fixes a bug on UP machines with SMP kernels where the idle thread
constantly switches after trying to steal work from the local cpu.
- Make the idle stealing code more robust against self selection.
- Prefer to steal from the cpu with the highest load that has at least one
transferable thread. Before we selected the cpu with the highest
transferable count which excludes bound threads.
Collaborated with: csjp
Approved by: re
to simply switch rather than lowering priority and switching. This allows
threads of equal priority to run but not lesser priority.
Discussed with: davidxu
Reported by: NIIMI Satoshi <sa2c@sa2c.net>
Approved by: re
critical_exit() owepreempt check. ULE will always use owepreempt to
preempt the idle thread. This change does not effect 4BSD since it will
never set owepreempt without PREEMPTION enabled.
- Remove some unused code from choosethread().
Discussed with: jhb
Approved by: re
not being independently freeable. This allows one to embed an mbuf in
the cluster itself. This confers the benefits of the packet zone on
all cluster sizes. Embedded mbufs currently suffer from the same
limitation that packet zone mbufs do in that one cannot disconnect
them and pass them around independently of the cluster. It would
likely be possible to eliminate this limitation in the future by
adding a second reference for the mbuf itself.
Approved by: re(gnn)
Before that fix, it was possible for the function to fail if number
of sharers changes between 'x = sx->sx_lock' step and atomic_cmpset_acq_ptr()
call.
This fixes ZFS problem when ZFS returns strange EIO errors under load.
In ZFS there is a code that depends on the fact that sx_try_slock() can
only fail if there is an exclusive owner.
Discussed with: attilio
Reviewed by: jhb
Approved by: re (kensmith)
after the switch leads to a race where the outgoing thread still owns
the local queue lock while another cpu may switch it in. This race
is only possible on machines where cpu_switch can take significantly
longer on different cpus which in practice means HTT machines with
unfair thread scheduling algorithms.
Found by: kris (of course)
Approved by: re
starvation caused by unbalanced interrupt loads.
- Change the rebalancer to work on stathz ticks but retain randomization.
- Simplify locking in tdq_idled() to use the tdq_lock_pair() rather than
complex sequences of locks to avoid deadlock.
Reported by: kris
Approved by: re
value for kern.sched.preempt_thresh appropriately. It can still by
adjusted at runtime. ULE will still use IPI_PREEMPT in certain
migration situations.
- Assert that we're not trying to compile ULE on an unsupported
architecture. To date, I believe only i386 and amd64 have implemented
the third cpu switch argument required.
Approved by: re
ways:
(1) Cached pages are no longer kept in the object's resident page
splay tree and memq. Instead, they are kept in a separate per-object
splay tree of cached pages. However, access to this new per-object
splay tree is synchronized by the _free_ page queues lock, not to be
confused with the heavily contended page queues lock. Consequently, a
cached page can be reclaimed by vm_page_alloc(9) without acquiring the
object's lock or the page queues lock.
This solves a problem independently reported by tegge@ and Isilon.
Specifically, they observed the page daemon consuming a great deal of
CPU time because of pages bouncing back and forth between the cache
queue (PQ_CACHE) and the inactive queue (PQ_INACTIVE). The source of
this problem turned out to be a deadlock avoidance strategy employed
when selecting a cached page to reclaim in vm_page_select_cache().
However, the root cause was really that reclaiming a cached page
required the acquisition of an object lock while the page queues lock
was already held. Thus, this change addresses the problem at its
root, by eliminating the need to acquire the object's lock.
Moreover, keeping cached pages in the object's primary splay tree and
memq was, in effect, optimizing for the uncommon case. Cached pages
are reclaimed far, far more often than they are reactivated. Instead,
this change makes reclamation cheaper, especially in terms of
synchronization overhead, and reactivation more expensive, because
reactivated pages will have to be reentered into the object's primary
splay tree and memq.
(2) Cached pages are now stored alongside free pages in the physical
memory allocator's buddy queues, increasing the likelihood that large
allocations of contiguous physical memory (i.e., superpages) will
succeed.
Finally, as a result of this change long-standing restrictions on when
and where a cached page can be reclaimed and returned by
vm_page_alloc(9) are eliminated. Specifically, calls to
vm_page_alloc(9) specifying VM_ALLOC_INTERRUPT can now reclaim and
return a formerly cached page. Consequently, a call to malloc(9)
specifying M_NOWAIT is less likely to fail.
