- 19 2月, 2009 2 次提交
-
-
由 Rafael J. Wysocki 提交于
Compilation of kprobes.c with CONFIG_PM unset is broken due to some broken config dependncies. Fix that. Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl> Reported-by: NIngo Molnar <mingo@elte.hu> Tested-by: NMasami Hiramatsu <mhiramat@redhat.com> Cc: Len Brown <lenb@kernel.org> Acked-by: NPavel Machek <pavel@suse.cz> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
-
由 Li Zefan 提交于
In cgroup_kill_sb(), root is freed before sb is detached from the list, so another sget() may find this sb and call cgroup_test_super(), which will access the root that has been freed. Reported-by: NAl Viro <viro@ZenIV.linux.org.uk> Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Acked-by: NPaul Menage <menage@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
-
- 16 2月, 2009 2 次提交
-
-
由 Pekka Paalanen 提交于
Impact: cosmetic change in Kconfig menu layout This patch was originally suggested by Peter Zijlstra, but seems it was forgotten. CONFIG_MMIOTRACE and CONFIG_MMIOTRACE_TEST were selectable directly under the Kernel hacking / debugging menu in the kernel configuration system. They were present only for x86 and x86_64. Other tracers that use the ftrace tracing framework are in their own sub-menu. This patch moves the mmiotrace configuration options there. Since the Kconfig file, where the tracer menu is, is not architecture specific, HAVE_MMIOTRACE_SUPPORT is introduced and provided only by x86/x86_64. CONFIG_MMIOTRACE now depends on it. Signed-off-by: NPekka Paalanen <pq@iki.fi> Signed-off-by: NSteven Rostedt <srostedt@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Pekka Paalanen 提交于
Impact: enhances lost events counting in mmiotrace The tracing framework, or the ring buffer facility it uses, has a switch to stop recording data. When recording is off, the trace events will be lost. The framework does not count these, so mmiotrace has to count them itself. Signed-off-by: NPekka Paalanen <pq@iki.fi> Signed-off-by: NSteven Rostedt <srostedt@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
- 14 2月, 2009 1 次提交
-
-
由 Serge E. Hallyn 提交于
uids in namespaces other than init don't get a sysfs entry. For those in the init namespace, while we're waiting to remove the sysfs entry for the uid the uid is still hashed, and alloc_uid() may re-grab that uid without getting a new reference to the user_ns, which we've already put in free_user before scheduling remove_user_sysfs_dir(). Reported-and-tested-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: NSerge E. Hallyn <serue@us.ibm.com> Acked-by: NDavid Howells <dhowells@redhat.com> Tested-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
-
- 13 2月, 2009 1 次提交
-
-
由 Peter Zijlstra 提交于
While reviewing the manpages, I noticed I'd missed some clock vs timer sites. Make sure that all timer functions call cpu_timer_sample_group() and not cpu_clock_sample_group(). This ensures that we enable the process wide timer in time, and therefore pay the O(n) thread group cost from the syscall. Not doing it here, will result in the first jiffy tick after setting the timer doing this, resulting in a very expensive tick (but only once) and a delay in actually starting the timer. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
- 12 2月, 2009 4 次提交
-
-
由 Ingo Molnar 提交于
rq_attach_root() does a kfree() with the runqueue lock held. That's not a very wise move, fix it. Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Li Zefan 提交于
I enabled all cgroup subsystems when compiling kernel, and then: # mount -t cgroup -o net_cls xxx /mnt # mkdir /mnt/0 This showed up immediately: BUG: MAX_LOCKDEP_SUBCLASSES too low! turning off the locking correctness validator. It's caused by the cgroup hierarchy lock: for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (ss->root == root) mutex_lock_nested(&ss->hierarchy_mutex, i); } Now we have 9 cgroup subsystems, and the above 'i' for net_cls is 8, but MAX_LOCKDEP_SUBCLASSES is 8. This patch uses different lockdep keys for different subsystems. Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Acked-by: NPaul Menage <menage@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
-
由 Sven Wegener 提交于
We need to pass an unsigned long as the minimum, because it gets casted to an unsigned long in the sysctl handler. If we pass an int, we'll access four more bytes on 64bit arches, resulting in a random minimum value. [rientjes@google.com: fix type of `old_bytes'] Signed-off-by: NSven Wegener <sven.wegener@stealer.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: NDavid Rientjes <rientjes@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
-
由 Peter Zijlstra 提交于
Catalin noticed that (38d47c1b: futex: rely on get_user_pages() for shared futexes) caused an mm_struct leak. Some tracing with the function graph tracer quickly pointed out that futex_wait() has exit paths with unbalanced reference counts. This regression was discovered by kmemleak. Reported-by: NCatalin Marinas <catalin.marinas@arm.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: N"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com> Tested-by: NCatalin Marinas <catalin.marinas@arm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
