Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.
Sorry john! (your next MFC will be a doosie!)
Reviewed by: peter@freebsd.org, dillon@freebsd.org
X-MFC after: ha ha ha ha
(this commit is just the first stage). Also add various GIANT_ macros to
formalize the removal of Giant, making it easy to test in a more piecemeal
fashion. These macros will allow us to test fine-grained locks to a degree
before removing Giant, and also after, and to remove Giant in a piecemeal
fashion via sysctl's on those subsystems which the authors believe can
operate without Giant.
vm_mtx does not recurse and is required for most low level
vm operations.
faults can not be taken without holding Giant.
Memory subsystems can now call the base page allocators safely.
Almost all atomic ops were removed as they are covered under the
vm mutex.
Alpha and ia64 now need to catch up to i386's trap handlers.
FFS and NFS have been tested, other filesystems will need minor
changes (grabbing the vm lock when twiddling page properties).
Reviewed (partially) by: jake, jhb
This is because calls with M_WAIT (now M_TRYWAIT) may not wait
forever when nothing is available for allocation, and may end up
returning NULL. Hopefully we now communicate more of the right thing
to developers and make it very clear that it's necessary to check whether
calls with M_(TRY)WAIT also resulted in a failed allocation.
M_TRYWAIT basically means "try harder, block if necessary, but don't
necessarily wait forever." The time spent blocking is tunable with
the kern.ipc.mbuf_wait sysctl.
M_WAIT is now deprecated but still defined for the next little while.
* Fix a typo in a comment in mbuf.h
* Fix some code that was actually passing the mbuf subsystem's M_WAIT to
malloc(). Made it pass M_WAITOK instead. If we were ever to redefine the
value of the M_WAIT flag, this could have became a big problem.
mail:
The problem seems to originate with NFS's postop_attr
information that is returned with a read or write RPC.
Within a vm_fault context, the code cannot deal with
vnode_pager_setsize() shrinking a vnode.
The workaround in the patch below stops the nfsm_postop_attr()
macro from ever shrinking a vnode. If the new size in the
postop_attr information is smaller, then it just sets the
nfsnode n_attrstamp to 0 to stop the wrong size getting
used in the future. This change only affects postop_attr
attributes; the nfsm_loadattr() macro works as normal.
The change is implemented by adding a new argument to
nfs_loadattrcache() called 'dontshrink'. When this is
non-zero, nfs_loadattrcache() will never reduce the
vnode/nfsnode size; instead it zeros n_attrstamp.
There remain other was processes can get stuck in vmopar.
Submitted by: Ian Dowse <iedowse@maths.tcd.ie>
Reviewed by: dillon
Tested by: Vadim Belman <voland@lflat.org>
with the new snapshot code.
Update addaliasu to correctly implement the semantics of the old
checkalias function. When a device vnode first comes into existence,
check to see if an anonymous vnode for the same device was created
at boot time by bdevvp(). If so, adopt the bdevvp vnode rather than
creating a new vnode for the device. This corrects a problem which
caused the kernel to panic when taking a snapshot of the root
filesystem.
Change the calling convention of vn_write_suspend_wait() to be the
same as vn_start_write().
Split out softdep_flushworklist() from softdep_flushfiles() so that
it can be used to clear the work queue when suspending filesystem
operations.
Access to buffers becomes recursive so that snapshots can recursively
traverse their indirect blocks using ffs_copyonwrite() when checking
for the need for copy on write when flushing one of their own indirect
blocks. This eliminates a deadlock between the syncer daemon and a
process taking a snapshot.
Ensure that softdep_process_worklist() can never block because of a
snapshot being taken. This eliminates a problem with buffer starvation.
Cleanup change in ffs_sync() which did not synchronously wait when
MNT_WAIT was specified. The result was an unclean filesystem panic
when doing forcible unmount with heavy filesystem I/O in progress.
Return a zero'ed block when reading a block that was not in use at
the time that a snapshot was taken. Normally, these blocks should
never be read. However, the readahead code will occationally read
them which can cause unexpected behavior.
