Commit Graph

1256 Commits

Author SHA1 Message Date
Poul-Henning Kamp
eb2da9a51f Simplify system time accounting for profiling.
Rename struct thread's td_sticks to td_pticks, we will need the
other name for more appropriately named use shortly.  Reduce it
from uint64_t to u_int.

Clear td_pticks whenever we enter the kernel instead of recording
its value as reference for userret().  Use the absolute value of
td->pticks in userret() and eliminate third argument.
2006-02-08 08:09:17 +00:00
Poul-Henning Kamp
5b1a8eb397 Modify the way we account for CPU time spent (step 1)
Keep track of time spent by the cpu in various contexts in units of
"cputicks" and scale to real-world microsec^H^H^H^H^H^H^H^Hclock_t
only when somebody wants to inspect the numbers.

For now "cputicks" are still derived from the current timecounter
and therefore things should by definition remain sensible also on
SMP machines.  (The main reason for this first milestone commit is
to verify that hypothesis.)

On slower machines, the avoided multiplications to normalize timestams
at every context switch, comes out as a 5-7% better score on the
unixbench/context1 microbenchmark.  On more modern hardware no change
in performance is seen.
2006-02-07 21:22:02 +00:00
Marius Strobl
44ac0964e9 Hook up le(4) to the build. For now it's only added to the sparc64 GENERIC
in order to support the on-board LANCE in Ultra 1 and to the MI NOTES as
it should work just fine with the AMD PCnet family of chips on all archs
but is not yet meant to replace lnc(4). If a kernel includes all of le(4),
lnc(4) and pcn(4) precedence is given to lnc(4)/pcn(4) for now.
2006-01-31 22:34:13 +00:00
Marius Strobl
bdbca4ddae o lsi64854_enet_intr():
- Like lsi64854_scsi_intr() return -1 in case there was a DMA error so
    the caller can distinguish it from a normal interrupt and leave the
    reset of the DMA engine to the caller so we don't kill any state there.
  - Move the static 'dodrain' flag to struct lsi64854_softc as there can
    be more than one LSI64854 used for a LANCE in a system and reset it
    again once draining the E-cache is done so we don't keep draining the
    cache with every interrupt.
  - Remove calling sc->sc_intrchain(), we will call lsi64854_enet_intr()
    via sc->intr() in the interrupt handler of the LANCE driver and not
    use it in chained mode.

o lsi64854_pp_intr():
  - Like lsi64854_scsi_intr() return -1 in case there was a DMA error so
    the caller can distinguish it from a normal interrupt.

o Remove the no longer used sc_intrchain* from struct lsi64854_softc.

o Make lsi64854_reset(), lsi64854_setup*() and lsi64854_*_intr() static
  to lsi64854.c as we do and will only call them via the respective
  function pointers in struct lsi64854_softc.

o While here fix style(9) bugs (variable definition inside a nested scope).
2006-01-31 12:50:02 +00:00
Marius Strobl
bc0dd76f3e Revert the part of rev. 1.3 which enabled the chaining of the DMA engine
interrupt handler for the LANCE devices and remove dma_setup_intr(). We
just can't completely ignore the DMA engine in a LANCE driver anyway and
calling the DMA engine interrupt handler in the LANCE driver directly
allows to cover it by the LANCE driver lock.
2006-01-30 21:43:14 +00:00
Marius Strobl
aa3ee926a9 - Register the generic implementations for the device shutdown, suspend
and resume methods so these events propagate through the device driver
  hierarchy.
- In dma(4) enable the chaining of the DMA engine interrupt handler for
  the LANCE devices via a dma_setup_intr(). This was commented out before
  as I was unsure whether I'd use it but this is probably cleaner than
  fiddling with the DMA engine interrupt in the LANCE driver directly.
- In ebus_setup_dinfo() free 'intrs' instead of 'reg' twice in case
  setting up a child fails due to routing one of its interrupts fails. [1]

Found by:	Coverity Prevent [1]
MFC after:	3 days
2006-01-26 21:14:32 +00:00
John Baldwin
14450110f3 Make the ACPI and OpenFirmware PCI bus drivers subclasses of the generic
PCI bus driver.
2006-01-20 22:01:34 +00:00
Kris Kennaway
0c6913cd9a Correct typos (s/OFERFLOW/OVERFLOW/).
Reviewed by:	jhb
2006-01-16 01:35:25 +00:00
Marius Strobl
a9f4f750ff - The inline asm in this file uses output operands before all input
operands are consumed so use the appropriate constraint modifier.
  Before this change GCC used one register for both an input and an
  unrelated output operand of in_addword(), causing the input to be
  overwritten before it was consumed and thus breaking in_addword().
  For in_cksum_hdr() and in_pseudo() this change is more or less
  cosmetic.
- Fix a misspelling in a nearby comment.

