work by yar, thompsa and myself. The checksum offloading part also involves
work done by Mihail Balikov.
The most important changes:
o Instead of global linked list of all vlan softc use a per-trunk
hash. The size of hash is dynamically adjusted, depending on
number of entries. This changes struct ifnet, replacing counter
of vlans with a pointer to trunk structure. This change is an
improvement for setups with big number of VLANs, several interfaces
and several CPUs. It is a small regression for a setup with a single
VLAN interface.
An alternative to dynamic hash is a per-trunk static array with
4096 entries, which is a compile time option - VLAN_ARRAY. In my
experiments the array is not an improvement, probably because such
a big trunk structure doesn't fit into CPU cache.
o Introduce an UMA zone for VLAN tags. Since drivers depend on it,
the zone is declared in kern_mbuf.c, not in optional vlan(4) driver.
This change is a big improvement for any setup utilizing vlan(4).
o Use rwlock(9) instead of mutex(9) for locking. We are the first
ones to do this! :)
o Some drivers can do hardware VLAN tagging + hardware checksum
offloading. Add an infrastructure for this. Whenever vlan(4) is
attached to a parent or parent configuration is changed, the flags
on vlan(4) interface are updated.
In collaboration with: yar, thompsa
In collaboration with: Mihail Balikov <mihail.balikov interbgc.com>
this is more consistent with the placement of slaves in /dev/pts. The
actual name doesn't matter as it's not part of the exposed API or used by
libc. In some sense, it would be nice if these device nodes didn't have to
have names in devfs at all.
Suggested by: Stephen McKay <smckay at internode dot on dot net>
specially crafted module. There are several handrolled sollutions to this
problem in the tree already which will be replaced with this. They include
iwi(4), ipw(4), ispfw(4) and digi(4).
No objection from: arch
MFC after: 2 weeks
X-MFC after: some drivers have been converted
implementation is by no means perfect as far as some of the algorithms
that it uses and the fact that it is missing some functionality (try
locks and upgrades/downgrades are not there yet), however it does seem
to work in my local testing. There is more detail in the comments in the
code, but the short version follows.
A reader/writer lock is very much like a regular mutex: it cannot be held
across a voluntary sleep; it can be acquired in an interrupt thread; if
the lock is held by a writer then the priority of any threads that block
on the lock will be lent to the owner; the simple case lock operations all
are done in a single atomic op. It also shares some similiarities
with sx locks: it supports reader/writer semantics (multiple readers,
but single writers); readers are allowed to recurse, but writers are not.
We can extend this implementation further by either improving algorithms
or adding new functionality, but this should at least give us a base to
work with now.
Reviewed by: arch (in theory)
Tested on: i386 (4 cpu box with a kernel module that used 4 threads
that randomly chose between read locks and write locks
that ran w/o panicing for over a day solid. It usually
panic'd within a few seconds when there were bugs during
testing. :) The kernel module source is available on
request.)
each turnstile. Also, allow for the owner thread pointer of a turnstile
to be NULL. This is needed for the upcoming reader/writer lock
implementation.
- Add a new ddb command 'show turnstile' that will look up the turnstile
associated with the given lock argument and display useful information
like the list of threads blocked on each queue, etc. If there isn't an
active turnstile for a lock at the specified address, then the function
will see if there is an active turnstile at the specified address and
display info about it if so.
- Adjust the mutex code to handle the turnstile API changes.
Tested on: i386 (all), alpha, amd64, sparc64 (1 and 3)
argument and looks for a sleep queue associated with that wait channel.
If it finds one it will display information such as the list of threads
sleeping on that queue. If it can't find a sleep queue for that wait
channel, then it will see if that address matches any of the active
sleep queues. If so, it will display information about the sleepq at the
specified address.
sysctl then it will clear the KTR buffer. Note that if you have active
KTR traces at the same time as a clear operation the behavior is undefined,
though it shouldn't panic.
It should play nicely with the existing BSD ptys.
By default, the system will use the BSD ptys, one can set the sysctl
kern.pts.enable to 1 to make it use the new pts system.
The max number of pty that can be allocated on a system can be changed with the
sysctl kern.pts.max. It defaults to 1000, and can be increased, but it is not
recommanded, as any pty with a number > 999 won't be handled by whatever uses
utmp(5).
modified bit emulation traps on Alpha while holding locks in the
sysctl handler.
