diff options
Diffstat (limited to 'sys/kern/subr_devstat.c')
| -rw-r--r-- | sys/kern/subr_devstat.c | 604 |
1 files changed, 604 insertions, 0 deletions
diff --git a/sys/kern/subr_devstat.c b/sys/kern/subr_devstat.c new file mode 100644 index 0000000..c44ef27 --- /dev/null +++ b/sys/kern/subr_devstat.c @@ -0,0 +1,604 @@ +/*- + * Copyright (c) 1997, 1998, 1999 Kenneth D. Merry. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "opt_kdtrace.h" + +#include <sys/param.h> +#include <sys/kernel.h> +#include <sys/systm.h> +#include <sys/bio.h> +#include <sys/devicestat.h> +#include <sys/sysctl.h> +#include <sys/malloc.h> +#include <sys/lock.h> +#include <sys/mutex.h> +#include <sys/conf.h> +#include <vm/vm.h> +#include <vm/pmap.h> + +#include <machine/atomic.h> + +#ifdef KDTRACE_HOOKS +#include <sys/dtrace_bsd.h> + +dtrace_io_start_probe_func_t dtrace_io_start_probe; +dtrace_io_done_probe_func_t dtrace_io_done_probe; +dtrace_io_wait_start_probe_func_t dtrace_io_wait_start_probe; +dtrace_io_wait_done_probe_func_t dtrace_io_wait_done_probe; + +uint32_t dtio_start_id; +uint32_t dtio_done_id; +uint32_t dtio_wait_start_id; +uint32_t dtio_wait_done_id; + +#define DTRACE_DEVSTAT_START() \ + if (dtrace_io_start_probe != NULL) \ + (*dtrace_io_start_probe)(dtio_start_id, NULL, ds); + +#define DTRACE_DEVSTAT_BIO_START() \ + if (dtrace_io_start_probe != NULL) \ + (*dtrace_io_start_probe)(dtio_start_id, bp, ds); + +#define DTRACE_DEVSTAT_DONE() \ + if (dtrace_io_done_probe != NULL) \ + (*dtrace_io_done_probe)(dtio_done_id, NULL, ds); + +#define DTRACE_DEVSTAT_BIO_DONE() \ + if (dtrace_io_done_probe != NULL) \ + (*dtrace_io_done_probe)(dtio_done_id, bp, ds); + +#define DTRACE_DEVSTAT_WAIT_START() \ + if (dtrace_io_wait_start_probe != NULL) \ + (*dtrace_io_wait_start_probe)(dtio_wait_start_id, NULL, ds); + +#define DTRACE_DEVSTAT_WAIT_DONE() \ + if (dtrace_io_wait_done_probe != NULL) \ + (*dtrace_io_wait_done_probe)(dtio_wait_done_id, NULL, ds); + +#else /* ! KDTRACE_HOOKS */ + +#define DTRACE_DEVSTAT_START() + +#define DTRACE_DEVSTAT_BIO_START() + +#define DTRACE_DEVSTAT_DONE() + +#define DTRACE_DEVSTAT_BIO_DONE() + +#define DTRACE_DEVSTAT_WAIT_START() + +#define DTRACE_DEVSTAT_WAIT_DONE() +#endif /* KDTRACE_HOOKS */ + +static int devstat_num_devs; +static long devstat_generation = 1; +static int devstat_version = DEVSTAT_VERSION; +static int devstat_current_devnumber; +static struct mtx devstat_mutex; +MTX_SYSINIT(devstat_mutex, &devstat_mutex, "devstat", MTX_DEF); + +static struct devstatlist device_statq = STAILQ_HEAD_INITIALIZER(device_statq); +static struct devstat *devstat_alloc(void); +static void devstat_free(struct devstat *); +static void devstat_add_entry(struct devstat *ds, const void *dev_name, + int unit_number, uint32_t block_size, + devstat_support_flags flags, + devstat_type_flags device_type, + devstat_priority priority); + +/* + * Allocate a devstat and initialize it + */ +struct devstat * +devstat_new_entry(const void *dev_name, + int unit_number, uint32_t block_size, + devstat_support_flags flags, + devstat_type_flags device_type, + devstat_priority priority) +{ + struct devstat *ds; + + mtx_assert(&devstat_mutex, MA_NOTOWNED); + + ds = devstat_alloc(); + mtx_lock(&devstat_mutex); + if (unit_number == -1) { + ds->id = dev_name; + binuptime(&ds->creation_time); + devstat_generation++; + } else { + devstat_add_entry(ds, dev_name, unit_number, block_size, + flags, device_type, priority); + } + mtx_unlock(&devstat_mutex); + return (ds); +} + +/* + * Take a malloced and zeroed devstat structure given to us, fill it in + * and add it to the queue of devices. + */ +static void +devstat_add_entry(struct devstat *ds, const void *dev_name, + int unit_number, uint32_t block_size, + devstat_support_flags flags, + devstat_type_flags device_type, + devstat_priority priority) +{ + struct devstatlist *devstat_head; + struct devstat *ds_tmp; + + mtx_assert(&devstat_mutex, MA_OWNED); + devstat_num_devs++; + + devstat_head = &device_statq; + + /* + * Priority sort. Each driver passes in its priority when it adds + * its devstat entry. Drivers are sorted first by priority, and + * then by probe order. + * + * For the first device, we just insert it, since the priority + * doesn't really matter yet. Subsequent devices are inserted into + * the list using the order outlined above. + */ + if (devstat_num_devs == 1) + STAILQ_INSERT_TAIL(devstat_head, ds, dev_links); + else { + STAILQ_FOREACH(ds_tmp, devstat_head, dev_links) { + struct devstat *ds_next; + + ds_next = STAILQ_NEXT(ds_tmp, dev_links); + + /* + * If we find a break between higher and lower + * priority items, and if this item fits in the + * break, insert it. This also applies if the + * "lower priority item" is the end of the list. + */ + if ((priority <= ds_tmp->priority) + && ((ds_next == NULL) + || (priority > ds_next->priority))) { + STAILQ_INSERT_AFTER(devstat_head, ds_tmp, ds, + dev_links); + break; + } else if (priority > ds_tmp->priority) { + /* + * If this is the case, we should be able + * to insert ourselves at the head of the + * list. If we can't, something is wrong. + */ + if (ds_tmp == STAILQ_FIRST(devstat_head)) { + STAILQ_INSERT_HEAD(devstat_head, + ds, dev_links); + break; + } else { + STAILQ_INSERT_TAIL(devstat_head, + ds, dev_links); + printf("devstat_add_entry: HELP! " + "sorting problem detected " + "for name %p unit %d\n", + dev_name, unit_number); + break; + } + } + } + } + + ds->device_number = devstat_current_devnumber++; + ds->unit_number = unit_number; + strlcpy(ds->device_name, dev_name, DEVSTAT_NAME_LEN); + ds->block_size = block_size; + ds->flags = flags; + ds->device_type = device_type; + ds->priority = priority; + binuptime(&ds->creation_time); + devstat_generation++; +} + +/* + * Remove a devstat structure from the list of devices. + */ +void +devstat_remove_entry(struct devstat *ds) +{ + struct devstatlist *devstat_head; + + mtx_assert(&devstat_mutex, MA_NOTOWNED); + if (ds == NULL) + return; + + mtx_lock(&devstat_mutex); + + devstat_head = &device_statq; + + /* Remove this entry from the devstat queue */ + atomic_add_acq_int(&ds->sequence1, 1); + if (ds->id == NULL) { + devstat_num_devs--; + STAILQ_REMOVE(devstat_head, ds, devstat, dev_links); + } + devstat_free(ds); + devstat_generation++; + mtx_unlock(&devstat_mutex); +} + +/* + * Record a transaction start. + * + * See comments for devstat_end_transaction(). Ordering is very important + * here. + */ +void +devstat_start_transaction(struct devstat *ds, struct bintime *now) +{ + + mtx_assert(&devstat_mutex, MA_NOTOWNED); + + /* sanity check */ + if (ds == NULL) + return; + + atomic_add_acq_int(&ds->sequence1, 1); + /* + * We only want to set the start time when we are going from idle + * to busy. The start time is really the start of the latest busy + * period. + */ + if (ds->start_count == ds->end_count) { + if (now != NULL) + ds->busy_from = *now; + else + binuptime(&ds->busy_from); + } + ds->start_count++; + atomic_add_rel_int(&ds->sequence0, 1); + DTRACE_DEVSTAT_START(); +} + +void +devstat_start_transaction_bio(struct devstat *ds, struct bio *bp) +{ + + mtx_assert(&devstat_mutex, MA_NOTOWNED); + + /* sanity check */ + if (ds == NULL) + return; + + binuptime(&bp->bio_t0); + devstat_start_transaction(ds, &bp->bio_t0); + DTRACE_DEVSTAT_BIO_START(); +} + +/* + * Record the ending of a transaction, and incrment the various counters. + * + * Ordering in this function, and in devstat_start_transaction() is VERY + * important. The idea here is to run without locks, so we are very + * careful to only modify some fields on the way "down" (i.e. at + * transaction start) and some fields on the way "up" (i.e. at transaction + * completion). One exception is busy_from, which we only modify in + * devstat_start_transaction() when