This is supposed to be a brief overview of the locking primatives.
It is not yet complete and contains many place-holders for information
I do not know.
The locking is getting so diverse that I've lost track of it all.
We need this page to keep outselves in sync with what the primitives do.
note.. not part of the build yet.
the background fsck indefinitely. This allows the administrator to run
it at a convenient time. To support running it from cron, the
forcestart argument now causes the fsck to start with no delay and all
output to be suppressed.
event. Locking primitives that support this (mtx, rw, and sx) now each
include their own foo_sleep() routine.
- Rename msleep() to _sleep() and change it's 'struct mtx' object to a
'struct lock_object' pointer. _sleep() uses the recently added
lc_unlock() and lc_lock() function pointers for the lock class of the
specified lock to release the lock while the thread is suspended.
- Add wrappers around _sleep() for mutexes (mtx_sleep()), rw locks
(rw_sleep()), and sx locks (sx_sleep()). msleep() still exists and
is now identical to mtx_sleep(), but it is deprecated.
- Rename SLEEPQ_MSLEEP to SLEEPQ_SLEEP.
- Rewrite much of sleep.9 to not be msleep(9) centric.
- Flesh out the 'RETURN VALUES' section in sleep.9 and add an 'ERRORS'
section.
- Add __nonnull(1) to _sleep() and msleep_spin() so that the compiler will
warn if you try to pass a NULL wait channel. The functions already have
a KASSERT to that effect.
interrupt sleeps. Rather, unmasked signals interrupt restarts and can
either interrupt the system call by having it return EINTR in userland or
force the system call to be restarted.
- Don't claim that the mutex is atomically reacquired when a cv_wait
routine returns. There's nothing atomic or magical about the lock
reacquire. The only magic is that we atomically drop the lock by
placing the thread on the sleep queue before dropping the lock.
- Markup sx_unlock() as a function rather than saying it is a macro.
The macro part is an implementation detail, and all the other sx_*lock()
functions are actually macros, too.
- Use the same style as rwlock(9) and mutex(9) to markup sx_assert() and
SX_SYSINIT() with respect to headers and kernel options.
- Add a missing MLINK.
for /tmp and /var. This makes the memory discs swap-backed instead
of malloc-backed. A swap-backed memory disc should not be worse
than a malloc-backed one in any scenario because it will start
touching swap only when needed. OTOH, a malloc-backed disc can
starve limited kernel resources and evenually crash the system.
Reflect the change in the rc.conf(5) manpage. Also stop telling
lies there about softupdates: it does not waste disc space, it
just can delay its freeing.
Suggested by: many
PR: kern/87255
MFC after: 1 week
<sys/extattr.h> to <ufs/ufs/extattr.h>. Move description
of extended attributes in UFS from man9/extattr.9 to
man5/fs.5.
Note that restore will not compile until <sys/extattr.h>
and <ufs/ufs/extattr.h> have been updated.
Suggested by: Robert Watson
While here, remove Xrefs to all other wlan drivers except the Intel ones,
these often get confused. Also remove pointers to the old ipw and iwi webpages,
they don't include any useful information that's not in the manpages yet.
Reviewed by: flz, ru
o uniform the driver_intr_t parameter name to 'ithread'
o delete any reference to INTR_FAST
o document a bit the difference between the filter and ithread
argument
Reviewed by: mdoc-police (ru)
- the issues with wakeup_one are due to address space clashes between
unrelated groups of threads.
- sleep() was removed in FreeBSD 2.2.
- date the page today, not 4 days ago.
- replace grammatically correct "woken" with "woken up" for
consistency with the function name.
- BIOCGDIRECTION and BIOCSDIRECTION get or set the setting determining
whether incoming, outgoing, or all packets on the interface should be
returned by BPF. Set to BPF_D_IN to see only incoming packets on the
interface. Set to BPF_D_INOUT to see packets originating locally and
remotely on the interface. Set to BPF_D_OUT to see only outgoing
packets on the interface. This setting is initialized to BPF_D_INOUT
by default. BIOCGSEESENT and BIOCSSEESENT are obsoleted by these but
kept for backward compatibility.
- BIOCFEEDBACK sets packet feedback mode. This allows injected packets
to be fed back as input to the interface when output via the interface is
successful. When BPF_D_INOUT direction is set, injected outgoing packet
is not returned by BPF to avoid duplication. This flag is initialized to
zero by default.
Note that libpcap has been modified to support BPF_D_OUT direction for
pcap_setdirection(3) and PCAP_D_OUT direction is functional now.
Reviewed by: rwatson