A better solution would be to pass a hint to the Alpha pmap code to
tell mark these pages as modified when they as they are being wired,
but that appears to be more difficult to implement.
Suggested by: jhb
MFC after: 3 days
placeholder similar to KTR_DEV. Explain the use of KTR_DEV and
KTR_SUBSYS in a comment as well.
- Retire KTR_WITNESS and instead have KTR_WITNESS default to off but use
KTR_SUBSYS if it is enabled.
1) unregsiter kqueue filter for EVFILT_LIO.
2) free uma_zones.
3) call setsid directly to enter another session rather than
implementing by itself.
Submitted by: jhb
The success of the cluster allocation is checked through a field in the
mbuf structure. This change is non-functional but properly silences code
inspection tools.
Found by: Coverity Prevent(tm)
Coverity ID: CID807
Sponsored by: TCP/IP Optimization Fundraise 2005
lookup() instead of EPERM when a DELETE or RENAME operation is
attempted on "..".
In kern_unlink(), remap EINVAL errors returned from namei() to EPERM
to match existing (and POSIX required) behaviour.
Discussed with: bde
MFC after: 3 days
used by utilities to reset moused(8), for example. The syntax is:
!system=kern subsystem=power type=resume
Note that it would be nice to have notification of suspend, but it's more
difficult since there would have to be a method of doing request/ack
to userland and automatically timing out if no response. apm(4) has a
similar mechanism.
MFC after: 2 weeks
An executable contains at most one PT_INTERP program header. Therefore,
the loop that searches for it can terminate after it is found rather than
iterating over the entire set of program headers.
Eliminate an unneeded initialization.
Reviewed by: tegge
the last component of the path name is "..". This keeps VOP_LOOKUP()
from locking vnodes in reverse order.
Tested by: Denis Shaposhnikov <dsh AT vlink DOT ru>
MFC after: 3 days
prototypes, as the majority of new functions added have been in this
style. Changing prototype style now results in gcc noticing that the
implementation of vn_pollrecord() has a 'short' argument instead of
'int' as prototyped in vnode.h, so correct that definition. In practice
this didn't matter as only poll flags in the lower 16 bits are used.
MFC after: 1 week
devclass's parent pointer if the two drivers share the same devclass. This
can happen if the drivers use the same new-bus name. For example, we
currently have 3 drivers that use the name "pci": the generic PCI bus
driver, the ACPI PCI bus driver, and the OpenFirmware PCI bus driver. If
the ACPI PCI bus driver was defined as a subclass of the generic PCI bus
driver, then without this check the "pci" devclass would point to itself
as its parent and device_probe_child() would spin forever when it
encountered the first PCI device that did have a matching driver.
Reviewed by: dfr, imp, new-bus@
equal to NULL several times later. p_ucred "should probably not" be NULL
if the process isn't PRS_NEW anyway. This is strongly reinforced by the fact
that we don't see frequent crashes here. Remove the checks after p_cansee and
add a KASSERT right before it.
Found by: Coverity Prevent (tm)
Also trim one nearby trailing space.
lock_obj objects:
- Add new lock_init() and lock_destroy() functions to setup and teardown
lock_object objects including KTR logging and registering with WITNESS.
- Move all the handling of LO_INITIALIZED out of witness and the various
lock init functions into lock_init() and lock_destroy().
- Remove the constants for static indices into the lock_classes[] array
and change the code outside of subr_lock.c to use LOCK_CLASS to compare
against a known lock class.
- Move the 'show lock' ddb function and lock_classes[] array out of
kern_mutex.c over to subr_lock.c.
Since we are using vfs_busy() on a freshly allocated mount structure, use
(void) to show that we do not care about the return value.
Found with: Coverity Prevent (tm)
MFC after: 2 weeks
taskqueue_start_threads(struct taskqueue **, int count, int pri,
const char *name, ...);
This allows the creation of 1 or more threads that will service a single
taskqueue. Also rework the taskqueue_create() API to remove the API change
that was introduced a while back. Creating a taskqueue doesn't rely on
the presence of a process structure, and the proc mechanics are much better
encapsulated in taskqueue_start_threads(). Also clean up the
taskqueue_terminate() and taskqueue_free() functions to safely drain
pending tasks and remove all associated threads.
