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2008-04-15Fix locking bug in "acquire_console_semaphore_for_printk()"Linus Torvalds1-2/+15
When I cleaned up printk() and split up the printk locking logic in commit 266c2e0abeca649fa6667a1a427ad1da507c6375 ("Make printk() console semaphore accesses sensible") I had incorrectly moved the call to have_callable_console() outside of the console semaphore. That was buggy. The console semaphore protects the console_drivers list that is used by have_callable_console(). Thanks go to Bongani Hlope who saw this as a hang on shutdown and reboot and bisected the bug to the right commit, and tested this patch. See http://lkml.org/lkml/2008/4/11/315 Bisected-and-tested-by: Bongani Hlope <bonganilinux@mweb.co.za> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-14revert "sched: fix fair sleepers"Ingo Molnar1-4/+2
revert "sched: fix fair sleepers" (e22ecef1d2658ba54ed7d3fdb5d60829fb434c23), because it is causing audio skipping, see: http://bugzilla.kernel.org/show_bug.cgi?id=10428 the patch is correct and the real cause of the skipping is not understood (tracing makes it go away), but time has run out so we'll revert it and re-try in 2.6.26. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-11cgroups: include hierarchy ids in /proc/<pid>/cgroupPaul Menage1-0/+1
Extend the /proc/<pid>/cgroup file to include the appropriate hierarchy ID on each line. Currently this ID isn't really needed since a hierarchy can be completely identified by the set of subsystems bound to it, but this is likely to change in the near future in order to support stateless subsystems and merging/rebinding of subsystems. Getting this change into 2.6.25 reduces the need for an API change later. Signed-off-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-10asmlinkage_protect replaces prevent_tail_callRoland McGrath2-13/+13
The prevent_tail_call() macro works around the problem of the compiler clobbering argument words on the stack, which for asmlinkage functions is the caller's (user's) struct pt_regs. The tail/sibling-call optimization is not the only way that the compiler can decide to use stack argument words as scratch space, which we have to prevent. Other optimizations can do it too. Until we have new compiler support to make "asmlinkage" binding on the compiler's own use of the stack argument frame, we have work around all the manifestations of this issue that crop up. More cases seem to be prevented by also keeping the incoming argument variables live at the end of the function. This makes their original stack slots attractive places to leave those variables, so the compiler tends not clobber them for something else. It's still no guarantee, but it handles some observed cases that prevent_tail_call() did not. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-04cgroups: add cgroup support for enabling controllers at boot timePaul Menage1-5/+37
The effects of cgroup_disable=foo are: - foo isn't auto-mounted if you mount all cgroups in a single hierarchy - foo isn't visible as an individually mountable subsystem As a result there will only ever be one call to foo->create(), at init time; all processes will stay in this group, and the group will never be mounted on a visible hierarchy. Any additional effects (e.g. not allocating metadata) are up to the foo subsystem. This doesn't handle early_init subsystems (their "disabled" bit isn't set be, but it could easily be extended to do so if any of the early_init systems wanted it - I think it would just involve some nastier parameter processing since it would occur before the command-line argument parser had been run. Hugh said: Ballpark figures, I'm trying to get this question out rather than processing the exact numbers: CONFIG_CGROUP_MEM_RES_CTLR adds 15% overhead to the affected paths, booting with cgroup_disable=memory cuts that back to 1% overhead (due to slightly bigger struct page). I'm no expert on distros, they may have no interest whatever in CONFIG_CGROUP_MEM_RES_CTLR=y; and the rest of us can easily build with or without it, or apply the cgroup_disable=memory patches. Unix bench's execl test result on x86_64 was == just after boot without mounting any cgroup fs.== mem_cgorup=off : Execl Throughput 43.0 3150.1 732.6 mem_cgroup=on : Execl Throughput 43.0 2932.6 682.0 == [lizf@cn.fujitsu.com: fix boot option parsing] Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-02markers: use synchronize_sched()Mathieu Desnoyers1-0/+9
