have some negative effect on interactivity but it yields great perf. gains.
This also brings the conditions under which ULE context switches inline
with SCHED_4BSD.
- Define some new kseq_* functions for manipulating the run queue.
- Add a new kseq member ksq_rslices and ksq_bload. rslices is the sum of
the slices of runnable kses. This will be used for push load balance
decisions. bload is the number of threads blocked waiting on IO.
I'm not convinced there is anything major wrong with the patch but
them's the rules..
I am using my "David's mentor" hat to revert this as he's
offline for a while.
than having change_dir() release the vnode lock on success, hold the
lock so that we can use it later when invoking MAC checks and
VOP_ACCESS() in the chroot() code. Update the comment to reflect
this calling convention. Update callers to unlock the vnode
lock. Correct a typo regarding vnode naming in the MAC case that
crept in via the previous patch applied.
cases: we might multiply vrele() a vnode when certain classes of
failures occur. This appears to stem from earlier Giant/file
descriptor lock pushdown and restructuring.
Submitted by: maxim
This implicitly removes the need for major numbers, but a number of
drivers still know things they shouldn't need to, and we need to
consider if there are applications which cache major(+minor) gleaned
from stat(2) and rely on it being constant over reboots before we
start assigning random majors.
sched_runnable() et all.
- Remove some dead code in sched_clock().
- Define two macros KSEQ_SELF() and KSEQ_CPU() for getting the kseq of the
current cpu or some alternate cpu.
- Start introducing kseq_() functions, such as kseq_choose() and kseq_setup().
run queue for each cpu.
- Introduce kse stealing into the sched_choose() code. This helps balance
cpus better in cases where process turnover is high. This implementation
is fairly trivial and will likely be only a temporary measure until
something more sophisticated has been written.
data structure called kse_upcall to manage UPCALL. All KSE binding
and loaning code are gone.
A thread owns an upcall can collect all completed syscall contexts in
its ksegrp, turn itself into UPCALL mode, and takes those contexts back
to userland. Any thread without upcall structure has to export their
contexts and exit at user boundary.
Any thread running in user mode owns an upcall structure, when it enters
kernel, if the kse mailbox's current thread pointer is not NULL, then
when the thread is blocked in kernel, a new UPCALL thread is created and
the upcall structure is transfered to the new UPCALL thread. if the kse
mailbox's current thread pointer is NULL, then when a thread is blocked
in kernel, no UPCALL thread will be created.
Each upcall always has an owner thread. Userland can remove an upcall by
calling kse_exit, when all upcalls in ksegrp are removed, the group is
atomatically shutdown. An upcall owner thread also exits when process is
in exiting state. when an owner thread exits, the upcall it owns is also
removed.
KSE is a pure scheduler entity. it represents a virtual cpu. when a thread
is running, it always has a KSE associated with it. scheduler is free to
assign a KSE to thread according thread priority, if thread priority is changed,
KSE can be moved from one thread to another.
When a ksegrp is created, there is always N KSEs created in the group. the
N is the number of physical cpu in the current system. This makes it is
possible that even an userland UTS is single CPU safe, threads in kernel still
can execute on different cpu in parallel. Userland calls kse_create to add more
upcall structures into ksegrp to increase concurrent in userland itself, kernel
is not restricted by number of upcalls userland provides.
The code hasn't been tested under SMP by author due to lack of hardware.
Reviewed by: julian
potential discontinuities in our UTC timescale.
Applications can monitor this variable if they want to be informed
about steps in the timescale. Slews (ntp and adjtime(2)) and
frequency adjustments (ntp) will not increment this counter, only
operations which set the clock. No attempt is made to classify
size or direction of the step.
correctly against PF_LOCAL. It seems that the test always fails then
sockaddr was not filled. So, I added else clause for workaround.
I doubt if it is right fix. However, it is better than nothing. I
found that NetBSD has same potential problem. But, fortunately,
NetBSD has equivalent else clause.
MFC after: 1 week
1. eliminate unnecessary loop which frees and re-allocates
the just allocated array
2. eliminate the newsize recomputation
3. eliminate unnecessary unlock and relock around free
4. correctly match the free with the malloc into M_KQUEUE instead of M_TEMP
5. eliminate conditional assignment of oldlist, which is equivalent to a
simple assignment
6. eliminate the oldlist temporary variable completely
Reviewed by: jhb
