- Dec 01, 2009
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David Howells authored
Move slow_work's debugging proc file to debugfs. Signed-off-by:
David Howells <dhowells@redhat.com> Requested-and-acked-by:
Ingo Molnar <mingo@elte.hu> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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David Howells authored
Commits 3d7a641e ("SLOW_WORK: Wait for outstanding work items belonging to a module to clear") introduced some code to make sure that all of a module's slow-work items were complete before that module was removed, and commit 3bde31a4 ("SLOW_WORK: Allow a requeueable work item to sleep till the thread is needed") further extended that, breaking it in the process if CONFIG_MODULES=n: CC kernel/slow-work.o kernel/slow-work.c: In function 'slow_work_execute': kernel/slow-work.c:313: error: 'slow_work_thread_processing' undeclared (first use in this function) kernel/slow-work.c:313: error: (Each undeclared identifier is reported only once kernel/slow-work.c:313: error: for each function it appears in.) kernel/slow-work.c: In function 'slow_work_wait_for_items': kernel/slow-work.c:950: error: 'slow_work_unreg_sync_lock' undeclared (first use in this function) kernel/slow-work.c:951: error: 'slow_work_unreg_wq' undeclared (first use in this function) kernel/slow-work.c:961: error: 'slow_work_unreg_work_item' undeclared (first use in this function) kernel/slow-work.c:974: error: 'slow_work_unreg_module' undeclared (first use in this function) kernel/slow-work.c:977: error: 'slow_work_thread_processing' undeclared (first use in this function) make[1]: *** [kernel/slow-work.o] Error 1 Fix this by: (1) Extracting the bits of slow_work_execute() that are contingent on CONFIG_MODULES, and the bits that should be, into inline functions and placing them into the #ifdef'd section that defines the relevant variables and adding stubs for moduleless kernels. This allows the removal of some #ifdefs. (2) #ifdef'ing out the contents of slow_work_wait_for_items() in moduleless kernels. The four functions related to handling module unloading synchronisation (and their associated variables) could be offloaded into a separate .c file, but each function is only used once and three of them are tiny, so doing so would prevent them from being inlined. Reported-by:
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- Nov 19, 2009
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David Howells authored
Add a function to allow a requeueable work item to sleep till the thread processing it is needed by the slow-work facility to perform other work. Sometimes a work item can't progress immediately, but must wait for the completion of another work item that's currently being processed by another slow-work thread. In some circumstances, the waiting item could instead - theoretically - put itself back on the queue and yield its thread back to the slow-work facility, thus waiting till it gets processing time again before attempting to progress. This would allow other work items processing time on that thread. However, this only works if there is something on the queue for it to queue behind - otherwise it will just get a thread again immediately, and will end up cycling between the queue and the thread, eating up valuable CPU time. So, slow_work_sleep_till_thread_needed() is provided such that an item can put itself on a wait queue that will wake it up when the event it is actually interested in occurs, then call this function in lieu of calling schedule(). This function will then sleep until either the item's event occurs or another work item appears on the queue. If another work item is queued, but the item's event hasn't occurred, then the work item should requeue itself and yield the thread back to the slow-work facility by returning. This can be used by CacheFiles for an object that is being created on one thread to wait for an object being deleted on another thread where there is nothing on the queue for the creation to go and wait behind. As soon as an item appears on the queue that could be given thread time instead, CacheFiles can stick the creating object back on the queue and return to the slow-work facility - assuming the object deletion didn't also complete. Signed-off-by: -
David Howells authored