Markers do not mix well with CONFIG_PREEMPT_RCU because it uses preempt_disable/enable() and not rcu_read_lock/unlock for minimal intrusiveness. We would need call_sched and sched_barrier primitives. Currently, the modification (connection and disconnection) of probes from markers requires changes to the data structure done in RCU-style : a new data structure is created, the pointer is changed atomically, a quiescent state is reached and then the old data structure is freed. The quiescent state is reached once all the currently running preempt_disable regions are done running. We use the call_rcu mechanism to execute kfree() after such quiescent state has been reached. However, the new CONFIG_PREEMPT_RCU version of call_rcu and rcu_barrier does not guarantee that all preempt_disable code regions have finished, hence the race. The "proper" way to do this is to use rcu_read_lock/unlock, but we don't want to use it to minimize intrusiveness on the traced system. (we do not want the marker code to call into much of the OS code, because it would quickly restrict what can and cannot be instrumented, such as the scheduler). The temporary fix, until we get call_rcu_sched and rcu_barrier_sched in mainline, is to use synchronize_sched before each call_rcu calls, so we wait for the quiescent state in the system call code path. It will slow down batch marker enable/disable, but will make sure the race is gone. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-30futex_compat __user annotationAl Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-30NULL noise: fs/*, mm/*, kernel/*Al Viro2-3/+3
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-28audit: silence two kerneldoc warnings in kernel/audit.cDave Jones1-3/+3
Silence two kerneldoc warnings. Warning(kernel/audit.c:1276): No description found for parameter 'string' Warning(kernel/audit.c:1276): No description found for parameter 'len' [also fix a typo for bonus points] Signed-off-by: Dave Jones <davej@codemonkey.org.uk> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-28memcgroup: fix spurious EBUSY on memory cgroup removalYAMAMOTO Takashi1-1/+1
Call mm_free_cgroup earlier. Otherwise a reference due to lazy mm switching can prevent cgroup removal. Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-27Give futex init a proper nameBenjamin Herrenschmidt1-2/+2
The futex init function is called init(). This is a pain in the neck when debugging when you code dies in ... init :-) This renames it to futex_init(). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-26Merge branch 'master' of ↵Linus Torvalds3-2/+53
git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt * 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt: NOHZ: reevaluate idle sleep length after add_timer_on() clocksource: revert: use init_timer_deferrable for clocksource_watchdog
2008-03-26relay: set an spd_release() hook for spliceJens Axboe1-0/+5
relay doesn't reference the pages it adds, however we need a non-NULL hook or splice_to_pipe() can oops. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-26set relay file can not be read by pread(2)Lai Jiangshan1-1/+1
I found that relay files can be read by pread(2). I fix it, for relay files are not capable of seeking. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-26NOHZ: reevaluate idle sleep length after add_timer_on()Thomas Gleixner2-1/+52
add_timer_on() can add a timer on a CPU which is currently in a long idle sleep, but the timer wheel is not reevaluated by the nohz code on that CPU. So a timer can be delayed for quite a long time. This triggered a false positive in the clocksource watchdog code. To avoid this we need to wake up the idle CPU and enforce the reevaluation of the timer wheel for the next timer event. Add a function, which checks a given CPU for idle state, marks the idle task with NEED_RESCHED and sends a reschedule IPI to notify the other CPU of the change in the timer wheel. Call this function from add_timer_on(). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: stable@kernel.org -- include/linux/sched.h | 6 ++++++ kernel/sched.c | 43 +++++++++++++++++++++++++++++++++++++++++++ kernel/timer.c | 10 +++++++++- 3 files changed, 58 insertions(+), 1 deletion(-)
2008-03-25clocksource: revert: use init_timer_deferrable for clocksource_watchdogThomas Gleixner1-1/+1
Revert commit 1077f5a917b7c630231037826b344b2f7f5b903f Author: Parag Warudkar <parag.warudkar@gmail.com> Date: Wed Jan 30 13:30:01 2008 +0100 clocksource.c: use init_timer_deferrable for clocksource_watchdog clocksource_watchdog can use a deferrable timer - reduces wakeups from idle per second. The watchdog timer needs to run with the specified interval. Otherwise it will miss the possible wrap of the watchdog clocksource. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org
