the data was supplied as a uio or an mbuf. Previously the limit was
ignored for mbuf data, and NFS could run the kernel out of mbufs
when an ipfw rule blocked retransmissions.
the pipe is locked and shouldn't be.
initialize pipe->pipe_mtxp to NULL when creating pipes in order not
to trip the above assertions.
swap pipe lock with giant around calls to pipe_destroy_write_buffer()
pipe_destroy_write_buffer issue noticed by: jhb
fully protect p_ucred yet so Giant is needed until all the p_ucred
locking is done. This is the original reason td_ucred was not used
immediately after its addition. Unfortunately, not using td_ucred is
not enough to avoid problems. Since p_ucred could be stale, we could
actually be dereferencing a stale pointer to dink with the refcount, so
we really need Giant to avoid foot-shooting. This allows td_ucred to
be safely used as well.
as arguments. The correct hostname is copied into the buffer
while having the prison's lock acquired in a jailed process'
case.
Reviewed by: jhb, rwatson
There is some unresolved badness that has been eluding me, particularly
affecting uniprocessor kernels. Turning off PG_G helped (which is a bad
sign) but didn't solve it entirely. Userland programs still crashed.
Both ends of the pipe share a pool_mutex, this makes allocation
and deadlock avoidance easy.
Remove some un-needed FILE_LOCK ops while I'm here.
There are some issues wrt to select and the f{s,g}etown code that
we'll have to deal with, I think we may also need to move the calls
to vfs_timestamp outside of the sections covered by PIPE_LOCK.
spares (the size of the field was changed from u_short to u_int to
reflect what it really ends up being). Accordingly, change users of
xucred to set and check this field as appropriate. In the kernel,
this is being done inside the new cru2x() routine which takes a
`struct ucred' and fills out a `struct xucred' according to the
former. This also has the pleasant sideaffect of removing some
duplicate code.
Reviewed by: rwatson
shootdowns in a couple of key places. Do the same for i386. This also
hides some physical addresses from higher levels and has it use the
generic vm_page_t's instead. This will help for PAE down the road.
Obtained from: jake (MI code, suggestions for MD part)
enabled in critical sections and streamline critical_enter() and
critical_exit().
This commit allows an architecture to leave interrupts enabled inside
critical sections if it so wishes. Architectures that do not wish to do
this are not effected by this change.
This commit implements the feature for the I386 architecture and provides
a sysctl, debug.critical_mode, which defaults to 1 (use the feature). For
now you can turn the sysctl on and off at any time in order to test the
architectural changes or track down bugs.
This commit is just the first stage. Some areas of the code, specifically
the MACHINE_CRITICAL_ENTER #ifdef'd code, is strictly temporary and will
be cleaned up in the STAGE-2 commit when the critical_*() functions are
moved entirely into MD files.
The following changes have been made:
* critical_enter() and critical_exit() for I386 now simply increment
and decrement curthread->td_critnest. They no longer disable
hard interrupts. When critical_exit() decrements the counter to
0 it effectively calls a routine to deal with whatever interrupts
were deferred during the time the code was operating in a critical
section.
Other architectures are unaffected.
* fork_exit() has been conditionalized to remove MD assumptions for
the new code. Old code will still use the old MD assumptions
in regards to hard interrupt disablement. In STAGE-2 this will
be turned into a subroutine call into MD code rather then hardcoded
in MI code.
The new code places the burden of entering the critical section
in the trampoline code where it belongs.
* I386: interrupts are now enabled while we are in a critical section.
The interrupt vector code has been adjusted to deal with the fact.
If it detects that we are in a critical section it currently defers
the interrupt by adding the appropriate bit to an interrupt mask.
* In order to accomplish the deferral, icu_lock is required. This
is i386-specific. Thus icu_lock can only be obtained by mainline
i386 code while interrupts are hard disabled. This change has been
made.
* Because interrupts may or may not be hard disabled during a
context switch, cpu_switch() can no longer simply assume that
PSL_I will be in a consistent state. Therefore, it now saves and
restores eflags.
* FAST INTERRUPT PROVISION. Fast interrupts are currently deferred.
The intention is to eventually allow them to operate either while
we are in a critical section or, if we are able to restrict the
use of sched_lock, while we are not holding the sched_lock.
* ICU and APIC vector assembly for I386 cleaned up. The ICU code
has been cleaned up to match the APIC code in regards to format
and macro availability. Additionally, the code has been adjusted
to deal with deferred interrupts.
* Deferred interrupts use a per-cpu boolean int_pending, and
masks ipending, spending, and fpending. Being per-cpu variables
it is not currently necessary to lock; bus cycles modifying them.
Note that the same mechanism will enable preemption to be
incorporated as a true software interrupt without having to
further hack up the critical nesting code.
* Note: the old critical_enter() code in kern/kern_switch.c is
currently #ifdef to be compatible with both the old and new
methodology. In STAGE-2 it will be moved entirely to MD code.