Reported & tested by:	yongari
MFC after:		1 week
2006-01-12 11:40:39 +00:00
Poul-Henning Kamp
d3e64681d6 Move the old BSD4.3 tty compatibility from (!BURN_BRIDGES && COMPAT_43)
to COMPAT_43TTY.

Add COMPAT_43TTY to NOTES and */conf/GENERIC

Compile tty_compat.c only under the new option.

Spit out
	#warning "Old BSD tty API used, please upgrade."
if ioctl_compat.h gets #included from userland.
2006-01-10 09:19:10 +00:00
John Baldwin
04dda605c5 - Make pcib_devclass private to sys/dev/pci/pci_pci.c and change all the
various pcib drivers to use their own private devclass_t variables for
  their modules.
- Use the DEFINE_CLASS_0() macro to declare drivers for the various pcib
  drivers while I'm here.
2006-01-06 19:22:19 +00:00
Joel Dahl
838036242a Remove references to snd_vortex1(4).
Approved by:	tanimura, ariff
2006-01-04 17:05:19 +00:00
Scott Long
72a067401e Use the correct units when handling the hw.physmem tunable. 2006-01-01 22:52:21 +00:00
Alexander Leidinger
ef39c05baa MI changes:
- provide an interface (macros) to the page coloring part of the VM system,
   this allows to try different coloring algorithms without the need to
   touch every file [1]
 - make the page queue tuning values readable: sysctl vm.stats.pagequeue
 - autotuning of the page coloring values based upon the cache size instead
   of options in the kernel config (disabling of the page coloring as a
   kernel option is still possible)

MD changes:
 - detection of the cache size: only IA32 and AMD64 (untested) contains
   cache size detection code, every other arch just comes with a dummy
   function (this results in the use of default values like it was the
   case without the autotuning of the page coloring)
 - print some more info on Intel CPU's (like we do on AMD and Transmeta
   CPU's)

Note to AMD owners (IA32 and AMD64): please run "sysctl vm.stats.pagequeue"
and report if the cache* values are zero (= bug in the cache detection code)
or not.

Based upon work by:	Chad David <davidc@acns.ab.ca> [1]
Reviewed by:		alc, arch (in 2004)
Discussed with:		alc, Chad David, arch (in 2004)
2005-12-31 14:39:20 +00:00
Pyun YongHyeon
1bd8f78656 Uncomment ti(4) as it's now working. 2005-12-28 02:59:16 +00:00
Maxim Sobolev
900b28f9f6 Remove kern.elf32.can_exec_dyn sysctl. Instead extend Brandinfo structure
with flags bitfield and set BI_CAN_EXEC_DYN flag for all brands that usually
allow executing elf dynamic binaries (aka shared libraries). When it is
requested to execute ET_DYN elf image check if this flag is on after we
know the elf brand allowing execution if so.

PR:		kern/87615
Submitted by:	Marcin Koziej <creep@desk.pl>
2005-12-26 21:23:57 +00:00
John Baldwin
b439e431bf Tweak how the MD code calls the fooclock() methods some. Instead of
passing a pointer to an opaque clockframe structure and requiring the
MD code to supply CLKF_FOO() macros to extract needed values out of the
opaque structure, just pass the needed values directly.  In practice this
means passing the pair (usermode, pc) to hardclock() and profclock() and
passing the boolean (usermode) to hardclock_cpu() and hardclock_process().
Other details:
- Axe clockframe and CLKF_FOO() macros on all architectures.  Basically,
  all the archs were taking a trapframe and converting it into a clockframe
  one way or another.  Now they can just extract the PC and usermode values
  directly out of the trapframe and pass it to fooclock().
- Renamed hardclock_process() to hardclock_cpu() as the latter is more
  accurate.
- On Alpha, we now run profclock() at hz (profhz == hz) rather than at
  the slower stathz.
- On Alpha, for the TurboLaser machines that don't have an 8254
  timecounter, call hardclock() directly.  This removes an extra
  conditional check from every clock interrupt on Alpha on the BSP.
  There is probably room for even further pruning here by changing Alpha
  to use the simplified timecounter we use on x86 with the lapic timer
  since we don't get interrupts from the 8254 on Alpha anyway.
- On x86, clkintr() shouldn't ever be called now unless using_lapic_timer
  is false, so add a KASSERT() to that affect and remove a condition
  to slightly optimize the non-lapic case.
- Change prototypeof  arm_handler_execute() so that it's first arg is a
  trapframe pointer rather than a void pointer for clarity.
- Use KCOUNT macro in profclock() to lookup the kernel profiling bucket.