Allow the executing and queued work items to be viewed through a /proc file for debugging purposes. The contents look something like the following: THR PID ITEM ADDR FL MARK DESC === ===== ================ == ===== ========== 0 3005 ffff880023f52348 a 952ms FSC: OBJ17d3: LOOK 1 3006 ffff880024e33668 2 160ms FSC: OBJ17e5 OP60d3b: Write1/Store fl=2 2 3165 ffff8800296dd180 a 424ms FSC: OBJ17e4: LOOK 3 4089 ffff8800262c8d78 a 212ms FSC: OBJ17ea: CRTN 4 4090 ffff88002792bed8 2 388ms FSC: OBJ17e8 OP60d36: Write1/Store fl=2 5 4092 ffff88002a0ef308 2 388ms FSC: OBJ17e7 OP60d2e: Write1/Store fl=2 6 4094 ffff88002abaf4b8 2 132ms FSC: OBJ17e2 OP60d4e: Write1/Store fl=2 7 4095 ffff88002bb188e0 a 388ms FSC: OBJ17e9: CRTN vsq - ffff880023d99668 1 308ms FSC: OBJ17e0 OP60f91: Write1/EnQ fl=2 vsq - ffff8800295d1740 1 212ms FSC: OBJ16be OP4d4b6: Write1/EnQ fl=2 vsq - ffff880025ba3308 1 160ms FSC: OBJ179a OP58dec: Write1/EnQ fl=2 vsq - ffff880024ec83e0 1 160ms FSC: OBJ17ae OP599f2: Write1/EnQ fl=2 vsq - ffff880026618e00 1 160ms FSC: OBJ17e6 OP60d33: Write1/EnQ fl=2 vsq - ffff880025a2a4b8 1 132ms FSC: OBJ16a2 OP4d583: Write1/EnQ fl=2 vsq - ffff880023cbe6d8 9 212ms FSC: OBJ17eb: LOOK vsq - ffff880024d37590 9 212ms FSC: OBJ17ec: LOOK vsq - ffff880027746cb0 9 212ms FSC: OBJ17ed: LOOK vsq - ffff880024d37ae8 9 212ms FSC: OBJ17ee: LOOK vsq - ffff880024d37cb0 9 212ms FSC: OBJ17ef: LOOK vsq - ffff880025036550 9 212ms FSC: OBJ17f0: LOOK vsq - ffff8800250368e0 9 212ms FSC: OBJ17f1: LOOK vsq - ffff880025036aa8 9 212ms FSC: OBJ17f2: LOOK In the 'THR' column, executing items show the thread they're occupying and queued threads indicate which queue they're on. 'PID' shows the process ID of a slow-work thread that's executing something. 'FL' shows the work item flags. 'MARK' indicates how long since an item was queued or began executing. Lastly, the 'DESC' column permits the owner of an item to give some information. Signed-off-by: -
Jens Axboe authored
This adds support for starting slow work with a delay, similar to the functionality we have for workqueues. Signed-off-by:
Jens Axboe <jens.axboe@oracle.com> Signed-off-by:
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Jens Axboe authored
Add support for cancellation of queued slow work and delayed slow work items. The cancellation functions will wait for items that are pending or undergoing execution to be discarded by the slow work facility. Attempting to enqueue work that is in the process of being cancelled will result in ECANCELED. Signed-off-by:
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Jens Axboe authored
Make the ability for the slow-work facility to take references on a work item optional as not everyone requires this. Even the internal slow-work stubs them out, so those can be got rid of too. Signed-off-by:
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David Howells authored
Wait for outstanding slow work items belonging to a module to clear when unregistering that module as a user of the facility. This prevents the put_ref code of a work item from being taken away before it returns. Signed-off-by:
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- Nov 18, 2009
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Tejun Heo authored
Commit 65a64464 ("HWPOISON: Allow schedule_on_each_cpu() from keventd") which allows schedule_on_each_cpu() to be called from keventd added a race condition. schedule_on_each_cpu() may race with cpu hotplug and end up executing the function twice on a cpu. Fix it by moving direct execution into the section protected with get/put_online_cpus(). While at it, update code such that direct execution is done after works have been scheduled for all other cpus and drop unnecessary cpu != orig test from flush loop. Signed-off-by:
Tejun Heo <tj@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Acked-by:
Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
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- Nov 12, 2009
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David S. Miller authored
Noticed by Thomas GLeixner. Signed-off-by:David S. Miller <davem@davemloft.net>
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- Nov 08, 2009
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Cyrill Gorcunov authored
root_task_group_empty is used only with FAIR_GROUP_SCHED so if we use other scheduler options we get: kernel/sched.c:314: warning: 'root_task_group_empty' defined but not used So move CONFIG_FAIR_GROUP_SCHED up that it covers root_task_group_empty(). Signed-off-by:
Cyrill Gorcunov <gorcunov@openvz.org> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20091026192414.GB5321@lenovo> Signed-off-by:
