It's still relatively uncommon to see C11 '<threads.h>' being used,
but it's worth documenting, especially since FreeBSD requires a
different library for C11 threads compared to glibc (part of '-lpthread')
or musl libc (included by default).
PR: 267551
Submitted by: Alois Klink <alois plus freebsd at aloisklink dot com>
Reviewed by: pauamma
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D37284
In kern_sched_setparam(), before setting any parameters, p_cansched() is
called to check that the thread has appropriate privileges.
PR: 175687
Reviewed by: markj
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D37020
When the node to insert in the rb_tree is known to precede or follow a
particular node, new methods RB_INSERT_PREV and RB_INSERT_NEXT,
defined here, allow the search for where to insert the new node begin
with that particular node, rather than at the root, to save a bit of
time.
Using those methods, instead of RB_INSERT, in managing a tree in
iommu_gas.c, saves a little time.
Reviewed by: kib
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D35516
RB-tree augmentation maintains data in each node of the tree that
represents the product of some associative operator applied to all the
nodes of the subtree rooted at that node. If a node in the tree
changes, augmentation data for the node is updated for that node and
all nodes on the path from that node to the tree root. However,
sometimes, augmenting a node changes no data in that node,
particularly if the associated operation is something involving 'max'
or 'min'. If augmentation changes nothing in a node, then the work of
walking to the tree root from that point is pointless, because
augmentation will change nothing in those nodes either. This change
makes it possible to avoid that wasted work.
Define RB_AUGMENT_CHECK as a macro much like RB_AUGMENT, but which
returns a value 'true' when augmentation changes the augmentation data
of a node, and false otherwise. Change code that unconditionally walks
and augments to the top of tree to code that stops once an
augmentation has no effect. In the case of rebalancing the tree after
insertion or deletion, where previously a node rotated into the path
was inevitably augmented on the march to the tree root, now check to
see if it needs augmentation because the march to the tree root
stopped before reaching it.
Change the augmentation function in iommu_gas.c so that it returns
true/false to indicate whether the augmentation had any effect.
Reviewed by: alc, kib
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D36509
In collaboration with: dougm
Reviewed by: alc
Sponsored by: The FreeBSD Foundation (kib)
MFC after: 3 days
Differential revision: https://reviews.freebsd.org/D36001
For an augmented rb_tree, allow a faster alternative to removing an
element from the tree, tweaking it slightly, and inserting it back
into the tree, knowing that its relative position in the tree is
unchanged. Instead, just change the element and invoke
RB_UPDATE_AUGMENT to fix the augmentation data for all the nodes in
the tree.
Reviewed by: kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D36010
Document the RB_AUGMENT macro, and provide an example of its use.
Reviewed by: alc, kib
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D35518
Linux has more tolerant checks of the user supplied cpuset_t's.
Minimum cpuset_t size that the Linux kernel permits in case of
getaffinity() is the maximum CPU id, present in the system / NBBY,
the maximum size is not limited.
For setaffinity(), Linux does not limit the size of the user-provided
cpuset_t, internally using only the meaningful part of the set, where
the upper bound is the maximum CPU id, present in the system, no larger
than the size of the kernel cpuset_t.
Unlike FreeBSD, Linux ignores high bits if set in the setaffinity(),
so clear it in the sched_setaffinity() and Linuxulator itself.
Reviewed by: Pau Amma (man pages)
In collaboration with: jhb
Differential revision: https://reviews.freebsd.org/D34849
MFC after: 2 weeks
vm_reserv.c uses its own bitstring implemenation for popmaps. Using
the bitstring_t type from a standard header eliminates the code
duplication, allows some bit-at-a-time operations to be replaced with
more efficient bitstring range operations, and, in
vm_reserv_test_contig, allows bit_ffc_area_at to more efficiently
search for a big-enough set of consecutive zero-bits.
Make bitstring changes improve the vm_reserv code. Define a bit_ntest
method to test whether a range of bits is all set, or all clear.
Define bit_ff_at and bit_ff_area_at to implement the ffs and ffc
versions with a parameter to choose between set- and clear- bits.
Improve the area_at implementation. Modify the bit_nset and
bit_nclear implementations to allow code optimization in the cases
when start or end are multiples of _BITSTR_BITS.
Add a few new cases to bitstring_test.
Discussed with: alc
Reviewed by: markj
Tested by: pho (earlier version)
Differential Revision: https://reviews.freebsd.org/D33312
This makes the left column narrower, leaving more space for the text.
Reviewed By: debdrup, 0mp
Differential Revision: https://reviews.freebsd.org/D33385
The descriptions may be more elaborated of course, but this is a good
step at starting providing any useful information in our man page, at all.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Differential revision: https://reviews.freebsd.org/D32243
The macro bit_foreach() traverses all set bits in the bitstring in the
forward direction, assigning each location in turn to variable.