Tested on:	alpha, amd64, arm, i386, ia64, sparc64
Reviewed by:	bde (mostly)
2005-12-22 22:16:09 +00:00
Pyun YongHyeon
57b183e13c Uncomment bge(4) as it's now working. 2005-12-22 01:46:28 +00:00
John Baldwin
4f9795b9fe Add a new method PCI_FIND_EXTCAP() to the pci bus interface that is used
to search for a specific extended capability.  If the specified capability
is found for the given device, then the function returns success and
optionally returns the offset of that capability.  If the capability is
not found, the function returns an error.
2005-12-20 19:57:47 +00:00
Marcel Moolenaar
757686b115 Make our ELF64 type definitions match standards. In particular this
means:
o  Remove Elf64_Quarter,
o  Redefine Elf64_Half to be 16-bit,
o  Redefine Elf64_Word to be 32-bit,
o  Add Elf64_Xword and Elf64_Sxword for 64-bit entities,
o  Use Elf_Size in MI code to abstract the difference between
   Elf32_Word and Elf64_Word.
o  Add Elf_Ssize as the signed counterpart of Elf_Size.

MFC after: 2 weeks
2005-12-18 04:52:37 +00:00
Marius Strobl
00d3c930da Fix a bug introduced in rev. 1.5; for retrieving the device_t of the
parent bridge of a PCI-PCI bridge we need two device_get_parent().
2005-12-12 16:07:11 +00:00
David E. O'Brien
ed698028bd style(9) nits 2005-12-07 03:41:12 +00:00
David E. O'Brien
87b00cfafe Add Sparc TLS relocation definitions. 2005-12-07 03:39:37 +00:00
John Baldwin
696effb697 - Cleanup whitespace and extra ()s in vtophys() macros.
- Move vtophys() macros next to vtopte() where vtopte() exists to match
  comments above vtopte().
- Remove references to the alternate address space in the comment above
  vtopte().  amd64 never had the alternate address space, and i386 lost it
  prior to PAE support being added.
- s/entires/entries/ in comments.

Reviewed by:	alc
2005-12-06 21:09:01 +00:00
Marius Strobl
b6c63e2a81 Use <sys/ktr.h> directly in .S files instead of exporting the
KTR_* class macros via genassym.c. Together with sys/sys/ktr.h
rev. 1.34 this has the desired side-effect of providing a default
value for KTR_COMPILE. Thus this fixes warnings from -Wundef
regarding KTR_COMPILE not being defined for .S files.

Requested by:	ru
Reviewed by:	ru
2005-12-06 16:38:08 +00:00
Ruslan Ermilov
224d140293 Drop _MACHINE_ARCH and _MACHINE defines (not to be confused with
MACHINE_ARCH and MACHINE).  Their purpose was to be able to test
in cpp(1), but cpp(1) only understands integer type expressions.
Using such unsupported expressions introduced a number of subtle
bugs, which were discovered by compiling with -Wundef.
2005-12-06 13:27:21 +00:00
Marius Strobl
58299dd09e - Move the declaration of struct upa_ranges and the UPA_RANGE_* macros
from sys/sparc64/include/ofw_upa.h to sys/sparc64/pci/ofw_pci.h and
  rename them to struct ofw_pci_ranges and OFW_PCI_RANGE_* respectively.
  This ranges struct only applies to host-PCI bridges but no to other
  bridges found on UPA. At the same time it applies to all host-PCI
  bridges regardless of whether the interconnection bus is Fireplane/
  Safari, JBus or UPA.
- While here rename the PCI_CS_* macros in sys/sparc64/pci/ofw_pci.h
  to OFW_PCI_CS_* in order to be consistent and change this header to
  use uintXX_t instead of u_intXX_t.
2005-12-03 19:52:20 +00:00
Marius Strobl
a244680c0f - Adhere style(9) (don't use function calls in initializers).
- Use FBSDID.
2005-12-03 18:52:31 +00:00
Marius Strobl
2c5bc54014 Remove unused sc_node from softc. 2005-12-03 18:14:47 +00:00
Marius Strobl
9ec0f71c35 - Adhere style(9) (don't use function calls in initializers, use uintXX_t
instead of u_intXX_t).
- Use FBSDID.
2005-12-03 18:11:26 +00:00
Marius Strobl
3a721a33cf - Register the PCI bus error interrupt handler according to which half of
the bridge (PCI bus A or B) we are attaching to rather than registering
  both handlers at once when attaching to the first half we encounter.
  This is a bit cleaner as it corresponds to which PCI bus error interrupt
  actually is assigned to the respective half by the OFW and allows to
  collapse both PCI bus error interrupt handlers into one function easily.
- Use the actual RID of the respective interrupt resource as index into
  sc_irq_res and also use it when allocating the resource. For now this
  is a bit cleaner and will be mandatory later on.
- According to OpenSolaris the spare hardware interrupt is used as the
  over-temperature interrupt in systems with Psycho bridges. Unlike as
  with the SBus-based workstations I didn't manage to trigger it when
  covering the fan outlets of an U60 but better be safe than sorry and
  register a handler anyway.