Clean up the debugging code that ensures that no blocks be written
on a filesystem while it is suspended. Snapshots must explicitly
label the blocks that they are writing during the suspension so that
they do not cause a `write on suspended filesystem' panic.
Reorganize ffs_copyonwrite() to eliminate a deadlock and also to
prevent a race condition that would permit the same block to be
copied twice. This change eliminates an unexpected soft updates
inconsistency in fsck caused by the double allocation.
Use bqrelse rather than brelse for buffers that will be needed
soon again by the snapshot code. This improves snapshot performance.
<sys/bio.h>.
<sys/bio.h> is now a prerequisite for <sys/buf.h> but it shall
not be made a nested include according to bdes teachings on the
subject of nested includes.
Diskdrivers and similar stuff below specfs::strategy() should no
longer need to include <sys/buf.> unless they need caching of data.
Still a few bogus uses of struct buf to track down.
Repocopy by: peter
there is nothing we can do about it. In fact, after further review
there simply are not very many instances of the two structures NFS
checks for 'bloat' so I've decided to simply rip the checks out entirely.
Submitted by: Andrew Gallatin <gallatin@cs.duke.edu>
NFSSERVER defined, useful for userland fileservers that want to
use a filehandle type interface to the filesystem.
Submitted by: Assar Westerlund assar@stacken.kth.se
PR: kern/15452
NFS packets, mainly initializing structure pointers to NULL which
are conditionally freed prior to return.
PR: kern/15249
Submitted by: Ian Dowse <iedowse@maths.tcd.ie>
blocks of zeros could wind up in a file written to over NFS by a client.
The problem only occurs a few times per several gigabytes of data. This
problem turned out to be bug #3 below.
bug #1:
B_CLUSTEROK must be cleared when an NFS buffer is reverted from
stage 2 (ready for commit rpc) to stage 1 (ready for write).
Reversions can occur when a dirty NFS buffer is redirtied with new
data.
Otherwise the VFS/BIO system may end up thinking that a stage 1
NFS buffer is clusterable. Stage 1 NFS buffers are not clusterable.
bug #2:
B_CLUSTEROK was inappropriately set for a 'short' NFS buffer (short
buffers only occur near the EOF of the file). Change to only set
when the buffer is a full biosize (usually 8K). This bug has no
effect but should be fixed in -current anyway. It need not be
backported.
bug #3:
B_NEEDCOMMIT was inappropriately set in nfs_flush() (which is
typically only called by the update daemon). nfs_flush()
does a multi-pass loop but due to the lack of vnode locking it
is possible for new buffers to be added to the dirtyblkhd list
while a flush operation is going on. This may result in nfs_flush()
setting B_NEEDCOMMIT on a buffer which has *NOT* yet gone through its
stage 1 write, causing only the commit rpc to be made and thus
causing the contents of the buffer to be thrown away (never sent to
the server).
The patch also contains some cleanup, which only applies to the commit
into -current.
Reviewed by: dg, julian
Originally Reported by: Dan Nelson <dnelson@emsphone.com>
Make the alias list a SLIST.
Drop the "fast recycling" optimization of vnodes (including
the returning of a prexisting but stale vnode from checkalias).
It doesn't buy us anything now that we don't hardlimit
vnodes anymore.
Rename checkalias2() and checkalias() to addalias() and
addaliasu() - which takes dev_t and udev_t arg respectively.
Make the revoke syscalls use vcount() instead of VALIASED.
Remove VALIASED flag, we don't need it now and it is faster
to traverse the much shorter lists than to maintain the
flag.
vfs_mountedon() can check the dev_t directly, all the vnodes
point to the same one.
Print the devicename in specfs/vprint().
Remove a couple of stale LFS vnode flags.
