Introduce TS_CONNECTED and TS_ZOMBIE states. TS_CONNECTED is set
while a connection is established. It is set while (TS_CARR_ON or
CLOCAL is set) and TS_ZOMBIE is clear. TS_ZOMBIE is set for on to
off transitions of TS_CARR_ON that occur when CLOCAL is clear and
is cleared for off to on transitions of CLOCAL. I/o can only occur
while TS_CONNECTED is set. TS_ZOMBIE prevents further i/o.
Split the input-event sleep address TSA_CARR_ON(tp) into TSA_CARR_ON(tp)
and TSA_HUP_OR_INPUT(tp). The former address is now used only for
off to on carrier transitions and equivalent CLOCAL transitions.
The latter is used for all input events, all carrier transitions
and certain CLOCAL transitions. There are some harmless extra
wakeups for rare connection- related events. Previously there were
too many extra wakeups for non-rare input events.
Drivers now call l_modem() instead of setting TS_CARR_ON directly
to handle even the initial off to on transition of carrier. They
should always have done this. l_modem() now handles TS_CONNECTED
and TS_ZOMBIE as well as TS_CARR_ON.
gnu/isdn/iitty.c:
Set TS_CONNECTED for first open ourself to go with bogusly setting
CLOCAL.
i386/isa/syscons.c, i386/isa/pcvt/pcvt_drv.c:
We fake carrier, so don't also fake CLOCAL.
kern/tty.c:
Testing TS_CONNECTED instead of TS_CARR_ON fixes TIOCCONS forgetting to
test CLOCAL. TS_ISOPEN was tested instead, but that broke when we disabled
the clearing of TS_ISOPEN for certain transitions of CLOCAL.
Testing TS_CONNECTED fixes ttyselect() returning false success for output
to devices in state !TS_CARR_ON && !CLOCAL.
Optimize the other selwakeup() call (this is not related to the other
changes).
kern/tty_pty.c:
ptcopen() can be declared in traditional C now that dev_t isn't short.
Make more functions static.
tty.c:
Use tcflag_t (u_long) and cc_t instead of u_char and int/long.
Don't record values that are only evaluated once.
Compare ints using imin(), not min(). min() is for comparing u_ints.
Old versions of tty.c used the type-safe but multiple-evaluation-unsafe
macro MIN(). The args are apparently never negative; otherwise this
change would be non-cosmetic.
Don't repeat the loop test in ttywait().
tty.h:
Improve English in and formatting of comments.
Use input buffer watermarks of TTYHOG-512 (high) and (high)*7/8
(low) instead of TTYHOG/2 (high) and TTYHOG/5 (low) to agree with
some drivers. 512 is magic and some things depended on TTYHOG/2
>= TTYHOG-512 to work; now they depend on the 512 magic not changing
and TTYHOG-512 being significantly larger than 0. This should be
handled in ttsetwater().
Separate the decision about whether to do input flow control from
doing it. ttyblock() now just starts input flow control (hardware
and/or software) and there is a new function ttyunblock() to stop
it. The decisions are the same except for the watermark changes
and allowing for input expansion for PARMRK.
When flushing input, try harder at first to send a start character
if required, but give up if the first attempt fails.
cy.c, rc.c, sio.c:
Simplify: let ttyinput() handle input flow control if it is not
being bypassed. Use ttyblock() to start flow control otherwise.
rc.c:
Use same input flow control test as elsewhere: test in a more
efficient order and start flow control at >= highwater instead of
at > highwater.
string as possible and return ENOMEM if the entire string cannot
be returned. This brings the routines in line with how the man
page says they work, and how the calling routines are expecting
them to work. This allows the dummy uname() routine in libc to
obtain the version string, since the kernel version string is
longer than that normally returned by the uname() routine.
This is 3/4 of the fix for PR# 462.
Reviewed by: Bruce Evans
as is required to be POSIXLY_CORRECT and "right". I interpret
"referring to a directory" as being a directory or becoming a
directory. E.g., the trailing slashes in mkdir("/nonesuch/"),
rename("/tmp", /nonesuch/") and link("/tmp", "/root_can_like_dirs/")
are ignored because the target will become a directory if the
syscall succeeds. A trailing slash on a symlink causes the symlink
to be followed (this is a bug if the symlink doesn't point to a
directory; fix later).
queues for TIOCSETA[W]. Swapping an even number of times broke
the queue resource limits. This would have broken CRTSCTS flow
control if the clist slush list was used up.
