vnode, we should not attempt to remove the namecache entry. this is because
vget() can sleep (eg. if VXLOCK is set because the vnode is being reclaimed),
and so multiple threads can end up in this context at the same time.
if this happens, each thread ends up removing the cache entry, but
the code to remove the entry assumes that the entry is still valid.
so we should just leave the (now stale) entry in the cache.
if another thread finds the entry again before it is reused,
that thread will notice that the entry is stale and remove it safely.
fixes PR 14042.
This is activated by defining POOL_SUBPAGE to the size of the new allocation
unit, and makes pools much more efficient on machines with obscenely large
pages. It might even make four-megabyte arm26 systems usable.
woken-up thread is guaranteed to pass the buck to the next guy before
going back to sleep, and the rest of the lockmgr() code doesn't do that.
from Bill Sommerfeld. fixes PR 14097.
overflow on LP64 architectures. This fixes kern/10070 by Juergen Weiss.
Fix tested on NetBSD/alpha by Bernd Ernesti, on NetBSD/sparc64
by David Brownlee and Eduardo Horvath.
(not just EPIPE), so that the higher-level code would note partial
write has happened and DTRT if the write was interrupted due to
e.g. delivery of signal.
This fixes kern/14087 by Frank van der Linden.
Much thanks to Frank for extensive help with debugging this, and review
of the fix.
Note: EPIPE/SIGPIPE delivery behaviour was retained - they're delivered
even if the write was partially successful.
not do short writes unless when using non-blocking I/O.
This fixes kern/13744 by Geoff C. Wing.
Note this partially undoes rev. 1.5 change. Upon closer examination,
it's been apparent that hbench-OS expectations were not actually justified.
are only wired if this flag is present (i.e. they are not wired by default now)
loaned pages are unloaned via new uvm_unloan(), uvm_unloananon() and
uvm_unloanpage() are no longer exported
adjust uvm_unloanpage() to unwire the pages if UVM_LOAN_WIRED is specified
mark uvm_loanuobj() and uvm_loanzero() static also in function implementation
kern/sys_pipe.c: uvm_unloanpage() --> uvm_unloan()
ALWAYS call uvm_unloanpage() in cleanup - it's necessary even
in pipe_loan_free() case, since uvm_km_free() doesn't seem
to implicitly unloan the loaned pages
format specific.
Struct emul has a e_setregs hook back, which points to emulation-specific
setregs function. es_setregs of struct execsw now only points to
optional executable-specific setup function (this is only used for
ECOFF).
checks root privs, and a lower part that does the actual job. The lower part
will be called by the upcoming clockctl driver. Approved by Christos
Also fixed a few cosmetic things
- remove special treatment of pager_map mappings in pmaps. this is
required now, since I've removed the globals that expose the address range.
pager_map now uses pmap_kenter_pa() instead of pmap_enter(), so there's
no longer any need to special-case it.
- eliminate struct uvm_vnode by moving its fields into struct vnode.
- rewrite the pageout path. the pager is now responsible for handling the
high-level requests instead of only getting control after a bunch of work
has already been done on its behalf. this will allow us to UBCify LFS,
which needs tighter control over its pages than other filesystems do.
writing a page to disk no longer requires making it read-only, which
allows us to write wired pages without causing all kinds of havoc.
- use a new PG_PAGEOUT flag to indicate that a page should be freed
on behalf of the pagedaemon when it's unlocked. this flag is very similar
to PG_RELEASED, but unlike PG_RELEASED, PG_PAGEOUT can be cleared if the
pageout fails due to eg. an indirect-block buffer being locked.
this allows us to remove the "version" field from struct vm_page,
and together with shrinking "loan_count" from 32 bits to 16,
struct vm_page is now 4 bytes smaller.
- no longer use PG_RELEASED for swap-backed pages. if the page is busy
because it's being paged out, we can't release the swap slot to be
reallocated until that write is complete, but unlike with vnodes we
don't keep a count of in-progress writes so there's no good way to
know when the write is done. instead, when we need to free a busy
swap-backed page, just sleep until we can get it busy ourselves.
- implement a fast-path for extending writes which allows us to avoid
zeroing new pages. this substantially reduces cpu usage.
- encapsulate the data used by the genfs code in a struct genfs_node,
which must be the first element of the filesystem-specific vnode data
for filesystems which use genfs_{get,put}pages().
- eliminate many of the UVM pagerops, since they aren't needed anymore
now that the pager "put" operation is a higher-level operation.
