in the face of multiple processes doing massive numbers of filesystem
operations. While this patch will work in nearly all situations, there
are still some perverse workloads that can overwhelm the system.
Detecting and handling these perverse workloads will be the subject
of another patch.
Reviewed by: Paul Saab <ps@yahoo-inc.com>
Obtained from: Ethan Solomita <ethan@geocast.com>
o Move building libperl and miniperl from build-tools to
cross-tools. libperl uses MACHINE_ARCH to determine the
right configuration, which doesn't match the build
machine when cross-building if they are built as build-
tools.
o Since miniperl needs to be built as a cross-tool, it
needs to be installed under /usr/obj so that it can be
used (cross-tools have a special object directory to
avoid build conflicts. As a downside, you can't easily
run cross-tools from their object directory). Remove
the install and distribute override targets. To avoid
having miniperl installed by installworld, remove it
from SUBDIR.
o We can't pickup miniperl from the object directory but
since it's installed, depend on PATH. This is save,
because the makefiles are run with a known path.
o Build libperl again as part of the library target. A
_libperl variable existed, but it was never defined.
o Add chmod to the list of saved tools, because perl
conditionally uses it during install.
The bootstrap-tools and cross-tools targets are modified to
avoid building profiled and shared libraries. While here,
have these targets build static binaries instead of shared
binaries.
Approved by: markm
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
over the past couple years. The most recent came to the general consensus
that this was the best time, but no one actually made the change, so I'll
don my asbestos undies and dive in.
Please note that this time was chosen with input from people in various
countries with various methods and schedules for switching to and from DST.
There is no perfect time to schedule this job that works for everyone, but
this time both A) Works for more people, and B) Causes problems for fewer
people. And, ultimately, you can always change it if you need to.
- 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
Added $FreeBSD tag (in the way the already present sccsid is
done). I've been told the rcsid stuff may be of dubious value
so I'm curious to know if folks (still) use it.
Submitted by: Brad Chisholm <blc@bsdwins.com>
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>
argument to setup indentation for the rest of the synopsis
line and to automatically emit a line break for a non-first
synopsis line. It does not require it anymore.
The following now works as expected:
.Sh NAME
.Nm utility
.Sh SYNOPSIS
.Nm
.Cm start
.Nm
.Cm stop
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.