Performance issues:
One of the purposes of this commit is to enhance critical section
performance, specifically to greatly reduce bus overhead to allow
the critical section code to be used to protect per-cpu caches.
These caches, such as Jeff's slab allocator work, can potentially
operate very quickly making the effective savings of the new
critical section code's performance very significant.
The second purpose of this commit is to allow architectures to
enable certain interrupts while in a critical section. Specifically,
the intention is to eventually allow certain FAST interrupts to
operate rather then defer.
The third purpose of this commit is to begin to clean up the
critical_enter()/critical_exit()/cpu_critical_enter()/
cpu_critical_exit() API which currently has serious cross pollution
in MI code (in fork_exit() and ast() for example).
The fourth purpose of this commit is to provide a framework that
allows kernel-preempting software interrupts to be implemented
cleanly. This is currently used for two forward interrupts in I386.
Other architectures will have the choice of using this infrastructure
or building the functionality directly into critical_enter()/
critical_exit().
Finally, this commit is designed to greatly improve the flexibility
of various architectures to manage critical section handling,
software interrupts, preemption, and other highly integrated
architecture-specific details.
on for a while:
- fine grained TLB shootdown for SMP on i386
- ranged TLB shootdowns.. eg: specify a range of pages to shoot down with
a single IPI, since the IPI is very expensive. Adjust some callers
that used to trigger this inside tight loops to do a ranged shootdown
at the end instead.
- PG_G support for SMP on i386 (options ENABLE_PG_G)
- defer PG_G activation till after we decide what we are going to do with
PSE and the 4MB pages at the start of the kernel. This should solve
some rumored strangeness about stale PG_G entries getting stuck
underneath the 4MB pages.
- add some instrumentation for the fine TLB shootdown
- convert some asm instruction wrappers from functions to inlines. gcc
seems to do a fair bit better with this.
- [temporarily!] pessimize the tlb shootdown IPI handlers. I will fix
this again shortly.
This has been working fairly well for me for a while, but I have tweaked
it again prior to commit since my last major testing round. The only
outstanding problem that I know of is PG_G related, which is why there
is an option for it (not on by default for SMP). I have seen a world
speedups by a few percent (as much as 4 or 5% in one case) but I have
*not* accurately measured this - I am a bit sceptical of these numbers.
but never accept'ed, so they must be destroyed. Originally, unp_drop()
detected this situation by checking if so->so_head is non-NULL.
However, since revision 1.54 of uipc_socket.c (Feb 1999), so->so_head
is set to NULL before calling soabort(), so any unix-domain sockets
waiting to be accept'ed are leaked if the server socket is closed.
Resolve this by moving the socket destruction code into uipc_abort()
itself, and making it unconditional (the other caller of unp_drop()
never needs the socket to be destroyed). Use unp_detach() to avoid
the original code duplication when destroying the socket.
PR: kern/17895
Reviewed by: dwmalone (an earlier version of the patch)
MFC after: 1 week
our feet when we look inside timecounter structures.
Make the "sync_other" code more robust by never overwriting the
tc_next field.
Add counters for the bin[up]time functions.
Call tc_windup() in tc_init() and switch_timecounter() to make sure
we all the fields set right.
New locks are:
- pgrpsess_lock which locks the whole pgrps and sessions,
- pg_mtx which protects the pgrp members, and
- s_mtx which protects the session members.
Please refer to sys/proc.h for the coverage of these locks.
Changes on the pgrp/session interface:
- pgfind() needs the pgrpsess_lock held.
- The caller of enterpgrp() is responsible to allocate a new pgrp and
session.
- Call enterthispgrp() in order to enter an existing pgrp.
- pgsignal() requires a pgrp lock held.
Reviewed by: jhb, alfred
Tested on: cvsup.jp.FreeBSD.org
(which is a quad-CPU machine running -current)
While in userland, keep the thread's ucred reference in a shadow
field so that the usual place to store it is NULL.
If DIAGNOSTIC is not set, the thread ucred is kept valid until the next
kernel entry, at which time it is checked against the process cred
and possibly corrected. Produces a BIG speedup in
kernels with INVARIANTS set. (A previous commit corrected it
for the non INVARIANTS case already)
Reviewed by: dillon@freebsd.org
Remove bowrite(), it is now unused.
This is the first step in getting entirely rid of BIO_ORDERED which is
a generally accepted evil thing.
Approved by: mckusick
- P_INMEM checks in all the functions. P_INMEM must be checked because
PHOLD() is broken. The old bits had bogus locking (using sched_lock)
to lock P_INMEM. After removing the P_INMEM checks, we were left with
just the bogus locking.
- large comments. They were too large, but better than nothing.
Remove obfuscations that were gained in transition in rev.1.76:
- PROC_REG_ACTION() is even more of an obfuscation than PROC_ACTION().
The change copies procfs_machdep.c rev.1.22 of i386/procfs_machdep.c
verbatim except for "fixing" the old-style function headers and adjusting
function names and comments. It doesn't remove the bogus locking.
Approved by: des