Discussed with: many over the course of the summer, including jeff@,
Justin Husted @ Isilon, peter@, tegge@
Tested by: an earlier version by kris@
Approved by: re (kensmith)
- Improve load long-term load balancer by always IPIing exactly once.
Previously the delay after rebalancing could cause problems with
uneven workloads.
- Allow nice to have a linear effect on the interactivity score. This
allows negatively niced programs to stay interactive longer. It may be
useful with very expensive Xorg servers under high loads. In general
it should not be necessary to alter the nice level to improve interactive
response. We may also want to consider never allowing positively niced
processes to become interactive at all.
- Initialize ccpu to 0 rather than 0.0. The decimal point was leftover
from when the code was copied from 4bsd. ccpu is 0 in ULE because ULE
only exports weighted cpu values.
Reported by: Steve Kargl (Load balancing problem)
Approved by: re
changes the units from seconds to the value of 'ticks' when swapped
in/out. ULE does not have a periodic timer that scans all threads in
the system and as such maintaining a per-second counter is difficult.
- Change computations requiring the unit in seconds to subtract ticks
and divide by hz. This does make the wraparound condition hz times
more frequent but this is still in the range of several months to
years and the adverse effects are minimal.
Approved by: re
In particular:
- smp_tlb_mtx is no longer used, so it is axed.
- smp rendezvous lock isn't really a leaf spin-mutex. Its bad placement in
the table, however, has been the source of a false positive LOR reporting
with the dt_lock. However, smp rendezvous lock would have had sched_lock
there for older lock, so it wasn't still a leaf lock.
- allpmaps is only used in ia32 architecture, so it is inserted in the
appropriate stub.
Addictionally:
- kse_zombie_lock is no longer present, so its definition is axed out.
- zombie_lock doesn't need to have an exported symbol, so just let's it be
declared as static.
Tested by: kris
Approved by: jeff (mentor)
Approved by: re
- p_sflag was mostly protected by PROC_LOCK rather than the PROC_SLOCK or
previously the sched_lock. These bugs have existed for some time.
- Allow swapout to try each thread in a process individually and then
swapin the whole process if any of these fail. This allows us to move
most scheduler related swap flags into td_flags.
- Keep ki_sflag for backwards compat but change all in source tools to
use the new and more correct location of P_INMEM.
Reported by: pho
Reviewed by: attilio, kib
Approved by: re (kensmith)
per-primitive macros like MTX_NOPROFILE, SX_NOPROFILE or RW_NOPROFILE) is
not really honoured. In particular lock_profile_obtain_lock_failure() and
lock_profile_obtain_lock_success() are naked respect this flag.
The bug leads to locks marked with no-profiling to be profiled as well.
In the case of the clock_lock, used by the timer i8254 this leads to
unpredictable behaviour both on amd64 and ia32 (double faults panic,
sudden reboots, etc.). The amd64 clock_lock is also not marked as
not profilable as it should be.
Fix these bugs adding proper checks in the lock profiling code and at
clock_lock initialization time.
i8254 bug pointed out by: kris
Tested by: matteo, Giuseppe Cocomazzi <sbudella at libero dot it>
Approved by: jeff (mentor)
Approved by: re
races for some struct thread members.
More specifically, this bug seems responsible for some memory dumping
problems people were experiencing.
Fix this adding correct thread locking.
Tested by: rwatson
Submitted by: tegge
Approved by: jeff
Approved by: re
prevents insmntque() from placing reallocated syncer vnode on mount
list, that causes panic in vfs_allocate_syncvnode().
Introduce MNTK_NOINSMNTQ flag, that marks the period when instmntque is
not allowed to success, instead of MNTK_UNMOUNT. The MNTK_NOINSMNTQ is
set and cleared simultaneously with MNTK_UNMOUNT, except on umount error
path, where it is cleaned just before the syncer vnode is going to be
allocated.
Reported by: Peter Jeremy <peterjeremy optushome com au>
Suggested by: tegge
Approved by: re (rwatson)
topology foo functions.
Working at the patch for topology problems in ia32/amd64 evicted some
problems regarding functions ordering in the SI_SUB_CPU family of
SYSINIT'ed subsystems.
In order to avoid problems with new modified to involved functions, a
correct ordering is not semantically specified for SI_SUB_CPU functions
(for a larger view of the issue please visit:
http://lists.freebsd.org/pipermail/freebsd-current/2007-July/075409.html )
Discussed with: peter
Tested by: kris, Rui Paulo <rpaulo@FreeBSD.org>
Approved by: jeff
Approved by: re
point to mac_check_vnode_unlink(), reflecting UNIX naming conventions.