Remove unimplemented/unused LK_DRAINED;
lockmgr locks. This commit should be functionally equivalent to the old
semantics. That is, all buffer locking is done with LK_EXCLUSIVE
requests. Changes to take advantage of LK_SHARED and LK_RECURSIVE will
be done in future commits.
txdr_hyper and fxdr_hyper tweaks to avoid excessive CPU order knowledge.
nfs_serv.c: don't call nfsm_adj() with negative values, windows clients
could crash servers when doing a readdir of a large directory.
nfs_socket.c: Use IP_PORTRANGE to get a priviliged port without a spin
loop trying to bind(). Don't clobber a mbuf pointer or we get panics
on a NFS3ERR_JUKEBOX error from a server when reusing a freed mbuf.
nfs_subs.c: Don't loose st_blocks on NFSv2 mounts when > 2GB.
Obtained from: OpenBSD
udev_t in the kernel but still called dev_t in userland.
Provide functions to manipulate both types:
major() umajor()
minor() uminor()
makedev() umakedev()
dev2udev() udev2dev()
For now they're functions, they will become in-line functions
after one of the next two steps in this process.
Return major/minor/makedev to macro-hood for userland.
Register a name in cdevsw[] for the "filedescriptor" driver.
In the kernel the udev_t appears in places where we have the
major/minor number combination, (ie: a potential device: we
may not have the driver nor the device), like in inodes, vattr,
cdevsw registration and so on, whereas the dev_t appears where
we carry around a reference to a actual device.
In the future the cdevsw and the aliased-from vnode will be hung
directly from the dev_t, along with up to two softc pointers for
the device driver and a few houskeeping bits. This will essentially
replace the current "alias" check code (same buck, bigger bang).
A little stunt has been provided to try to catch places where the
wrong type is being used (dev_t vs udev_t), if you see something
not working, #undef DEVT_FASCIST in kern/kern_conf.c and see if
it makes a difference. If it does, please try to track it down
(many hands make light work) or at least try to reproduce it
as simply as possible, and describe how to do that.
Without DEVT_FASCIST I belive this patch is a no-op.
Stylistic/posixoid comments about the userland view of the <sys/*.h>
files welcome now, from userland they now contain the end result.
Next planned step: make all dev_t's refer to the same devsw[] which
means convert BLK's to CHR's at the perimeter of the vnodes and
other places where they enter the game (bootdev, mknod, sysctl).
changes to the VM system to support the new swapper, VM bug
fixes, several VM optimizations, and some additional revamping of the
VM code. The specific bug fixes will be documented with additional
forced commits. This commit is somewhat rough in regards to code
cleanup issues.
Reviewed by: "John S. Dyson" <root@dyson.iquest.net>, "David Greenman" <dg@root.com>
second argument. np_size is a 64 bit int, so is the second arg. This
might have caused needless 2G/4G file size problems.
I believe it was Bruce who queried this.
detachment of vfs sysctls. Unloading of vfs LKMs doesn't actually
work for any vfs, since it leaves garbage pointers to memory
allocation control structures.
when nfs is an LKM. Declare it in a header file. Don't forget to use
it in non-Lite2 code. Initialize it to -1 instead of to 0, since 0
will soon be the mount type number for the first vfs loaded.
NetBSD uses strcmp() to avoid this ugly global.
Pre-2.8 versions of gcc generate a call to __divdi3() for all 64-bit
signed divisions, but egcs optimizes them to a shift and fixup when
the divisor is a constant power of 2. Unfortunately, it generates
a call to __cmpdi2() for the fixup, although all except possibly
ancient versions of gcc and egcs do ordinary 64-bit comparisons
inline.
of this part of commits is to minimize unnecessary differences between
the other NFS's of similar origin. Yes, there are gratuitous changes here
that the style folks won't like, but it makes the catch-up less difficult.
for better packing. This means that we can choose better values for the
various hash entries without having to try and get it all to fit within
an artificial power of two limit for malloc's sake.
We had run out of bits in the nfs mount flags, I have moved the internal
state flags into a seperate variable. These are no longer visible via
statfs(), but I don't know of anything that looks at them.
"time" wasn't a atomic variable, so splfoo() protection were needed
around any access to it, unless you just wanted the seconds part.