The macro bit_foreach_at() traverses all set bits in the bitstring in
the forward direction at or after the zero-based bit index, assigning
each location in turn to variable.
The bit_foreach_unset() and bit_foreach_unset_at() macros which
traverses unset bits are implemented for completeness.
Reviewed by: asomers, dougm
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D31469
The syscall number is stored in the same register as the syscall return
on amd64 (and possibly other architectures) and so it is impossible to
recover in the signal handler after the call has returned. This small
tweak delivers it in the `si_value` field of the signal, which is
sufficient to catch capability violations and emulate them with a call
to a more-privileged process in the signal handler.
This reapplies 3a522ba1bc with a fix for
the static assertion failure on i386.
Approved by: markj (mentor)
Reviewed by: kib, bcr (manpages)
Differential Revision: https://reviews.freebsd.org/D29185
The syscall number is stored in the same register as the syscall return
on amd64 (and possibly other architectures) and so it is impossible to
recover in the signal handler after the call has returned. This small
tweak delivers it in the `si_value` field of the signal, which is
sufficient to catch capability violations and emulate them with a call
to a more-privileged process in the signal handler.
Approved by: markj (mentor)
Reviewed by: kib, bcr (manpages)
Differential Revision: https://reviews.freebsd.org/D29185
This is a prerequisite to allowing the use of hardware watchpoints for
userspace debuggers.
This is also a slight departure from the x86 behaviour, since `si_addr`
returns the data address that triggered the watchpoint, not the
address of the instruction that was executed. Otherwise, there is no
straightforward way for the application to determine which watchpoint
was triggered. Make a note of this in the siginfo(3) man page.
Reviewed by: jhb, markj (earlier version)
Tested by: Michał Górny (mgorny@gentoo.org)
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D28561
WITHOUT_LIBTHR has been broken for a little over five years now, since the
xz 5.2.0 update introduced a hard liblzma dependency on libthr, and building
a useful system without threading support is becoming increasingly more
difficult.
Additionally, in the five plus years that it's been broken more reverse
dependencies have cropped up in libzstd, libsqlite3, and libcrypto (among
others) that make it more and more difficult to reconcile the effort needed
to fix these options.
Remove the broken options.
PR: 252760
Reviewed by: brooks, emaste, kib
Differential Revision: https://reviews.freebsd.org/D28263
- Extend the list of main libraries of section 3
- Extend the library functions that are included in the libc
MFC after: 2 weeks
Submitted by: Naga Chaitanya Vellanki <pnagato at protonmail dot com>
Approved by: gbe
Differential Revision: https://reviews.freebsd.org/D26476
- In the initial description of si_addr, do not claim that it is
always the faulting instruction.
- For si_addr, document that it is generally set to the PC for
synchronous signals, but that it can be set to the the address of
the faulting memory reference for some signals including SIGSEGV and
SIGBUS. In particular, while SIGSEGV generally sets si_addr to the
faulting memory reference, SIGBUS can vary. On some platforms, some
SIGBUS signals set si_addr to the PC and other SIGBUS signals set
si_addr to the faulting address depending on the specific hardware
exception.
- For si_trapno, synchronous signals should set this to some value.
Reviewed by: kib
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D25777
AVL trees, red-black trees, and others. Weak AVL (wavl) trees are a
recently discovered member of that class. This change replaces
red-black rebalancing with weak AVL rebalancing in the RB tree macros.
Wavl trees sit between AVL and red-black trees in terms of how
strictly balance is enforced. They have the stricter balance of AVL
trees as the tree is built - a wavl tree is an AVL tree until the
first deletion. Once removals start, wavl trees are lazier about
rebalancing than AVL trees, so that removals can be fast, but the
balance of the tree can decay to that of a red-black tree. Subsequent
insertions can push balance back toward the stricter AVL conditions.
Removing a node from a wavl tree never requires more than two
rotations, which is better than either red-black or AVL
trees. Inserting a node into a wavl tree never requires more than two
rotations, which matches red-black and AVL trees. The only
disadvantage of wavl trees to red-black trees is that more insertions
are likely to adjust the tree a bit. That's the cost of keeping the
tree more balanced.
Testing has shown that for the cases where red-black trees do worst,
wavl trees better balance leads to faster lookups, so that if lookups
outnumber insertions by a nontrivial amount, lookup time saved exceeds
the extra cost of balancing.
Reviewed by: alc, gbe, markj
Tested by: pho
Discussed with: emaste
Differential Revision: https://reviews.freebsd.org/D25480
pthread_get_name_np() and pthread_set_name_np().
