flags, to rwlock. Lock it in read mode when used from subroutines
called from buffer release code paths.
The needsbuffer is now updated using atomics, while read lock of
nblock prevents loosing the wakeups from bufspacewakeup() and
bufcountadd() in getnewbuf_bufd_help().
In several interesting loads, needsbuffer flags are never set, while
buffers are reused quickly. This causes brelse() and bqrelse() from
different threads to content on the nblock. Now they take nblock in
read mode, together with needsbuffer not needing an update, allowing
higher parallelism.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
This allows to mostly avoid lock usage in getnewvnode_[drop_]reserve(),
that reduces number of global vnode_free_list_mtx mutex acquisitions
from 4 to 2 per NFS request on ZFS, improving SMP scalability.
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
using a direct hook called from kern_vfs_bio_buffer_alloc().
Mark ffs_rawread.c as requiring both ffs and directio options to be
compiled into the kernel. Add ffs_rawread.c to the list of ufs.ko
module' sources.
In addition to stopping breaking the layering violation, it also
allows to link kernel when FFS is configured as module and DIRECTIO is
enabled.
One consequence of the change is that ffs_rawread.o is always linked
into the module regardless of the DIRECTIO option. This is similar to
the option QUOTA and ufs_quota.c.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
In the .o file, this only changes some line numbers (head amd64) because
element 0 is no longer explicitly initialized.
This should make bugs like FreeBSD-SA-14:12.ktrace less likely.
Discussed with: des
MFC after: 1 week
interface allows the ifnet structure to be defined as an opaque
type in NIC drivers. This then allows the ifnet structure to be
changed without a need to change or recompile NIC drivers.
Put differently, NIC drivers can be written and compiled once and
be used with different network stack implementations, provided of
course that those network stack implementations have an API and
ABI compatible interface.
This commit introduces the 'if_t' type to replace 'struct ifnet *'
as the type of a network interface. The 'if_t' type is defined as
'void *' to enable the compiler to perform type conversion to
'struct ifnet *' and vice versa where needed and without warnings.
The functions that implement the API are the only functions that
need to have an explicit cast.
The MII code has been converted to use the driver API to avoid
unnecessary code churn. Code churn comes from having to work with
both converted and unconverted drivers in correlation with having
callback functions that take an interface. By converting the MII
code first, the callback functions can be defined so that the
compiler will perform the typecasts automatically.
As soon as all drivers have been converted, the if_t type can be
redefined as needed and the API functions can be fix to not need
an explicit cast.
The immediate benefactors of this change are:
1. Juniper Networks - The network stack implementation in Junos
is entirely different from FreeBSD's one and this change
allows Juniper to build "stock" NIC drivers that can be used
in combination with both the FreeBSD and Junos stacks.
2. FreeBSD - This change opens the door towards changing ifnet
and implementing new features and optimizations in the network
stack without it requiring a change in the many NIC drivers
FreeBSD has.
Submitted by: Anuranjan Shukla <anshukla@juniper.net>
Reviewed by: glebius@
Obtained from: Juniper Networks, Inc.
This _was_ right, a last minute suggestion and not enough testing makes
Adrian a bad boy.
Tested:
* igb(4) with RSS patches, by hand verifying each igb(4) taskqueue
tid from procstat -ka using cpuset -g -t <tid>.
flags that has several bits cleared. The RF_WANTED and RF_FIRSTSHARE
bits are invalid in this context, and we want to defer setting RF_ACTIVE
in r_flags until later. This should make rman_get_flags() return
the correct answer in all cases.
Add a KASSERT() to catch callers which incorrectly pass the RF_WANTED
or RF_FIRSTSHARE flags.
Do a strict equality check on the share type bits of flags. In
particular, do an equality check on RF_PREFETCHABLE. The previous
code would allow one type of mismatch of RF_PREFETCHABLE but disallow
the other type of mismatch. Also, ignore the the RF_ALIGNMENT_MASK
bits since alignment validity should be handled by the amask check.
This field contains an integer value, but previous code did a strange
bitwise comparison on it.
Leave the original value of flags unmolested as a minor debug aid.
Change the start+amask overflow check to a KASSERT() since it is just
meant to catch a highly unlikely programming error in the caller.
Reviewed by: jhb
MFC after: 1 month
taskqueue worker thread(s) to.
For now it isn't a taskqueue/taskthread error to fail to pin
to the given cpuid.
Thanks to rpaulo@, kib@ and jhb@ for feedback.
Tested:
* igb(4), with local RSS patches to pin taskqueues.
TODO:
* ask the doc team for help in documenting the new API call.
* add a taskqueue_start_threads_cpuset() method which takes
a cpuset_t - but this may require a bunch of surgery to
bring cpuset_t into scope.
Assert that the hold count has not fallen below the use count, a situation
that would only happen when a vref() (or similar) is erroneously paired
with a vdrop(). This situation has not been observed in the wild, but
could be helpful for someone implementing a new filesystem.
Reviewed by: kib
Approved by: hrs (mentor)
on execve(2), it calls vmspace_exec(), which frees the current
vmspace. The thread executing an exec syscall gets new vmspace
assigned, and old vmspace is freed if only referenced by the current
process. The free operation includes pmap_release(), which
de-constructs the paging structures used by hardware.