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Randy Dunlap authored
Fix variable name in sched.c kernel-doc notation. Fixes this DocBook warning: Warning(kernel/sched.c:2008): No description found for parameter 'p' Warning(kernel/sched.c:2008): Excess function parameter 'k' description in 'kthread_bind' Signed-off-by:
Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <4AF4B1BC.8020604@oracle.com> Signed-off-by:
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- Nov 07, 2009
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Yong Zhang authored
Prarit reported: ================================= [ INFO: inconsistent lock state ] 2.6.32-rc5 #1 --------------------------------- inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. swapper/0 [HC0[0]:SC1[1]:HE1:SE0] takes: (&irq_desc_lock_class){?.-...}, at: [<ffffffff810c264e>] try_one_irq+0x32/0x138 {IN-HARDIRQ-W} state was registered at: [<ffffffff81095160>] __lock_acquire+0x2fc/0xd5d [<ffffffff81095cb4>] lock_acquire+0xf3/0x12d [<ffffffff814cdadd>] _spin_lock+0x40/0x89 [<ffffffff810c3389>] handle_level_irq+0x30/0x105 [<ffffffff81014e0e>] handle_irq+0x95/0xb7 [<ffffffff810141bd>] do_IRQ+0x6a/0xe0 [<ffffffff81012813>] ret_from_intr+0x0/0x16 irq event stamp: 195096 hardirqs last enabled at (195096): [<ffffffff814cd7f7>] _spin_unlock_irq+0x3a/0x5c hardirqs last disabled at (195095): [<ffffffff814cdbdd>] _spin_lock_irq+0x29/0x95 softirqs last enabled at (195088): [<ffffffff81068c92>] __do_softirq+0x1c1/0x1ef softirqs last disabled at (195093): [<ffffffff8101304c>] call_softirq+0x1c/0x30 other info that might help us debug this: 1 lock held by swapper/0: #0: (kernel/irq/spurious.c:21){+.-...}, at: [<ffffffff81070cf2>] run_timer_softirq+0x1a9/0x315 stack backtrace: Pid: 0, comm: swapper Not tainted 2.6.32-rc5 #1 Call Trace: <IRQ> [<ffffffff81093e94>] valid_state+0x187/0x1ae [<ffffffff81093fe4>] mark_lock+0x129/0x253 [<ffffffff810951d4>] __lock_acquire+0x370/0xd5d [<ffffffff81095cb4>] lock_acquire+0xf3/0x12d [<ffffffff814cdadd>] _spin_lock+0x40/0x89 [<ffffffff810c264e>] try_one_irq+0x32/0x138 [<ffffffff810c2795>] poll_all_shared_irqs+0x41/0x6d [<ffffffff810c27dd>] poll_spurious_irqs+0x1c/0x49 [<ffffffff81070d82>] run_timer_softirq+0x239/0x315 [<ffffffff81068bd3>] __do_softirq+0x102/0x1ef [<ffffffff8101304c>] call_softirq+0x1c/0x30 [<ffffffff81014b65>] do_softirq+0x59/0xca [<ffffffff810686ad>] irq_exit+0x58/0xae [<ffffffff81029b84>] smp_apic_timer_interrupt+0x94/0xba [<ffffffff81012a33>] apic_timer_interrupt+0x13/0x20 The reason is that try_one_irq() is called from hardirq context with interrupts disabled and from softirq context (poll_all_shared_irqs()) with interrupts enabled. Disable interrupts before calling it from poll_all_shared_irqs(). Reported-and-tested-by:Prarit Bhargava <prarit@redhat.com> Signed-off-by:
Yong Zhang <yong.zhang0@gmail.com> LKML-Reference: <1257563773-4620-1-git-send-email-yong.zhang0@gmail.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de>
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- Nov 04, 2009
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Li Zefan authored
When a command is passed to the set_ftrace_filter, then the ftrace_regex_lock is still held going back to user space. # echo 'do_open : foo' > set_ftrace_filter (still holding ftrace_regex_lock when returning to user space!) Signed-off-by:
Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4AEF7F8A.3080300@cn.fujitsu.com> Signed-off-by:
Steven Rostedt <rostedt@goodmis.org>
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Lai Jiangshan authored
We got a sudden panic when we reduced the size of the ringbuffer. We can reproduce the panic by the following steps: echo 1 > events/sched/enable cat trace_pipe > /dev/null & while ((1)) do echo 12000 > buffer_size_kb echo 512 > buffer_size_kb done (not more than 5 seconds, panic ...) Reported-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by:
Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4AF01735.9060409@cn.fujitsu.com> Signed-off-by:
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- Nov 03, 2009
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Ian Campbell authored