MFC after:	1 month
2005-12-03 16:36:54 +00:00
Marius Strobl
114bfbb64e - Improve the comment regarding the workaround for the E250 interrupt map
bug by explaining what the problem is and how the workaround works.
- Fix some cosmetics nits, mainly properly terminate sentences in comments,
  which I missed when backporting the style changes to psycho(4) in psycho.c
  rev. 1.54 due to lack of corresponding code.
- The "USIIe version of the Sabre bridge" actually is termed "Hummingbird";
  name it as such in comments and messages.
2005-12-03 13:08:05 +00:00
Marius Strobl
abffa5185a Remove superfluous bzero()'ing of the softc. 2005-11-30 16:13:49 +00:00
Marius Strobl
0b5f0b533a Remove superfluous inclusion of upa.h. 2005-11-30 16:09:10 +00:00
Ruslan Ermilov
6646524f34 - Allow duplicate "machine" directives with the same arguments.
- Move existing "machine" directives to DEFAULTS.
2005-11-27 23:17:00 +00:00
Marius Strobl
d13ea234b3 - Add a workaround (change the interrupt map mask to compare the full
INO) for incorrect interrupt map entries on E250 machines. These
  incorrect entries caused the INO of the on-board HME to be also
  assigned to the second on-board NS16550 and to the on-board printer
  port controller. Further down the road caused hme(4) to fail to attach
  to the on-board HME in FreeBSD 5 and 6 as INTR_FAST and non-INTR_FAST
  handlers can't share the same IRQ there (it's unknown what whould
  happen in -CURRENT now that INTR_FAST and non-INTR_FAST handlers can
  share an IRQ but I'd expect funny problems with uart(4)).
- Make sure there are exactly 4 PCI ranges instead of just checking
  that the bridge has a 'ranges' property in the OFW device tree at all.
  Besides the fact that currently the 64bit memory range isn't used by
  this driver it we can't really work with less than 4 ranges and don't
  have memory for more than 4 bus handles for the ranges in the softc.
- Remove sc_range and sc_nrange from softc; for the bridges supported
  by this driver we no longer need to know the ranges besides the bus
  handles obtained from them once this driver is attached. That way we
  also can free the memory allocated for sc_range during attach again.
- Remove sc_dvmabase from the softc and pass it to psycho_iommu_init()
  via an additional argument as we no longer need to know the DVMA base
  in this driver once the IOMMU is initialized.
- Remove sc_dmatag from the softc, there isn't much sense in keeping
  the nexus dma tag around locally.

PR:		88279 [1]
Info from:	OpenSolaris [1]
Tested by:	kensmith [1]
MFC after:	1 month
2005-11-22 22:32:50 +00:00
Marius Strobl
dcb740a42a Some clean-up, style changes and changes that will reduce differences
between this driver and other Host-PCI bridge drivers based on this one:

- Make the code fit into 80 columns.
- Make the code adhere style(9) (don't use function calls in initializers,
  use uintXX_t instead of u_intXX_t, add missing prototypes, ...).
- Remove unused and superfluous struct declaration, softc member, casts,
  includes, etc.
- Use FBSDID.
- Sprinkle const.
- Try to make comments and messages consistent in style throughout the
  driver.
- Use convenience macros for the number of interrupts and ranges of the
  bridge.
- Use __func__ instead of hardcoded function names in panic strings and
  error messages. Some of the hardcoded function names actually were
  outdated through moving code around. [1]
- Rename softc members related to the PCI side of the bridge to sc_pci_*
  in order to make it clear which side of the bridge they refer to (so
  stuff like sc_bushandle vs. sc_bh is less confusing while reading the
  code).