If the calling process is multithreaded, other threads are suspended
in the thread_suspend_check(), and need to be unsuspended and run to
be able to exit on successfull exec. Now, since the old vmspace is
destroyed, paging structures are invalid, threads are resumed on the
non-existent pmaps (page tables), which leads to triple fault on x86.
To fix, postpone the free of old vmspace until the threads are resumed
and exited. To avoid modifications to all image activators all of
which use exec_new_vmspace(), memoize the current (old) vmspace in
kern_execve(), and notify it about the need to call vmspace_free()
with a thread-private flag TDP_EXECVMSPC.
http://bugs.debian.org/743141
Reported by: Ivo De Decker <ivo.dedecker@ugent.be> through secteam
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Replace with the existing loop termination test with a similar
condition from the nested "if" that may terminate the loop a bit
sooner, but still not too early. This condition can then be removed
from the nested "if". Relocate an operator to be style(9) compliant.
MFC after: 3 days
If the underlying protocol reported an error (e.g. because a connection was
closed while waiting in the queue), this error was also indicated by
returning a zero-length address. For all other kinds of errors (e.g.
[EAGAIN], [ENFILE], [EMFILE]), *addrlen is unmodified and there are
successful cases where a zero-length address is returned (e.g. a connection
from an unbound Unix-domain socket), so this error indication is not
reliable.
As reported in Austin Group bug #836, modifying *addrlen on error may cause
subtle bugs if applications retry the call without resetting *addrlen.
running at, guess the nearest value instead of looking for a value within
25 MHz of the observed frequency.
Prior to this change, if a system booted with Intel Turbo Boost enabled,
the dev.cpu.0.freq sysctl is nonfunctional, since the ACPI-reported
frequency for Turbo Boost states does not match the actual clock frequency
(and thus no levels are within 25 MHz of the observed frequency) and the
current performance level is read before a new level is set.
MFC after: 3 days
Relnotes: Bug fix in power management on CPUs with Intel Turbo Boost
Under enough load, the swi's can actually be preempted and migrated
to other currently free cores. When doing RSS experiments, this lead
to the per-CPU TCP timers not lining up any more with the RX CPU said
flows were ending up on, leading to increased lock contention.
Since there was a little pushback on flipping them on by default,
I've left the default at "don't pin."
The other less obvious problem here is that the default swi
is also the same as the destination swi for CPU #0. So if one
pins the swi on CPU #0, there's no default floating swi.
A nice future project would be to create a separate swi for
the "default" floating swi, as well as per-CPU swis that are
(optionally) pinned.
Tested:
* parallel TCP tests (2 x 1g unfortunately for now);
CPU: Intel(R) Xeon(R) CPU E5-2650
Note:
This is based on some initial investigation into RSS/TCP stack lock
contention on FreeBSD-HEAD whilst at Netflix in January 2014.
rman_reserve_resource_bound() to return incorrect results.
Continue the initial search until the first viable region is found.
Add a comment to explain the search termination test.
PR: kern/188534
Reviewed by: jhb (previous version)
MFC after: 1 week
for lockmgr and sx interlocks, but unused since optimised versions of
those sleep locks were introduced. This will save a (quite) small
amount of memory in all kernel configurations. The sleep mutex pool is
retained as it is used for 'struct bio' and several other consumers.
Discussed with: jhb
MFC after: 3 days
It can fail if pipe map is exhausted (as a result of too many pipes created),
but it is not fatal and could be provoked by unprivileged users. The only
consequence is worse performance with given pipe.
Reported by: ivoras
Suggested by: kib
MFC after: 1 week
If time_t is 64-bit (i.e. isn't 32-bit) allow any value of year, not
just years less than 2038.
Don't bother fixing the underflow in the case of years before 1903.
MFC after: 1 week
Sponsored by: DARPA, AFRL
pmap pvlist locks which are scaled by MAXCPU.
This allows an amd64 system to boot with MAXCPU set
to 256, which is currently FreeBSD's hard limit without
x2apic support.
Compile-tested for other arch's.
PR: 185831
Discussed with: jhb
MFC after: 3 weeks
old devd's and thus hosts that get IP addresses from DHCP was too much
of a POLA violation.
The sysctl may be removed again after r263758 has been merged to at
least stable/9 and stable/10, and releases have been cut from those
branches.
Discussed with: mjg
Reported by: theraven, rwatson
the cpufreq code. Replace its use with smp_started. There's at least
one userland tool that still looks at the kern.smp.active sysctl, so
preserve it but point it to smp_started as well.
Discussed with: peter, jhb
MFC after: 3 days
Obtained from: Netflix
Due to the way those timers are implemented, we can't handle very short
intervals. In addition to that mentioned patch caused math overflows
for short intervals. To avoid that round those intervals to 1 tick.
PR: kern/187668
MFC after: 1 week
SBT_MAX, to make it more robust in case internal type representation will
change in the future. All the consumers were migrated to SBT_MAX and
every new consumer (if any) should from now use this interface.
Requested by: bapt, jmg, Ryan Lortie (implictly)
Reviewed by: mav, bde
execution to a emumation program via parsing of ELF header information.
With this kernel module and userland tool, poudriere is able to build
ports packages via the QEMU userland tools (or another emulator program)
in a different architecture chroot, e.g. TARGET=mips TARGET_ARCH=mips
I'm not connecting this to GENERIC for obvious reasons, but this should
allow the kernel module to be built by default and enable the building
of the userland tool (which automatically loads the kernel module).
Submitted by: sson@
Reviewed by: jhb@
