lockmgr lkp, when held in exclusive mode, is recursed
- Introduce the function BUF_RECURSED() which does the same for bufobj
locks based on the top of lockmgr_recursed()
- Introduce the function BUF_ISLOCKED() which works like the counterpart
VOP_ISLOCKED(9), showing the state of lockmgr linked with the bufobj
BUF_RECURSED() and BUF_ISLOCKED() entirely replace the usage of bogus
BUF_REFCNT() in a more explicative and SMP-compliant way.
This allows us to axe out BUF_REFCNT() and leaving the function
lockcount() totally unused in our stock kernel. Further commits will
axe lockcount() as well as part of lockmgr() cleanup.
KPI results, obviously, broken so further commits will update manpages
and freebsd version.
Tested by: kris (on UFS and NFS)
unp_connect(): it is expected to return with the lock held, and two
possible error paths otherwise returned with it unlocked.
The fix committed here is slightly different from the patch in the
PR, but along an alternative line suggested in the PR.
PR: 119778
MFC after: 3 days
Submitted by: James Juran <james dot juran at baesystems dot com>
was missed. As result, pty_create_slave() may index out of the names[]
bounds, creating wrong slave tty names.
Tested by: kensmith
Reviewed by: jhb
MFC after: 3 days
other. The first one survives, the rest are removed. So far, it appears
only some acpi_perf(4) BIOS tables have these invalid states, but address
this in the core to be sure to handle other potential driver data.
PR: kern/114722
Tested by: stefan.lambrev / moneybookers.com
MFC after: 3 days
lowest priority on the queue for the current cpu vs curthread's
priority. In the case that curthread is waking up many threads of a
lower priority as would happen with a turnstile_broadcast() or wakeup()
of many threads this prevents them from all ending up on the current cpu.
- In sched_add() make the relationship between a scheduled ithread and
the current cpu advisory rather than strict. Only give the ithread
affinity for the current cpu if it's actually being scheduled from
a hardware interrupt. This prevents it from migrating when it simply
blocks on a lock.
Sponsored by: Nokia
conjuction with 'thread' argument passing which is always curthread.
Remove the unuseful extra-argument and pass explicitly curthread to lower
layer functions, when necessary.
KPI results broken by this change, which should affect several ports, so
version bumping and manpage update will be further committed.
Tested by: kris, pho, Diego Sardina <siarodx at gmail dot com>
panic but it won't actually lock anything.
This can lead some paths to reach lockmgr_disown() with inconsistent
lock which will let trigger the relative assertions.
Fix those in order to recognize panic situation and to not trigger.
Reported by: pho
Submitted by: kib
maintain a separate td_incruntime to hold unbilled CPU usage for
the thread that has the previous properties of td_runtime.
When thread information is requested using the thread monitoring
sysctls, export thread td_runtime instead of process rusage runtime
in kinfo_proc.
This restores the display of individual ithread and other kernel
thread CPU usage since inception in ps -H and top -SH, as well for
libthr user threads, valuable debugging information lost with the
move to try kthreads since they are no longer independent processes.
There is universal agreement that we should rewrite the process and
thread export sysctls, but this commit gets things going a bit
better in the mean time. Likewise, there are resevations about the
continued validity of statclock given the speed of modern processors.
Reviewed by: attilio, emaste, jhb, julian
Remove this argument and pass curthread directly to underlying
VOP_LOCK1() VFS method. This modify makes the code cleaner and in
particular remove an annoying dependence helping next lockmgr() cleanup.
KPI results, obviously, changed.
Manpage and FreeBSD_version will be updated through further commits.
As a side note, would be valuable to say that next commits will address
a similar cleanup about VFS methods, in particular vop_lock1 and
vop_unlock.
Tested by: Diego Sardina <siarodx at gmail dot com>,
Andrea Di Pasquale <whyx dot it at gmail dot com>
Now, lockmgr() function can only be called passing curthread and the
KASSERT() is upgraded according with this.