Don'concatenate the queues for TIOCSETA[W] if one of the queues
has a resource limit of 0. Concatenation would cause a panic if
one of the queues is nonempty and the other is limited to length
0. This may have caused panics in PPPDISC.
Wake up readers after all transitions of ICANON. When ICANON is
turned off it is quite likely that characters will become available
to be read.
Reduce indentation near these changes.
on output below low water) and TS_SO_OCOMPLETE (sleep on output complete).
Most of the support for this has already been committed. Drivers should
call ttwwakeup() to handle wakeups whenever output is below low water
(and some output event causes this condition to be checked) or TS_BUSY is
cleared.
tty.c:
Fix the livelock in ttywait() properly by sleeping on output complete, not
on output below low water.
Use ttwwakeup() instead of separate select and output wakeups for all
wakeups of writers.
Add wakeups of writers for output flushes and carrier/clocal transitions.
Don't go to sleep in ttycheckoutq() if ttstart() reduces the queue to below
low water.
Use the timeout built into tsleep() in ttycheckoutq().
Optimize the select wakeup in ttwwakeup(). It seems reasonable to know
too much about the internals of tp->t_wsel now that the knowledge is
localised in tty.c.
Remove nullmodem().
It may be useful to have a null modem routine, but nullmodem()
wasn't one. nullmodem() was identical to ttymodem() except it
didn't implement MDMBUF (carrier) flow control, didn't do any
wakeups for off to on carrier transitions, and didn't flush the
i/o queues for on to off carrier transitions (flushing has the side
effect of waking up readers and writers) although it did generate
SIGHUPs. The wakeups must normally be done even if nullmodem() is
null in case something is sleeping waiting for a carrier transition.
In any case, the wakeups should be harmless. They may cause bogus
results for select(), but select() is already bogus for nonstandard
line disciplines.
different types of panics/inconsistencies with NFS clients.
Cleared PG_WANTED where appropriate.
Added checks for buffer busy in allocbuf and biodone.
Reviewed by: John Dyson
ended that fork() uses to determine the time that the process
started when calculating the elapsed time. This prevents the
ac_etime field in the accounting record from getting set to -1
if the process exists for a VERY short period of time.
ttwwakeup(). The conditions for doing the wakeup will soon become
more complicated and I don't want them duplicated in all drivers.
It's probably not worth making ttwwakeup() a macro or an inline
function. The cost of the function call is relatively small when
there is a process to wake up. There is usually a process to wake
up for large writes and the system call overhead dwarfs the function
call overhead for small writes.
Temporarily nuke TS_WOPEN. It was only used for the obscure MDMBUF
flow control option in the kernel and for informational purposes
in `pstat -t'. The latter worked properly only for ptys. In
general there may be multiple processes sleeping in open() and
multiple processes that successfully opened the tty by opening it
in O_NONBLOCK mode or during a window when CLOCAL was set. tty.c
doesn't have enough information to maintain the flag but always
cleared it in ttyopen().
TS_WOPEN should be restored someday just so that `pstat -t' can
display it (MDMBUF is already fixed). Fixing it requires counting
of processes sleeping in open() in too many serial drivers.
Don't put partial PARMRK escape sequences in the input queue. Use
MAX_INPUT = TTYHOG instead of TTYHOG directly for the maximum input
queue size. Don't use the bogus MAX_INPUT advertised in
<sys/syslimits.h>.
First of many changes required to restore lost stability to the tty
driver.
ECHONL is supposed to enable echoing of NL when ECHO is off, but it
enabled echoing of everything except NL.
VBLK vnodes isn't adequate since all NFS nodes aren't locked, either. The
result is a race condition that would lead to duplicate buffers at the
same block offset.
Submitted by: John Dyson
emul code when compiling with "options KTRACE".
ktrsyscall() was expecting an array of integers, this was passing the
address of a structure containing an array of integers..
The cosmetic problem was that it was calling the "enter syscall"
trace hook twice - this looks like a cut/paste error/typo.
notebooks where a powerfail condition (external power drop; battery
state low) is signalled by an NMI. Makes it beep instead of panicing.