2008-03-24Make printk() console semaphore accesses sensibleLinus Torvalds1-35/+48
The printk() logic on when/how to get the console semaphore was unreadable, this splits the code up into a few helper functions and makes it easier to follow what is going on. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-24bsd_acct: using task_struct->tgid is not right in pid-namespacesPavel Emelyanov1-6/+15
In case we're accounting from a sub-namespace, the tgids reported will not refer to the right namespace. Save the pid_namespace we're accounting in on the acct_glbs and use it in do_acct_process. Two less :) places using the task_struct.tgid member. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-24bsd_acct: plain current->real_parent access is not always safePavel Emelyanov1-1/+3
This is minor, but dereferencing even current real_parent is not safe on debug kernels, since the memory, this points to, can be unmapped - RCU protection is required. Besides, the tgid field is deprecated and is to be replaced with task_tgid_xxx call (the 2nd patch), so RCU will be required anyway. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-24markers: remove ACCESS_ONCEMathieu Desnoyers1-6/+6
As Paul pointed out, the ACCESS_ONCE are not needed because we already have the explicit surrounding memory barriers. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Christoph Hellwig <hch@infradead.org> Cc: Mike Mason <mmlnx@us.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: David Smith <dsmith@redhat.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Adrian Bunk <adrian.bunk@movial.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-24markers: update preempt_disable. call_rcu, rcu_barrier commentsMathieu Desnoyers1-11/+8
Add comments requested by Andrew. Updated comments about synchronize_sched(). Since we use call_rcu and rcu_barrier now, these comments were out of sync with the code. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Christoph Hellwig <hch@infradead.org> Cc: Mike Mason <mmlnx@us.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: David Smith <dsmith@redhat.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Adrian Bunk <adrian.bunk@movial.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-24Don't 'printk()' while holding xtime lock for writingLinus Torvalds1-0/+4
The printk() can deadlock because it can wake up klogd(), and task enqueueing will try to read the time in order to set a hrtimer. Reported-by: Marcin Slusarz <marcin.slusarz@gmail.com> Debugged-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-21sched: add arch_update_cpu_topology hook.Heiko Carstens1-0/+5
Will be called each time the scheduling domains are rebuild. Needed for architectures that don't have a static cpu topology. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-21sched: add exported arch_reinit_sched_domains() to header file.Heiko Carstens1-1/+1
Needed so it can be called from outside of sched.c. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-21sched: remove double unlikely from schedule()Roel Kluin1-1/+1
Combine two unlikely's Signed-off-by: Roel Kluin <12o3l@tiscali.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-21sched: cleanup old and rarely used 'debug' features.Peter Zijlstra2-20/+2
TREE_AVG and APPROX_AVG are initial task placement policies that have been disabled for a long while.. time to remove them. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> CC: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-21Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds1-3/+8
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (46 commits) [NET] ifb: set separate lockdep classes for queue locks [IPV6] KCONFIG: Fix description about IPV6_TUNNEL. [TCP]: Fix shrinking windows with window scaling netpoll: zap_completion_queue: adjust skb->users counter bridge: use time_before() in br_fdb_cleanup() [TG3]: Fix build warning on sparc32. MAINTAINERS: bluez-devel is subscribers-only audit: netlink socket can be auto-bound to pid other than current->pid (v2) [NET]: Fix permissions of /proc/net [SCTP]: Fix a race between module load and protosw access [NETFILTER]: ipt_recent: sanity check hit count [NETFILTER]: nf_conntrack_h323: logical-bitwise & confusion in process_setup() [RT2X00] drivers/net/wireless/rt2x00/rt2x00dev.c: remove dead code, fix warning [IPV4]: esp_output() misannotations [8021Q]: vlan_dev misannotations xfrm: ->eth_proto is __be16 [IPV4]: ipv4_is_lbcast() misannotations [SUNRPC]: net/* NULL noise [SCTP]: fix misannotated __sctp_rcv_asconf_lookup() [PKT_SCHED]: annotate cls_u32 ...