nr_processes() returns the sum of the per cpu counter process_counts for all online CPUs. This counter is incremented for the current CPU on fork() and decremented for the current CPU on exit(). Since a process does not necessarily fork and exit on the same CPU the process_count for an individual CPU can be either positive or negative and effectively has no meaning in isolation. Therefore calculating the sum of process_counts over only the online CPUs omits the processes which were started or stopped on any CPU which has since been unplugged. Only the sum of process_counts across all possible CPUs has meaning. The only caller of nr_processes() is proc_root_getattr() which calculates the number of links to /proc as stat->nlink = proc_root.nlink + nr_processes(); You don't have to be all that unlucky for the nr_processes() to return a negative value leading to a negative number of links (or rather, an apparently enormous number of links). If this happens then you can get failures where things like "ls /proc" start to fail because they got an -EOVERFLOW from some stat() call. Example with some debugging inserted to show what goes on: # ps haux|wc -l nr_processes: CPU0: 90 nr_processes: CPU1: 1030 nr_processes: CPU2: -900 nr_processes: CPU3: -136 nr_processes: TOTAL: 84 proc_root_getattr. nlink 12 + nr_processes() 84 = 96 84 # echo 0 >/sys/devices/system/cpu/cpu1/online # ps haux|wc -l nr_processes: CPU0: 85 nr_processes: CPU2: -901 nr_processes: CPU3: -137 nr_processes: TOTAL: -953 proc_root_getattr. nlink 12 + nr_processes() -953 = -941 75 # stat /proc/ nr_processes: CPU0: 84 nr_processes: CPU2: -901 nr_processes: CPU3: -137 nr_processes: TOTAL: -954 proc_root_getattr. nlink 12 + nr_processes() -954 = -942 File: `/proc/' Size: 0 Blocks: 0 IO Block: 1024 directory Device: 3h/3d Inode: 1 Links: 4294966354 Access: (0555/dr-xr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2009-11-03 09:06:55.000000000 +0000 Modify: 2009-11-03 09:06:55.000000000 +0000 Change: 2009-11-03 09:06:55.000000000 +0000 I'm not 100% convinced that the per_cpu regions remain valid for offline CPUs, although my testing suggests that they do. If not then I think the correct solution would be to aggregate the process_count for a given CPU into a global base value in cpu_down(). This bug appears to pre-date the transition to git and it looks like it may even have been present in linux-2.6.0-test7-bk3 since it looks like the code Rusty patched in http://lwn.net/Articles/64773/ was already wrong. Signed-off-by:Ian Campbell <ian.campbell@citrix.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by:
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Jiri Slaby authored
Finish a line by \n when load_image fails in the middle of loading. Signed-off-by:
Jiri Slaby <jirislaby@gmail.com> Acked-by:
Pavel Machek <pavel@ucw.cz> Signed-off-by:
Rafael J. Wysocki <rjw@sisk.pl>
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Jiri Slaby authored
There are too many retval variables in save_image(). Thus error return value from snapshot_read_next() may be ignored and only part of the snapshot (successfully) written. Remove 'error' variable, invert the condition in the do-while loop and convert the loop to use only 'ret' variable. Switch the rest of the function to consider only 'ret'. Also make sure we end printed line by \n if an error occurs. Signed-off-by:
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Jiri Slaby authored
While cruising through the swsusp code I found few blkdev reference leaks of resume_bdev. swsusp_read: remove blkdev_put altogether. Some fail paths do not do that. swsusp_check: make sure we always put a reference on fail paths software_resume: all fail paths between swsusp_check and swsusp_read omit swsusp_close. Add it in those cases. And since swsusp_read doesn't drop the reference anymore, do it here unconditionally. [rjw: Fixed a small coding style issue.] Signed-off-by: -
Mike Galbraith authored
Eric Paris reported that commit f685ceac causes boot time PREEMPT_DEBUG complaints. [ 4.590699] BUG: using smp_processor_id() in preemptible [00000000] code: rmmod/1314 [ 4.593043] caller is task_hot+0x86/0xd0 Since kthread_bind() messes with scheduler internals, move the body to sched.c, and lock the runqueue. Reported-by:
Eric Paris <eparis@redhat.com> Signed-off-by:
Mike Galbraith <efault@gmx.de> Tested-by:
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- Nov 02, 2009
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Paul E. McKenney authored
