Maintain a count of free slabs in the per-domain keg structure and use
that to clear the free slab list in constant time for most cases. This
helps minimize lock contention induced by reclamation, in preparation
for proactive trimming of excesses of free memory.
Reviewed by: jeff, rlibby
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D23532
When processing a taskqueue and a task has associated epoch, then
enter for duration of the task. If consecutive tasks belong to the
same epoch, batch them. Now we are talking about the network epoch
only.
Shrink the ta_priority size to 8-bits. No current consumers use
a priority that won't fit into 8 bits. Also complexity of
taskqueue_enqueue() is a square of maximum value of priority, so
we unlikely ever want to go over UCHAR_MAX here.
Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D23518
vdrop can set the hold count to 0 and wait for the ->mnt_listmtx held by
mnt_vnode_next_lazy_relock caller. The routine incorrectly asserted the
count has to be > 0.
Reported by: pho
Tested by: pho
The reason for this change is to make it clear the scope of the in-kernel usage
of IFM_TYPE_DESCRIPTIONS and IFM_SUBTYPE_ETHERNET_DESCRIPTIONS macros. Also it
is somewhat better C.
Reviewed by: hselasky
Sponsored by: Mellanox Technologies
Differential revision: https://reviews.freebsd.org/D23620
Platform (N1SDP).
Neoverse N1 is a high-performance ARM microarchitecture designed
by the ARM Holdings for the server market.
The PCI part on N1SDP was shipped untested and suffers from some
integration issues.
For instance accessing to not existing BDFs causes System Error
(SError) exception. To mitigate this, the firmware scans the bus,
catches SErrors and creates a table with valid BDFs. That allows
us to filter-out accesses to invalid BDFs in this driver.
Also the root complex config space (BDF == 0) has an unusual
location in memory map, so remapping accesses to it is required.
Finally, the config space is restricted to 32-bit accesses only.
This was tested on the ARM boxes kindly provided by the ARM Ltd
to the DARPA CHERI Project.
In collaboration with: andrew
Reviewed by: andrew
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D23349
The race is:
CPU1 CPU2
devfs_reclaim_vchr
make v_usecount 0
VI_LOCK
sees v_usecount == 0, no updates
vp->v_rdev = NULL;
...
VI_UNLOCK
VI_LOCK
v_decr_devcount
sees v_rdev == NULL, no updates
In this scenario si_devcount decrement is not performed.
Note this can only happen if the vnode lock is not held.
Reviewed by: kib
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D23529
handler.
Interrupt handlers are removed via intr_event_execute_handlers() when
IH_DEAD is set. The thread removing the interrupt is woken up, and
calls intr_event_update(). When this happens, the ie_hflags are
cleared and re-built from all the remaining handlers sharing the
event. When the last IH_NET handler is removed, the IH_NET flag will
be cleared from ih_hflags (or ie_hflags may still be being rebuilt in
a different context), and the ithread_execute_handlers() may return
with ie_hflags missing IH_NET. This can lead to a scenario where
IH_NET was present before calling ithread_execute_handlers, and is not
present at its return, meaning the need for epoch must be cached
locally.
This can happen when loading and unloading network drivers. Also make
sure the ie_hflags is not cleared before being updated.
This is a regression issue after r357004.
Backtrace:
panic()
# trying to access epoch tracker on stack of dead thread
_epoch_enter_preempt()
ifunit_ref()
ifioctl()
fo_ioctl()
kern_ioctl()
sys_ioctl()
syscallenter()
amd64_syscall()
Differential Revision: https://reviews.freebsd.org/D23483
Reviewed by: glebius@, gallatin@, mav@, jeff@ and kib@
Sponsored by: Mellanox Technologies
Currently, the vm.panic_on_oom sysctl is a boolean which controls the
behavior of the VM system when it encounters an out-of-memory situation.
If set to 0, the VM system kills the largest process. If set to any other
value, the VM system will initiate a panic.
This change makes the sysctl a count of events. If set to 0, the VM system
kills the largest process. If set to any other value, the VM system will
kill the largest process until it has seen the specified number of
out-of-memory events. Once it reaches the specified number of events, it
will initiate a panic.
This change is helpful in capturing cores when the system is in a perpetual
cycle of out-of-memory events (as opposed to just hitting one or two
sporadic out-of-memory events).
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D23601
vrele is supposed to be called with an unlocked vnode, but this was never
asserted for if v_usecount was > 0. For such counts the lock is never touched
by the routine. As a result the kernel has several consumers which expect
vunref semantics and get away with calling vrele since they happen to never do
it when this is the last reference (and for some of them this may happen to be
a guarantee).
Work around the problem by changing vrele semantics to tolerate being called
with a lock. This eliminates a possible bug where the lock is already held and
vputx takes it anyway.
Reviewed by: kib
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D23528
- only compute the target address once
- remove spurious type casting, zpcpu_get already return the correct type
While here add missing newlines to other routines.
The intent is to provide bsd-specific flags relevant to interpreter
and C runtime. I did not want to reuse AT_FLAGS which is common ELF
auxv entry.
Use bsdflags to report kernel support for sigfastblock(2). This
allows rtld and libthr to safely infer the syscall presence without
SIGSYS. The tunable kern.elf{32,64}.sigfastblock blocks reporting.
Tested by: pho
Disscussed with: cem, emaste, jilles
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D12773
A new syscall sigfastblock(2) is added which registers a uint32_t
variable as containing the count of blocks for signal delivery. Its
content is read by kernel on each syscall entry and on AST processing,
non-zero count of blocks is interpreted same as the signal mask
blocking all signals.
The biggest downside of the feature that I see is that memory
corruption that affects the registered fast sigblock location, would
cause quite strange application misbehavior. For instance, the process
would be immune to ^C (but killable by SIGKILL).
With consumers (rtld and libthr added), benchmarks do not show a
slow-down of the syscalls in micro-measurements, and macro benchmarks
like buildworld do not demonstrate a difference. Part of the reason is
that buildworld time is dominated by compiler, and clang already links
to libthr. On the other hand, small utilities typically used by shell
scripts have the total number of syscalls cut by half.
The syscall is not exported from the stable libc version namespace on
purpose. It is intended to be used only by our C runtime
implementation internals.
Tested by: pho
Disscussed with: cem, emaste, jilles
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D12773
This patch introduces processing of the frames
up to 9kB by the mvneta driver. Some versions of
this NIC limit TX checksum offloading, depending
on the frame size, so add appropriate handling
of this feature.
Submitted by: Kornel Duleba
Obtained from: Semihalf
Sponsored by: Stormshield
Differential Revision: https://reviews.freebsd.org/D23225
To make the PMC tool pmcstat working properly on Hygon platform, add
support for Hygon Dhyana family 18h by using the PMC initialization
code path of AMD family 17h.
Submitted by: Pu Wen <puwen@hygon.cn>
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D23562
Currently the installer will tag geliboot partitions with both BOOT and
GELIBOOT; the former allows the kernel to taste it at boot, while the latter
is what loaders keys off of.
However, it seems reasonable to assume that if a provider's been tagged with
GELIBOOT that the kernel should also take that as a hint to taste/attach at
boot. This would allow us to stop tagging GELIBOOT partitions with BOOT in
bsdinstall, but I'm not sure that there's a compelling reason to do so any
time soon.
Reviewed by: oshogbo
Differential Revision: https://reviews.freebsd.org/D23387