- 11 2月, 2009 4 次提交
-
-
由 Peter Zijlstra 提交于
Intel reported a 10% regression (mysql+sysbench) on a 16-way machine with these patches: 1596e297: sched: symmetric sync vs avg_overlap d942fb6c: sched: fix sync wakeups Revert them. Reported-by: N"Zhang, Yanmin" <yanmin_zhang@linux.intel.com> Bisected-by: NLin Ming <ming.m.lin@intel.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Peter Zijlstra 提交于
The POSIX timer interface allows for absolute time expiry values through the TIMER_ABSTIME flag, therefore we have to synchronize the timer to the clock every time we start it. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Peter Zijlstra 提交于
To decrease the chance of a missed enable, always enable the timer when we sample it, we'll always disable it when we find that there are no active timers in the jiffy tick. This fixes a flood of warnings reported by Mike Galbraith. Reported-by: NMike Galbraith <efault@gmx.de> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Oleg Nesterov 提交于
I noticed by pure accident we have ptrace_fork() and friends. This was added by "x86, bts: add fork and exit handling", commit bf53de90. I can't test this, ds_request_bts() returns -EOPNOTSUPP, but I strongly believe this needs the fix. I think something like this program int main(void) { int pid = fork(); if (!pid) { ptrace(PTRACE_TRACEME, 0, NULL, NULL); kill(getpid(), SIGSTOP); fork(); } else { struct ptrace_bts_config bts = { .flags = PTRACE_BTS_O_ALLOC, .size = 4 * 4096, }; wait(NULL); ptrace(PTRACE_SETOPTIONS, pid, NULL, PTRACE_O_TRACEFORK); ptrace(PTRACE_BTS_CONFIG, pid, &bts, sizeof(bts)); ptrace(PTRACE_CONT, pid, NULL, NULL); sleep(1); } return 0; } should crash the kernel. If the task is traced by its natural parent ptrace_reparented() returns 0 but we should clear ->btsxxx anyway. Signed-off-by: NOleg Nesterov <oleg@redhat.com> Acked-by: NMarkus Metzger <markus.t.metzger@intel.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
- 10 2月, 2009 1 次提交
-
-
由 Hugh Dickins 提交于
Impact: fix broken /proc/profile on UP machines Commit c309b917 "cpumask: convert kernel/profile.c" broke profiling. prof_cpu_mask was previously initialized to CPU_MASK_ALL, but left uninitialized in that commit. We need to copy cpu_possible_mask (cpu_online_mask is not enough). Signed-off-by: NHugh Dickins <hugh@veritas.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
- 09 2月, 2009 5 次提交
-
-
由 Stefan Richter 提交于
list.h provides a dedicated primitive for "list_del followed by list_add_tail"... list_move_tail. Signed-off-by: NArjan van de Ven <arjan@linux.intel.com> Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de>
-
由 Cornelia Huck 提交于
Rename the async_*_special() functions to async_*_domain(), which describes the purpose of these functions much better. [Broke up long lines to silence checkpatch] Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
-
由 Cornelia Huck 提交于
Add some kerneldoc to the async interface. Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
-
由 Cornelia Huck 提交于
If we fail to create the manager thread, fall back to non-fastboot. If we fail to create an async thread, try again after waiting for a bit. Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
-
由 Cornelia Huck 提交于
async_schedule() should pass in async_running as the running list, and run_one_entry() should put the entry to be run on the provided running list instead of always on the generic one. Reported-by: NJonathan Corbet <corbet@lwn.net> Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
-
- 07 2月, 2009 1 次提交
-
-
由 Li Zefan 提交于
I happened to forked lots of processes, and hit NULL pointer dereference. It is because in copy_process() after checking max_threads, 0 is returned but not -EAGAIN. The bug is introduced by "CRED: Detach the credentials from task_struct" (commit f1752eec). Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Signed-off-by: NDavid Howells <dhowells@redhat.com> Acked-by: NJames Morris <jmorris@namei.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
-
- 06 2月, 2009 3 次提交
-
-
由 Johannes Weiner 提交于
With exclusive waiters, every process woken up through the wait queue must ensure that the next waiter down the line is woken when it has finished. Interruptible waiters don't do that when aborting due to a signal. And if an aborting waiter is concurrently woken up through the waitqueue, noone will ever wake up the next waiter. This has been observed with __wait_on_bit_lock() used by lock_page_killable(): the first contender on the queue was aborting when the actual lock holder woke it up concurrently. The aborted contender didn't acquire the lock and therefor never did an unlock followed by waking up the next waiter. Add abort_exclusive_wait() which removes the process' wait descriptor from the waitqueue, iff still queued, or wakes up the next waiter otherwise. It does so under the waitqueue lock. Racing