- enhance the genfs code to allow NFS to use the genfs_{get,put}pages
instead of a modified copy.
- clean up struct vnode by removing all the fields that used to be used by
the vfs_cluster.c code (which we don't use anymore with UBC).
- remove kmem_object and mb_object since they were useless.
instead of allocating pages to these objects, we now just allocate
pages with no object. such pages are mapped in the kernel until they
are freed, so we can use the mapping to find the page to free it.
this allows us to remove splvm() protection in several places.
The sum of all these changes improves write throughput on my
decstation 5000/200 to within 1% of the rate of NetBSD 1.5
and reduces the elapsed time for "make release" of a NetBSD 1.5
source tree on my 128MB pc to 10% less than a 1.5 kernel took.
adjusted via sysctl. file systems that have hash tables which are
sized based on the value of this variable now resize those hash tables
using the new value. the max number of FFS softdeps is also recalculated.
convert various file systems to use the <sys/queue.h> macros for
their hash tables.
"earliest" firing callout in a bucket. This allows us to skip
the scan up the bucket if no callouts are due in the bucket.
A cheap O(1) hint update is done at callout insertion (if new callout
is earlier than hint) and removal (is bucket empty). A thorough
refresh of the hint is done when the bucket is traversed.
This doesn't matter much on machines with small values of hz
(e.g. i386), but on systems with large values of hz (e.g. Alpha),
it has a definite positive effect.
Also, keep the callwheel stats in evcnts, so that you can view them
with "vmstat -e".
guard pages. Can only debug one malloc type at a time, and nothing
larger than 1 page. But can be useful for debugging certain types
of "data modified on freelist" type problems.
Modified from code in OpenBSD.
the stack, so that it can be modified.
- pass the error code in the exit code in addition to aborting.
- kill the second exit1() call; it does not make any sense.
ctor/dtor feature, it's still faster to allocate from the cache groups
than it is from the pool (cache groups are analogous to "magazines"
in the Solaris SLAB allocator).
of some selective pieces. This fixes problem with NEW_PIPE in kernels
with DEBUG option, reported via e-mail by Chuck Silvers.
sys_pipe(): g/c fdp, provide it at the chunk of FreeBSD code where it's used
init vfs so it can the size into account when creating its hash lists.
This means that for a 2GB system, it'll have a default of 65536 buckets
instead of 2048 and when you have 200,000+ vnodes that makes a significant
difference.
disabled loans for writes (a.k.a "direct write"), oops; use uio->uio_resid
for the check instead
don't bother updating uio->uio_offset in pipe_direct_write(), it's not used
by upper layers anyway
arrange things as needed. Unfortunately, the check in sockargs()
have to stay, since 4.3BSD bind(2), connect(2) and sendto(2) were
not versioned at the time :(
This code was tested to pass regression tests.
required. This duplicates the behavour used by DDB in db_stop_at_pc()
Architectures that emulate single step in software (SOFTWARE_SSTEP) don't
clear their temporary breakpoints making it impossible to restart on the
same instruction.
than PIPE_CHUNK_SIZE, just transfer first PIPE_CHUNK_SIZE and return short
write, expecting the caller to call us again later (if they need). Previous
behaviour (besides being wrong for O_NONBLOCK reads) hung hbench under some
circumstances and other applications may have similar expectations as hbench.
This might also fix port-vax/13333 by Manuel Bowyer.
Other changes to pipe_direct_write() include:
* return short write (and success) on EOF if any data were already read;
we return EPIPE on next write(2) call
* simplify error handling, actually handle uvm_loan() failure correctly,
call pipe_loan_free() on error explicitly and only call uvm_unloan()
if the address space was _not_ already freed by pipe_loan_free()
Thanks Chuck Silvers for uvm_unloan() hints :)
Fallthough to common write in pipe_write() if pipe_direct_write()
returns ENOMEM, otherwise always break out immediatelly.
Use uvm_km_valloc_wait() instead uvm_km_valloc() in pipe_loan_alloc().
table actually match state in NetBSD 0.9 (checked against sys/mount.h
rev. 1.11).
The array is not to be modified from now on, comment updated accordingly.
that fails, just try to recycle a vnode. If we can't allocate or
recycle, issue a warning, sleep a bit, and try the whole thing
again.