there are no outstanding transactions, + * and thus it can't be modified in devstat_end_transaction() + * simultaneously. + * + * The sequence0 and sequence1 fields are provided to enable an application + * spying on the structures with mmap(2) to tell when a structure is in a + * consistent state or not. + * + * For this to work 100% reliably, it is important that the two fields + * are at opposite ends of the structure and that they are incremented + * in the opposite order of how a memcpy(3) in userland would copy them. + * We assume that the copying happens front to back, but there is actually + * no way short of writing your own memcpy(3) replacement to guarantee + * this will be the case. + * + * In addition to this, being a kind of locks, they must be updated with + * atomic instructions using appropriate memory barriers. + */ +void +devstat_end_transaction(struct devstat *ds, uint32_t bytes, + devstat_tag_type tag_type, devstat_trans_flags flags, + struct bintime *now, struct bintime *then) +{ + struct bintime dt, lnow; + + /* sanity check */ + if (ds == NULL) + return; + + if (now == NULL) { + now = &lnow; + binuptime(now); + } + + atomic_add_acq_int(&ds->sequence1, 1); + /* Update byte and operations counts */ + ds->bytes[flags] += bytes; + ds->operations[flags]++; + + /* + * Keep a count of the various tag types sent. + */ + if ((ds->flags & DEVSTAT_NO_ORDERED_TAGS) == 0 && + tag_type != DEVSTAT_TAG_NONE) + ds->tag_types[tag_type]++; + + if (then != NULL) { + /* Update duration of operations */ + dt = *now; + bintime_sub(&dt, then); + bintime_add(&ds->duration[flags], &dt); + } + + /* Accumulate busy time */ + dt = *now; + bintime_sub(&dt, &ds->busy_from); + bintime_add(&ds->busy_time, &dt); + ds->busy_from = *now; + + ds->end_count++; + atomic_add_rel_int(&ds->sequence0, 1); + DTRACE_DEVSTAT_DONE(); +} + +void +devstat_end_transaction_bio(struct devstat *ds, struct bio *bp) +{ + devstat_trans_flags flg; + + /* sanity check */ + if (ds == NULL) + return; + + if (bp->bio_cmd == BIO_DELETE) + flg = DEVSTAT_FREE; + else if (bp->bio_cmd == BIO_READ) + flg = DEVSTAT_READ; + else if (bp->bio_cmd == BIO_WRITE) + flg = DEVSTAT_WRITE; + else + flg = DEVSTAT_NO_DATA; + + devstat_end_transaction(ds, bp->bio_bcount - bp->bio_resid, + DEVSTAT_TAG_SIMPLE, flg, NULL, &bp->bio_t0); + DTRACE_DEVSTAT_BIO_DONE(); +} + +/* + * This is the sysctl handler for the devstat package. The data pushed out + * on the kern.devstat.all sysctl variable consists of the current devstat + * generation number, and then an array of devstat structures, one for each + * device in the system. + * + * This is more cryptic that obvious, but basically we neither can nor + * want to hold the devstat_mutex for any amount of time, so we grab it + * only when we need to and keep an eye on devstat_generation all the time. + */ +static int +sysctl_devstat(SYSCTL_HANDLER_ARGS) +{ + int error; + long mygen; + struct devstat *nds; + + mtx_assert(&devstat_mutex, MA_NOTOWNED); + + /* + * XXX devstat_generation should really be "volatile" but that + * XXX freaks out the sysctl macro below. The places where we + * XXX change it and inspect it are bracketed in the mutex which + * XXX guarantees us proper write barriers. I don't belive the + * XXX compiler is allowed to optimize mygen away across calls + * XXX to other functions, so the following is belived to be safe. + */ + mygen = devstat_generation; + + error = SYSCTL_OUT(req, &mygen, sizeof(mygen)); + + if (devstat_num_devs == 0) + return(0); + + if (error != 0) + return (error); + + mtx_lock(&devstat_mutex); + nds = STAILQ_FIRST(&device_statq); + if (mygen != devstat_generation) + error = EBUSY; + mtx_unlock(&devstat_mutex); + + if (error != 0) + return (error); + + for (;nds != NULL;) { + error = SYSCTL_OUT(req, nds, sizeof(struct devstat)); + if (error != 0) + return (error); + mtx_lock(&devstat_mutex); + if (mygen != devstat_generation) + error = EBUSY; + else + nds = STAILQ_NEXT(nds, dev_links); + mtx_unlock(&devstat_mutex); + if (error != 0) + return (error); + } + return(error); +} + +/* + * Sysctl entries for devstat. The first one is a node that all the rest + * hang off of. + */ +static SYSCTL_NODE(_kern, OID_AUTO, devstat, CTLFLAG_RD, NULL, + "Device Statistics"); + +SYSCTL_PROC(_kern_devstat, OID_AUTO, all, CTLFLAG_RD|CTLTYPE_OPAQUE, + NULL, 0, sysctl_devstat, "S,devstat", "All devices in the devstat list"); +/* + * Export the number of devices in the system so that userland utilities + * can determine how much memory to allocate to hold all the devices. + */ +SYSCTL_INT(_kern_devstat, OID_AUTO, numdevs, CTLFLAG_RD, + &devstat_num_devs, 0, "Number of devices in the devstat list"); +SYSCTL_LONG(_kern_devstat, OID_AUTO, generation, CTLFLAG_RD, + &devstat_generation, 0, "Devstat list generation"); +SYSCTL_INT(_kern_devstat, OID_AUTO, version, CTLFLAG_RD, + &devstat_version, 0, "Devstat list version number"); + +/* + * Allocator for struct devstat structures. We sub-allocate these from pages + * which we get from malloc. These pages are exported for mmap(2)'ing through + * a miniature device driver + */ + +#define statsperpage (PAGE_SIZE / sizeof(struct devstat)) + +static d_mmap_t devstat_mmap; + +static struct cdevsw devstat_cdevsw = { + .d_version = D_VERSION, + .d_flags = D_NEEDGIANT, + .d_mmap = devstat_mmap, + .d_name = "devstat", +}; + +struct statspage { + TAILQ_ENTRY(statspage) list; + struct devstat *stat; + u_int nfree; +}; + +static TAILQ_HEAD(, statspage) pagelist = TAILQ_HEAD_INITIALIZER(pagelist); +static MALLOC_DEFINE(M_DEVSTAT, "devstat", "Device statistics"); + +static int +devstat_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr, + int nprot, vm_memattr_t *memattr) +{ + struct statspage *spp; + + if (nprot != VM_PROT_READ) + return (-1); + TAILQ_FOREACH(spp, &pagelist, list) { + if (offset == 0) { + *paddr = vtophys(spp->stat); + return (0); + } + offset -= PAGE_SIZE; + } + return (-1); +} + +static struct devstat * +devstat_alloc(void) +{ + struct devstat *dsp; + struct statspage *spp, *spp2; + u_int u; + static int once; + + mtx_assert(&devstat_mutex, MA_NOTOWNED); + if (!once) { + make_dev_credf(MAKEDEV_ETERNAL | MAKEDEV_CHECKNAME, + &devstat_cdevsw, 0, NULL, UID_ROOT, GID_WHEEL, 0400, + DEVSTAT_DEVICE_NAME); + once = 1; + } + spp2 = NULL; + mtx_lock(&devstat_mutex); + for (;;) { + TAILQ_FOREACH(spp, &pagelist, list) { + if (spp->nfree > 0) + break; + } + if (spp != NULL) + break; + mtx_unlock(&devstat_mutex); + spp2 = malloc(sizeof *spp, M_DEVSTAT, M_ZERO | M_WAITOK); + spp2->stat = malloc(PAGE_SIZE, M_DEVSTAT, M_ZERO | M_WAITOK); + spp2->nfree = statsperpage; + + /* + * If free statspages were added while the lock was released + * just reuse them. + */ + mtx_lock(&devstat_mutex); + TAILQ_FOREACH(spp, &pagelist, list) + if (spp->nfree > 0) + break; + if (spp == NULL) { + spp = spp2; + + /* + * It would make more sense to add the new page at the + * head but the order on the list determine the + * sequence of the mapping so we can't do that. + */ + TAILQ_INSERT_TAIL(&pagelist, spp, list); + } else + break; + } + dsp = spp->stat; + for (u = 0; u < statsperpage; u++) { + if (dsp->allocated == 0) + break; + dsp++; + } + spp->nfree--; + dsp->allocated = 1; + mtx_unlock(&devstat_mutex); + if (spp2 != NULL && spp2 != spp) { + free(spp2->stat, M_DEVSTAT); + free(spp2, M_DEVSTAT); + } + return (dsp); +} + +static void +devstat_free(struct devstat *dsp) +{ + struct statspage *spp; + + mtx_assert(&devstat_mutex, MA_OWNED); + bzero(dsp, sizeof *dsp); + TAILQ_FOREACH(spp, &pagelist, list) { + if (dsp >= spp->stat && dsp < (spp->stat + statsperpage)) { + spp->nfree++; + return; + } + } +} + +SYSCTL_INT(_debug_sizeof, OID_AUTO, devstat, CTLFLAG_RD, + NULL, sizeof(struct devstat), "sizeof(struct devstat)"); |