The TASKQUEUE_DEFINE and TASKQUEUE_DEFINE_THREAD macros have been changed
to use the new API, but drivers compiled against the old definitions will
still work. Thus, recompiling drivers is not a strict requirement.
intended for use solely with atomic datagram socket types, and relies
on the previous break-out of sosend_copyin(). Changes to allow UDP to
optionally use this instead of sosend() will be committed as a
follow-up.
to COMPAT_43TTY.
Add COMPAT_43TTY to NOTES and */conf/GENERIC
Compile tty_compat.c only under the new option.
Spit out
#warning "Old BSD tty API used, please upgrade."
if ioctl_compat.h gets #included from userland.
fast taskqueues. The following have been added:
TASKQUEUE_FAST_DEFINE() - create a global task queue.
an arbitrary execution context.
TASKQUEUE_FAST_DEFINE_THREAD() - create a global taskqueue that uses a
dedicated kthread.
taskqueue_create_fast() - create a local/private taskqueue.
These are all complimentary of the standard taskqueue functions. They are
primarily useful for fast interrupt handlers that can only use spinlock for
synchronization.
I personally think that the taskqueue API is starting to get too narrow and
hairy, but fixing it will require a major redesign on the API. Such a
redesign would be good but would break compatibility with FreeBSD 6.x, so
it really isn't desirable at this time.
Submitted by: sam
and subsequently broke the build. This change is supposed to fix the
case where doing a mtx_destroy() off a spin mutex while you hold it fails.
If it had been tested I would just leave it in, but it hasn't been tested
yet, so it will have to wait until later.
struct sx). Instead of storing a direct pointer to a our lock_class
struct in lock_object, reserve 4 bits in the lo_flags field to serve as an
index into a global lock_classes array that contains pointers to the lock
classes. Only debugging code such as WITNESS or INVARIANTS checks and KTR
logging need to access the lock_class member, so this shouldn't add any
overhead to production kernels. It might add some slight overhead to
kernels using those debug options however.
As with the previous set of changes to lock_object, this is going to
completely obliterate the kernel ABI, so be sure to recompile all your
modules.
returns EBADF. That errno is correct and is mandated by POSIX. It also
goes back to revision 1.1 of our CVS history (i.e. 4.4BSD).
The _fget() function should probably also be upated as it currently returns
EINVAL in that case rather than EBADF. (It does return EBADF for reads
on a write-only descriptor without any XXX comments oddly enough.)
Discussed with: scottl, grog, mjacob, bde
that a file's atime and mtime are only set to correct fractional
second values (0-999999000ns with the current interface).
Prior to this change users could create files with values outside
that range. Moreover, on 32-bit machines tv_usec offsets larger than
4.3s would result in an unnormalized AND wrong timestamp value,
due to overflow.
MFC after: 1 week
- provide an interface (macros) to the page coloring part of the VM system,
this allows to try different coloring algorithms without the need to
touch every file [1]
- make the page queue tuning values readable: sysctl vm.stats.pagequeue
- autotuning of the page coloring values based upon the cache size instead
of options in the kernel config (disabling of the page coloring as a
kernel option is still possible)
MD changes:
- detection of the cache size: only IA32 and AMD64 (untested) contains
cache size detection code, every other arch just comes with a dummy
function (this results in the use of default values like it was the
case without the autotuning of the page coloring)
- print some more info on Intel CPU's (like we do on AMD and Transmeta
CPU's)
Note to AMD owners (IA32 and AMD64): please run "sysctl vm.stats.pagequeue"
and report if the cache* values are zero (= bug in the cache detection code)
or not.
Based upon work by: Chad David <davidc@acns.ab.ca> [1]
Reviewed by: alc, arch (in 2004)
Discussed with: alc, Chad David, arch (in 2004)
- Provide tunable vm.memguard.desc, so one can specify memory type without
changing the code and recompiling the kernel.
- Allow to use memguard for kernel modules by providing sysctl
vm.memguard.desc, which can be changed to short description of memory
type before module is loaded.
- Move as much memguard code as possible to memguard.c.
- Add sysctl node vm.memguard. and move memguard-specific sysctl there.
- Add malloc_desc2type() function for finding memory type based on its
short description (ks_shortdesc field).
- Memory type can be changed (via vm.memguard.desc sysctl) only if it
doesn't exist (will be loaded later) or when no memory is allocated yet.
If there is allocated memory for the given memory type, return EBUSY.
- Implement two ways of memory types comparsion and make safer/slower the
default.
The race is very real, but conditions needed for triggering it are rather
hard to meet now.