This prevents us from blocking forever if we want to use a very large
number of vnodes, but don't have {memory,kva} resources from which to
allocate them.
an spl-protected "interrupt safe map" list, simply require that callers
of uvm_fault() never call us in interrupt context (MD code must make
the assertion), and check for interrupt-safe maps in uvmfault_lookup()
before we lock the map.
has VXLOCK set - it's already being vgoned, most likely by one of our
callers. If we call vgone, we can end up sleeping against ourself
with VXLOCK set - we'll start the race for root.
Pointed out by Love <lha@stacken.kth.se> on tech-kern. Analysis from
Artur Grabowski <art@openbsd.org> via Love.
Should resolve PR kern/13077
is supposed to point directly to struct mbuf or struct sockaddr in kernel
space as appropriate, rather than being a pointer to memory in userland.
This is to be used by compat/* when emulation needs to wrap
send{to|msg}(2)/recv{from|msg}(2) and modify the passed struct
sockaddr.
The end we want to do selwakeup() on is not necessarily same as the one
we send SIGIO to. Make pipeselwakeup() accept two parameters and update
callers accordingly. This change fixes behaviour for code, which does
select(2)s on the write end waiting for reader (watched on gv, the problem
manifestated itself as a too long delay before the document was displayed).
Clearly separate the resource free code for FreeBSD
and NetBSD case in pipeclose(), so that it's a bit clearer what's going on.
Also LK_DRAIN the lock before the memory is returned to pipe_pool.
Add missing wakeup() in pipe_write() for PIPE_WANTCLOSE case.
used to make ELF binaries unmatched by any signature check to be run under
NetBSD 'emulation'. This causes problems like kern/12253.
The old behaviour is available with option EXEC_ELF_CATCHALL.
struct socket so_state field to decide if we need to send asynchronous
notifications. This makes possible to request notification on write but
not on read, and vice versa.
This is used in Linux emulation code, because when async I/O is requested,
Linux does not send SIGIO to write end of sockets, and it never send any
SIGIO to any end of pipes. Il Linux emulation code, we then set SB_ASYNC
only on the read end of sockets, and on no end for pipes.
for FreeBSD project. Besides huge speed boost compared with socketpair-based
pipes, this implementation also uses pagable kernel memory instead of mbufs.
Significant differences to FreeBSD version:
* uses uvm_loan() facility for direct write
* async/SIGIO handling correct also for sync writer, async reader
* limits settable via sysctl, amountpipekva and nbigpipes available via sysctl
* pipes are unidirectional - this is enforced on file descriptor level
for now only, the code would be updated to take advantage of it
eventually
* uses lockmgr(9)-based locks instead of home brew variant
* scatter-gather write is handled correctly for direct write case, data
is transferred by PIPE_DIRECT_CHUNK bytes maximum, to avoid running out of kva
All FreeBSD/NetBSD specific code is within appropriate #ifdef, in preparation
to feed changes back to FreeBSD tree.
This pipe implementation is optional for now, add 'options NEW_PIPE'
to your kernel config to use it.
MNT_NOSUID, just check MNT_NOSUID to clear the S{U,G}ID bits
in the attributes for the vnode we're about to exec.
We now check P_TRACED right before we would actually perform
the s{u,g}id function in the exec code.
This closes a race condition between exec of a setuid binary
and ptrace(2).
between creation of a file descriptor and close(2) when using kernel
assisted threads. What we do is stick descriptors in the table, but
mark them as "larval". This causes essentially everything to treat
it as a non-existent descriptor, except for fdalloc(), which sees a
filled slot so that it won't (incorrectly) allocate it again. When
a descriptor is fully constructed, the code that has constructed it
marks it as "mature" (which actually clears the "larval" flag), and
things continue to work as normal.
While here, gather all the code that gets a descriptor from the table
into a fd_getfile() function, and call it, rather than having the
same (sometimes incorrect) code copied all over the place.
fdexpand(). The former will return ENOSPC if there is not space
in the current filedesc table. The latter performs the expansion
of the filedesc table. This means that fdalloc() won't ever block,
and it gives callers an opportunity to clean up before the
potentially-blocking fdexpand() call.
Update all fdalloc() callers to deal with the need-to-fdexpand() case.
Rewrite unp_externalize() to use fdalloc() and fdexpand() in a
safe way, using an algorithm suggested by Bill Sommerfeld:
- Use a temporary array of integers to hold the new filedesc table
indexes. This allows us to repeat the loop if necessary.
- Loop through the array of file *'s, assigning them to filedesc table
slots. If fdalloc() indicates expansion is necessary, undo the
assignments we've done so far, expand, and retry the whole process.
