races. This isn't currently necessary for libpthread or libthr, but
without it external threads libraries like the linuxthreads port are
not safe to use.
Reported by: ganbold@micom.mng.net
NULL. We currently do allow this to happen, but may want to remove that
possibility in the future. This case can occur when a socket is left
open after TCP wraps up, and the timewait state is recycled. This will
be cleaned up in the future.
Found by: Kazuaki Oda <kaakun at highway dot ne dot jp>
MFC after: 3 months
recycling for an unrelated filesystem. I really don't like potentially
acquiring giant in the context of a giantless filesystem but there
are reasonable objections to removing the recycling from this path.
Sponsored by: Isilon Systems, Inc.
have to be calculated once per allocator operation.
Make nil const.
Update various comments.
Remove/avoid division where possible.
For the one division operation that remains in the critical path, add a
switch statement that has a case for each small size class, and do division
with a constant divisor in each case. This allows the compiler to generate
optimized code that does not use hardware division [1].
Obtained from: peter [1]
o use atomic operations to fiddle with stopped_cpus and started_cpus.
o disable interrupts while we're waiting to be started.
o remove logic relating to cpustop_restartfunc as it's not used.
PCB in which the context of stopped CPUs is stored. To access this
PCB from KDB, we introduce a new define, called KDB_STOPPEDPCB. The
definition, when present, lives in <machine/kdb.h> and abstracts
where MD code saves the context. Define KDB_STOPPEDPCB on i386,
amd64, alpha and sparc64 in accordance to previous code.
with large mmap files mapped into many processes, this saves hundreds of
megabytes of ram.
pv entries were individually allocated and had two tailq entries and two
pointers (or addresses). Each pv entry was linked to a vm_page_t and
a process's address space (pmap). It had the virtual address and a
pointer to the pmap.
This change replaces the individual allocation with a per-process
allocation system. A page ("pv chunk") is allocated and this provides
168 pv entries for that process. We can now eliminate one of the 16 byte
tailq entries because we can simply iterate through the pv chunks to find
all the pv entries for a process. We can eliminate one of the 8 byte
pointers because the location of the pv entry implies the containing
pv chunk, which has the pointer. After overheads from the pv chunk
bitmap and tailq linkage, this works out that each pv entry has an
effective size of 24.38 bytes.
Future work still required, and other problems:
* when running low on pv entries or system ram, we may need to defrag
the chunk pages and free any spares. The stats (vm.pmap.*) show that
this doesn't seem to be that much of a problem, but it can be done if
needed.
* running low on pv entries is now a much bigger problem. The old
get_pv_entry() routine just needed to reclaim one other pv entry.
Now, since they are per-process, we can only use pv entries that are
assigned to our current process, or by stealing an entire page worth
from another process. Under normal circumstances, the pmap_collect()
code should be able to dislodge some pv entries from the current
process. But if needed, it can still reclaim entire pv chunk pages
from other processes.
* This should port to i386 really easily, except there it would reduce
pv entries from 24 bytes to about 12 bytes.
(I have integrated Alan's recent changes.)
- Use FBSDID in trap.c
- Make the global trap_sig[] static as it's not used outside of trap.c.
- In sendsig() remove an unused variable.
- In trap() sync with the other archs; for fast data access MMU miss and
data access protection traps set ksi_addr to the SFAR reg which contains
the faulting address and otherwise to the TPC reg. Generally the TCP reg
contains the address of the instruction that caused the exception, except
for fast instruction access traps (and some others; more refinement may
be needed here) it also contains the faulting address.
Previously sendsig() always set si_addr to the SFAR reg which is wrong
for most traps.
- In sendsig() add support for FreeBSD old-style signals.
These changes are inspired by kmacy's sun4v changes and allow libsigsegv
to build on FreeBSD/sparc64, but it doesn't pass all checks and tests it
actually should, yet.
MFC after: 5 days
in the commit log) submitted support for some NO_* knobs for delete-old*
and check-old. I converted it to the new WITHOUT_* knobs (more correctly:
MK_*) and added some dummy ones so that people can see what's missing.
Volunteers can have a look at http://phk.freebsd.dk/misc/build_options/
for a list of files.
The location looks a little bit odd to me, but I don't care about the
color of this bikeshed and follow the suggestion of our build
infrastructure guru to place it "somewhere under src/tools/ please". [1]
The build/mk/ directory looks more sane to me than the other ones there.
Submitted by: milosz.galazka@gmail.com
Suggested by: ru [1]
intr_disable() and intr_restore() resp. Previously, critical
regions would have interrupts disabled, but that was changed.
Consequently, the debugger could run with interrupts enabled.
This could cause problems for the low-level console code where
received characters would trigger an interrupt that causes
the interrupt handler to read the character instead of the
cngetc() function.
The INP_DROPPED check replaces the current NULL checks; the INP_TIMEWAIT
checks appear to have always been required, but not been there, which
is/was a bug. This avoids unconditionally casting of in_ppcb to a tcpcb,
when it may be a twtcb, which may have resulted in obscure ICMP-related
panics in earlier releases.
MFC after: 3 months
casts.
Consistently use intotw() to cast inp_ppcb pointers to struct tcptw *
pointers.
Consistently use intotcpcb() to cast inp_ppcb pointers to struct tcpcb *
pointers.
Don't assign tp to the results to intotcpcb() during variable declation
at the top of functions, as that is before the asserts relating to
locking have been performed. Do this later in the function after
appropriate assertions have run to allow that operation to be conisdered
safe.
MFC after: 3 months
