should use multiple structures. */ #define KSTAT_INTR_HARD 0 #define KSTAT_INTR_SOFT 1 #define KSTAT_INTR_WATCHDOG 2 #define KSTAT_INTR_SPURIOUS 3 #define KSTAT_INTR_MULTSVC 4 #define KSTAT_NUM_INTRS 5 typedef struct kstat_intr { uint_t intrs[KSTAT_NUM_INTRS]; /* interrupt counters */ } kstat_intr_t; #define KSTAT_INTR_PTR(kptr) ((kstat_intr_t *)(kptr)->ks_data) /* * I/O statistics. */ typedef struct kstat_io { /* * Basic counters. * * The counters should be updated at the end of service * (e.g., just prior to calling biodone()). */ u_longlong_t nread; /* number of bytes read */ u_longlong_t nwritten; /* number of bytes written */ uint_t reads; /* number of read operations */ uint_t writes; /* number of write operations */ /* * Accumulated time and queue length statistics. * * Accumulated time statistics are kept as a running sum * of "active" time. Queue length statistics are kept as a * running sum of the product of queue length and elapsed time * at that length -- i.e., a Riemann sum for queue length * integrated against time. (You can also think of the active time * as a Riemann sum, for the boolean function (queue_length > 0) * integrated against time, or you can think of it as the * Lebesgue measure of the set on which queue_length > 0.) * * ^ * | _________ * 8 | i4 | * | | | * Queue 6 | | * Length | _________ | | * 4 | i2 |_______| | * | | i3 | * 2_______| | * | i1 | * |_______________________________| * Time-> t1 t2 t3 t4 * * At each change of state (entry or exit from the queue), * we add the elapsed time (since the previous state change) * to the active time if the queue length was non-zero during * that interval; and we add the product of the elapsed time * times the queue length to the running length*time sum. * * This method is generalizable to measuring residency * in any defined system: instead of queue lengths, think * of "outstanding RPC calls to server X". * * A large number of I/O subsystems have at least two basic * "lists" of transactions they manage: one for transactions * that have been accepted for processing but for which processing * has yet to begin, and one for transactions which are actively * being processed (but not done). For this reason, two cumulative * time statistics are defined here: wait (pre-service) time, * and run (service) time. * * All times are 64-bit nanoseconds (hrtime_t), as returned by * gethrtime(). * * The units of cumulative busy time are accumulated nanoseconds. * The units of cumulative length*time products are elapsed time * times queue length. * * Updates to the fields below are performed implicitly by calls to * these five functions: * * kstat_waitq_enter() * kstat_waitq_exit() * kstat_runq_enter() * kstat_runq_exit() * * kstat_waitq_to_runq() (see below) * kstat_runq_back_to_waitq() (see below) * * Since kstat_waitq_exit() is typically followed immediately * by kstat_runq_enter(), there is a single kstat_waitq_to_runq() * function which performs both operations. This is a performance * win since only one timestamp is required. * * In some instances, it may be necessary to move a request from * the run queue back to the wait queue, e.g. for write throttling. * For these situations, call kstat_runq_back_to_waitq(). * * These fields should never be updated by any other means. */ hrtime_t wtime; /* cumulative wait (pre-service) time */ hrtime_t wlentime; /* cumulative wait length*time product */ hrtime_t wlastupdate; /* last time wait queue changed */ hrtime_t rtime; /* cumulative run (service) time */ hrtime_t rlentime; /* cumulative run length*time product */ hrtime_t rlastupdate; /* last time run queue changed */ uint_t wcnt; /* count of elements in wait state */ uint_t rcnt; /* count of elements in run state */ } kstat_io_t; #define KSTAT_IO_PTR(kptr) ((kstat_io_t *)(kptr)->ks_data) /* * Event timer statistics - cumulative elapsed time and number of events. * * Updates to these fields are performed implicitly by calls to * kstat_timer_start() and kstat_timer_stop(). */ typedef struct kstat_timer { char name[KSTAT_STRLEN]; /* event name */ uchar_t resv; /* reserved */ u_longlong_t num_events; /* number of events */ hrtime_t elapsed_time; /* cumulative elapsed time */ hrtime_t min_time; /* shortest event duration */ hrtime_t max_time; /* longest event duration */ hrtime_t start_time; /* previous event start time */ hrtime_t stop_time; /* previous event stop time */ } kstat_timer_t; #define KSTAT_TIMER_PTR(kptr) ((kstat_timer_t *)(kptr)->ks_data) #if defined(_KERNEL) || defined(_FAKE_KERNEL) #include <sys/t_lock.h> extern kid_t kstat_chain_id; /* bumped at each state change */ extern void kstat_init(void); /* initialize kstat framework */ /* * Adding and deleting kstats. * * The typical sequence to add a kstat is: * * ksp = kstat_create(module, instance, name, class, type, ndata, flags); * if (ksp) { * ... provider