with a wake up means the aborting process is either already woken (removed from the queue) and will wake up the next waiter, or it will remove itself from the queue and the concurrent wake up will apply to the next waiter after it. Use abort_exclusive_wait() in __wait_event_interruptible_exclusive() and __wait_on_bit_lock() when they were interrupted by other means than a wake up through the queue. [akpm@linux-foundation.org: coding-style fixes] Reported-by: NChris Mason <chris.mason@oracle.com> Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Mentored-by: NOleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Chuck Lever <cel@citi.umich.edu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> ["after some testing"] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
-
由 Andrew Morton 提交于
Revert commit 0c2d64fb because it causes (arguably poorly designed) existing userspace to spend interminable periods closing billions of not-open file descriptors. We could bring this back, with some sort of opt-in tunable in /proc, which defaults to "off". Peter's alanysis follows: : I spent several hours trying to get to the bottom of a serious : performance issue that appeared on one of our servers after upgrading to : 2.6.28. In the end it's what could be considered a userspace bug that : was triggered by a change in 2.6.28. Since this might also affect other : people I figured I'd at least document what I found here, and maybe we : can even do something about it: : : : So, I upgraded some of debian.org's machines to 2.6.28.1 and immediately : the team maintaining our ftp archive complained that one of their : scripts that previously ran in a few minutes still hadn't even come : close to being done after an hour or so. Downgrading to 2.6.27 fixed : that. : : Turns out that script is forking a lot and something in it or python or : whereever closes all the file descriptors it doesn't want to pass on. : That is, it starts at zero and goes up to ulimit -n/RLIMIT_NOFILE and : closes them all with a few exceptions. : : Turns out that takes a long time when your limit -n is now 2^20 (1048576). : : With 2.6.27.* the ulimit -n was the standard 1024, but with 2.6.28 it is : now a thousand times that. : : 2.6.28 included a patch titled "rlimit: permit setting RLIMIT_NOFILE to : RLIM_INFINITY" (0c2d64fb)[1] that : allows, as the title implies, to set the limit for number of files to : infinity. : : Closer investigation showed that the broken default ulimit did not apply : to "system" processes (like stuff started from init). In the end I : could establish that all processes that passed through pam_limit at one : point had the bad resource limit. : : Apparently the pam library in Debian etch (4.0) initializes the limits : to some default values when it doesn't have any settings in limit.conf : to override them. Turns out that for nofiles this is RLIM_INFINITY. : Commenting out "case RLIMIT_NOFILE" in pam_limit.c:267 of our pam : package version 0.79-5 fixes that - tho I'm not sure what side effects : that has. : : Debian lenny (the upcoming 5.0 version) doesn't have this issue as it : uses a different pam (version). Reported-by: NPeter Palfrader <weasel@debian.org> Cc: Adam Tkac <vonsch@gmail.com> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: <stable@kernel.org> [2.6.28.x] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
-
由 Andrew Morton 提交于
alpha: kernel/async.c: In function 'run_one_entry': kernel/async.c:141: warning: format '%lli' expects type 'long long int', but argument 2 has type 'async_cookie_t' kernel/async.c:149: warning: format '%lli' expects type 'long long int', but argument 2 has type 'async_cookie_t' kernel/async.c:149: warning: format '%lld' expects type 'long long int', but argument 4 has type 's64' kernel/async.c: In function 'async_synchronize_cookie_special': kernel/async.c:250: warning: format '%lli' expects type 'long long int', but argument 3 has type 's64' Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
-
- 05 2月, 2009 3 次提交
-
-
由 Peter Zijlstra 提交于
Change the process wide cpu timers/clocks so that we: 1) don't mess up the kernel with too many threads, 2) don't have a per-cpu allocation for each process, 3) have no impact when not used. In order to accomplish this we're going to split it into two parts: - clocks; which can take all the time they want since they run from user context -- ie. sys_clock_gettime(CLOCK_PROCESS_CPUTIME_ID) - timers; which need constant time sampling but since they're explicity used, the user can pay the overhead. The clock readout will go back to a full sum of the thread group, while the timers will run of a global 'clock' that only runs when needed, so only programs that make use of the facility pay the price. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Peter Zijlstra 提交于