This re-applies r361770 after compatibility fixes.
Reviewed by: antoine, jkim, markj
Tested by: antoine (exp-run)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D25117
for pthread_get_name_np() and pthread_set_name_np(), to be
compatible with Linux.
PR: 238404
Proposed and reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D25117
- Abbreviated month name in .Dd
- position of HISTORY section
- alphabetical ordering within SEE ALSO section
- adding .Ed before .Sh DESCRIPTION
- remove trailing whitespaces
- Line break after a sentence stop
- Use BSD OS macros instead of hardcoded strings
No .Dd bumps as there was no actual content change made
in any of these pages.
Submitted by: Gordon Bergling gbergling_gmail.com
Approved by: bcr
Differential Revision: https://reviews.freebsd.org/D24591
Escape sequences like "\n" have to be escaped twice in examples in our
mdoc(7)-based manual pages in order to be displayed properly. The problem
is that otherwise they are interpreted by mdoc(7), which results in:
printf("parent: received '%s'0, buf);
being shown to the user instead of:
printf("parent: received '%s'\n", buf);
Approved by: bcr (mentor)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D24056
The function allows to peek at the thread exit status and even see
return value, without joining (and thus finally destroying) the target
thread.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation (kib)
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D23676
Add bit_ffs_area_at and bit_ffc_area_at functions for searching a bit
string for a sequence of contiguous set or unset bits of at least the
specified size.
The bit_ffc_area function will be used by the Intel ice driver for
implementing resource assignment logic using a bitstring to represent
whether or not a given index has been assigned or is currently free.
The bit_ffs_area, bit_ffc_area_at and bit_ffs_area_at functions are
implemented for completeness.
I'd like to add further test cases for the new functions, but I'm not
really sure how to add them easily. The new functions depend on specific
sequences of bits being set, while the bitstring tests appear to run for
varying bit sizes.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Submitted by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed by: asomers@, erj@
MFC after: 1 week
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D22400
This provides a framework to define a template describing
a set of "variables of interest" and the intended way for
the framework to maintain them (for example the maximum, sum,
t-digest, or a combination thereof). Afterwards the user
code feeds in the raw data, and the framework maintains
these variables inside a user-provided, opaque stats blobs.
The framework also provides a way to selectively extract the
stats from the blobs. The stats(3) framework can be used in
both userspace and the kernel.
See the stats(3) manual page for details.
This will be used by the upcoming TCP statistics gathering code,
https://reviews.freebsd.org/D20655.
The stats(3) framework is disabled by default for now, except
in the NOTES kernel (for QA); it is expected to be enabled
in amd64 GENERIC after a cool down period.
Reviewed by: sef (earlier version)
Obtained from: Netflix
Relnotes: yes
Sponsored by: Klara Inc, Netflix
Differential Revision: https://reviews.freebsd.org/D20477
and reinserting it back with an updated key.
This is one of dependencies for the upcoming stats(3) code.
Reviewed by: cem
Obtained from: Netflix
MFC after: 2 weeks
Sponsored by: Klara Inc, Netflix
Differential Revision: https://reviews.freebsd.org/D21786
to the traditional tree(3) RB trees, but using an array (preallocated,
linear chunk of memory) to store the tree.
This avoids allocation overhead, improves memory locality,
and makes it trivially easy to share/transfer/copy the entire tree
without the need for marshalling. The downside is that the size
is fixed at initialization time; there is no mechanism to resize
it.
This is one of the dependencies for the new stats(3) framework
(https://reviews.freebsd.org/D20477).
Reviewed by: bcr (man pages), markj
Discussed with: cem
MFC after: 2 weeks
Sponsored by: Klara Inc, Netflix
Obtained from: Netflix
Differential Revision: https://reviews.freebsd.org/D20324
This makes it possible to perform mathematical operations on
fractional values without using floating point. It operates on Q
numbers, which are integer-sized, opaque structures initialized
to hold a chosen number of integer and fractional bits.
For a general description of the Q number system, see the "Fixed Point
Representation & Fractional Math" whitepaper[1]; for the actual
API see the qmath(3) man page.
This is one of dependencies for the upcoming stats(3) framework[2]
that will be applied to the TCP stack in a later commit.
1. https://www.superkits.net/whitepapers/Fixed%20Point%20Representation%20&%20Fractional%20Math.pdf
2. https://reviews.freebsd.org/D20477
Reviewed by: bcr (man pages, earlier version), sef (earlier version)
Discussed with: cem, dteske, imp, lstewart
Sponsored By: Klara Inc, Netflix
Obtained from: Netflix
Differential Revision: https://reviews.freebsd.org/D20116
