lower extremities.
Setting bit 4 in debugflags (sysctl kern.geom.debugflags=16) will
allow any open to succeed on rank#1 providers. This will generally
correspond to the physical disk devices: ad0, da0, md0 etc.
This fundamentally violates the mechanics of GEOMs autoconfiguration,
and is only provided as a debugging facility, so obviously error
reports on GEOM where this bit is or has been set will not be
accepted.
disk I/O processing.
The intent is that the disk driver in its hardware interrupt
routine will simply schedule the bio on the task queue with
a routine to finish off whatever needs done.
The g_up thread will then schedule this routine, the likely
outcome of which is a biodone() which queues the bio on
g_up's regular queue where it will be picked up and processed.
Compared to the using the regular taskqueue, this saves one
contextswitch.
Change our scheduling of the g_up and g_down queues to be water-tight,
at the cost of breaking the userland regression test-shims.
Input and ideas from: scottl
Cut up requests into smaller bits if they are longer than the drivers
disk->d_maxsize or dev->si_iosize_max.
Properly handle the race condition when using g_clone_bio() is used
without having the single-threadedness of g_down/g_up secure locking.
and d_stripesisze;
Introduce si_stripesize and si_stripeoffset in struct cdev so we
can make the visible to clustering code.
Add stripesize and stripeoffset to providers.
DTRT with stripesize and stripeoffset in various places in GEOM.
idle time.
Statistics now default to "on" and can be turned off with
sysctl kern.geom.collectstats=0
Performance impact of statistics collection is on the order of
800 nsec per consumer/provider set on a 700MHz Athlon.
Insted of embedding a struct g_stat in consumers and providers, merely
include a pointer.
Remove a couple of <sys/time.h> includes now unneeded.
Add a special allocator for struct g_stat. This allocator will allocate
entire pages and hand out g_stat functions from there. The "id" field
indicates free/used status.
Add "/dev/geom.stats" device driver whic exports the pages from the
allocator to userland with mmap(2) in read-only mode.
This mmap(2) interface should be considered a non-public interface and
the functions in libgeom (not yet committed) should be used to access
the statistics data.
Add debug.sizeof.g_stat sysctl.
Set the id field of the g_stat when we create consumers and providers.
Remove biocount from consumer, we will use the counters in the g_stat
structure instead. Replace one field which will need to be atomically
manipulated with two fields which will not (stat.nop and stat.nend).
Change add companion field to bio_children: bio_inbed for the exact
same reason.
Don't output the biocount in the confdot output.
Fix KASSERT in g_io_request().
Add sysctl kern.geom.collectstats defaulting to off.
Collect the following raw statistics conditioned on this sysctl:
for each consumer and provider {
total number of operations started.
total number of operations completed.
time last operation completed.
sum of idle-time.
for each of BIO_READ, BIO_WRITE and BIO_DELETE {
number of operations completed.
number of bytes completed.
number of ENOMEM errors.
number of other errors.
sum of transaction time.
}
}
API for getting hold of these statistics data not included yet.
We may actually be increasing Giant contention doing so because the
actual stuff we do is very cheap.
Also I am not convinced there is not a tiny window for a race here.
Change the si_name of dev_t's to be a char * and put a private buffer for
holding the name at then end of the struct.
Initialize si_name to point to the private buffer.
Put a KASSERT in geom_disk to prevent overrun on the fake dev_t we still
have to generate for the disk_drivers.
this will cause volume labels to be exposed in /dev/vol/<volname>. Currently,
there is no conflict resolution if more than one FS has the same volume name.
Reviewed by: phk
Make passing the methods in a cdevsw structure optional.
Move "CANFREE" and "NOGIANT" flags into struct disk instead of the
cdevsw which may or may not be there.
Rename CANFREE to CANDELETE to match BIO_DELETE operation.
Add "OPEN" flag so drivers don't have to provide open/close methods
just to maintain such a flag.
Add temporary stopgap include of <sys/conf.h> to <sys/disk.h> until
the files which have them in the other order are fixed.
Add KASSERTS to make sure we don't get fed too many NULL pointers.
Clear our geom's softc pointer before we wither.