PR:	76052 [1]
2005-11-22 21:34:26 +00:00
Marius Strobl
a1a074b6b3 - Convert these bus drivers to make use of the newly introduced set of
ofw_bus_gen_get_*() for providing the ofw_bus KOBJ interface in order
  to reduce code duplication.
- While here sync the various sparc64 bus drivers a bit (handle failure
  to attach a child gracefully instead of panicing, move the printing
  of child resources common to bus_print_child() and bus_probe_nomatch()
  implementations of a bus into a <bus>_print_res() function, ...) and
  fix some minor bugs and nits (plug memory leaks present when attaching
  a bus or child device fails, remove unused struct members, ...).

Additional testing by:	kris (central(4) and fhc(4))
2005-11-22 16:39:44 +00:00
John Baldwin
72590141ef Turn PUC_FASTINTR back off on by default on sparc64 since it breaks with
the built-in serial ports on the ultra60 and e4500.

In collusion with:	kris
2005-11-21 21:40:33 +00:00
John Baldwin
7417e80b4e Don't enable PUC_FASTINTR by default in the source. Instead, enable it
via the DEFAULTS kernel configs.  This allows folks to turn it that option
off in the kernel configs if desired without having to hack the source.
This is especially useful since PUC_FASTINTR hangs the kernel boot on my
ultra60 which has two uart(4) devices hung off of a puc(4) device.

I did not enable PUC_FASTINTR by default on powerpc since powerpc does not
currently allow sharing of INTR_FAST with non-INTR_FAST like the other
archs.
2005-11-21 20:22:35 +00:00
John Baldwin
d0750fb9b0 Create DEFAULTS files for alpha, ia64, powerpc, and sparc64 and move
'device mem' over from GENERIC to DEFAULTS to be consistent with i386 and
amd64.  Additionally, on ia64 enable ACPI by default since ia64 requires
acpi.
2005-11-21 20:17:46 +00:00
Alan Cox
97a0c226d6 Eliminate pmap_init2(). It's no longer used. 2005-11-20 06:09:49 +00:00
Pyun YongHyeon
15757a936d Uncomment em(4) as it's now working. 2005-11-09 08:49:46 +00:00
Alan Cox
7a35a21e7b Reimplement the reclamation of PV entries. Specifically, perform
reclamation synchronously from get_pv_entry() instead of
asynchronously as part of the page daemon.  Additionally, limit the
reclamation to inactive pages unless allocation from the PV entry zone
or reclamation from the inactive queue fails.  Previously, reclamation
destroyed mappings to both inactive and active pages.  get_pv_entry()
still, however, wakes up the page daemon when reclamation occurs.  The
reason being that the page daemon may move some pages from the active
queue to the inactive queue, making some new pages available to future
reclamations.

Print the "reclaiming PV entries" message at most once per minute, but
don't stop printing it after the fifth time.  This way, we do not give
the impression that the problem has gone away.

Reviewed by: tegge
2005-11-09 08:19:21 +00:00
John Baldwin
091e8307d0 Add stoppcbs[] arrays on Alpha and sparc64 and have each CPU save its
current context in the IPI_STOP handler so that we can get accurate stack
traces of threads on other CPUs on these two archs like we do now on i386
and amd64.

