1) mpsafe (protect the refcount with a mutex).
2) reduce duplicated code by removing the inlined crdup() from crcopy()
and make crcopy() call crdup().
3) use M_ZERO flag when allocating initial structs instead of calling bzero
after allocation.
4) expand the size of the refcount from a u_short to an u_int, by using
shorts we might have an overflow.
Glanced at by: jake
use a mutex lock when looking up/deleting entries on the hashlist
use a mutex lock on each uidinfo when updating fields
make uifree() a void function rather than 'int' since no one cares
allocate uidinfo structs with the M_ZERO flag and don't explicitly initialize
them
Assisted by: eivind, jhb, jakeb
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
could not compress into clusters. This could result in lots of
wasted clusters while recieving small packets from an interface
that uses clusters for all it's packets.
Patch is partially from BSDi (limiting the size of the copy) and
based on a patch for 4.1 by Ian Dowse <iedowse@maths.tcd.ie> and
myself.
Reviewed by: bmilekic
Obtained From: BSDi
Submitted by: iedowse
- Use the mutex in hardclock to ensure no races between it and
softclock.
- Make softclock be INTR_MPSAFE and provide a flag,
CALLOUT_MPSAFE, which specifies that a callout handler does not
need giant. There is still no way to set this flag when
regstering a callout.
Reviewed by: -smp@, jlemon
Removed most of the hacks that were trying to deal with low-memory
situations prior to now.
The new code is based on the concept that I/O must be able to function in
a low memory situation. All major modules related to I/O (except
networking) have been adjusted to allow allocation out of the system
reserve memory pool. These modules now detect a low memory situation but
rather then block they instead continue to operate, then return resources
to the memory pool instead of cache them or leave them wired.
Code has been added to stall in a low-memory situation prior to a vnode
being locked.
Thus situations where a process blocks in a low-memory condition while
holding a locked vnode have been reduced to near nothing. Not only will
I/O continue to operate, but many prior deadlock conditions simply no
longer exist.
Implement a number of VFS/BIO fixes
(found by Ian): in biodone(), bogus-page replacement code, the loop
was not properly incrementing loop variables prior to a continue
statement. We do not believe this code can be hit anyway but we
aren't taking any chances. We'll turn the whole section into a
panic (as it already is in brelse()) after the release is rolled.
In biodone(), the foff calculation was incorrectly
clamped to the iosize, causing the wrong foff to be calculated
for pages in the case of an I/O error or biodone() called without
initiating I/O. The problem always caused a panic before. Now it
doesn't. The problem is mainly an issue with NFS.
Fixed casts for ~PAGE_MASK. This code worked properly before only
because the calculations use signed arithmatic. Better to properly
extend PAGE_MASK first before inverting it for the 64 bit masking
op.
In brelse(), the bogus_page fixup code was improperly throwing
away the original contents of 'm' when it did the j-loop to
fix the bogus pages. The result was that it would potentially
invalidate parts of the *WRONG* page(!), leading to corruption.
There may still be cases where a background bitmap write is
being duplicated, causing potential corruption. We have identified
a potentially serious bug related to this but the fix is still TBD.
So instead this patch contains a KASSERT to detect the problem
and panic the machine rather then continue to corrupt the filesystem.
The problem does not occur very often.. it is very hard to
reproduce, and it may or may not be the cause of the corruption
people have reported.
Review by: (VFS/BIO: mckusick, Ian Dowse <iedowse@maths.tcd.ie>)
Testing by: (VM/Deadlock) Paul Saab <ps@yahoo-inc.com>
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>
are in softclock() for a long time. The old code already did an
splx()/slphigh() pair here, I just missed adding in the equivalent mutex
operations on sched_lock earlier.
may block on a mutex while on the sleep queue without corrupting
it.
- Move dropping of Giant to after the acquire of sched_lock.
Tested by: John Hay <jhay@icomtek.csir.co.za>
jhb
untimeout() not being called with Giant in those functions. For now,
use the sched_lock to protect the callout wheel in softclock() and in
the various timeout and callout functions.
Noticed by: tegge
acquire Giant as needed in functions that call mi_switch(). The releases
need to be done outside of the sched_lock to avoid potential deadlocks
from trying to acquire Giant while interrupts are disabled.
Submitted by: witness
idea to be holding the sched_lock while we are calling it. As such,
release sched_lock before calling CURSIG() in msleep() and mawait() and
reacquire it after CURSIG() returns.
Submitted by: witness
tsleep(). Namely, mawait() takes an extra argument which is a mutex
to drop when going to sleep. Just as with msleep(), if the priority
argument includes the PDROP flag, then the mutex will be dropped and will
not be reacquired when the process wakes up.
- Add in a backwards compatible macro await() that passes in NULL as the
mutex argument to mawait().
macros which provide the same functionality and are a bit more
efficient, convert use of CIRCLEQ's in resource manager to TAILQ's.
Approved by: Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
whether the given ext_buf is shared.
* Have the sf_bufs be setup with the mbuf subsystem using MEXTADD() with the
two new arguments.
Note: m_pulldown() is somewhat crotchy; the added comment explains the
situation.
Reviewed by: jlemon
could debug processes after the commit that introduced the typo.
Security is good, but security is not always the same as turning things
off :-).
PR: kern/22711
Obtained from: brooks@one-eyed-alien.net
device tree and resource manager contents. This is the kernel side of
the upcoming libdevinfo, which will expose this information to userspace
applications in a trivial fashion.
Remove the now-obsolete DEVICE_SYSCTLS code.
syscall compare against a variable sv_minsigstksz in struct
sysentvec as to properly take the size of the machine- and
ABI dependent struct sigframe into account.
The SVR4 and iBCS2 modules continue to have a minsigstksz of
8192 to preserve behavior. The real values (if different) are
not known at this time. Other ABI modules use the real
values.
The native MINSIGSTKSZ is now defined as follows:
Arch MINSIGSTKSZ
---- -----------
alpha 4096
i386 2048
ia64 12288
Reviewed by: mjacob
Suggested by: bde
function declared in kern_ktr.c. The only inline checks left are the
checks that compare KTR_COMPILE with the supplied mask and thus should
be optimized away into either nothing or a direct call to ktr_tracepoint().
- Move several KTR-related options to opt_ktr.h now that they are only
needed by kern_ktr.c and not by ktr.h.
- Add in the ktr_verbose functionality if KTR_EXTEND is turned on. If the
global variable 'ktr_verbose' is non-zero, then KTR messages will be
dumped to the console. This variable can be set by either kernel code
or via the 'debug.ktr_verbose' sysctl. It defaults to off unless the
KTR_VERBOSE kernel option is specified in which case it defaults to on.
This can be useful when the machine locks up spinning in a loop with
interrupts disabled as you might be able to see what it is doing when it
locks up.
Requested by: phk