We're going to split the process wide cpu accounting into two parts: - clocks; which can take all the time they want since they run from user context. - timers; which need constant time tracing but can affort the overhead because they're default off -- and rare. The clock readout will go back to a full sum of the thread group, for this we need to re-add the exit stats that were removed in the initial itimer rework (f06febc9: timers: fix itimer/many thread hang). Furthermore, since that full sum can be rather slow for large thread groups and we have the complete dead task stats, revert the do_notify_parent time computation. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Suresh Siddha 提交于
Christian Borntraeger reports: > After a logical cpu offline, even on a complete idle system, there > is one cpu with full ticks. It turns out that nohz.cpu_mask has the > the offlined cpu still set. > > In select_nohz_load_balancer() we check if the system is completely > idle to turn of load balancing. We compare cpu_online_map with > nohz.cpu_mask. Since cpu_online_map is updated on cpu unplug, > but nohz.cpu_mask is not, the check fails and the scheduler believes > that we need an "idle load balancer" even on a fully idle system. > Since the ilb cpu does not deactivate the timer tick this breaks NOHZ. Fix the select_nohz_load_balancer() to not set the nohz.cpu_mask while a cpu is going offline. Reported-by: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NSuresh Siddha <suresh.b.siddha@intel.com> Tested-by: NChristian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
- 04 2月, 2009 1 次提交
-
-
由 Oleg Nesterov 提交于
"ftrace: use struct pid" commit 978f3a45 converted ftrace_pid_trace to "struct pid*". But we can't use do_each_pid_task() without rcu_read_lock() even if we know the pid itself can't go away (it was pinned in ftrace_pid_write). The exiting task can detach itself from this pid at any moment. Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
- 03 2月, 2009 1 次提交
-
-
由 Eric Dumazet 提交于
Current refcounting for modules (done if CONFIG_MODULE_UNLOAD=y) is using a lot of memory. Each 'struct module' contains an [NR_CPUS] array of full cache lines. This patch uses existing infrastructure (percpu_modalloc() & percpu_modfree()) to allocate percpu space for the refcount storage. Instead of wasting NR_CPUS*128 bytes (on i386), we now use nr_cpu_ids*sizeof(local_t) bytes. On a typical distro, where NR_CPUS=8, shiping 2000 modules, we reduce size of module files by about 2 Mbytes. (1Kb per module) Instead of having all refcounters in the same memory node - with TLB misses because of vmalloc() - this new implementation permits to have better NUMA properties, since each CPU will use storage on its preferred node, thanks to percpu storage. Signed-off-by: NEric Dumazet <dada1@cosmosbay.com> Signed-off-by: NRusty Russell <rusty@rustcorp.com.au> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
-
- 01 2月, 2009 6 次提交
-
-
由 Yinghai Lu 提交于
Eric Paris reported: > I have an hp dl785g5 which is unable to successfully run > 2.6.29-0.66.rc3.fc11.x86_64 or 2.6.29-rc2-next-20090126. During bootup > (early in userspace daemons starting) I get the below BUG, which quickly > renders the machine dead. I assume it is because sparse_irq_lock never > gets released when the BUG kills that task. Adjust lock sequence when migrating a descriptor with CONFIG_NUMA_MIGRATE_IRQ_DESC enabled. Signed-off-by: NYinghai Lu <yinghai@kernel.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Rusty Russell 提交于
cpumask_and() only initializes nr_cpu_ids bits, so the (deprecated) first_cpu() might find one of those uninitialized bits if nr_cpu_ids is less than NR_CPUS (as it can be for CONFIG_CPUMASK_OFFSTACK). Signed-off-by: NRusty Russell <rusty@rustcorp.com.au> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Peter Zijlstra 提交于
Similar to the previous patch, by not clearing buddies we can select entities past their run quota, which can increase latency. This means we have to clear group buddies as well. Do not use the group clear for pick_next_task(), otherwise that'll get O(n^2). Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Mike Galbraith 提交于
It was noticed that a task could get re-elected past its run quota due to buddy affinities. This could increase latency a little. Cure it by more aggresively clearing buddy state. We do so in two situations: - when we force preempt - when we select a buddy to run Signed-off-by: NMike Galbraith <efault@gmx.de> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Peter Zijlstra 提交于
Reinstate the weakening of the sync hint if set. This yields a more symmetric usage of avg_overlap. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Peter Zijlstra 提交于
Pawel Dziekonski reported that the openssl benchmark and his quantum chemistry application both show slowdowns due to the scheduler under-parallelizing execution. The reason are pipe wakeups still doing 'sync' wakeups which overrides the normal buddy wakeup logic - even if waker and wakee are loosely coupled. Fix an inversion of logic in the buddy wakeup code. Reported-by: NPawel Dziekonski <dzieko@gmail.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
- 31 1月, 2009 4 次提交
-
-
由 Thomas Gleixner 提交于
