used for up to "vfs.aio.max_buf_aio" of the requests. If a request
size is MAXPHYS, but the request base isn't page aligned, vmapbuf()
will map the end of the user space buffer into the start of the kva
allocated for the next physical buffer. Don't use a physical buffer
in this case. (This change addresses problem report 25617.)
When an aio_read/write() on a raw device has completed, timeout() is
used to schedule a signal to the process. Thus, the reporting is
delayed up to 10 ms (assuming hz is 100). The process might have
terminated in the meantime, causing a trap 12 when attempting to
deliver the signal. Thus, the timeout must be cancelled when removing
the job.
aio jobs in state JOBST_JOBQGLOBAL should be removed from the
kaio_jobqueue list during process rundown.
During process rundown, some aio jobs might move from one list to a
different list that has already been "emptied", causing the rundown to
be incomplete. Retry the rundown.
A call to BUF_KERNPROC() is needed after obtaining a physical buffer
to disassociate the lock from the running process since it can return
to userland without releasing that lock.
PR: 25617
Submitted by: tegge
but potentially significant in -4.x.)
Eliminate a pointless parameter to aio_fphysio().
Remove unnecessary casts from aio_fphysio() and aio_physwakeup().
aiocb's allocated by zalloc(). In other words, zfree() was never
called. Now, we call zfree(). Why eliminate this micro-
optimization? At some later point, when we multithread the AIO
system, we would need a mutex to synchronize access to aio_freejobs,
making its use nearly indistinguishable in cost from zalloc() and
zfree().
Remove unnecessary fhold() and fdrop() calls from aio_qphysio(),
undo'ing a part of revision 1.86. The reference count on the file
structure is already incremented by _aio_aqueue() before it calls
aio_qphysio(). (Update the comments to document this fact.)
Remove unnecessary casts from _aio_aqueue(), aio_read(), aio_write()
and aio_waitcomplete().
Remove an unnecessary "return;" from aio_process().
Add "static" in various places.
related code from aio_read() and aio_write(). This field was
intended, but never used, to allow a mythical user-level library to
make an aio_read() or aio_write() behave like an ordinary read() or
write(), i.e., a blocking I/O operation.
mtx_enter(lock, type) becomes:
mtx_lock(lock) for sleep locks (MTX_DEF-initialized locks)
mtx_lock_spin(lock) for spin locks (MTX_SPIN-initialized)
similarily, for releasing a lock, we now have:
mtx_unlock(lock) for MTX_DEF and mtx_unlock_spin(lock) for MTX_SPIN.
We change the caller interface for the two different types of locks
because the semantics are entirely different for each case, and this
makes it explicitly clear and, at the same time, it rids us of the
extra `type' argument.
The enter->lock and exit->unlock change has been made with the idea
that we're "locking data" and not "entering locked code" in mind.
Further, remove all additional "flags" previously passed to the
lock acquire/release routines with the exception of two:
MTX_QUIET and MTX_NOSWITCH
The functionality of these flags is preserved and they can be passed
to the lock/unlock routines by calling the corresponding wrappers:
mtx_{lock, unlock}_flags(lock, flag(s)) and
mtx_{lock, unlock}_spin_flags(lock, flag(s)) for MTX_DEF and MTX_SPIN
locks, respectively.
Re-inline some lock acq/rel code; in the sleep lock case, we only
inline the _obtain_lock()s in order to ensure that the inlined code
fits into a cache line. In the spin lock case, we inline recursion and
actually only perform a function call if we need to spin. This change
has been made with the idea that we generally tend to avoid spin locks
and that also the spin locks that we do have and are heavily used
(i.e. sched_lock) do recurse, and therefore in an effort to reduce
function call overhead for some architectures (such as alpha), we
inline recursion for this case.
Create a new malloc type for the witness code and retire from using
the M_DEV type. The new type is called M_WITNESS and is only declared
if WITNESS is enabled.
Begin cleaning up some machdep/mutex.h code - specifically updated the
"optimized" inlined code in alpha/mutex.h and wrote MTX_LOCK_SPIN
and MTX_UNLOCK_SPIN asm macros for the i386/mutex.h as we presently
need those.
Finally, caught up to the interface changes in all sys code.
Contributors: jake, jhb, jasone (in no particular order)
from struct proc, which are now unused (p_nthread already was).
Remove process flag P_KTHREADP which was untested and only set
in vfs_aio.c (it should use kthread_create). Move the yield
system call to kern_synch.c as kern_threads.c has been removed
completely.
moral support from: alfred, jhb
a kevent upon completion of the I/O. Specifically, introduce a new type
of sigevent notification, SIGEV_EVENT. If sigev_notify is SIGEV_EVENT,
then sigev_notify_kqueue names the kqueue that should receive the event
and sigev_value contains the "void *" is copied into the kevent's udata
field.
In contrast to the existing interface, this one: 1) works on
the Alpha 2) avoids the extra copyin() call for the kevent because all
of the information needed is in the sigevent and 3) could be
applied to request a single kevent upon completion of an entire lio_listio().
Reviewed by: jlemon
Pre-rfork code assumed inherent locking of a process's file descriptor
array. However, with the advent of rfork() the file descriptor table
could be shared between processes. This patch closes over a dozen
serious race conditions related to one thread manipulating the table
(e.g. closing or dup()ing a descriptor) while another is blocked in
an open(), close(), fcntl(), read(), write(), etc...