Very long RCU read-side critical sections (50 milliseconds or so) can cause a race between force_quiescent_state() and rcu_start_gp() as follows on kernel builds with multi-level rcu_node hierarchies: 1. CPU 0 calls force_quiescent_state(), sees that there is a grace period in progress, and acquires ->fsqlock. 2. CPU 1 detects the end of the grace period, and so cpu_quiet_msk_finish() sets rsp->completed to rsp->gpnum. This operation is carried out under the root rnp->lock, but CPU 0 has not yet acquired that lock. Note that rsp->signaled is still RCU_SAVE_DYNTICK from the last grace period. 3. CPU 1 calls rcu_start_gp(), but no one wants a new grace period, so it drops the root rnp->lock and returns. 4. CPU 0 acquires the root rnp->lock and picks up rsp->completed and rsp->signaled, then drops rnp->lock. It then enters the RCU_SAVE_DYNTICK leg of the switch statement. 5. CPU 2 invokes call_rcu(), and now needs a new grace period. It calls rcu_start_gp(), which acquires the root rnp->lock, sets rsp->signaled to RCU_GP_INIT (too bad that CPU 0 is already in the RCU_SAVE_DYNTICK leg of the switch statement!) and starts initializing the rcu_node hierarchy. If there are multiple levels to the hierarchy, it will drop the root rnp->lock and initialize the lower levels of the hierarchy. 6. CPU 0 notes that rsp->completed has not changed, which permits both CPU 2 and CPU 0 to try updating it concurrently. If CPU 0's update prevails, later calls to force_quiescent_state() can count old quiescent states against the new grace period, which can in turn result in premature ending of grace periods. Not good. This patch adds an RCU_GP_IDLE state for rsp->signaled that is set initially at boot time and any time a grace period ends. This prevents CPU 0 from getting into the workings of force_quiescent_state() in step 4. Additional locking and checks prevent the concurrent update of rsp->signaled in step 6. Signed-off-by:Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1256742889199-git-send-email-> Signed-off-by:
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Thomas Gleixner authored
Ingo triggered the following warning: WARNING: at lib/debugobjects.c:255 debug_print_object+0x42/0x50() Hardware name: System Product Name ODEBUG: init active object type: timer_list Modules linked in: Pid: 2619, comm: dmesg Tainted: G W 2.6.32-rc5-tip+ #5298 Call Trace: [<81035443>] warn_slowpath_common+0x6a/0x81 [<8120e483>] ? debug_print_object+0x42/0x50 [<81035498>] warn_slowpath_fmt+0x29/0x2c [<8120e483>] debug_print_object+0x42/0x50 [<8120ec2a>] __debug_object_init+0x279/0x2d7 [<8120ecb3>] debug_object_init+0x13/0x18 [<810409d2>] init_timer_key+0x17/0x6f [<81041526>] free_uid+0x50/0x6c [<8104ed2d>] put_cred_rcu+0x61/0x72 [<81067fac>] rcu_do_batch+0x70/0x121 debugobjects warns about an enqueued timer being initialized. If CONFIG_USER_SCHED=y the user management code uses delayed work to remove the user from the hash table and tear down the sysfs objects. free_uid is called from RCU and initializes/schedules delayed work if the usage count of the user_struct is 0. The init/schedule happens outside of the uidhash_lock protected region which allows a concurrent caller of find_user() to reference the about to be destroyed user_struct w/o preventing the work from being scheduled. If the next free_uid call happens before the work timer expired then the active timer is initialized and the work scheduled again. The race was introduced in commit 5cb350ba (sched: group scheduling, sysfs tunables) and made more prominent by commit 3959214f (sched: delayed cleanup of user_struct) Move the init/schedule_delayed_work inside of the uidhash_lock protected region to prevent the race. Signed-off-by:
Dhaval Giani <dhaval@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@us.ibm.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: stable@kernel.org
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Rusty Russell authored
I got a boot crash when forcing cpumasks offstack on 32 bit, because find_new_ilb() returned 3 on my UP system (nohz.cpu_mask wasn't zeroed). AFAICT the others need to be zeroed too: only nohz.ilb_grp_nohz_mask is initialized before use. Signed-off-by:
Rusty Russell <rusty@rustcorp.com.au> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <200911022037.21282.rusty@rustcorp.com.au> Signed-off-by:
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- Oct 29, 2009
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Alexey Dobriyan authored
Having ->procname but not ->proc_handler is valid when PROC_SYSCTL=n, people use such combination to reduce ifdefs with non-standard handlers. Addresses http://bugzilla.kernel.org/show_bug.cgi?id=14408 Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Reported-by:
Peter Teoh <htmldeveloper@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by:
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KOSAKI Motohiro authored
cgroup_write_X64() and cgroup_write_string() ignore the return value of strstrip(). it makes small inconsistent behavior. example: ========================= # cd /mnt/cgroup/hoge # cat memory.swappiness 60 # echo "59 " > memory.swappiness # cat memory.swappiness 59 # echo " 58" > memory.swappiness bash: echo: write error: Invalid argument This patch fixes it. Cc: Li Zefan <lizf@cn.fujitsu.com> Acked-by:
Paul Menage <menage@google.com> Signed-off-by:
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Christian Borntraeger authored
Since commit 02b51df1 (proc connector: add event for process becoming session leader) we have the following warning: Badness at kernel/softirq.c:143 [...] Krnl PSW : 0404c00180000000 00000000001481d4 (local_bh_enable+0xb0/0xe0) [...] Call Trace: ([<000000013fe04100>] 0x13fe04100) [<000000000048a946>] sk_filter+0x9a/0xd0 [<000000000049d938>] netlink_broadcast+0x2c0/0x53c [<00000000003ba9ae>] cn_netlink_send+0x272/0x2b0 [<00000000003baef0>] proc_sid_connector+0xc4/0xd4 [<0000000000142604>] __set_special_pids+0x58/0x90 [<0000000000159938>] sys_setsid+0xb4/0xd8 [<00000000001187fe>] sysc_noemu+0x10/0x16 [<00000041616cb266>] 0x41616cb266 The warning is ---> WARN_ON_ONCE(in_irq() || irqs_disabled()); The network code must not be called with disabled interrupts but sys_setsid holds the tasklist_lock with spinlock_irq while calling the connector. After a discussion we agreed that we can move proc_sid_connector from __set_special_pids to sys_setsid. We also agreed that it is sufficient to change the check from task_session(curr) != pid into err > 0, since if we don't change the session, this means we were already the leader and return -EPERM. One last thing: There is also daemonize(), and some people might want to get a notification in that case. Since daemonize() is only needed if a user space does kernel_thread this does not look important (and there seems to be no consensus if this connector should be called in daemonize). If we really want this, we can add proc_sid_connector to daemonize() in an additional patch (Scott?) Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com> Cc: Scott James Remnant <scott@ubuntu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: David S. Miller <davem@davemloft.net> Acked-by:
Evgeniy Polyakov <zbr@ioremap.net> Acked-by:
David Rientjes <rientjes@google.com> Signed-off-by:
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- Oct 28, 2009
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Rusty Russell authored
We create a dummy struct kernel_param on the stack for parsing each array element, but we didn't initialize the flags word. This matters for arrays of type "bool", where the flag indicates if it really is an array of bools or unsigned int (old-style). Reported-by:
Takashi Iwai <tiwai@suse.de> Signed-off-by:
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Rusty Russell authored
kp->arg is always true: it's the contents of that pointer we care about. Reported-by:
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Rusty Russell authored
e180a6b7 "param: fix charp parameters set via sysfs" fixed the case where charp parameters written via sysfs were freed, leaving drivers accessing random memory. Unfortunately, storing a flag in the kparam struct was a bad idea: it's rodata so setting it causes an oops on some archs. But that's not all: 1) module_param_array() on charp doesn't work reliably, since we use an uninitialized temporary struct kernel_param. 2) there's a fundamental race if a module uses this parameter and then it's changed: they will still access the old, freed, memory. The simplest fix (ie. for 2.6.32) is to never free the memory. This prevents all these problems, at cost of a memory leak. In practice, there are only 18 places where a charp is writable via sysfs, and all are root-only writable. Reported-by:
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Thomas Gleixner authored
