- 25 Jun, 2005 40 commits
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Olivier Croquette authored
Presently, a process without the capability CAP_SYS_NICE can not change its own policy, which is OK. But it can also not decrease its RT priority (if scheduled with policy SCHED_RR or SCHED_FIFO), which is what this patch changes. The rationale is the same as for the nice value: a process should be able to require less priority for itself. Increasing the priority is still not allowed. This is for example useful if you give a multithreaded user process a RT priority, and the process would like to organize its internal threads using priorities also. Then you can give the process the highest priority needed N, and the process starts its threads with lower priorities: N-1, N-2... The POSIX norm says that the permissions are implementation specific, so I think we can do that. In a sense, it makes the permissions consistent whatever the policy is: with this patch, process scheduled by SCHED_FIFO, SCHED_RR and SCHED_OTHER can all decrease their priority. From: Ingo Molnar <mingo@elte.hu> cleaned up and merged to -mm. Signed-off-by:
Ingo Molnar <mingo@elte.hu> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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Chen Shang authored
micro-optimize task requeueing in schedule() & clean up recalc_task_prio(). Signed-off-by:
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Nick Piggin authored
The maximum rebalance interval allowed by the multiprocessor balancing backoff is often not large enough to handle corner cases where there are lots of tasks pinned on a CPU. Suresh reported: I see system livelock's if for example I have 7000 processes pinned onto one cpu (this is on the fastest 8-way system I have access to). After this patch, the machine is reported to go well above this number. Signed-off-by:
Nick Piggin <nickpiggin@yahoo.com.au> Acked-by:
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Nick Piggin authored
Consolidate balance-on-exec with balance-on-fork. This is made easy by the sched-domains RCU patches. As well as the general goodness of code reduction, this allows the runqueues to be unlocked during balance-on-fork. schedstats is a problem. Maybe just have balance-on-event instead of distinguishing fork and exec? Signed-off-by:
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Nick Piggin authored
One of the problems with the multilevel balance-on-fork/exec is that it needs to jump through hoops to satisfy sched-domain's locking semantics (that is, you may traverse your own domain when not preemptable, and you may traverse others' domains when holding their runqueue lock). balance-on-exec had to potentially migrate between more than one CPU before finding a final CPU to migrate to, and balance-on-fork needed to potentially take multiple runqueue locks. So bite the bullet and make sched-domains go completely RCU. This actually simplifies the code quite a bit. From: Ingo Molnar <mingo@elte.hu> schedstats RCU fix, and a nice comment on for_each_domain, from Ingo. Signed-off-by:
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Nick Piggin authored
The fundamental problem that Suresh has with balance on exec and fork is that it only tries to balance the top level domain with the flag set. This was worked around by removing degenerate domains, but is still a problem if people want to start using more complex sched-domains, especially multilevel NUMA that ia64 is already using. This patch makes balance on fork and exec try balancing over not just the top most domain with the flag set, but all the way down the domain tree. Signed-off-by:
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Suresh Siddha authored
Remove degenerate scheduler domains during the sched-domain init. For example on x86_64, we always have NUMA configured in. On Intel EM64T systems, top most sched domain will be of NUMA and with only one sched_group in it. With fork/exec balances(recent Nick's fixes in -mm tree), we always endup taking wrong decisions because of this topmost domain (as it contains only one group and find_idlest_group always returns NULL). We will endup loading HT package completely first, letting active load balance kickin and correct it. In general, this patch also makes sense with out recent Nick's fixes in -mm. From: Nick Piggin <nickpiggin@yahoo.com.au> Modified to account for more than just sched_groups when scanning for degenerate domains by Nick Piggin. And allow a runqueue's sd to go NULL rather than keep a single degenerate domain around (this happens when you run with maxcpus=1). Signed-off-by:
Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by:
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Nick Piggin authored
Fix the last 2 places that directly access a runqueue's sched-domain and assume it cannot be NULL. That allows the use of NULL for domain, instead of a dummy domain, to signify no balancing is to happen. No functional changes. Signed-off-by:
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Nick Piggin authored
Instead of requiring architecture code to interact with the scheduler's locking implementation, provide a couple of defines that can be used by the architecture to request runqueue unlocked context switches, and ask for interrupts to be enabled over the context switch. Also replaces the "switch_lock" used by these architectures with an oncpu flag (note, not a potentially slow bitflag). This eliminates one bus locked memory operation when context switching, and simplifies the task_running function. Signed-off-by:
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Ingo Molnar authored
"Chen, Kenneth W" <kenneth.w.chen@intel.com> uninline task_timeslice() - reduces code footprint noticeably, and it's slowpath code. Signed-off-by: -
Nick Piggin authored
Do some basic initial tuning. Signed-off-by:
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Nick Piggin authored