- Once all file *'s have been assigned to slots, update the f_msgcount
and unp_rights counters.
- Right before we return, copy the temporary integer array to the message
buffer, and trim the length as before.
Note that once locking is added to the filedesc array, this entire
operation will be `atomic', in that the lock will be held while
file *'s are assigned to embryonic table slots, thus preventing anything
else from using them.
descriptor array, which may have blocked. Change callers of
fdalloc() to restart whatever they\'re doing if this condition
happens. (XXX unp_externalize() needs some work, but that will
be tackled later.)
Change finishdup() to close the descriptor in the `new\' slot if
one exists, and change sys_dup2() accordingly.
Closes a race condition when using kernel-assisted user threads.
While here, garbage-collect UF_MAPPED -- it is not used anywhere.
The ISO C standard says in 6.10.3.3 that if the result of using the
'##' operator "is not a valid preprocessing token, the behaviour is
undefined." Gcc 3.0 warns about this.
unions `union_elem: ...', and use c99 syntax `.union_elem = ...' only
where necessary.
in this case, there's no need to tag elf_probe_func because that's the
first union element, and therefore, the implicit case. only specifically
mention ecoff_probe_func where necessary.
if we decide to not use this c99 feature for now, at least there's now
less stuff to rip out.
Previously, we passed __FILE__ and __LINE__ on all pool_get/pool_set calls.
This change results in a measured 1.2% performance improvement in
ping-flood packets-per-second as reported by ping(8).
that the caller allocate the pool_item_header when it allocates the
pool page, so we can avoid a locking pitfall (sleeping with a simple
lock held).
Also revive pool_prime(), as there are some letigimate uses of it,
but in doing so, eliminate some of the bogosities of the old version
(i.e. don't do an implicit "setlowat", just prime the pool, and incr
the minpages for each additional page we add, and compute the number
of pages to prime in a way that callers would expect).
to 512. Apparently, there are ELF binaries with more than 128 section
headers - an example is one of Linux Word Perfect 8 utilities.
This fixes kern/12455 by Mark Davies.
flag.
EMUL_BSD_ASYNCIO_PIPE notes that the emulated binaries expect the original
BSD pipe behavior for asynchronous I/O, which is to fire SIGIO on read() and
write(). OSes without this flag do not expect any SIGIO to be fired on
read() and write() for pipes, even when async I/O was requested. As far as
we know, the OSes that need EMUL_BSD_ASYNCIO_PIPE are NetBSD, OSF/1 and
Darwin.
EMUL_BSD_ASYNCIO_PIPE notes that the emulated binaries expect the original
BSD pipe behavior for asynchronous I/O, which is to fire SIGIO on read() and
write(). OSes without this flag do not expect any SIGIO to be fired on
read() and write() for pipes, even when async I/O was requested. As far as
we know, the OSes that need EMUL_BSD_ASYNCIO_PIPE are NetBSD, OSF/1 and
Darwin.
EMUL_NO_SIGIO_ON_READ notes that the emulated binaries that requested
asynchrnous I/O expect the reader process to be notified by a SIGIO, but
not the writer process. OSes without this flag expect the reader and the
writer to be notified when some data has arrived or when some data have been
read. As far as we know, the OSes that need EMUL_NO_SIGIO_ON_READ are Linux
and SunOS.
SPINLOCK_SPIN_HOOK, so that we actually check for
pending IPIs on the Alpha more than once. Also,
when we call alpha_ipi_process(), make sure to go
to splipi().
vfs_busy'ing just before the dounmount() call. This is to avoid
sleeping with the mountlist_slock held -- but we must acquire
syncer_lock before vfs_busy because the syncer itself uses
syncer_lock -> vfs_busy locking order.
callers and appropriate routines to cope. This makes fo_stat more
consistent with rest of fileops routines and also makes the fo_stat
match FreeBSD as an added bonus.
Discussed with Luke Mewburn on tech-kern@.
Use a relative path (../..) instead of /sys.
Enhance the sed expression to work with .'s in paths.
Quote sed expressions in single quotes rather than double
quotes unless there's a good reason otherwise.
mappings (vnode -> name) in the reverse mapping hash table. Without
this option, there is no change; only directories will be entered to
speed up getcwd. This is an option because it will cause getcwd
to hit longer hash chains, and at the moment its usefulness is
still limited.
return NULL instead of restarting the loop since we might sleep
while starting the i/o. this tells getblk() to check if someone else
created the buffer while we slept. from OpenBSD.