Tested on:	alpha, sparc64
2005-11-03 21:08:20 +00:00
John Baldwin
e0f66ef861 Reorganize the interrupt handling code a bit to make a few things cleaner
and increase flexibility to allow various different approaches to be tried
in the future.
- Split struct ithd up into two pieces.  struct intr_event holds the list
  of interrupt handlers associated with interrupt sources.
  struct intr_thread contains the data relative to an interrupt thread.
  Currently we still provide a 1:1 relationship of events to threads
  with the exception that events only have an associated thread if there
  is at least one threaded interrupt handler attached to the event.  This
  means that on x86 we no longer have 4 bazillion interrupt threads with
  no handlers.  It also means that interrupt events with only INTR_FAST
  handlers no longer have an associated thread either.
- Renamed struct intrhand to struct intr_handler to follow the struct
  intr_foo naming convention.  This did require renaming the powerpc
  MD struct intr_handler to struct ppc_intr_handler.
- INTR_FAST no longer implies INTR_EXCL on all architectures except for
  powerpc.  This means that multiple INTR_FAST handlers can attach to the
  same interrupt and that INTR_FAST and non-INTR_FAST handlers can attach
  to the same interrupt.  Sharing INTR_FAST handlers may not always be
  desirable, but having sio(4) and uhci(4) fight over an IRQ isn't fun
  either.  Drivers can always still use INTR_EXCL to ask for an interrupt
  exclusively.  The way this sharing works is that when an interrupt
  comes in, all the INTR_FAST handlers are executed first, and if any
  threaded handlers exist, the interrupt thread is scheduled afterwards.
  This type of layout also makes it possible to investigate using interrupt
  filters ala OS X where the filter determines whether or not its companion
  threaded handler should run.
- Aside from the INTR_FAST changes above, the impact on MD interrupt code
  is mostly just 's/ithread/intr_event/'.
- A new MI ddb command 'show intrs' walks the list of interrupt events
  dumping their state.  It also has a '/v' verbose switch which dumps
  info about all of the handlers attached to each event.
- We currently don't destroy an interrupt thread when the last threaded
  handler is removed because it would suck for things like ppbus(8)'s
  braindead behavior.  The code is present, though, it is just under
  #if 0 for now.
- Move the code to actually execute the threaded handlers for an interrrupt
  event into a separate function so that ithread_loop() becomes more
  readable.  Previously this code was all in the middle of ithread_loop()
  and indented halfway across the screen.
- Made struct intr_thread private to kern_intr.c and replaced td_ithd
  with a thread private flag TDP_ITHREAD.
- In statclock, check curthread against idlethread directly rather than
  curthread's proc against idlethread's proc. (Not really related to intr
  changes)

Tested on:	alpha, amd64, i386, sparc64
Tested on:	arm, ia64 (older version of patch by cognet and marcel)
2005-10-25 19:48:48 +00:00
Pyun YongHyeon
4ba2acb3c4 Remove "nodevice snd_es137x" as it is supported now. 2005-10-25 04:05:48 +00:00
David Xu
0a567c0fcd Fix compiling. 2005-10-15 02:09:43 +00:00
Kris Kennaway
3c2adf40e9 Add a default value for VM_BCACHE_SIZE_MAX of 400MB. This is copied from
amd64, and is a factor of 3 less than the value previously auto-sized on
a 12GB machine, which would cause an overflow in calculations involving the
maxbcache int, causing bufinit() to loop forever at boot.

Reviewed by:	mlaier, peter
2005-10-14 20:31:12 +00:00
David Xu
9104847f21 1. Change prototype of trapsignal and sendsig to use ksiginfo_t *, most
changes in MD code are trivial, before this change, trapsignal and
   sendsig use discrete parameters, now they uses member fields of
   ksiginfo_t structure. For sendsig, this change allows us to pass
   POSIX realtime signal value to user code.

2. Remove cpu_thread_siginfo, it is no longer needed because we now always
   generate ksiginfo_t data and feed it to libpthread.

3. Add p_sigqueue to proc structure to hold shared signals which were
   blocked by all threads in the proc.

4. Add td_sigqueue to thread structure to hold all signals delivered to
   thread.

5. i386 and amd64 now return POSIX standard si_code, other arches will
   be fixed.

6. In this sigqueue implementation, pending signal set is kept as before,
   an extra siginfo list holds additional siginfo_t data for signals.
   kernel code uses psignal() still behavior as before, it won't be failed
   even under memory pressure, only exception is when deleting a signal,
   we should call sigqueue_delete to remove signal from sigqueue but
   not SIGDELSET. Current there is no kernel code will deliver a signal
   with additional data, so kernel should be as stable as before,
   a ksiginfo can carry more information, for example, allow signal to
   be delivered but throw away siginfo data if memory is not enough.
   SIGKILL and SIGSTOP have fast path in sigqueue_add, because they can
   not be caught or masked.
   The sigqueue() syscall allows user code to queue a signal to target
   process, if resource is unavailable, EAGAIN will be returned as
   specification said.
   Just before thread exits, signal queue memory will be freed by
   sigqueue_flush.
   Current, all signals are allowed to be queued, not only realtime signals.

Earlier patch reviewed by: jhb, deischen
Tested on: i386, amd64
2005-10-14 12:43:47 +00:00