Most uses of time.tv_sec now uses the new variable time_second instead.
gettime() changed to getmicrotime(0.
Remove a couple of unneeded splfoo() protections, the new getmicrotime()
is atomic, (until Bruce sets a breakpoint in it).
A couple of places needed random data, so use read_random() instead
of mucking about with time which isn't random.
Add a new nfs_curusec() function.
Mark a couple of bogosities involving the now disappeard time variable.
Update ffs_update() to avoid the weird "== &time" checks, by fixing the
one remaining call that passwd &time as args.
Change profiling in ncr.c to use ticks instead of time. Resolution is
the same.
Add new function "tvtohz()" to avoid the bogus "splfoo(), add time, call
hzto() which subtracts time" sequences.
Reviewed by: bde
plus the previous changes to use the zone allocator decrease the useage
of malloc by half. The Zone allocator will be upgradeable to be able
to use per CPU-pools, and has more intelligent usage of SPLs. Additionally,
it has reasonable stats gathering capabilities, while making most calls
inline.
socket addresses in mbufs. (Socket buffers are the one exception.) A number
of kernel APIs needed to get fixed in order to make this happen. Also,
fix three protocol families which kept PCBs in mbufs to not malloc them
instead. Delete some old compatibility cruft while we're at it, and add
some new routines in the in_cksum family.
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.
The system boots and can mount UFS filesystems.
Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
Mount_std mounts will not work until the getfsent
library routine is changed.
Reviewed by: various people
Submitted by: Jeffery Hsu <hsu@freebsd.org>
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
existing mechanism uses a global queue for some buffers and the
vp->b_dirtyblkhd queue for others. This turns sequential writes into
randomly ordered writes to the server, affecting both read and write
performance. The existing mechanism also copes badly with hung
servers, tending to block accesses to other servers when all the iods
are waiting for a hung server.
The new mechanism uses a queue for each mount point. All asynchronous
i/o goes through this queue which preserves the ordering of requests.
A simple mechanism ensures that the iods are shared out fairly between
active mount points. This removes the sysctl variable vfs.nfs.dwrite
since the new queueing mechanism removes the old delayed write code
completely.
This should go into the 2.2 branch.
/*
* Structure defined by POSIX.4 to be like a timeval.
*/
struct timespec {
time_t ts_sec; /* seconds */
long ts_nsec; /* and nanoseconds */
};
The correct names of the fields are tv_sec and tv_nsec.
Reminded by: James Drobina <jdrobina@infinet.com>
The interface into the "VMIO" system has changed to be more consistant
and robust. Essentially, it is now no longer necessary to call vn_open
to get merged VM/Buffer cache operation, and exceptional conditions
such as merged operation of VBLK devices is simpler and more correct.
This code corrects a potentially large set of problems including the
problems with ktrace output and loaded systems, file create/deletes,
etc.
Most of the changes to NFS are cosmetic and name changes, eliminating
a layer of subroutine calls. The direct calls to vput/vrele have
been re-instituted for better cross platform compatibility.
Reviewed by: davidg
rick@snowhite.cis.uoguelph.ca:
1. Clear B_NEEDCOMMIT in nfs_write to make sure that dirty data is
correctly send to the server. If a buffer was dirtied when it was in
the B_DELWRI+B_NEEDCOMMIT state, the state of the buffer was left
unchanged and when the buffer was later cleaned, just a commit rpc was
made to the server to complete the previous write. Clearing
B_NEEDCOMMIT ensures that another write is made to the server.
2. If a server returned a server (for whatever reason) returned an
answer to a write RPC that implied that fewer bytes than requested
were written, bad things would happen.
3. The setattr operation passed on the atime in stead of the mtime to
the server. The fix is trivial.
4. XIDs always started at 0, but this caused some servers (older DEC
OSF/1 3.0 so I've been told) who had very long-lasting XID caches to
get confused if, after a reboot of a BSD client, RPCs came in with a
XID that had in the past been used before from that client. Patch is
to use the current time in seconds as a starting point for XIDs. The
patch below is not perfect, because it requires the root fs to be
mounted first. This is because of the check BSD systems do, comparing
FS time to system time.