In order to support on-the-fly owner switching, the new function
lockmgr_disown() has been introduced and gets used in BUF_KERNPROC().
KPI, so, results changed and FreeBSD version will be bumped soon.
Differently from previous code, we assume idle thread cannot try to
acquire the lockmgr as it cannot sleep, so loose the relative check[1]
in BUF_KERNPROC().
Tested by: kris
[1] kib asked for a KASSERT in the lockmgr_disown() about this
condition, but after thinking at it, as this is a well known general
rule, I found it not really necessary.
implement shm_open(2) and shm_unlink(2) in the kernel:
- Each shared memory file descriptor is associated with a swap-backed vm
object which provides the backing store. Each descriptor starts off with
a size of zero, but the size can be altered via ftruncate(2). The shared
memory file descriptors also support fstat(2). read(2), write(2),
ioctl(2), select(2), poll(2), and kevent(2) are not supported on shared
memory file descriptors.
- shm_open(2) and shm_unlink(2) are now implemented as system calls that
manage shared memory file descriptors. The virtual namespace that maps
pathnames to shared memory file descriptors is implemented as a hash
table where the hash key is generated via the 32-bit Fowler/Noll/Vo hash
of the pathname.
- As an extension, the constant 'SHM_ANON' may be specified in place of the
path argument to shm_open(2). In this case, an unnamed shared memory
file descriptor will be created similar to the IPC_PRIVATE key for
shmget(2). Note that the shared memory object can still be shared among
processes by sharing the file descriptor via fork(2) or sendmsg(2), but
it is unnamed. This effectively serves to implement the getmemfd() idea
bandied about the lists several times over the years.
- The backing store for shared memory file descriptors are garbage
collected when they are not referenced by any open file descriptors or
the shm_open(2) virtual namespace.
Submitted by: dillon, peter (previous versions)
Submitted by: rwatson (I based this on his version)
Reviewed by: alc (suggested converting getmemfd() to shm_open())
dev2udev() when a tty was being detached concurrently with the sysctl
handler:
- Hold the 'tty_list_mutex' lock while we read all the fields out of the
struct tty for copying out later. Previously the pty(4) and pts(4)
destroy routines could set t_dev to NULL, drop their reference on the
tty and destroy the cdev while the sysctl handler was attempting to
invoke dev2udev() on the cdev being destroyed. This happened when the
sysctl handler read the value of t_dev prior to it being set to NULL
either due to it being stale or due to timing races. By holding the
list lock we guarantee that the destroy routines will block in ttyrel()
in that case and not destroy the cdev until after we've copied all of our
data. We may see a NULL cdev pointer or we may see the previous value,
but the previous value will no longer point to a destroyed cdev if we
see it.
- Fix the ttyfree() routine used by tty device drivers in their detach
methods to use ttyrel() on the tty so we don't leak them. Also, fix it
to use the same order of operations as pty/pts destruction (set t_dev
NULL, ttyrel(), destroy_dev()) so it cooperates with the sysctl handler.
MFC after: 3 days
Tested by: avatar
This makes it possible to support ftruncate() on non-vnode file types in
the future.
- 'struct fileops' grows a 'fo_truncate' method to handle an ftruncate() on
a given file descriptor.
- ftruncate() moves to kern/sys_generic.c and now just fetches a file
object and invokes fo_truncate().
- The vnode-specific portions of ftruncate() move to vn_truncate() in
vfs_vnops.c which implements fo_truncate() for vnode file types.
- Non-vnode file types return EINVAL in their fo_truncate() method.
Submitted by: rwatson
- spell 16384 as 16384 and not as BKVASIZE. 16384 is (not quite) just a
magic size that works well in practice. BKVASIZE should be MAXBSIZE
(65536), but is 16384 because i386's don't have enough kva for it to
be MAXBSIZE; 16384 works (not so well) for it for much the same reasons
that it works well in the heuristic.