Reviewed by: davidg
made a change to NFS that caused buffers at EOF to be variable size. This
had the undesired side-effect of breaking delayed writes on NFS. This
fixes it.
Submitted by: John Dyson
proc or any VM system structure will have to be rebuilt!!!
Much needed overhaul of the VM system. Included in this first round of
changes:
1) Improved pager interfaces: init, alloc, dealloc, getpages, putpages,
haspage, and sync operations are supported. The haspage interface now
provides information about clusterability. All pager routines now take
struct vm_object's instead of "pagers".
2) Improved data structures. In the previous paradigm, there is constant
confusion caused by pagers being both a data structure ("allocate a
pager") and a collection of routines. The idea of a pager structure has
escentially been eliminated. Objects now have types, and this type is
used to index the appropriate pager. In most cases, items in the pager
structure were duplicated in the object data structure and thus were
unnecessary. In the few cases that remained, a un_pager structure union
was created in the object to contain these items.
3) Because of the cleanup of #1 & #2, a lot of unnecessary layering can now
be removed. For instance, vm_object_enter(), vm_object_lookup(),
vm_object_remove(), and the associated object hash list were some of the
things that were removed.
4) simple_lock's removed. Discussion with several people reveals that the
SMP locking primitives used in the VM system aren't likely the mechanism
that we'll be adopting. Even if it were, the locking that was in the code
was very inadequate and would have to be mostly re-done anyway. The
locking in a uni-processor kernel was a no-op but went a long way toward
making the code difficult to read and debug.
5) Places that attempted to kludge-up the fact that we don't have kernel
thread support have been fixed to reflect the reality that we are really
dealing with processes, not threads. The VM system didn't have complete
thread support, so the comments and mis-named routines were just wrong.
We now use tsleep and wakeup directly in the lock routines, for instance.
6) Where appropriate, the pagers have been improved, especially in the
pager_alloc routines. Most of the pager_allocs have been rewritten and
are now faster and easier to maintain.
7) The pagedaemon pageout clustering algorithm has been rewritten and
now tries harder to output an even number of pages before and after
the requested page. This is sort of the reverse of the ideal pagein
algorithm and should provide better overall performance.
8) Unnecessary (incorrect) casts to caddr_t in calls to tsleep & wakeup
have been removed. Some other unnecessary casts have also been removed.
9) Some almost useless debugging code removed.
10) Terminology of shadow objects vs. backing objects straightened out.
The fact that the vm_object data structure escentially had this
backwards really confused things. The use of "shadow" and "backing
object" throughout the code is now internally consistent and correct
in the Mach terminology.
11) Several minor bug fixes, including one in the vm daemon that caused
0 RSS objects to not get purged as intended.
12) A "default pager" has now been created which cleans up the transition
of objects to the "swap" type. The previous checks throughout the code
for swp->pg_data != NULL were really ugly. This change also provides
the rudiments for future backing of "anonymous" memory by something
other than the swap pager (via the vnode pager, for example), and it
allows the decision about which of these pagers to use to be made
dynamically (although will need some additional decision code to do
this, of course).
13) (dyson) MAP_COPY has been deprecated and the corresponding "copy
object" code has been removed. MAP_COPY was undocumented and non-
standard. It was furthermore broken in several ways which caused its
behavior to degrade to MAP_PRIVATE. Binaries that use MAP_COPY will
continue to work correctly, but via the slightly different semantics
of MAP_PRIVATE.
14) (dyson) Sharing maps have been removed. It's marginal usefulness in a
threads design can be worked around in other ways. Both #12 and #13
were done to simplify the code and improve readability and maintain-
ability. (As were most all of these changes)
TODO:
1) Rewrite most of the vnode pager to use VOP_GETPAGES/PUTPAGES. Doing
this will reduce the vnode pager to a mere fraction of its current size.
2) Rewrite vm_fault and the swap/vnode pagers to use the clustering
information provided by the new haspage pager interface. This will
substantially reduce the overhead by eliminating a large number of
VOP_BMAP() calls. The VOP_BMAP() filesystem interface should be
improved to provide both a "behind" and "ahead" indication of
contiguousness.
3) Implement the extended features of pager_haspage in swap_pager_haspage().
It currently just says 0 pages ahead/behind.