When gjournal will be committed (where it is quite easy to trigger) we need
to fix it.
For now, verify if it is really hard to trigger.
Discussed with: kan
of msleep(). msleep_spin() doesn't support changing the priority of the
thread while it is asleep nor does it support interruptible sleeps (PCATCH)
or the PDROP flag. It does support timeouts however. It differs from
msleep() in that the passed in mutex is a spin mutex. This means one can
use msleep_spin() and wakeup() with a spin mutex similar to msleep() and
wakeup() with a regular mutex. Note that the spin mutex in question needs
to come before sched_lock and the sleepq locks in lock order.
spin locks that are not in the static order list. It is not safe to call
printf while holding the witness spin mutex since the console drivers that
back printf may need to use their own spin locks which would try to talk
to witness when they were locked. Given this, it is possible for one
CPU to lock a console driver lock (such as sio) which then tries to lock
the witness lock while another CPU is doing the printf while holding the
witness lock. Fix this by moving the printf outside of the witness lock.
All other printf's in witness are already correct.
MFC after: 3 days
UMA_SLAB_MALLOC flag.
In some circumstances (I observed it when I was doing a lot of reallocs)
UMA_SLAB_MALLOC can be set even if us_keg != NULL.
If this is the case we have wonderful, silent data corruption, because less
data is copied to the newly allocated region than should be.
I'm not sure when this bug was introduced, it could be there undetected
for years now, as we don't have a lot of realloc(9) consumers and it was
hard to reproduce it...
...but what I know for sure, is that I don't want to know who introduce
the bug:) It took me two/three days to track it down (of course most of
the time I was looking for the bug in my own code).
with flags bitfield and set BI_CAN_EXEC_DYN flag for all brands that usually
allow executing elf dynamic binaries (aka shared libraries). When it is
requested to execute ET_DYN elf image check if this flag is on after we
know the elf brand allowing execution if so.
PR: kern/87615
Submitted by: Marcin Koziej <creep@desk.pl>
Specifically, it is required for the I/O that may be performed by
elfN_load_section().
Avoid an obscure deadlock in the a.out, elf, and gzip image
activators. Add a comment describing why the deadlock does not occur
in the common case and how it might occur in less usual circumstances.
Eliminate an unused variable from exec_aout_imgact().
In collaboration with: tegge
by debugger, e.g process is dumping core. Only access p_xthread if
P_STOPPED_TRACE is set, this means thread is ready to exchange signal
with debugger, print a warning if P_STOPPED_TRACE is not set due to
some bugs in other code, if there is.
The patch has been tested by Anish Mistry mistry.7 at osu dot edu, and
is slightly adjusted.
passing a pointer to an opaque clockframe structure and requiring the
MD code to supply CLKF_FOO() macros to extract needed values out of the
opaque structure, just pass the needed values directly. In practice this
means passing the pair (usermode, pc) to hardclock() and profclock() and
passing the boolean (usermode) to hardclock_cpu() and hardclock_process().
Other details:
- Axe clockframe and CLKF_FOO() macros on all architectures. Basically,
all the archs were taking a trapframe and converting it into a clockframe
one way or another. Now they can just extract the PC and usermode values
directly out of the trapframe and pass it to fooclock().
- Renamed hardclock_process() to hardclock_cpu() as the latter is more
accurate.
- On Alpha, we now run profclock() at hz (profhz == hz) rather than at
the slower stathz.
- On Alpha, for the TurboLaser machines that don't have an 8254
timecounter, call hardclock() directly. This removes an extra
conditional check from every clock interrupt on Alpha on the BSP.
There is probably room for even further pruning here by changing Alpha
to use the simplified timecounter we use on x86 with the lapic timer
since we don't get interrupts from the 8254 on Alpha anyway.
- On x86, clkintr() shouldn't ever be called now unless using_lapic_timer
is false, so add a KASSERT() to that affect and remove a condition
to slightly optimize the non-lapic case.
- Change prototypeof arm_handler_execute() so that it's first arg is a
trapframe pointer rather than a void pointer for clarity.
- Use KCOUNT macro in profclock() to lookup the kernel profiling bucket.
Tested on: alpha, amd64, arm, i386, ia64, sparc64
Reviewed by: bde (mostly)
it and reacquiring it in vrele(). Consequently, there is no reason to
increase the reference count on the vm object caching the file's pages.