- expand and/or add comments about this and other details.
- don't explicitly inline this function.
- fix some other style bugs.
ABI override binary isn't found. This could probably be smoother, but
it is what I did in p4 change #126891 on 2007/09/27. It should solve
the "ld-elf32.so.1"-in-chroot problem.
happen if there are no files open. Accounting for these can
eventually return a negative value for olenp causing sysctl to
crash with a bad malloc.
Reported by: Pawel Worach <pawel.worach@gmail.com>
- Clear all of the gc flags before doing a run. Stale flags were causing
us to skip some descriptors.
- If a unp socket has been marked REF in a gc pass it can't be dead.
Found by: rwatson's test tool.
- Introduce a finit() which is used to initailize the fields of struct file
in such a way that the ops vector is only valid after the data, type,
and flags are valid.
- Protect f_flag and f_count with atomic operations.
- Remove the global list of all files and associated accounting.
- Rewrite the unp garbage collection such that it no longer requires
the global list of all files and instead uses a list of all unp sockets.
- Mark sockets in the accept queue so we don't incorrectly gc them.
Tested by: kris, pho
machine-independent support for superpages. (The earlier part was
the rewrite of the physical memory allocator.) The remainder of the
code required for superpages support is machine-dependent and will
be added to the various pmap implementations at a later date.
Initially, I am only supporting one large page size per architecture.
Moreover, I am only enabling the reservation system on amd64. (In
an emergency, it can be disabled by setting VM_NRESERVLEVELS to 0
in amd64/include/vmparam.h or your kernel configuration file.)
so that the results end up in the DDB output stream rather than the
console output stream.
This should likely also be done for the vprint() function it calls.
MFC after: 3 months
This option just adds complexity and the new implementation no longer
will support it, so axing it now that it is unused is probabilly the
better idea.
FreeBSD version is bumped in order to reflect the KPI breakage introduced
by this patch.
In the ports tree, kris found that only old OSKit code uses it, but as
it is thought to work only on 2.x kernels serie, version bumping will
solve any problem.
with the interlock), owner of the lock should be only curthread or at
least, for its limited usage, NULL which identifies LK_KERNPROC.
The thread "extra argument" for the lockmgr interface is going to be
removed in the near future, but for the moment, just let kernel run for
some days with this check on in order to find potential deadlocking
places around the kernel and fix them.
p_candebug() will return EAGAIN which, if the other process never
leaves execve(), will result in the sysctl spinning and never returning
to userspace. Processes should always eventually leave execve(), but
spinning in kernel while we wait is bad for countless reasons, and
particularly harmful if execve() itself is deadlocked.
Possibly we should return another error, or return a marker indicating
the thread is in execve() so it can be reported that way in userspace.
Reported by: kris
equivalent with this and so operate the switch.
That call is the only one remaining LK_EXCLUPGRADE consumer and removing
it will prepare the ground for LK_EXCLUPGRADE axing and further
lockmgr improvements.
Discussed with: jeff, ups
mounted FS' problems. These are more along the lines of 'avoiding an
avoidable panic' than a complete solution to removable devices. We
now close the barn door after the horse has gotten lose and has been
hit by a truck, as it were. The barn no longer catches fire in this
case, but the horse is still dead :-).
The vfs_bio.c fix causes us not to put a failed write back into the
dirty pool if the error returned was ENXIO. In that case, the buffer
is treated like any other clean buffer that's being retured. ENXIO
means the device isn't there anymore and will never be there again in
the future, so retrying is futile.
The vfs_mount.c fix treats 'ENXIO' as success for unmounting a file
system. If the device is gone, retrying later won't help and we'll
never be able to unmount the device.
These two are part of a larger patch set submitted by the author. The
other patches will be forth coming. I added comments to these two
patches.
Submitted by: Henrik Gulbrandsen
Reviewed by: phk@
PR: usb/46176 (partial)