2008-03-20audit: netlink socket can be auto-bound to pid other than current->pid (v2)Pavel Emelyanov1-3/+8
From: Pavel Emelyanov <xemul@openvz.org> This patch is based on the one from Thomas. The kauditd_thread() calls the netlink_unicast() and passes the audit_pid to it. The audit_pid, in turn, is received from the user space and the tool (I've checked the audit v1.6.9) uses getpid() to pass one in the kernel. Besides, this tool doesn't bind the netlink socket to this id, but simply creates it allowing the kernel to auto-bind one. That's the preamble. The problem is that netlink_autobind() _does_not_ guarantees that the socket will be auto-bound to the current pid. Instead it uses the current pid as a hint to start looking for a free id. So, in case of conflict, the audit messages can be sent to a wrong socket. This can happen (it's unlikely, but can be) in case some task opens more than one netlink sockets and then the audit one starts - in this case the audit's pid can be busy and its socket will be bound to another id. The proposal is to introduce an audit_nlk_pid in audit subsys, that will point to the netlink socket to send packets to. It will most often be equal to audit_pid. The socket id can be got from the skb's netlink CB right in the audit_receive_msg. The audit_nlk_pid reset to 0 is not required, since all the decisions are taken based on audit_pid value only. Later, if the audit tools will bind the socket themselves, the kernel will have to provide a way to setup the audit_nlk_pid as well. A good side effect of this patch is that audit_pid can later be converted to struct pid, as it is not longer safe to use pid_t-s in the presence of pid namespaces. But audit code still uses the tgid from task_struct in the audit_signal_info and in the audit_filter_syscall. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-19revert "clocksource: make clocksource watchdog cycle through online CPUs"Andrew Morton1-10/+4
Revert commit 1ada5cba6a0318f90e45b38557e7b5206a9cba38 ("clocksource: make clocksource watchdog cycle through online CPUs") due to the regression reported by Gabriel C at http://lkml.org/lkml/2008/2/24/281 (short vesion: it makes TSC be marked as always unstable on his machine). Cc: Andi Kleen <ak@suse.de> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Robert Hancock <hancockr@shaw.ca> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Gabriel C <nix.or.die@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-19sched: retune wake granularityIngo Molnar1-2/+2
reduce wake-up granularity for better interactivity. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-19sched: wakeup-buddy tasks are cache-hotIngo Molnar1-0/+6
Wakeup-buddy tasks are cache-hot - this makes it a bit harder for the load-balancer to tear them apart. (but it's still possible, if the load is sufficiently assymetric) Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-19sched: improve affine wakeupsIngo Molnar3-17/+47
improve affine wakeups. Maintain the 'overlap' metric based on CFS's sum_exec_runtime - which means the amount of time a task executes after it wakes up some other task. Use the 'overlap' for the wakeup decisions: if the 'overlap' is short, it means there's strong workload coupling between this task and the woken up task. If the 'overlap' is large then the workload is decoupled and the scheduler will move them to separate CPUs more easily. ( Also slightly move the preempt_check within try_to_wake_up() - this has no effect on functionality but allows 'early wakeups' (for still-on-rq tasks) to be correctly accounted as well.) Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-19sched: clean up wakeup balancing, code flowIngo Molnar1-15/+10
Clean up the code flow. No code changed: kernel/sched.o: text data bss dec hex filename 42521 2858 232 45611 b22b sched.o.before 42521 2858 232 45611 b22b sched.o.after md5: 09b31c44e9aff8666f72773dc433e2df sched.o.before.asm 09b31c44e9aff8666f72773dc433e2df sched.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-19sched: clean up wakeup balancing, rename variablesIngo Molnar1-12/+20
rename 'cpu' to 'prev_cpu'. No code changed: kernel/sched.o: text data bss dec hex filename 42521 2858 232 45611 b22b sched.o.before 42521 2858 232 45611 b22b sched.o.after md5: 09b31c44e9aff8666f72773dc433e2df sched.o.before.asm 09b31c44e9aff8666f72773dc433e2df sched.o.after.asm Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-19sched: clean up wakeup balancing, move wake_affine()Ingo Molnar1-59/+75