Reviewed by: tegge
Eliminate unused parameters to elfN_load_file().
The purpose of this change is consistency (not performance improvement:)),
as it was hard to tell if fdrop() is MPSAFE or not when I saw it sometimes
under the Giant and sometimes without it.
Glanced at by: ssouhlal, kan
means:
o Remove Elf64_Quarter,
o Redefine Elf64_Half to be 16-bit,
o Redefine Elf64_Word to be 32-bit,
o Add Elf64_Xword and Elf64_Sxword for 64-bit entities,
o Use Elf_Size in MI code to abstract the difference between
Elf32_Word and Elf64_Word.
o Add Elf_Ssize as the signed counterpart of Elf_Size.
MFC after: 2 weeks
and KTR_IO as they were never used. Remove KTR_CLK since it was only
used for hardclock firing and use KTR_INTR there instead. Remove
KTR_CRITICAL since it was only used for crit enter/exit and use
KTR_CONTENTION instead.
really should be a fptrdiff_t if we had that) in profclock().
- Don't try to profile kernel pc's that are >= the kernel lowpc to avoid
underflows when computing a profiling index.
- Use the PC_TO_I() macro to compute the kernel profiling index rather than
doing it inline.
Discussed with: bde
ephemeral mappings that are used as the source for three copy
operations from kernel space to user space. There are two reasons for
making this change: (1) Under heavy load exec_map can fill up causing
vm_map_find() to fail. When it fails, the nascent process is aborted
(SIGABRT). Whereas, this reimplementation using sf_buf_alloc()
sleeps. (2) Although it is possible to sleep on vm_map_find()'s
failure until address space becomes available (see kmem_alloc_wait()),
using sf_buf_alloc() is faster. Furthermore, the reimplementation
uses a CPU private mapping, avoiding a TLB shootdown on
multiprocessors.
Problem uncovered by: kris@
Reviewed by: tegge@
MFC after: 3 weeks
mbuf chain that starts with a cluster containing just MHLEN bytes. This
happened because m_dup called m_get or m_getcl depending on the amount of
data to copy, but then always set the size available in the first mbuf to
MHLEN.
Submitted by: Matt Koivisto <mkoivisto at sandvine dot com>
Approved by: jmg
Silence from: rwatson (mentor)
class, then it displays various information about the lock and calls a
new function pointer in lock_class (lc_ddb_show) to dump class-specific
information about the lock as well (such as the owner of a mutex or
xlock'ed sx lock). This is easier than staring at hex dumps of locks to
figure out who owns the lock, etc. Note that extending lock_class doesn't
affect the ABI for any kernel modules as the only code that deals with
lock_class structures directly is kern_mutex.c, kern_sx.c, and witness.
MFC after: 1 week
- Implement cv_wait_unlock() method which has semantics compatible
with the sv_wait() method in IRIX. For cv_wait_unlock(), the lock
must be held before entering the function, but is not held when the
function is exited.
- Implement the existing cv_wait() function in terms of cv_wait_unlock().
Submitted by: kan
Feedback from: jhb, trhodes, Christoph Hellwig <hch at infradead dot org>
being hold by current thread or ignored by current process,
otherwise, it is very possible the thread will enter an infinite loop
and lead to an administrator's nightmare.
4k clusters in addition to 9k and 16k ones.
struct mbuf *m_getjcl(int how, short type, int flags, int size)
void *m_cljget(struct mbuf *m, int how, int size)
m_getjcl() returns an mbuf with a cluster of the specified size attached
like m_getcl() does for 2k clusters.
m_cljget() is different from m_clget() as it can allocate clusters
without attaching them to an mbuf. In that case the return value
is the pointer to the cluster of the requested size. If an mbuf was
specified, it gets the cluster attached to it and the return value
can be safely ignored.
For size both take MCLBYTES, MJUM4BYTES, MJUM9BYTES, MJUM16BYTES.
Reviewed by: glebius
Tested by: glebius
Sponsored by: TCP/IP Optimization Fundraise 2005
lock object (and thus off of each mutex and sx lock):
- Rename the all_locks list to pending_locks and only put locks initialized
before SI_SUB_WITNESS on the list so that the SI_SUB_WITNESS can add them
to witness once it starts up.
- Now that pending_locks is only used during early startup, change it from
a TAILQ to an STAILQ. This removes a pointer from the STAILQ_ENTRY in
struct lock_object.
