This introduces a facility to EVENTHANDLER(9) for explicitly defining a
reference to an event handler list. This is useful since previously all
invokers of events had to do a locked traversal of the global list of
event handler lists in order to find the appropriate event handler list.
By keeping a pointer to the appropriate list an invoker can avoid this
traversal completely. The pointer is initialized with SYSINIT(9) during
the eventhandler stage. Users registering interest in events do not need
to know if the event is backed by such a list, since the list is added
to the global list of lists. As with lists that are not pre-defined it
is safe to register for the events before the list has been created.
This converts the process_* and thread_* events to using the new
facility, as these are events whose locked traversals end up showing up
significantly in ports build workflows (and presumably other workflows
with many short lived threads/procs). It may be advantageous to convert
other events to using the new facility.
The el_flags field is now unused, but leave it be so that this revision
can be MFC'd.
Reviewed by: bdrewery, markj, mjg
Approved by: rstone (mentor)
In collaboration with: ian
MFC after: 4 weeks
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D12814
similar to the kernel memory allocator.
This simplifies NUMA allocation because the domain will be known at wait
time and races between failure and sleeping are eliminated. This also
reduces boilerplate code and simplifies callers.
A wait primitive is supplied for uma zones for similar reasons. This
eliminates some non-specific VM_WAIT calls in favor of more explicit
sleeps that may be satisfied without new pages.
Reviewed by: alc, kib, markj
Tested by: pho
Sponsored by: Netflix, Dell/EMC Isilon
Since the case of an empty chain was already covered, it si very likely
that the existing entry is matching. Skipping readlocking saves on lock
upgrade.
It is used on each new entry addition to decide whether to whack an existing
negative entry in order to prevent a blow out in size, but the parameter was
set years ago and never revisited.
Building with poudriere results in about 400 evictions per second which
unnecessarily grab entries from the hot list.
With the new parameter there are next to no evictions of the sort.
When multiple threads wish to report a tracing event to a debugger,
both threads call ptracestop() and one thread will win the race to be
the reporting thread (p->p_xthread). The debugger uses PT_LWPINFO
with the process ID to determine which thread / LWP is reporting an
event and the details of that event. This event is cleared as a side
effect of the subsequent ptrace event that resumed the process
(PT_CONTINUE, PT_STEP, etc.). However, ptrace() was clearing the
event identified by the LWP ID passed to the resume request even if
that wasn't the 'p_xthread'. This could result in clearing an event
that had not yet been observed by the debugger and leaving the
existing event for 'p_thread' pending so that it was reported a second
time.
Specifically, if the debugger stopped due to a software breakpoint in
one thread, but then switched to another thread that was used to
resume (e.g. if the user switched to a different thread and issued a
step), the resume request (PT_STEP) cleared a pending event (if any)
for the thread being stepped. However, the process immediately
stopped and the first thread reported it's breakpoint event a second
time. The debugger decremented the PC for "both" breakpoint events
which resulted in the PC now pointing into the middle of an
instruction (on x86) and a SIGILL fault when the process was resumed a
second time.
To fix, always clear the pending event for 'p_xthread' when resuming a
process. ptrace() still honors the requested LWP ID when enabling
single-stepping (PT_STEP) or setting a different PC (PT_CONTINUE).
Reported by: GDB testsuite (gdb.threads/continue-pending-status.exp)
Reviewed by: kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D12794
An off-by-one error has been present since the system call was first present
in 185878. It additionally became a memory corruption bug after change
324941. The failure is actually revealed by our existing AIO tests.
However, apparently nobody's been running those in 32-bit emulation mode.
Reported by: Coverity, cem
CID: 1382114
MFC after: 18 days
X-MFC-With: 324941
Sponsored by: Spectra Logic Corp
When using a kernel built with the GZIO config option, dumpon -z can be
used to configure gzip compression using the in-kernel copy of zlib.
This is useful on systems with large amounts of RAM, which require a
correspondingly large dump device. Recovery of compressed dumps is also
faster since fewer bytes need to be copied from the dump device.