split out the affine-wakeup bits. No code changed: kernel/sched.o: text data bss dec hex filename 42521 2858 232 45611 b22b sched.o.before 42521 2858 232 45611 b22b sched.o.after md5: 9d76738f1272aa82f0b7affd2f51df6b sched.o.before.asm 09b31c44e9aff8666f72773dc433e2df sched.o.after.asm (the md5's changed because stack slots changed and some registers get scheduled by gcc in a different order - but otherwise the before and after assembly is instruction for instruction equivalent.) Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-17relay: fix subbuf_splice_actor() adding too many pagesJens Axboe1-2/+3
If subbuf_pages was larger than the max number of pages the pipe buffer will hold, subbuf_splice_actor() would happily go beyond the array size. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-15sched: simplify sched_slice()Ingo Molnar1-6/+2
Use the existing calc_delta_mine() calculation for sched_slice(). This saves a divide and simplifies the code because we share it with the other /cfs_rq->load users. It also improves code size: text data bss dec hex filename 42659 2740 144 45543 b1e7 sched.o.before 42093 2740 144 44977 afb1 sched.o.after Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2008-03-15sched: fix fair sleepersIngo Molnar1-2/+4
Fair sleepers need to scale their latency target down by runqueue weight. Otherwise busy systems will gain ever larger sleep bonus. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2008-03-15sched: fix overload performance: buddy wakeupsPeter Zijlstra2-1/+27
Currently we schedule to the leftmost task in the runqueue. When the runtimes are very short because of some server/client ping-pong, especially in over-saturated workloads, this will cycle through all tasks trashing the cache. Reduce cache trashing by keeping dependent tasks together by running newly woken tasks first. However, by not running the leftmost task first we could starve tasks because the wakee can gain unlimited runtime. Therefore we only run the wakee if its within a small (wakeup_granularity) window of the leftmost task. This preserves fairness, but does alternate server/client task groups. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-15sched: fix calc_delta_mine()Ingo Molnar1-1/+1
lw->weight can be 0 for a short time during bootup. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2008-03-15sched: fix update_load_add()/sub()Ingo Molnar1-0/+2
Clear the cached inverse value when updating load. This is needed for calc_delta_mine() to work correctly when using the rq load. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2008-03-15sched: min_vruntime fixPeter Zijlstra1-18/+28
Current min_vruntime tracking is incorrect and will cause serious problems when we don't run the leftmost task for some reason. min_vruntime does two things; 1) it's used to determine a forward direction when the u64 vruntime wraps, 2) it's used to track the leftmost vruntime to position newly enqueued tasks from. The current logic advances min_vruntime whenever the current task's vruntime advance. Because the current task may pass the leftmost task still waiting we're failing the second goal. This causes new tasks to be placed too far ahead and thus penalizes their runtime. Fix this by making min_vruntime the min_vruntime of the waiting tasks by tracking it in enqueue/dequeue, and compare against current's vruntime to obtain the absolute minimum when placing new tasks. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-15sched: fix race in schedule()Hiroshi Shimamoto1-22/+16
Fix a hard to trigger crash seen in the -rt kernel that also affects the vanilla scheduler. There is a race condition between schedule() and some dequeue/enqueue functions; rt_mutex_setprio(), __setscheduler() and sched_move_task(). When scheduling to idle, idle_balance() is called to pull tasks from other busy processor. It might drop the rq lock. It means that those 3 functions encounter on_rq=0 and running=1. The current task should be put when running. Here is a possible scenario: CPU0 CPU1 | schedule() | ->deactivate_task() | ->idle_balance() | -->load_balance_newidle() rt_mutex_setprio() | | --->double_lock_balance() *get lock *rel lock * on_rq=0, ruuning=1 | * sched_class is changed | *rel lock *get lock : | : ->put_prev_task_rt() ->pick_next_task_fair() => panic The current process of CPU1(P1) is scheduling. Deactivated P1, and the scheduler looks for another process on other CPU's runqueue because CPU1 will be idle. idle_balance(), load_balance_newidle() and double_lock_balance() are called and double_lock_balance() could drop the rq lock. On the other hand, CPU0 is trying to boost the priority of P1. The result of boosting only P1's prio and sched_class are changed to RT. The sched entities of P1 and P1's group are never put. It makes cfs_rq invalid, because the cfs_rq has curr and no leaf, but pick_next_task_fair() is called, then the kernel panics. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-13Merge branches 'release' and 'doc' into releaseLen Brown1-1/+1