- Since the pending_locks list is only used during the single-threaded
early boot it no longer needs to be protected by a mutex, so remove
all_mtx.
- Since the lo_list member of struct lock_object is now only used during
early boot before witness is running, collapse lo_list and lo_witness
into a union. This shaves the second pointer off of struct lock_object.
- Axe lock_cur_cnt and lock_max_cnt.
With these changes, struct mtx shrinks from 36 to 28 bytes on 32-bit
platforms and from 72 to 56 bytes on 64-bit platforms. Note that this
commit will completely and utterly destroy the kernel ABI, so no MFC.
Tested on: alpha, amd64, i386, sparc64
sosend(). Robert accidentally changed the snderr() macro to jump to the
out label which assumes the lock is already released rather than the
release label which drops the lock in his previous change to sosend().
This should fix the recent panics about returning from write(2) with the
socket lock held and the most recent LOR on current@.
process as over the limit when its time is >= to the limit rather than >
the limit. Technically, if p->p_rux.rux_runtime.sec == p->p_pcpulimit
and p->p_rux.rux_runtime.frac == 0, the process hasn't exceeded the limit
yet. However, having the fraction exactly equal to 0 is rather rare, and
it is not worth the overhead to handle that edge case. With just the >
comparison, the process would have to exceed its limit by almost a second
before it was killed.
PR: kern/83192
Submitted by: Maciej Zawadzinski mzawadzinski at gmail dot com
Reviewed by: bde
MFC after: 1 week
chains and copying in mbufs from the body of the send logic, creating
a new function sosend_copyin(). This changes makes sosend() almost
readable, and will allow the same logic to be used by tailored socket
send routines.
MFC after: 1 month
Reviewed by: andre, glebius
application wishes to request high precision time stamps be returned:
Alias Existing
CLOCK_REALTIME_PRECISE CLOCK_REALTIME
CLOCK_MONOTONIC_PRECISE CLOCK_MONOTONIC
CLOCK_UPTIME_PRECISE CLOCK_UPTIME
Add experimental low-precision clockid_t names corresponding to these
clocks, but implemented using cached timestamps in kernel rather than
a full time counter query. This offers a minimum update rate of 1/HZ,
but in practice will often be more frequent due to the frequency of
time stamping in the kernel:
New clockid_t name Approximates existing clockid_t
CLOCK_REALTIME_FAST CLOCK_REALTIME
CLOCK_MONOTONIC_FAST CLOCK_MONOTONIC
CLOCK_UPTIME_FAST CLOCK_UPTIME
Add one additional new clockid_t, CLOCK_SECOND, which returns the
current second without performing a full time counter query or cache
lookup overhead to make sure the cached timestamp is stable. This is
intended to support very low granularity consumers, such as time(3).
The names, visibility, and implementation of the above are subject
to change, and will not be MFC'd any time soon. The goal is to
expose lower quality time measurement to applications willing to
sacrifice accuracy in performance critical paths, such as when taking
time stamps for the purpose of rescheduling select() and poll()
timeouts. Future changes might include retrofitting the time counter
infrastructure to allow the "fast" time query mechanisms to use a
different time counter, rather than a cached time counter (i.e.,
TSC).
NOTE: With different underlying time mechanisms exposed, using
different time query mechanisms in the same application may result in
relative non-monoticity or the appearance of clock stalling for a
single clockid_t, as a cached time stamp queried after a precision
time stamp lookup may be "before" the time returned by the earlier
live time counter query.
directly. We need to copyin() the strings in the iovec before
we can strcmp() them. Also, when we want to send the errmsg back
to userspace, we need to copyout()/copystr() the string.
Add a small helper function vfs_getopt_pos() which takes in the
name of an option, and returns the array index of the name in the iovec,
or -1 if not found. This allows us to locate an option in
the iovec without actually manipulating the iovec members. directly via
strcmp().
Noticed by: kris on sparc64
connection queue for a new connection. It was removing connections
from the wrong list.
Submitted by: Paul Mikesell
Sponsored by: Isilon Systems
MFC after: 1 week
When all file systems have a time stamp of zero, which is the case
for example when the root file system is on a read-only medium, we
ended up not calling inittodr() at all. A potential uncleanliness
existed as well. If multiple file systems had a non-zero time stamp,
we would call inittodr() multiple times. While this should not be
harmful, it's definitely not ideal.
