being incomplete, it currently has to know how to drop and pick back
up the vm_object's mutex if it has to sleep and drop the page queue
mutex. The problem with this is that if the page is busy, while we
are sleeping, the page can be freed and object disappear. When trying
to lock m->object, we'd get a stale or NULL pointer and crash.
The object is now cached, but this makes the assumption that
the object is referenced in some manner and will not itself
disappear while it is unlocked. Since this only happens if
the object is locked, I had to remove an assumption earlier in
contigmalloc() that reversed the order of locking the object and
doing vm_page_sleep_if_busy(), not the normal order.
(WITNESS) for code paths that always call uma_zalloc_arg() shortly
after where the check was, because uma_zalloc_arg() already does
a similar check.
No objections from Alfred. Thanks Alfred.
RTF_BLACKHOLE as well.
To quote the submitter:
The uRPF loose-check implementation by the industry vendors, at least on Cisco
and possibly Juniper, will fail the check if the route of the source address
is pointed to Null0 (on Juniper, discard or reject route). What this means is,
even if uRPF Loose-check finds the route, if the route is pointed to blackhole,
uRPF loose-check must fail. This allows people to utilize uRPF loose-check mode
as a pseudo-packet-firewall without using any manual filtering configuration --
one can simply inject a IGP or BGP prefix with next-hop set to a static route
that directs to null/discard facility. This results in uRPF Loose-check failing
on all packets with source addresses that are within the range of the nullroute.
Submitted by: James Jun <james@towardex.com>
you've specified a directory. It is intended to be used in building
custom releases over NFS where locking may be unreliable at best and
there is no contention that the locking is designed to arbitrate.
Other uses of this flag are discouraged. Document same in usage and
man page (including the warning about unwise).
Sponsored by: Timing Solutions
(1) use strlcpy instead of strncpy since the use here of the latter
was incorrect.
(2) Move 'N' case into proper sorted order (sorted the same way that
ls sorts its args).
work very infrequently, and often results in a compound panic which
confuses debugging; locking/SMP have made the layering violation (and
risks) of this more obvious over time.
Discussed with: green, bde, et al.
convenient when the source string isn't null-terminated.
Implement the other conversion functions (mbstowcs(), mbsrtowcs(), wcstombs(),
wcsrtombs()) in terms of these new functions.
the thread ID and call db_trace_thread().
Since arm has all the logic in db_stack_trace_cmd(), rename the
new DB_COMMAND function to db_stack_trace to avoid conflicts on
arm.
While here, have db_stack_trace parse its own arguments so that
we can use a more natural radix for IDs. If the ID is not a thread
ID, or more precisely when no thread exists with the ID, try if
there's a process with that ID and return the first thread in it.
This makes it easier to print stack traces from the ps output.
requested by: rwatson@
tested on: amd64, i386, ia64
init and fini handlers. Our vm system removes all userland mappings at
exit prior to calling pmap_release. It just so happens that we might
as well reuse the pmap for the next process since the userland slate
has already been wiped clean.
However. There is a functional benefit to this as well. For platforms
that share userland and kernel context in the same pmap, it means that
the kernel portion of a pmap remains valid after the vmspace has been
freed (process exit) and while it is in uma's cache. This is significant
for i386 SMP systems with kernel context borrowing because it avoids
a LOT of IPIs from the pmap_lazyfix() cleanup in the usual case.
Tested on: amd64, i386, sparc64, alpha
Glanced at by: alc
for statfs(2). This is false, if the pathname specified
is a regular file, then the information for the file
system that the file lives on will be returned.
Approved by: bmilekic (mentor)
invalid information will be printed if the -t flag is specified.
$ df -t ufs
Filesystem 1K-blocks Used Avail Capacity Mounted on
/dev/ad0s1a 495726 139944 316124 31% /
/dev/ad0s1e 253678 6438 226946 3% /tmp
/dev/ad0s1f 56206340 13594248 38115586 26% /usr
/dev/ad0s1d 694126 19812 618784 3% /var
/dev/ad0s1d 694126 19812 618784 3% /var
$
Note that the mount point which is not accessible shows
up as the previous file system that was printed. The reason
for this is that df -t will call statfs(2) on the pathname
supplied by getfsstat(2).
This is done to refresh the file system statistics in the
event that a previous file system had a long delay in
providing its stats.
This change affects the df utility in the following ways:
o Teach df has to deal with statfs(2) failing. If statfs(2)
fails, fall back on the possibly stale stats provided by
the initial call to getfsstat(2).
o Print a warning that the fs stats could possibly be stale
o Modify the man page and document this new behavior
as a bug.
Approved by: bmilekic (mentor)
PR: 68165