2008-03-12documentation: Move power-related files to Documentation/power/Randy Dunlap1-1/+1
Move 00-INDEX entries to power/00-INDEX (and add entry for pm_qos_interface.txt). Update references to moved filenames. Fix some trailing whitespace. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Len Brown <len.brown@intel.com>
2008-03-11Hibernation: Fix mark_nosave_pages()Rafael J. Wysocki1-7/+34
There is a problem in the hibernation code that triggers on some NUMA systems on which pfn_valid() returns 'true' for some PFNs that don't belong to any zone. Namely, there is a BUG_ON() in memory_bm_find_bit() that triggers for PFNs not belonging to any zone and passing the pfn_valid() test. On the affected systems it triggers when we mark PFNs reported by the platform as not saveable, because the PFNs in question belong to a region mapped directly using iorepam() (i.e. the ACPI data area) and they pass the pfn_valid() test. Modify memory_bm_find_bit() so that it returns an error if given PFN doesn't belong to any zone instead of crashing the kernel and ignore the result returned by it in mark_nosave_pages(), while marking the "nosave" memory regions. This doesn't affect the hibernation functionality, as we won't touch the PFNs in question anyway. http://bugzilla.kernel.org/show_bug.cgi?id=9966 . Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Len Brown <len.brown@intel.com>
2008-03-11keep rd->online and cpu_online_map in syncGregory Haskins1-1/+2
It is possible to allow the root-domain cache of online cpus to become out of sync with the global cpu_online_map. This is because we currently trigger removal of cpus too early in the notifier chain. Other DOWN_PREPARE handlers may in fact run and reconfigure the root-domain topology, thereby stomping on our own offline handling. The end result is that rd->online may become out of sync with cpu_online_map, which results in potential task misrouting. So change the offline handling to be more tightly coupled with the global offline process by triggering on CPU_DYING intead of CPU_DOWN_PREPARE. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-11Revert "cpu hotplug: adjust root-domain->online span in response to hotplug ↵Gregory Haskins1-7/+11
event" This reverts commit 393d94d98b19089ec172566e23557997931b137e. Lets fix this right. Signed-off-by: Gregory Haskins <ghaskins@novell.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-03-10rcu: move PREEMPT_RCU config option back under PREEMPTPaul E. McKenney1-0/+15
The original preemptible-RCU patch put the choice between classic and preemptible RCU into kernel/Kconfig.preempt, which resulted in build failures on machines not supporting CONFIG_PREEMPT. This choice was therefore moved to init/Kconfig, which worked, but placed the choice between classic and preemptible RCU at the top level, a very obtuse choice indeed. This patch changes from the Kconfig "choice" mechanism to a pair of booleans, only one of which (CONFIG_PREEMPT_RCU) is user-visible, and is located in kernel/Kconfig.preempt, where one would expect it to be. The other (CONFIG_CLASSIC_RCU) is in init/Kconfig so that it is available to all architectures, hopefully avoiding build breakage. Thanks to Roman Zippel for suggesting this approach. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Josh Triplett <josh@freedesktop.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-10modules: warn about suspicious return values from module's ->init() hookAlexey Dobriyan1-0/+8
Return value convention of module's init functions is 0/-E. Sometimes, e.g. during forward-porting mistakes happen and buggy module created, where result of comparison "workqueue != NULL" is propagated all the way up to sys_init_module. What happens is that some other module created workqueue in question, our module created it again and module was successfully loaded. Or it could be some other bug. Let's make such mistakes much more visible. In retrospective, such messages would noticeably shorten some of my head-scratching sessions. Note, that dump_stack() is just a way to get attention from user. Sample message: sys_init_module: 'foo'->init suspiciously returned 1, it should follow 0/-E convention sys_init_module: loading module anyway... Pid: 4223, comm: modprobe Not tainted 2.6.24-25f666300625d894ebe04bac2b4b3aadb907c861 #5 Call Trace: [<ffffffff80254b05>] sys_init_module+0xe5/0x1d0 [<ffffffff8020b39b>] system_call_after_swapgs+0x7b/0x80 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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