Impact: prevent false positive WARN_ON() in clockevents_program_event() clock_was_set() changes the base->offset of CLOCK_REALTIME and enforces the reprogramming of the clockevent device to expire timers which are based on CLOCK_REALTIME. If the clock change is large enough then the subtraction of the timer expiry value and base->offset can become negative which triggers the warning in clockevents_program_event(). Check the subtraction result and set a negative value to 0. Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
-
由 Sebastien Dugue 提交于
Impact: fix CPU hotplug hang on Power6 testbox On architectures that support offlining all cpus (at least powerpc/pseries), hot-unpluging the tick_do_timer_cpu can result in a system hang. This comes from the fact that if the cpu going down happens to be the cpu doing the tick, then as the tick_do_timer_cpu handover happens after the cpu is dead (via the CPU_DEAD notification), we're left without ticks, jiffies are frozen and any task relying on timers (msleep, ...) is stuck. That's particularly the case for the cpu looping in __cpu_die() waiting for the dying cpu to be dead. This patch addresses this by having the tick_do_timer_cpu handover happen earlier during the CPU_DYING notification. For this, a new clockevent notification type is introduced (CLOCK_EVT_NOTIFY_CPU_DYING) which is triggered in hrtimer_cpu_notify(). Signed-off-by: NSebastien Dugue <sebastien.dugue@bull.net> Cc: <stable@kernel.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Frederic Weisbecker 提交于
Impact: avoid timer IRQ hanging slow systems While using the function graph tracer on a virtualized system, the hrtimer_interrupt can hang the system on an infinite loop. This can be caused in several situations: - the hardware is very slow and HZ is set too high - something intrusive is slowing the system down (tracing under emulation) ... and the next clock events to program are always before the current time. This patch implements a reasonable compromise: if such a situation is detected, we share the CPUs time in 1/4 to process the hrtimer interrupts. This is enough to let the system running without serious starvation. It has been successfully tested under VirtualBox with 1000 HZ and 100 HZ with function graph tracer launched. On both cases, the clock events were increased until about 25 ms periodic ticks, which means 40 HZ. So we change a hard to debug hang into a warning message and a system that still manages to limp along. Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
由 Steven Rostedt 提交于
The smp_call_function can be passed a wait parameter telling it to wait for all the functions running on other CPUs to complete before returning, or to return without waiting. Unfortunately, this is currently just a suggestion and not manditory. That is, the smp_call_function can decide not to return and wait instead. The reason for this is because it uses kmalloc to allocate storage to send to the called CPU and that CPU will free it when it is done. But if we fail to allocate the storage, the stack is used instead. This means we must wait for the called CPU to finish before continuing. Unfortunatly, some callers do no abide by this hint and act as if the non-wait option is mandatory. The MTRR code for instance will deadlock if the smp_call_function is set to wait. This is because the smp_call_function will wait for the other CPUs to finish their called functions, but those functions are waiting on the caller to continue. This patch changes the generic smp_call_function code to use per cpu variables if the allocation of the data fails for a single CPU call. The smp_call_function_many will fall back to the smp_call_function_single if it fails its alloc. The smp_call_function_single is modified to not force the wait state. Since we now are using a single data per cpu we must synchronize the callers to prevent a second caller modifying the data before the first called IPI functions complete. To do so, I added a flag to the call_single_data called CSD_FLAG_LOCK. When the single CPU is called (which can be called when a many call fails an alloc), we set the LOCK bit on this per cpu data. When the caller finishes it clears the LOCK bit. The caller must wait till the LOCK bit is cleared before setting it. When it is cleared, there is no IPI function using it. Signed-off-by: NSteven Rostedt <srostedt@redhat.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: NJens Axboe <jens.axboe@oracle.com> Acked-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
-
- 30 1月, 2009 1 次提交
-
-
由 Paul Menage 提交于
root_count was being incremented in cgroup_get_sb() after all error checking was complete, but decremented in cgroup_kill_sb(), which can be called on a superblock that we gave up on due to an error. This patch changes cgroup_kill_sb() to only decrement root_count if the root was previously linked into the list of roots. Signed-off-by: NPaul Menage <menage@google.com> Tested-by: NSerge Hallyn <serue@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
-