Because we have no way of knowing the final size of a compressed dump
until it is written, the kernel will always attempt to dump when
compression is configured, regardless of the dump device size. If the
dump is aborted because we run out of space, an error is reported on
the console.
savecore(8) is modified to handle compressed dumps and save them to
vmcore.<index>.gz, as it does when given the -z option.
A new rc.conf variable, dumpon_flags, is added. Its value is added to
the boot-time dumpon(8) invocation that occurs when a dump device is
configured in rc.conf.
Reviewed by: cem (earlier version)
Discussed with: def, rgrimes
Relnotes: yes
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D11723
In r322258 I made p1003_1b.aio_listio_max a tunable. However, further
investigation shows that there was never any good reason for that limit to
exist in the first place. It's used in two completely different ways:
* To size a UMA zone, which globally limits the number of concurrent
aio_suspend calls.
* To artifically limit the number of operations in a single lio_listio call.
There doesn't seem to be any memory allocation associated with this limit.
This change does two things:
* Properly names aio_suspend's UMA zone, and sizes it based on a new constant.
* Eliminates the artifical restriction on lio_listio. Instead, lio_listio
calls will now be limited by the more generous max_aio_queue_per_proc. The
old p1003_1b.aio_listio_max is now an alias for
vfs.aio.max_aio_queue_per_proc, so sysconf(3) will still work with
_SC_AIO_LISTIO_MAX.
Reported by: bde
Reviewed by: jhb
MFC after: 3 weeks
Sponsored by: Spectra Logic Corp
Differential Revision: https://reviews.freebsd.org/D12120
While here cache-align chains.
This shortens longest found chain during poudriere -j 80 from 32 to 16.
Pushing this higher up will probably require allocation on boot.
VBAD type.
FFS ffs_write() VOP catches such vnodes and panics, other VOPs do not
check for the type and their behaviour is really undefined. The
comment claims that this support was done for 'badsect' to flag bad
sectors, we do not have such facility in kernel anyway.
Reported by: Dmitry Vyukov <dvyukov@google.com>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
- allocate value for new AT_HWCAP2 auxiliary vector on all platforms.
- expand 'struct sysentvec' by new 'u_long *sv_hwcap2', in exactly
same way as for AT_HWCAP.
MFC after: 1 month
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D12699
The end of the loop must re-lookup the next buf since the bufobj lock
is dropped in the loop body. If the lookup fails, the loop is restarted.
This mechanism non-obviously also terminates the loop when the end of
the buf list is reached. Split up the two loops termination cases to
make the code a bit less fragile. No functional change intended.
Reviewed by: kib
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D12730
1) shorten the fast path by pushing the lockstat probe to the slow path
2) test for kernel panic only after it turns out we will have to spin,
in particular test only after we know we are not recursing
MFC after: 1 week
The previous limit of just one page is hit by ps.
The entire mechanism should be reworked, if not whacked. It seems the intent
is to reduce kernel dos-ability - some handlers wire the amount of memory
passed here. Handlers should probably stop wiring in the first place or in
the worst case indicate they are doing so so that the check is done only if
necessary. It should also probably be a counter, not a lock.
MFC after: 1 week
Not only this lock doesn't play any role here, dirtying it slows down
other things a little bit as giant-held checks (e.g. DROP_GIANT) are
spread all over the kernel.
MFC after: 1 week
All of the kernel dump implementations keep track of the current offset
("dumplo") within the dump device. However, except for textdumps, they
all write the dump sequentially, so we can reduce code duplication by
having the MI code keep track of the current offset. The new
dump_append() API can be used to write at the current offset.
This is needed to implement support for kernel dump compression in the
MI kernel dump code.
Also simplify dump_encrypted_write() somewhat: use dump_write() instead
of duplicating its bounds checks, and get rid of the redundant offset
tracking.
Reviewed by: cem
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D11722
mbpool existed to support NICs with memory interfaces and all remaining
comsumers were removed earlier this year with NATM.
Reviewed by: jhb
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D10513
MNT_VNODE_FOREACH_ALL() is supposed to avoid returning doomed vnodes,
but the VI_DOOMED check it used was done without the vnode interlock
held, so it could race with a concurrent vgone().
Submitted by: Don Morris <don.morris@isilon.com>
Reviewed by: kib, mckusick
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D12704