The requeue_pi path doesn't use unqueue_me() (and the racy lock_ptr == NULL test) nor does it use the wake_list of futex_wake() which where the reason for commit 41890f2 (futex: Handle spurious wake up) See debugging discussing on LKML Message-ID: <4AD4080C.20703@us.ibm.com> The changes in this fix to the wait_requeue_pi path were considered to be a likely unecessary, but harmless safety net. But it turns out that due to the fact that for unknown $@#!*( reasons EWOULDBLOCK is defined as EAGAIN we built an endless loop in the code path which returns correctly EWOULDBLOCK. Spurious wakeups in wait_requeue_pi code path are unlikely so we do the easy solution and return EWOULDBLOCK^WEAGAIN to user space and let it deal with the spurious wakeup. Cc: Darren Hart <dvhltc@us.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: John Stultz <johnstul@linux.vnet.ibm.com> Cc: Dinakar Guniguntala <dino@in.ibm.com> LKML-Reference: <4AE23C74.1090502@us.ibm.com> Cc: stable@kernel.org Signed-off-by: -
Jiri Kosina authored
Commit 34d76c41 introduced percpu array update_shares_data, size of which being proportional to NR_CPUS. Unfortunately this blows up ia64 for large NR_CPUS configuration, as ia64 allows only 64k for .percpu section. Fix this by allocating this array dynamically and keep only pointer to it percpu. The per-cpu handling doesn't impose significant performance penalty on potentially contented path in tg_shares_up(). ... ffffffff8104337c: 65 48 8b 14 25 20 cd mov %gs:0xcd20,%rdx ffffffff81043383: 00 00 ffffffff81043385: 48 c7 c0 00 e1 00 00 mov $0xe100,%rax ffffffff8104338c: 48 c7 45 a0 00 00 00 movq $0x0,-0x60(%rbp) ffffffff81043393: 00 ffffffff81043394: 48 c7 45 a8 00 00 00 movq $0x0,-0x58(%rbp) ffffffff8104339b: 00 ffffffff8104339c: 48 01 d0 add %rdx,%rax ffffffff8104339f: 49 8d 94 24 08 01 00 lea 0x108(%r12),%rdx ffffffff810433a6: 00 ffffffff810433a7: b9 ff ff ff ff mov $0xffffffff,%ecx ffffffff810433ac: 48 89 45 b0 mov %rax,-0x50(%rbp) ffffffff810433b0: bb 00 04 00 00 mov $0x400,%ebx ffffffff810433b5: 48 89 55 c0 mov %rdx,-0x40(%rbp) ... After: ... ffffffff8104337c: 65 8b 04 25 28 cd 00 mov %gs:0xcd28,%eax ffffffff81043383: 00 ffffffff81043384: 48 98 cltq ffffffff81043386: 49 8d bc 24 08 01 00 lea 0x108(%r12),%rdi ffffffff8104338d: 00 ffffffff8104338e: 48 8b 15 d3 7f 76 00 mov 0x767fd3(%rip),%rdx # ffffffff817ab368 <update_shares_data> ffffffff81043395: 48 8b 34 c5 00 ee 6d mov -0x7e921200(,%rax,8),%rsi ffffffff8104339c: 81 ffffffff8104339d: 48 c7 45 a0 00 00 00 movq $0x0,-0x60(%rbp) ffffffff810433a4: 00 ffffffff810433a5: b9 ff ff ff ff mov $0xffffffff,%ecx ffffffff810433aa: 48 89 7d c0 mov %rdi,-0x40(%rbp) ffffffff810433ae: 48 c7 45 a8 00 00 00 movq $0x0,-0x58(%rbp) ffffffff810433b5: 00 ffffffff810433b6: bb 00 04 00 00 mov $0x400,%ebx ffffffff810433bb: 48 01 f2 add %rsi,%rdx ffffffff810433be: 48 89 55 b0 mov %rdx,-0x50(%rbp) ... Signed-off-by:
Jiri Kosina <jkosina@suse.cz> Acked-by:
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- Oct 24, 2009
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Jiri Olsa authored
The cpu argument is not used inside the rb_time_stamp() function. Plus fix a typo. Signed-off-by:
Jiri Olsa <jolsa@redhat.com> Signed-off-by:
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Jiri Olsa authored
Trivial patch to fix a documentation example and to fix a comment. Signed-off-by:
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Jiri Olsa authored
trace_seq_printf() return value is a little ambiguous. It currently returns the length of the space available in the buffer. printf usually returns the amount written. This is not adequate here, because: trace_seq_printf(s, ""); is perfectly legal, and returning 0 would indicate that it failed. We can always see the amount written by looking at the before and after values of s->len. This is not quite the same use as printf. We only care if the string was successfully written to the buffer or not. Make trace_seq_printf() return 0 if the trace oversizes the buffer's free space, 1 otherwise. Signed-off-by:
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Jiri Olsa authored
Instead of directly updating filp->f_pos we should update the *ppos argument. The filp->f_pos gets updated within the file_pos_write() function called from sys_write(). Signed-off-by:
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- Oct 23, 2009
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Mike Galbraith authored