Add SCHEDSTAT statistics for sched-balance-fork. Signed-off-by:
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Nick Piggin authored
Reimplement the balance on exec balancing to be sched-domains aware. Use this to also do balance on fork balancing. Make x86_64 do balance on fork over the NUMA domain. The problem that the non sched domains aware blancing became apparent on dual core, multi socket opterons. What we want is for the new tasks to be sent to a different socket, but more often than not, we would first load up our sibling core, or fill two cores of a single remote socket before selecting a new one. This gives large improvements to STREAM on such systems. Signed-off-by:
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Nick Piggin authored
Remove the very aggressive idle stuff that has recently gone into 2.6 - it is going against the direction we are trying to go. Hopefully we can regain performance through other methods. Signed-off-by:
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Nick Piggin authored
Do less affine wakeups. We're trying to reduce dbt2-pgsql idle time regressions here... make sure we don't don't move tasks the wrong way in an imbalance condition. Also, remove the cache coldness requirement from the calculation - this seems to induce sharp cutoff points where behaviour will suddenly change on some workloads if the load creeps slightly over or under some point. It is good for periodic balancing because in that case have otherwise have no other context to determine what task to move. But also make a minor tweak to "wake balancing" - the imbalance tolerance is now set at half the domain's imbalance, so we get the opportunity to do wake balancing before the more random periodic rebalancing gets preformed. Signed-off-by:
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Nick Piggin authored
Do CPU load averaging over a number of different intervals. Allow each interval to be chosen by sending a parameter to source_load and target_load. 0 is instantaneous, idx > 0 returns a decaying average with the most recent sample weighted at 2^(idx-1). To a maximum of 3 (could be easily increased). So generally a higher number will result in more conservative balancing. Signed-off-by:
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Nick Piggin authored
Remove the special casing for idle CPU balancing. Things like this are hurting for example on SMT, where are single sibling being idle doesn't really warrant a really aggressive pull over the NUMA domain, for example. Signed-off-by:
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Nick Piggin authored
These conditions should now be impossible, and we need to fix them if they happen. Signed-off-by:
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Nick Piggin authored
SMT balancing has a couple of problems. Firstly, active_load_balance is too complex - basically it should be a dumb helper for when the periodic balancer has determined there is an imbalance, but gets stuck because the task is running. So rip out all its "smarts", and just make it move one task to the target CPU. Second, the busy CPU's sched-domain tree was being used for active balancing. This means that it may not see that nr_balance_failed has reached a critical level. So use the target CPU's sched-domain tree for this. We can do this because we hold its runqueue lock. Lastly, reset nr_balance_failed to a point where we allow cache hot migration. This will help ensure active load balancing is successful. Thanks to Suresh Siddha for pointing out these issues. Signed-off-by:
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Nick Piggin authored
Fix up active load balancing a bit so it doesn't get called when it shouldn't. Reset the nr_balance_failed counter at more points where we have found conditions to be balanced. This reduces too aggressive active balancing seen on some workloads. Signed-off-by:
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Nick Piggin authored
John Hawkes explained the problem best: A large number of processes that are pinned to a single CPU results in every other CPU's load_balance() seeing this overloaded CPU as "busiest", yet move_tasks() never finds a task to pull-migrate. This condition occurs during module unload, but can also occur as a denial-of-service using sys_sched_setaffinity(). Several hundred CPUs performing this fruitless load_balance() will livelock on the busiest CPU's runqueue lock. A smaller number of CPUs will livelock if the pinned task count gets high. Expanding slightly on John's patch, this one attempts to work out whether the balancing failure has been due to too many tasks pinned on the runqueue. This allows it to be basically invisible to the regular blancing paths (ie. when there are no pinned tasks). We can use this extra knowledge to shut down the balancing faster, and ensure the migration threads don't start running which is another problem observed in the wild. Signed-off-by:
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Nick Piggin authored
New sched-domains code means we don't get spans with offline CPUs in them. Signed-off-by:
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Jon Smirl authored
We don't need to use do_div() on a 32-bit quantity. Signed-off-by:
Jon Smirl <jonsmirl@gmail.com> Signed-off-by:
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Qu Fuping authored
Reiserfs's readpage does not notice i/o errors. This patch makes reiserfs_readpage to return -EIO when i/o error appears. This patch makes reiserfs to not ignore I/O error on readpage. Signed-off-by:
Qu Fuping <fs@ercist.iscas.ac.cn> Signed-off-by:
Vladimir V. Saveliev <vs@namesys.com> Signed-off-by:
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Jean-Christophe Dubois authored
This is failing on my cross-compilation environment (From a solaris system) using gcc-3.4.1 (as the compiler can't find a prototype for the setlocale() function). Signed-off-by:
Jean-Christophe Dubois <jdubois@mc.com> Signed-off-by:
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Badari Pulavarty authored
Here is the fix for the problem described in http://bugzilla.kernel.org/show_bug.cgi?id=4721 Basically, problem is generic_file_buffered_write() is accessing beyond end of the iov[] vector after handling the last vector. If we happen to cross page boundary, we get a fault. I think this simple patch is good enough. If we really don't want to depend on the "count", then we need pass nr_segs to filemap_set_next_iovec() and decrement it and check it. Signed-off-by:
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Hugh Dickins authored
Any filesystem which is using simple_dir_operations will retunr -EINVAL for fsync() on a directory. Make it return zero instead. Signed-off-by:
Hugh Dickins <hugh@veritas.com> Signed-off-by:
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Kylene Jo Hall authored
I was using invalid memory for the miscdevice.name. This patch fixes the problem which was manifested by an ugly entry in /proc/misc. Signed-off-by:
Kylene Hall <kjhall@us.ibm.com> Signed-off-by:
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Kylene Jo Hall authored
Fix parsing of the PUBEK for display which was leading to showing the wrong modulus length and modulus. Signed-off-by:
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Kylene Jo Hall authored
This patch is work to support new National TPMs that problems were reported with on Thinkpad T43 and Thinkcentre S51. Thanks to Jens and Gang for their debugging work on these issues. Signed-off-by:
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Paul E. McKenney authored
2.6.12-rc6-mm1 has a few remaining synchronize_kernel()s, some (but not all) in comments. This patch changes these synchronize_kernel() calls (and comments) to synchronize_rcu() or synchronize_sched() as follows: - arch/x86_64/kernel/mce.c mce_read(): change to synchronize_sched() to handle races with machine-check exceptions (synchronize_rcu() would not cut it given RCU implementations intended for hardcore realtime use. - drivers/input/serio/i8042.c i8042_stop(): change to synchronize_sched() to handle races with i8042_interrupt() interrupt handler. Again, synchronize_rcu() would not cut it given RCU implementations intended for hardcore realtime use. - include/*/kdebug.h comments: change to synchronize_sched() to handle races with NMIs. As before, synchronize_rcu() would not cut it... - include/linux/list.h comment: change to synchronize_rcu(), since this comment is for list_del_rcu(). - security/keys/key.c unregister_key_type(): change to synchronize_rcu(), since this is interacting with RCU read side. - security/keys/process_keys.c install_session_keyring(): change to synchronize_rcu(), since this is interacting with RCU read side. Signed-off-by:
"Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by:
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Alexey Dobriyan authored
Fixes http://bugme.osdl.org/show_bug.cgi?id=4726Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by:
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Lee Nicks authored
The following patch fix gcc 4 compilation errors in drivers/serial/mpsc.c Signed-off-by:
Lee Nicks <allinux@gmail.com> Signed-off-by:
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Michael Holzheu authored
This patch changes the memory allocation method for the s390 debug feature. Trace buffers had been allocated using the get_free_pages() function before. Therefore it was not possible to get big memory areas in a running system due to memory fragmentation. Now the trace buffers are subdivided into several subbuffers with pagesize. Therefore it is now possible to allocate more memory for the trace buffers and more trace records can be written. In addition to that, dynamic specification of the size of the trace buffers is implemented. It is now possible to change the size of a trace buffer using a new debugfs file instance. When writing a number into this file, the trace buffer size is changed to 'number * pagesize'. In the past all the traces could be obtained from userspace by accessing files in the "proc" filesystem. Now with debugfs we have a new filesystem which should be used for debugging purposes. This patch moves the debug feature from procfs to debugfs. Since the interface of debug_register() changed, all device drivers, which use the debug feature had to be adjusted. Signed-off-by:
Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by:
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Christian Borntraeger authored
Add interface to issue VM control program commands. Signed-off-by:
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Heiko Carstens authored
Improved machine check handling. Kernel is now able to receive machine checks while in kernel mode (system call, interrupt and program check handling). Also register validation is now performed. Signed-off-by:
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Cornelia Huck authored
Fix compile breakage in the dcss block driver introduced by the attribute changes. Signed-off-by:
Cornelia Huck <cohuck@de.ibm.com> Signed-off-by:
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Cornelia Huck authored
Convert the dasd driver to use the new klist interface. Signed-off-by:
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Cornelia Huck authored
Convert the common I/O layer to use the klist interfaces. This patch has been adapted from the previous version to the changed interface semantics. Also, gcc 4.0 compile warnings have been removed. Signed-off-by:
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Paolo 'Blaisorblade' Giarrusso authored
Cope with a conditional i386 definition, which is wrong for UML. Before we just used that one, but it wasn't defined for CONFIG_SMP, so in that case we got link errors. Signed-off-by:
Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by:
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