Fix both issues by iterating over the mounted file systems to find
the largest time stamp and call inittodr() exactly once with that
time stamp. This could of course be a zero time stamp if none of the
mounted file systems have a non-zero time stamp. In that case the
annoying errors mentioned in the commit log for revision 1.186 still
haven't been avoided. The bottom line is that inittodr() should not
complain when it gets a time base of zero. At the time of this
commit only alpha seems to have that problem.
Reported by: Dario Freni (saturnero at freesbie dot org)
MFC after: 1 week
is called. It looks like there are lots of different mount flags checked
in vfs_domount(), so we need to do the parsing for these particular
mount flags earlier on. The new flags parsed are:
async, force, multilabel, noasync, noatime, noclusterr, noclusterw,
noexec, nosuid, nosymfollow, snapshot, suiddir, sync, union.
Existing code which uses mount() to mount UFS filesystems is not
affected, but new code which uses nmount() to mount UFS filesystems
should behave better.
in, and if so, set MNT_UPDATE filesystem flag.
vfs_nmount() calls vfs_domount(), and there is special logic
inside vfs_domount() if MNT_UPDATE is set. This is very important
when we want to do an update mount of the root filesystem, using nmount().
execute a ET_DYN binary (shared object).
This does not make much sense, but some linux scripts expect to be able to
execute /lib/ld-linux.so.2 (ldd comes to mind).
The sysctl defaults to 0.
MFC after: 3 days
currently present is minor and offers no real semantic issues, it also
doesn't make sense since an earlier lockless check has already
occurred. Also hold the mutex longer, over a manipulation of
per-process ktrace state, which requires synchronization.
MFC after: 1 month
Pointed out by: jhb
reliability when tracing fast-moving processes or writing traces to
slow file systems by avoiding unbounded queueuing and dropped records.
Record loss was previously possible when the global pool of records
become depleted as a result of record generation outstripping record
commit, which occurred quickly in many common situations.
These changes partially restore the 4.x model of committing ktrace
records at the point of trace generation (synchronous), but maintain
the 5.x deferred record commit behavior (asynchronous) for situations
where entering VFS and sleeping is not possible (i.e., in the
scheduler). Records are now queued per-process as opposed to
globally, with processes responsible for committing records from their
own context as required.
- Eliminate the ktrace worker thread and global record queue, as they
are no longer used. Keep the global free record list, as records
are still used.
- Add a per-process record queue, which will hold any asynchronously
generated records, such as from context switches. This replaces the
global queue as the place to submit asynchronous records to.
- When a record is committed asynchronously, simply queue it to the
process.
- When a record is committed synchronously, first drain any pending
per-process records in order to maintain ordering as best we can.
Currently ordering between competing threads is provided via a global
ktrace_sx, but a per-process flag or lock may be desirable in the
future.
- When a process returns to user space following a system call, trap,
signal delivery, etc, flush any pending records.
- When a process exits, flush any pending records.
- Assert on process tear-down that there are no pending records.
- Slightly abstract the notion of being "in ktrace", which is used to
prevent the recursive generation of records, as well as generating
traces for ktrace events.
Future work here might look at changing the set of events marked for
synchronous and asynchronous record generation, re-balancing queue
depth, timeliness of commit to disk, and so on. I.e., performing a
drain every (n) records.
MFC after: 1 month
Discussed with: jhb
Requested by: Marc Olzheim <marcolz at stack dot nl>
happiness, as well as correct other bugs:
- Replace notion of current and saved accounting credential/vnode with a
single credential/vnode and an acct_suspended flag. This simplifies the
accounting logic substantially.
- Replace acct_mtx with acct_sx, a sleepable lock held exclusively during
reconfiguration and space polling, but shared during log entry
generation. This avoids holding a mutex over sleepable VFS operations.
- Hold the sx lock over the duration of the I/O so that the vnode I/O
cannot occur after vnode close, which could occur previously if
accounting was disabled as a process exited.
- Write the accounting log entry with Giant conditionally acquired based
on the file system where the log is stored. Previously, the accounting
code relied on the caller acquiring Giant.
- Acquire Giant conditionally in the accounting callout based on the file
system where the accounting log is stored. Run the callout MPSAFE.
- Expose acct_suspended via a read-only sysctl so it is possibly to
programmatically determine whether accounting is suspended or not without
attempting to parse logs.
- Check both acct_vp and acct_suspended lock-free before entering the
accounting sx lock in acct().