This patch restores the effectiveness of LAST_BUDDY in preventing pgsql+oltp from collapsing due to wakeup preemption. It also switches LAST_BUDDY to exclusively do what it does best, namely mitigate the effects of aggressive wakeup preemption, which improves vmark throughput markedly, and restores mysql+oltp scalability. Since buddies are about scalability, enable them beginning at the point where we begin expanding sched_latency, namely sched_nr_latency. Previously, buddies were cleared aggressively, which seriously reduced their effectiveness. Not clearing aggressively however, produces a small drop in mysql+oltp throughput immediately after peak, indicating that LAST_BUDDY is actually doing some harm. This is right at the point where X on the desktop in competition with another load wants low latency service. Ergo, do not enable until we need to scale. To mitigate latency induced by buddies, or by a task just missing wakeup preemption, check latency at tick time. Last hunk prevents buddies from stymieing BALANCE_NEWIDLE via CACHE_HOT_BUDDY. Supporting performance tests: tip = v2.6.32-rc5-1497-ga525b32 tipx = NO_GENTLE_FAIR_SLEEPERS NEXT_BUDDY granularity knobs = 31 knobs + 31 buddies tip+x = NO_GENTLE_FAIR_SLEEPERS granularity knobs = 31 knobs (Three run averages except where noted.) vmark: ------ tip 108466 messages per second tip+ 125307 messages per second tip+x 125335 messages per second tipx 117781 messages per second 2.6.31.3 122729 messages per second mysql+oltp: ----------- clients 1 2 4 8 16 32 64 128 256 .......................................................................................... tip 9949.89 18690.20 34801.24 34460.04 32682.88 30765.97 28305.27 25059.64 19548.08 tip+ 10013.90 18526.84 34900.38 34420.14 33069.83 32083.40 30578.30 28010.71 25605.47 tipx 9698.71 18002.70 34477.56 33420.01 32634.30 31657.27 29932.67 26827.52 21487.18 2.6.31.3 8243.11 18784.20 34404.83 33148.38 31900.32 31161.90 29663.81 25995.94 18058.86 pgsql+oltp: ----------- clients 1 2 4 8 16 32 64 128 256 .......................................................................................... tip 13686.37 26609.25 51934.28 51347.81 49479.51 45312.65 36691.91 26851.57 24145.35 tip+ (1x) 13907.85 27135.87 52951.98 52514.04 51742.52 50705.43 49947.97 48374.19 46227.94 tip+x 13906.78 27065.81 52951.19 52542.59 52176.11 51815.94 50838.90 49439.46 46891.00 tipx 13742.46 26769.81 52351.99 51891.73 51320.79 50938.98 50248.65 48908.70 46553.84 2.6.31.3 13815.35 26906.46 52683.34 52061.31 51937.10 51376.80 50474.28 49394.47 47003.25 Signed-off-by:
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Soeren Sandmann authored
Getting samples for the idle task is often not interesting, so don't generate them when exclude_idle is set for the event in question. Signed-off-by:
Søren Sandmann Pedersen <sandmann@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <ye8pr8fmlq7.fsf@camel16.daimi.au.dk> Signed-off-by:
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Soeren Sandmann authored
perf events: Fix swevent hrtimer sampling by keeping track of remaining time when enabling/disabling swevent hrtimers Make the hrtimer based events work for sysprof. Whenever a swevent is scheduled out, the hrtimer is canceled. When it is scheduled back in, the timer is restarted. This happens every scheduler tick, which means the timer never expired because it was getting repeatedly restarted over and over with the same period. To fix that, save the remaining time when disabling; when reenabling, use that saved time as the period instead of the user-specified sampling period. Also, move the starting and stopping of the hrtimers to helper functions instead of duplicating the code. Signed-off-by:
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- Oct 21, 2009
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Rafael J. Wysocki authored
Increase TEST_SUSPEND_SECONDS to 10 so the warning in suspend_test_finish() doesn't annoy the users of slower systems so much. Also, make the warning print the suspend-resume cycle time, so that we know why the warning actually triggered. Patch prepared during the hacking session at the Kernel Summit in Tokyo. Signed-off-by:
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- Oct 19, 2009
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Andi Kleen authored
Right now when calling schedule_on_each_cpu() from keventd there is a deadlock because it tries to schedule a work item on the current CPU too. This happens via lru_add_drain_all() in hwpoison. Just call the function for the current CPU in this case. This is actually faster too. Debugging with Fengguang Wu & Max Asbock Signed-off-by:Andi Kleen <ak@linux.intel.com>
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