Reviewed by: Bruce Evans, Terry Lambert.
Obtained from: frank@fwi.uva.nl (Frank van der Linden) via rick@snowhite.cis.uoguelph.ca
Poul mentioned that he thought this was some kind of timing problem, and
that started me thinking. After a little poking around, I found that
nfs_timer() was completely disabled when NFS_NOSERVER was #defined.
But after looking at nfs_timer(), it seemed like it was something
required by both the client and server code, and disabling it outright
just didn't seem to make any sense. Parts of it relate only to the
NFS server side code, so I disabled those, but I re-enabled the rest
of the function and made sure that it would be called from nfs_init()
(in nfs_subs.c).
With nfs_timer() re-enabled, everything seems to work again. The only
other changes I made were to #ifdef away some variable declarations
in the NFS_NOSERVER case so that gcc would stop complaining about
unused variables.
Reviewed by: phk
Submitted by: Bill Paul <wpaul@skynet.ctr.columbia.edu>
Speed up for vfs_bio -- addition of a routine bqrelse to greatly diminish
overhead for merged cache.
Efficiency improvement for vfs_cluster. It used to do alot of redundant
calls to cluster_rbuild.
Correct the ordering for vrele of .text and release of credentials.
Use the selective tlb update for 486/586/P6.
Numerous fixes to the size of objects allocated for files. Additionally,
fixes in the various pagers.
Fixes for proper positioning of vnode_pager_setsize in msdosfs and ext2fs.
Fixes in the swap pager for exhausted resources. The pageout code
will not as readily thrash.
Change the page queue flags (PG_ACTIVE, PG_INACTIVE, PG_FREE, PG_CACHE) into
page queue indices (PQ_ACTIVE, PQ_INACTIVE, PQ_FREE, PQ_CACHE),
thereby improving efficiency of several routines.
Eliminate even more unnecessary vm_page_protect operations.
Significantly speed up process forks.
Make vm_object_page_clean more efficient, thereby eliminating the pause
that happens every 30seconds.
Make sequential clustered writes B_ASYNC instead of B_DELWRI even in the
case of filesystems mounted async.
Fix a panic with busy pages when write clustering is done for non-VMIO
buffers.
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.
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.
The version 2 support has been tested (client+server) against FreeBSD-2.0,
IRIX 5.3 and FreeBSD-current (using a loopback mount). The version 2 support
is stable AFAIK.
The version 3 support has been tested with a loopback mount and minimally
against an IRIX 5.3 server. It needs more testing and may have problems.
I have patched amd to support the new variable length filehandles although
it will still only use version 2 of the protocol.
Before booting a kernel with these changes, nfs clients will need to at least
build and install /usr/sbin/mount_nfs. Servers will need to build and
install /usr/sbin/mountd.
NFS diskless support is untested.
Obtained from: Rick Macklem <rick@snowhite.cis.uoguelph.ca>
is an ambiguity in the NFS version 2 protocol.
VREG should be taken literally as a regular file. If a
server intents to return some type information differently
in the upper bits of the mode field (e.g. for sockets, or
FIFOs), NFSv2 mandates fa_type to be VNON. Anyway, we
leave the examination of the mode bits even in the VREG
case to avoid breakage for bogus servers, but we make sure
that there are actually type bits set in the upper part of
fa_mode (and failing that, trust the va_type field).
NFSv3 cleared the issue, and requires fa_mode to not
contain any type information (while also introduing sockets
and FIFOs for fa_type).
The fix has been tested against a variety of NFS servers.
It fixes problems with the ``Tropic'' NFS server for Windows,
while apparently not breaking anything.
Pointed-out by: scott@zorch.sf-bay.org (Scott Hazen Mueller)
handled correctly. This would manifest itself as "object deallocated too
many times" panics and perhaps other strange inconsistencies on NFS servers.
Reviewed by: me, of course
Submitted by: John Dyson