- When accounting is disabled due to a VBAD vnode (i.e., forceable unmount),
generate a log message indicating accounting has been disabled.
- Correct a long-standing bug in how free space is calculated and compared
to the required space: generate and compare signed results, not unsigned
results, or negative free space will cause accounting to not be suspended
when required, or worse, incorrectly resumed once negative free space is
reached.
MFC after: 2 weeks
socket file descriptor garbage collection code, which is intended to
detect and clear cycles of orphaned file descriptors that are "in-flight"
in a socket when that socket is closed before they are received. The
algorithm present was both run at poor times (resulting in recursion and
reentrance), and also buggy in the presence of parallelism. In order to
fix these problems, make the following changes:
- When there are in-flight sockets and a UNIX domain socket is destroyed,
asynchronously schedule the garbage collector, rather than running it
synchronously in the current context. This avoids lock order issues
when the garbage collection code reenters the UNIX domain socket code,
avoiding lock order reversals, deadlocks, etc. Run the code
asynchronously in a task queue.
- In the garbage collector, when skipping file descriptors that have
entered a closing state (i.e., have f_count == 0), re-test the FDEFER
flag, and decrement unp_defer. As file descriptors can now transition
to a closed state, while the garbage collector is running, it is no
longer the case that unp_defer will remain an accurate count of
deferred sockets in the mark portion of the GC algorithm. Otherwise,
the garbage collector will loop waiting waiting for unp_defer to reach
zero, which it will never do as it is skipping file descriptors that
were marked in an earlier pass, but now closed.
- Acquire the UNIX domain socket subsystem lock in unp_discard() when
modifying the unp_rights counter, or a read/write race is risked with
other threads also manipulating the counter.
While here:
- Remove #if 0'd code regarding acquiring the socket buffer sleep lock in
the garbage collector, this is not required as we are able to use the
socket buffer receive lock to protect scanning the receive buffer for
in-flight file descriptors on the socket buffer.
- Annotate that the description of the garbage collector implementation
is increasingly inaccurate and needs to be updated.
- Add counters of the number of deferred garbage collections and recycled
file descriptors. This will be removed and is here temporarily for
debugging purposes.
With these changes in place, the unp_passfd regression test now appears
to be passed consistently on UP and SMP systems for extended runs,
whereas before it hung quickly or panicked, depending on which bug was
triggered.
Reported by: Philip Kizer <pckizer at nostrum dot com>
MFC after: 2 weeks
state about each open file, and identify the first process in the process
table that references the file. This is helpful in debugging leaks of
file descriptors.
MFC after: 1 week
The PR and patch have the details. The ultimate fix requires architectural
changes and clarifications to the VFS API, but this will prevent the system
from panicking when someone does "ls /dev" while running in a shell under the
linuxulator.
This issue affects HEAD and RELENG_6 only.
PR: 88249
Submitted by: "Devon H. O'Dell" <dodell@ixsystems.com>
MFC after: 3 days
with the file descriptor. When a file descriptor is closed as a result
of garbage collecting a UNIX domain socket, the file descriptor will
not have any associated thread, so the logic to identify advisory locks
held by that thread is not appropriate. Check the thread for NULL to
avoid this scenario. Expand an existing comment to say a bit more about
this.
MFC after: 1 week
thread context. While it doesn't matter too much at the moment, in
the future we could be back in the same boat if/when more restrictions
are placed (or enforced) in a SWI.
Suggested by: njl, bde, jhb, scottl
in the hardware interrupt context (even if it is likely just an
ithread). We don't document that suspend/resume routines are run from
such a context and some of the things that happen in those routines
aren't interrupt safe. Since there's no real need to run from that
context, this restores assumptions that suspend routines have made.
This fixes Thierry Herbelot's 'Trying to sleep while sleeping is
prohibited' problem.
to user-space if a parameter named "errmsg" is passed into the iovec.
Used in conjunction with vfs_mount_error(), more useful error messages
than errno can be passed back to userspace when mounting a filesystem
fails.
Discussed with: phk, pjd
have started aio, instead, initialize aio management structure
if it hasn't been done, the reason to adjust this behavior is
to make it a bit friendly for threaded program, consider two
threads, one submits aio_write, and another just calls
aio_waitcomplete to wait any I/O to be completed and recycle the
aio requests, before submitter doing any I/O, the recycler wants
to wait in kernel. This also fixes inconsistency with other aio
syscalls.