4) Re-implement the swap device (swstrategy) in a more elegant way, perhaps
via a much more general mechanism that could also be used for disk
striping of regular filesystems.
5) Do something to improve the architecture of vm_object_collapse(). The
fact that it makes calls into the swap pager and knows too much about
how the swap pager operates really bothers me. It also doesn't allow
for collapsing of non-swap pager objects ("unnamed" objects backed by
other pagers).
that call vnode_pager_alloc() so that a failure return can be dealt with.
This fixes a panic seen on NFS clients when a file being opened is deleted
on the server before the open completes.
syscall to allow applications linked against their libc's uname() to
work. Netscape 1.1N being a prime example, which prints:
"uname() failed. cant tell what system we're running on".
This change is a little ugly, but that's mainly because of the "interesting"
semantics of the BSDI extension.
Since ogetkerninfo() is only enabled by COMPAT_43, Netscape will only
be affected on kernels with that option (eg: "GENERIC")
Reviewed by: davidg
might not be handled by the same FS as the directory (e.g. special device
files)...so it must be special-cased. This bug is seen when doing
"ln /dev/console /dev/foo" or equivilent and first appeared after I fixed
the argument order of VOP_LINK. YUCK! There really needs to be a way of
specifying what vp to use in the VCALL; doing this could fix the strategy
and bwrite special-cases, too.
2) Removed unnecessary vm_object_lookup()/pager_cache(object, TRUE) pairs
after vnode_pager_alloc() calls - the object is already guaranteed to be
persistent.
3) Removed some gratuitous casts.
VOP_CLOSE() takes `F' (file) flags, not `IO' flags. At least that's
what close() passes. I previously fixed ttylclose() to check
FNONBLOCK instead of IO_NDELAY. This broke the call from vclean()
and cleaning of ptys sometimes deadlocked.
when syscons stops mapping the console to minor MAXCONS. There is
usually no corresponding device in /dev, and the correct device has
minor 0.
cons.c:
Initialize cn_tty properly, so that CPU_CONSDEV can work.
Comment about too many variants of the console tty pointer.
machdep.c:
Return device NODEV and not error EFAULT when there is no console device.
in the wrong place. Blank padding in the right place or zero padding
would be inconsistent with user mode.
Put case 'p' in alphabetical order.
Implement %p in sprintf() too. I'd like only a single, more complete
printf() core, perhaps one based on vsnprintf().
in machdep.c (it should use the global nmbclusters). Moved the calculation
of nmbclusters into conf/param.c (same place where nmbclusters has always
been assigned), and made the calculation include an extra amount based
on "maxusers". NMBCLUSTERS can still be overrided in the kernel config
file as always, but this change will make that generally unnecessary. This
fixes the "bug" reports from people who have misconfigured kernels seeing
the network "hang" when the mbuf cluster pool runs out.
Reviewed by: John Dyson
device.
v_numoutput wasn't incremented to match the b_iodone nesting. It's still
fishy that vwakeup() clears B_WRITEINPROG before biodone() has finished;
however, B_WRITEINPROG seems to be never used.
Submitted by: Bruce Evans
1) Files weren't properly synced on filesystems other than UFS. In some
cases, this lead to lost data. Most likely would be noticed on NFS.
The fix is to make the VM page sync/object_clean general rather than
in each filesystem.
2) Mixing regular and mmaped file I/O on NFS was very broken. It caused
chunks of files to end up as zeroes rather than the intended contents.
The fix was to fix several race conditions and to kludge up the
"b_dirtyoff" and "b_dirtyend" that NFS relies upon - paying attention
to page modifications that occurred via the mmapping.
Reviewed by: David Greenman
Submitted by: John Dyson
These changes solve the problem in a general way by moving the
initialization out of the individual fs_mountroot's and into swaponvp().
Submitted by: Poul-Henning Kamp
when the single user shell was terminated. These changes disallow mounting
or R/W upgrading filesystems that are dirty unless "-f" (force) option
is used with mount. /etc/rc has been modified to abort the startup if
one or more non-nfs partitions fail to mount.
Reviewed by: Poul-Henning Kamp, Rod Grimes
require specific partitions be mentioned in the kernel config
file ("swap on foo" is now obsolete).
From Poul-Henning:
The visible effect is this:
As default, unless
options "NSWAPDEV=23"
is in your config, you will have four swap-devices.
