you on the current queue. In the future, it would be nice if priority
propagation could deterministicly pluck a thread off of the next queue
and put it on the current queue. Until then this hack stops us from
holding up our entire current queue, including interrupt handlers, while
a thread on the next queue is blocked while holding Giant.
- Inherit our pctcpu information from our parent.
kqueue write events on a socket and you regularly create tons of pipes
which overwrites the structure causing a panic when removing the knote
from the list. If the peer has gone away (and it's a write knote), then
don't bother trying to remove the knote from the list.
Submitted by: Brian Buchanan and myself
Obtained from: nCircle
caused snapshot related problems.
- The vp can not be NULL here or we would panic in vfs_bio_awrite(). Stop
confusing the logic by checking for it in several places.
Submitted by: kirk and then rototilled by me to remove vp == NULL checks.
Use pre-emption detection to avoid the need for wiring a userland buffer
when copying opaque data structures.
sysctl_wire_old_buffer() is now a no-op. Other consumers of this
API should use pre-emption detection to notice update collisions.
vslock() and vsunlock() should no longer be called by any code
and should be retired in subsequent commits.
Discussed with: pete, phk
MFC after: 1 week
go away in due course. Involuntary pre-emption means that we can't count
on wiring of pages alone for consistency when performing a SYSCTL_OUT()
bigger than PAGE_SIZE.
Discussed with: pete, phk
LK_RETRY either, we don't want this vnode if it turns into another.
- Remove the code that checks the mount point after acquiring the lock
we are guaranteed to either fail or get the vnode that we wanted.
- In vtryrecycle() try to vgonel the vnode if all of the previous checks
passed. We won't vgonel if someone has either acquired a hold or usecount
or started the vgone process elsewhere. This is because we may have been
removed from the free list while we were inspecting the vnode for
recycling.
- The VI_TRYLOCK stops two threads from entering getnewvnode() and recycling
the same vnode. To further reduce the likelyhood of this event, requeue
the vnode on the tail of the list prior to calling vtryrecycle(). We can
not actually remove the vnode from the list until we know that it's
going to be recycled because other interlock holders may see the VI_FREE
flag and try to remove it from the free list.
- Kill a bogus XXX comment. If XLOCK is set we shouldn't wait for it
regardless of MNT_WAIT because the vnode does not actually belong to
this filesystem.
purge, the purge in vclean, and the filesystems purge, we had 3 purges
per vnode.
- Move the insmntque(vp, 0) to vclean() so that we may remove it from the
two vgone() functions and reduce the number of lock operations required.
whether or not the sync failed. This could potentially get set between
the time that we VOP_UNLOCK and VI_LOCK() but the race would harmelssly
lead to the sync being delayed by an extra 30 seconds. If we do not move
the vnode it could cause an endless loop if it continues to fail to sync.
- Use vhold and vdrop to stop the vnode from changing identities while we
have it unlocked. Other internal vfs lists are likely to follow this
scheme.
- Create a new function, vgonechrl(), which performs vgone for an in-use
character device. Move the code from vflush() that did this into
vgonechrl().
- Hold the xlock across the entirety of vgonel() and vgonechrl() so that
at no point will an invalid vnode exist on any list without XLOCK set.
- Move the xlock code out of vclean() now that it is in the vgone*()
functions.
This is so that we may grab the interlock while still holding the
sync_mtx. We have to VI_TRYLOCK() because in all other cases the lock
order runs the other way.
- If we don't meet any of the preconditions, reinsert the vp into the
list for the next second.
- We don't need to panic if we fail to sync here because each FSYNC
function handles this case. Removing this redundant code also
simplifies locking.
fail. Remove the panic from that case and document why it might fail.
- Document the reason for calling cache_purge() on a newly created vnode.
- In insmntque() order the operations so that we can call mtx_unlock()
one fewer times. This makes the code somewhat clearer as well.
- Add XXX comments in sched_sync() and vflush().
- In vget(), do not sleep while waiting for XLOCK to clear if LK_NOWAIT is
set.
- In vclean() we don't need to acquire a lock around a single TAILQ_FIRST
call. It's ok if we race here, the vinvalbuf will just do nothing.