initialization, if necessary * kstat_install(ksp); * } * * There are three logically distinct steps here: * * Step 1: System Initialization (kstat_create) * * kstat_create() performs system initialization. kstat_create() * allocates memory for the entire kstat (header plus data), initializes * all header fields, initializes the data section to all zeroes, assigns * a unique KID, and puts the kstat onto the system's kstat chain. * The returned kstat is marked invalid (KSTAT_FLAG_INVALID is set), * because the provider (caller) has not yet had a chance to initialize * the data section. * * By default, kstats are exported to all zones on the system. A kstat may be * created via kstat_create_zone() to specify a zone to which the statistics * should be exported. kstat_zone_add() may be used to specify additional * zones to which the statistics are to be exported. * * Step 2: Provider Initialization * * The provider performs any necessary initialization of the data section, * e.g. setting the name fields in a KSTAT_TYPE_NAMED. Virtual kstats set * the ks_data field at this time. The provider may also set the ks_update, * ks_snapshot, ks_private, and ks_lock fields if necessary. * * Step 3: Installation (kstat_install) * * Once the kstat is completely initialized, kstat_install() clears the * INVALID flag, thus making the kstat accessible to the outside world. * kstat_install() also clears the DORMANT flag for persistent kstats. * * Removing a kstat from the system * * kstat_delete(ksp) removes ksp from the kstat chain and frees all * associated system resources. NOTE: When you call kstat_delete(), * you must NOT be holding that kstat's ks_lock. Otherwise, you may * deadlock with a kstat reader. * * Persistent kstats * * From the provider's point of view, persistence is transparent. The only * difference between ephemeral (normal) kstats and persistent kstats * is that you pass KSTAT_FLAG_PERSISTENT to kstat_create(). Magically, * this has the effect of making your data visible even when you're * not home. Persistence is important to tools like iostat, which want * to get a meaningful picture of disk activity. Without persistence, * raw disk i/o statistics could never accumulate: they would come and * go with each open/close of the raw device. * * The magic of persistence works by slightly altering the behavior of * kstat_create() and kstat_delete(). The first call to kstat_create() * creates a new kstat, as usual. However, kstat_delete() does not * actually delete the kstat: it performs one final update of the data * (i.e., calls the ks_update routine), marks the kstat as dormant, and * sets the ks_lock, ks_update, ks_private, and ks_snapshot fields back * to their default values (since they might otherwise point to garbage, * e.g. if the provider is going away). kstat clients can still access * the dormant kstat just like a live kstat; they just continue to see * the final data values as long as the kstat remains dormant. * All subsequent kstat_create() calls simply find the already-existing, * dormant kstat and return a pointer to it, without altering any fields. * The provider then performs its usual initialization sequence, and * calls kstat_install(). kstat_install() uses the old data values to * initialize the native data (i.e., ks_update is called with KSTAT_WRITE), * thus making it seem like you were never gone. */ extern kstat_t *kstat_create(const char *, int, const char *, const char *, uchar_t, uint_t, uchar_t); extern kstat_t *kstat_create_zone(const char *, int, const char *, const char *, uchar_t, uint_t, uchar_t, zoneid_t); extern void kstat_install(kstat_t *); extern void kstat_delete(kstat_t *); extern void kstat_named_setstr(kstat_named_t *knp, const char *src); extern void kstat_set_string(char *, const char *); extern void kstat_delete_byname(const char *, int, const char *); extern void kstat_delete_byname_zone(const char *, int, const char *, zoneid_t); extern void kstat_named_init(kstat_named_t *, const char *, uchar_t); extern void kstat_timer_init(kstat_timer_t *, const char *); extern void kstat_waitq_enter(kstat_io_t *); extern void kstat_waitq_exit(kstat_io_t *); extern void kstat_runq_enter(kstat_io_t *); extern void kstat_runq_exit(kstat_io_t *); extern void kstat_waitq_to_runq(kstat_io_t *); extern void kstat_runq_back_to_waitq(kstat_io_t *); extern void kstat_timer_start(kstat_timer_t *); extern void kstat_timer_stop(kstat_timer_t *); extern void kstat_zone_add(kstat_t *, zoneid_t); extern void kstat_zone_remove(kstat_t *, zoneid_t); extern int kstat_zone_find(kstat_t *, zoneid_t); extern kstat_t *kstat_hold_bykid(kid_t kid, zoneid_t); extern kstat_t *kstat_hold_byname(const char *, int, const char *, zoneid_t); extern void kstat_rele(kstat_t *); #endif /* defined(_KERNEL) */ #ifdef __cplusplus } #endif #endif /* _SYS_KSTAT_H */