You can swapon(2) any block device you feel like, it doesn't have
to be in the kernel config.
There is a performance/resource win available by getting the NSWAPDEV right
(but only if you have just one swap-device ??), but using that as default
would be too restrictive.
The invisible effect is that:
Swap-handling disappears from the $arch part of the kernel.
It gets a lot simpler (-145 lines) and cleaner.
Reviewed by: John Dyson, David Greenman
Submitted by: Poul-Henning Kamp, with minor changes by me.
is more representative of worst case situations of 4 files/directory. (If
that last sentence doesn't make any sense, I'm not surprised. It's rather
compilcated how this all fits together....).
This should fix a problem that Ed Hudson has been complaining about where
directories with lots of symlinks could cause excessive disk I/O.
there may even be LKMs.) Also, change the internal name of `unixdomain'
to `localdomain' since AF_LOCAL is now the preferred name of this family.
Declare netisr correctly and in the right place.
Reopen the bdev for the raw partition and not the cdev if only the bdev
was open.
Don't use a bogus limit for the number of partitions to possibly reopen
(bug found by Julian).
Add function dssize() to help fix wdsize() and sdsize(). The slice
layer knows more about (un)open partitions and partition sizes than
the driver layer.
in read() and write(). FNONBLOCK is valid in ioctl() and close().
The bug caused hung ptys when a process talked to itself using nonblocking
i/o and exited while the slave pty had output to flush. ttywait() was
called and hung. Signals didn't work because the process was exiting.
`comcontrol /dev/ttyp0 drainwait 1' worked to terminate the wait. This
shows that comcontrol is not limited to hardware control. It has no i386
or driver dependencies and doesn't belong in src/sbin/i386.
Bruce
initializing proc0's frame base, too, using cpu_set_init_frame(). It's
a kludge because that macro is intended to be used only for init, but
does what we want nonetheless.
if an invalid ioctl is done on /dev/klog. logioctl() needs to return
an errno instead of -1 on a failed ioctl.
Submitted by: Mike Pritchard <mpp@mpp.com>
some (hopefully) less offensive stupidity:
If we detect that a user has loaded a module that fails to initialize
itself correctly, panic. There really isn't a safe way to recover from
something like this; we can't know that the module is bad until after
the entry point is called, by which time it's too late to do anything
about it.
- Add $Id$ string.
- Fix comment ("we might *not* be able to unload the
module afterwards without panicking...")
- Get rid of variable 'j' that I used in name checking
for(;;) loop and use 'i' instead (I thought there'd be
a problem with this, but there isn't).
if_tun_mod, etc...) from crashing the system. These modules are useful,
but because they don't yet have proper load()/unload() functions,
they can lead to panics: if, for example, you load the if_ppp module,
any user can panic the system by running modstat.
You can also hang the system outright if you try to unload the PPP
module too.
Changes are as follows:
- Save the name passed to us during the RESERVE stage for name matching
(we can't load if_ppp_mod twice: we've have two ppp0's and two ppp1's,
which is beyond strange). This makes the lkmexists() cheks somewhat
redundant, but there's no way around it that I can see.
- If we call the module entry point and find that we have no lkm_any
structure in our 'private' section, create a fake one. This keeps
modstat happy. We mark such modules as LM_UNKNOWN.
- Don't allow LM_UNLOAD modules to be unloaded: it just ain't
possible. (Unless someone wants to write a pppunattach() function. :( )
- In lkmunreserve(), mark private.lkm_any as NULL so we don't get
confused later. I think this is bogus, but I can't prove it.
XXX: the name matching used to keep the user from loading two
instances of the same module can easily be defeated simply by
changing the module name or, in the case of the oddball modules,
simply by renaming the module files. I haven't found a nice simple
way to tell one module from another.
is necessary in order for panic+sync to work. Will also gloss over a panic
that Jordan was having with the install floppies that remains unexplainable.
2) Handle "bogus_page" a little better.
3) Set page protection to VM_PROT_NONE if the entire page has become !valid.
Submitted by: John Dyson (2&3), me (1).
through a temporary buffer instead of one character at a time. The old
method takes about 6 usec/char on a 486DX2/66. This is larger than than
the combined interrupt and PIO overhead for a 16550!