- Increase the scope of the lock in vgonel() to reduce the number of lock
operations that are performed.
validating the offset within a given memory buffer before handing the
real work off to uiomove(9).
Use uiomove_frombuf in procfs to correct several issues with
integer arithmetic that could result in underflows/overflows. As a
side-effect, the code is significantly simplified.
Add additional sanity checks when computing a memory allocation size
in pfs_read.
Submitted by: rwatson (original uiomove_frombuf -- bugs are mine :-)
Reported by: Joost Pol <joost@pine.nl> (integer underflows/overflows)
fd_cmask field in the file descriptor structure for the first process
indirectly from CMASK, and when an fd structure is initialized before
being filled in, and instead just use CMASK. This appears to be an
artifact left over from the initial integration of quotas into BSD.
Suggested by: peter
the TLB and ~1600 if it is not. Therefore, it is more effecient to
invalidate the TLB after operations that use CMAP rather than before.
- So that the tlb is invalidated prior to switching off of a processor, we
must change the switchin functions to switchout functions.
- Remove td_switchout from the thread and move it to the x86 pcb.
- Move the code that calls switchout into swtch.s. These changes make this
optimization truely x86 specific.
use the ability on ia64 to map the register stack. The orientation of
the stack (i.e. its grow direction) is passed to vm_map_stack() in the
overloaded cow argument. Since the grow direction is represented by
bits, it is possible and allowed to create bi-directional stacks.
This is not an advertised feature, more of a side-effect.
Fix a bug in vm_map_growstack() that's specific to rstacks and which
we could only find by having the ability to create rstacks: when
the mapped stack ends at the faulting address, we have not actually
mapped the faulting address. we need to include or cover the faulting
address.
Note that at this time mmap(2) has not been extended to allow the
creation of rstacks by processes. If such a need arises, this can
be done.
Tested on: alpha, i386, ia64, sparc64
do exactly the same as vop_nopoll() for consistency and put a
comment in the two pointing at each other.
Retire seltrue() in favour of no_poll().
Create private default functions in kern_conf.c instead of public
ones.
Change default strategy to return the bio with ENODEV instead of
doing nothing which would lead the bio stranded.
Retire public nullopen() and nullclose() as well as the entire band
of public no{read,write,ioctl,mmap,kqfilter,strategy,poll,dump}
funtions, they are the default actions now.
Move the final two trivial functions from subr_xxx.c to kern_conf.c
and retire the now empty subr_xxx.c
provide no methods does not make any sense, and is not used by any
driver.
It is a pretty hard to come up with even a theoretical concept of
a device driver which would always fail open and close with ENODEV.
Change the defaults to be nullopen() and nullclose() which simply
does nothing.
Remove explicit initializations to these from the drivers which
already used them.
consdev structure.
If the consdev name is not set and we have a cn_dev, set the name
from there. Try to issue a printf about this, even though it may
not have a place to go.
Modify the sysctl related code to pick up the name from the consdev
instead.
systems where the data/stack/etc limits are too big for a 32 bit process.
Move the 5 or so identical instances of ELF_RTLD_ADDR() into imgact_elf.c.
Supply an ia32_fixlimits function. Export the clip/default values to
sysctl under the compat.ia32 heirarchy.
Have mmap(0, ...) respect the current p->p_limits[RLIMIT_DATA].rlim_max
value rather than the sysctl tweakable variable. This allows mmap to
place mappings at sensible locations when limits have been reduced.
Have the imgact_elf.c ld-elf.so.1 placement algorithm use the same
method as mmap(0, ...) now does.
Note that we cannot remove all references to the sysctl tweakable
maxdsiz etc variables because /etc/login.conf specifies a datasize
of 'unlimited'. And that causes exec etc to fail since it can no
longer find space to mmap things.
freed belong to the kernel object.)
- Increase the granularity of the vm object locking in vm_hold_load_pages()
in order to reduce the number of times that we acquire and release the
same lock.
Doing so creates a race where the buf is on neither list.
- Only vfree() in an error case in vclean() if VSHOULDFREE() thinks we
should.
- Convert the error case in vclean() to INVARIANTS from DIAGNOSTIC as this
really should not happen and is fast to check.