This is the first of several commits to synchronize the MAC Framework
in FreeBSD 7.0 with the MAC Framework as it will appear in Mac OS X
Leopard.
Reveiwed by: csjp, Samy Bahra <sbahra at gwu dot edu>
Submitted by: Jacques Vidrine <nectar at apple dot com>
Obtained from: Apple Computer, Inc.
Sponsored by: SPARTA, SPAWAR
Approved by: re (bmah)
used, rather than the one passed via 'req', which may not reflect a
rewrite. This call to useracc() is redundant to validation performed by
later copyin()/copyout() calls, so there isn't a security issue here,
but this could technically lead to excessive validation of addresses if
the length in newlen is shorter than req.newlen.
Approved by: re (kensmith)
Reviewed by: jhb
Submitted by: Constantine A. Murenin <cnst+freebsd@bugmail.mojo.ru>
Sponsored by: Google Summer of Code 2007
the callout_lock spin lock and the sleepqueue spin locks. In the fix,
callout_drain() has to drop the callout_lock so it can acquire the
sleepqueue lock. The state of the callout can change while the
callout_lock is held however (for example, it can be rescheduled via
callout_reset()). The previous code assumed that the only state change
that could happen is that the callout could finish executing. This change
alters callout_drain() to effectively restart and recheck everything
after it acquires the sleepqueue lock thus handling all the possible
states that the callout could be in after any changes while callout_lock
was dropped.
Approved by: re (kensmith)
Tested by: kris
ktruserret() is invoked, an unlocked check of the per-process queue
is performed inline, thus, we don't lock the ktrace_sx on every userret().
Pointy hat to: jhb
Approved by: re (kensmith)
Pointy hat recovered from: rwatson
64-bit counters) to a 4.x statfs structure (with long-sized counters).
- For block counters, we scale up the block size sufficiently large so
that the resulting block counts fit into a the long-sized (long for the
ABI, so 32-bit in freebsd32) counters. In 4.x the NFS client's statfs
VOP did this already. This can lie about the block size to 4.x binaries,
but it presents a more accurate picture of the ratios of free and
available space.
- For non-block counters, fix the freebsd32 stats converter to cap the
values at INT32_MAX rather than losing the upper 32-bits to match the
behavior of the 4.x statfs conversion routine in vfs_syscalls.c
Approved by: re (kensmith)
the last message on the send stream was "null" but still
there, a state we allow, we could get hung and not clean
it up and wait for the shutdown guard timer to clear the
association without a graceful close. Fix this so that
that we properly clean up.
- Added support for Multiple ASCONF per new RFC. We only
(so far) accept input of these and cannot yet generate
a multi-asconf.
- Sysctl'd support for experimental Fast Handover feature. Always
disabled unless sysctl or socket option changes to enable.
- Error case in add-ip where the peer supports AUTH and ADD-IP
but does NOT require AUTH of ASCONF/ASCONF-ACK. We need to
ABORT in this case.
- According to the Kyoto summit of socket api developers
(Solaris, Linux, BSD). We need to have:
o non-eeor mode messages be atomic - Fixed
o Allow implicit setup of an assoc in 1-2-1 model if
using the sctp_**() send calls - Fixed
o Get rid of HAVE_XXX declarations - Done
o add a sctp_pr_policy in hole in sndrcvinfo structure - Done
o add a PR_SCTP_POLICY_VALID type flag - yet to-do in a future patch!
- Optimize sctp6 calls to reuse code in sctp_usrreq. Also optimize
when we close sending out the data and disabling Nagle.
- Change key concatenation order to match the auth RFC
- When sending OOTB shutdown_complete always do csum.
- Don't send PKT-DROP to a PKT-DROP
- For abort chunks just always checksums same for
shutdown-complete.
- inpcb_free front state had a bug where in queue
data could wedge an assoc. We need to just abandon
ones in front states (free_assoc).
- If a peer sends us a 64k abort, we would try to
assemble a response packet which may be larger than
64k. This then would be dropped by IP. Instead make
a "minimum" size for us 64k-2k (we want at least
2k for our initack). If we receive such an init
discard it early without all the processing.
- When we peel off we must increment the tcb ref count
to keep it from being freed from underneath us.
- handling fwd-tsn had bugs that caused memory overwrites
when given faulty data, fixed so can't happen and we
also stop at the first bad stream no.
- Fixed so comm-up generates the adaption indication.
- peeloff did not get the hmac params copied.