PR: kern/11629
Discussed with: Alexander Viro <viro@math.psu.edu>
Otherwise, aio_read() and aio_write() on sockets are broken if a kevent is
registered. (The code after kevent registration for handling sockets assumes
that the struct file pointer "fp" still refers to the socket, not the kqueue.)
performed twice. Eliminate initialization that is already performed
by _aio_aqueue.
aio_physwakeup: Eliminate redundant synchronization that is already
performed by bufdone.
chgsbsize(), which are called rather frequently and may be called from an
interrupt context in the case of chgsbsize(). Instead, do the hash table
lookup and maintenance when credentials are changed, which is a lot less
frequent. Add pointers to the uidinfo structures to the ucred and pcred
structures for fast access. Pass a pointer to the credential to chgproccnt()
and chgsbsize() instead of passing the uid. Add a reference count to the
uidinfo structure and use it to decide when to free the structure rather
than freeing the structure when the resource consumption drops to zero.
Move the resource tracking code from kern_proc.c to kern_resource.c. Move
some duplicate code sequences in kern_prot.c to separate helper functions.
Change KASSERTs in this code to unconditional tests and calls to panic().
!VFS_AIO case. Lots of things have hooks into here (kqueue, exit(),
sockets, etc), I elected to keep the external interfaces the same
rather than spread more #ifdefs around the kernel.
<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
(Much of this done by script)
Move B_ORDERED flag to b_ioflags and call it BIO_ORDERED.
Move b_pblkno and b_iodone_chain to struct bio while we transition, they
will be obsoleted once bio structs chain/stack.
Add bio_queue field for struct bio aware disksort.
Address a lot of stylistic issues brought up by bde.
substitute BUF_WRITE(foo) for VOP_BWRITE(foo->b_vp, foo)
substitute BUF_STRATEGY(foo) for VOP_STRATEGY(foo->b_vp, foo)
This patch is machine generated except for the ccd.c and buf.h parts.
field in struct buf: b_iocmd. The b_iocmd is enforced to have
exactly one bit set.
B_WRITE was bogusly defined as zero giving rise to obvious coding
mistakes.
Also eliminate the redundant struct buf flag B_CALL, it can just
as efficiently be done by comparing b_iodone to NULL.
Should you get a panic or drop into the debugger, complaining about
"b_iocmd", don't continue. It is likely to write on your disk
where it should have been reading.
This change is a step in the direction towards a stackable BIO capability.
A lot of this patch were machine generated (Thanks to style(9) compliance!)
Vinum users: Greg has not had time to test this yet, be careful.
VFS_AIO option is specified, all aio-related syscalls return ENOSYS.
The aio code is very fragile right now, and is unsuitable for default
inclusion in a production shell box.
Approved by: jkh
Make gratuitous style(9) fixes (me, not the submitter) to make the aio
code more readable.
PR: kern/12053
Submitted by: Chris Sedore <cmsedore@maxwell.syr.edu>
"rw" argument, rather than hijacking B_{READ|WRITE}.
Fix two bugs (physio & cam) resulting by the confusion caused by this.
Submitted by: Tor.Egge@fast.no
Reviewed by: alc, ken (partly)
far-reaching in fd-land, so you'll want to consult the code for
changes. The biggest change is that now, you don't use
fp->f_ops->fo_foo(fp, bar)
but instead
fo_foo(fp, bar),
which increments and decrements the fp refcount upon entry and exit.
Two new calls, fhold() and fdrop(), are provided. Each does what it
seems like it should, and if fdrop() brings the refcount to zero, the
fd is freed as well.
Thanks to peter ("to hell with it, it looks ok to me.") for his review.
Thanks to msmith for keeping me from putting locks everywhere :)
Reviewed by: peter
Introduce BUF_STRATEGY(struct buf *, int flag) macro, and use it throughout.
please see comment in sys/conf.h about the flag argument.
Remove strategy argument from all the diskslice/label/bad144
implementations, it should be found from the dev_t.
Remove bogus and unused strategy1 routines.
Remove open/close arguments from dssize(). Pick them up from dev_t.
Remove unused and unfinished setgeom support from diskslice/label/bad144 code.
SYSINIT_KT() etc (which is a static, compile-time procedure), use a
NetBSD-style kthread_create() interface. kproc_start is still available
as a SYSINIT() hook. This allowed simplification of chunks of the
sysinit code in the process. This kthread_create() is our old kproc_start
internals, with the SYSINIT_KT fork hooks grafted in and tweaked to work
the same as the NetBSD one.
One thing I'd like to do shortly is get rid of nfsiod as a user initiated
process. It makes sense for the nfs client code to create them on the
fly as needed up to a user settable limit. This means that nfsiod
doesn't need to be in /sbin and is always "available". This is a fair bit
easier to do outside of the SYSINIT_KT() framework.
the caller can easily find the child proc struct. fork(), rfork() etc
syscalls set p->p_retval[] themselves. Simplify the SYSINIT_KT() code
and other kernel thread creators to not need to use pfind() to find the
child based on the pid. While here, partly tidy up some of the fork1()
code for RF_SIGSHARE etc.
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.
Made a new (inline) function devsw(dev_t dev) and substituted it.
Changed to the BDEV variant to this format as well: bdevsw(dev_t dev)
DEVFS will eventually benefit from this change too.