This change was first implemented in 1.1.5. It was rewritten for 2.1.
The clist access functions allow a simpler implementation at some cost
in correctness and speed. There needs to be an ungetc() function to
recover from EFAULT, and it wastes time to copy through a temporary
buffer.
Don't snoop on single characters that weren't read due to EFAULT.
Rewrite a snoop comment in my approximation to English.
Undo bogus exportation of ttnread().
Fixed remaining known bugs in the buffer IO and VM system.
vfs_bio.c:
Fixed some race conditions and locking bugs. Improved performance
by removing some (now) unnecessary code and fixing some broken
logic.
Fixed process accounting of # of FS outputs.
Properly handle NFS interrupts (B_EINTR).
(various)
Replaced calls to clrbuf() with calls to an optimized routine
call vfs_bio_clrbuf().
(various FS sync)
Sync out modified vnode_pager backed pages.
ffs_vnops.c:
Do two passes: Sync out file data first, then indirect blocks.
vm_fault.c:
Fixed deadly embrace caused by acquiring locks in the wrong order.
vnode_pager.c:
Changed to use buffer I/O system for writing out modified pages. This
should fix the problem with the modification date previous not getting
updated. Also dramatically simplifies the code. Note that this is
going to change in the future and be implemented via VOP_PUTPAGES().
vm_object.c:
Fixed a pile of bugs related to cleaning (vnode) objects. The performance
of vm_object_page_clean() is terrible when dealing with huge objects,
but this will change when we implement a binary tree to keep the object
pages sorted.
vm_pageout.c:
Fixed broken clustering of pageouts. Fixed race conditions and other
lockup style bugs in the scanning of pages. Improved performance.
drivers to protect DDB from being invoked while the console is in
process-controlled (i.e., graphics) mode.
Implement the logic to use this hook from within pcvt. (I'm sure
Søren will do the syscons part RSN).
I've still got one occasion where the system stalled, but my attempts
to trigger the situation artificially resulted int the expected
behaviour. It's hard to track bugs without the console and DDB
available. :-/
Added a new type to uiomove - "UIO_NOCOPY" which causes it to update
pointers and counts, but doesn't do any data copying. This is needed
for upcoming changes to the way that the vnode pager does its page
outs.
Added a new hash init function call "phashinit" that allocates and
initializes a prime number sized hash table.
vfs_cache.c:
Changed hashing algorithm to use the remainder of dividing by a prime
number to improve the distribution characteristcs. Uses new phashinit
function in kern_subr.c.
#179). The fix implements a ttyhalfclose() (sort of), resetting the
session and pgrp pointers when the physical device is about to be
closed.
Suggested by: bde
1) Preserve old buffer contents when input buffer overflows.
Old code clear buffer and rewrite it again, if !MAXBEL
(for MAXBEL it does right thing :-).
F.e. if you type too long string, last chars passed,
not first ones as expected.
Moreover, it flush output queue too in this case without any needs.
2) Don't do IXOFF, if IGNCR and c==\r, ignore completely.
3) If PARMRK is active and !ISTRIP and char == 0377
put yet one 0377 to distinguish it from parity mark sequence.
POSIX standard (thanx Bruce).
Reviewed by:
Submitted by:
Obtained from:
CVS:
merged cache changes, and figure it out based on the B_VMIO buffer flag.
Fixes a problem where delayed write VMIO buffers would sometimes get
recopied into kernel-alloced memory.
Submitted by: John Dyson
- ignore the partition table if it is identical with the bogus one in
/usr/src/sys/i386/boot/biosboot/start.S. Honoring the bogus size
field was fatal. The error is detected but other compatibilty
cruft weakens the error handling too much for this case.
- weaken the partition entry checking to allow the following treatments
of C/H/S addresses when C should be >= 1024:
(1) allow C = 1023, H = max, S = max.
(2) allow C to be correct modulo 1024.
Other compatibilty cruft weakens the error handling to allow all
C/H/S addresses, but there too many errors were reported.
Improve error messages:
- print C/H/S addresses if relevant.
- distinguish primary partition table from extended partition tables.
- don't use diskerr() except for i/o errors.
to the user address space unless pcb_onfault is set. The code is currently
commented out because iBCS2 and process debugging parts of the kernel
need to be changed/fixed first.