- fix it so we lock the addr list when doing src-addr selection
(in future we need to use a multi-reader/one writer lock here)
- During lowlevel output, we could end up with a _l_addr set
to null if the iterator is calling the output routine. This
means we would possibly crash when we gather the MTU info.
Fix so we only do the gather where we have a src address
cached.
- we need to be sure to set abort flag on conn state when
we receive an abort.
- peeloff could leak a socket. Moved code so the close will
find the socket if the peeloff fails (uipc_syscalls.c)
Approved by: re@freebsd.org(Ken Smith)
aio_proc_rundown.
Do not allow for zero-length read to be passed to the fo_read file method
by aio.
Reported and tested by: Peter Holm
Approved by: re (kensmith)
of the bits we want to ignore on the first pass rather than doing a
linear scan. This puts us within a few instructions of the cost of
runq_findbit() and removes this function from the top of profiling output
for context switch heavy workloads.
Approved by: re
on 2cpu machines by reducing it to 1 by default. This improves loaded
operation on 8cpu machines by increasing it to 3 where the extra idle
time is not as critical.
Approved by: re
have caused a hang, but we got lucky with the available multi-CPU states
on actual hardware.
Submitted by: Bjorn Koenig <bkoenig / alpha-tierchen.de>
Approved by: re
MFC after: 3 days
% mount | grep home
/dev/ad4s1e on /home (ufs, local, noatime, soft-updates)
% mount -u -o atime /home
% mount | grep home
/dev/ad4s1e on /home (ufs, local, soft-updates)
Restore this behavior for on 7.x for the following mount options:
noatime, noclusterr, noclusterw, noexec, nosuid, nosymfollow
In addition, on 7.x, the following are equivalent:
mount -u -o atime /home
mount -u -o nonoatime /home
Ideally, when we introduce new mount options, we should avoid
options starting with "no". :)
Requested by: jhb
Reported by: Karol Kwiat <karol.kwiat gmail com>, Scott Hetzel <swhetzel gmail com>
Approved by: re (bmah)
Proxy commit for: rodrigc
previously conditionally acquired Giant based on debug.mpsafenet. As that
has now been removed, they are no longer required. Removing them
significantly simplifies error-handling in the socket layer, eliminated
quite a bit of unwinding of locking in error cases.
While here clean up the now unneeded opt_net.h, which previously was used
for the NET_WITH_GIANT kernel option. Clean up some related gotos for
consistency.
Reviewed by: bz, csjp
Tested by: kris
Approved by: re (kensmith)
tdq_group structure. Hyper-threaded cores won't really benefit from
seperate locks anyway.
- Seperate out the migration case from sched_switch to simplify the main
switch code. We only migrate here if called via sched_bind().
- When preempted place the preempted thread back in the same queue at
the head.
- Improve the cpu group and topology infrastructure.
Tested by: many on current@
Approved by: re
framework for non-MPSAFE network protocols:
- Remove debug_mpsafenet variable, sysctl, and tunable.
- Remove NET_NEEDS_GIANT() and associate SYSINITSs used by it to force
debug.mpsafenet=0 if non-MPSAFE protocols are compiled into the kernel.
- Remove logic to automatically flag interrupt handlers as non-MPSAFE if
debug.mpsafenet is set for an INTR_TYPE_NET handler.
- Remove logic to automatically flag netisr handlers as non-MPSAFE if
debug.mpsafenet is set.
- Remove references in a few subsystems, including NFS and Cronyx drivers,
which keyed off debug_mpsafenet to determine various aspects of their own
locking behavior.
- Convert NET_LOCK_GIANT(), NET_UNLOCK_GIANT(), and NET_ASSERT_GIANT into
no-op's, as their entire behavior was determined by the value in
debug_mpsafenet.
- Alias NET_CALLOUT_MPSAFE to CALLOUT_MPSAFE.
Many remaining references to NET_.*_GIANT() and NET_CALLOUT_MPSAFE are still
present in subsystems, and will be removed in followup commits.
Reviewed by: bz, jhb
Approved by: re (kensmith)
should call uma_zfree() with various spinlock helds. Rearranging the
code would not help here because we cannot break atomicity respect
prcess spinlock, so the only one choice we have is to defer the operation.
In order to do this use a global queue synchronized through the kse_lock
spinlock which is freed at any thread_alloc() / thread_wait() through a
call to thread_reap().
Note that this approach is not ideal as we should want a per-process
list of zombie upcalls, but it follows initial guidelines of KSE authors.
Tested by: jkim, pav
Approved by: jeff, julian
Approved by: re
