- 09 9月, 2009 1 次提交
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由 Mike Galbraith 提交于
Set child_runs_first default to off. It hurts 'optimal' make -j<NR_CPUS> workloads as make jobs get preempted by child tasks, reducing parallelism. Note, this patch might make existing races in user applications more prominent than before - so breakages might be bisected to this commit. Child-runs-first is broken on SMP to begin with, and we already had it off briefly in v2.6.23 so most of the offenders ought to be fixed. Would be nice not to revert this commit but fix those apps finally ... Signed-off-by: NMike Galbraith <efault@gmx.de> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1252486344.28645.18.camel@marge.simson.net> [ made the sysctl independent of CONFIG_SCHED_DEBUG, in case people want to work around broken apps. ] Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 04 9月, 2009 4 次提交
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由 Peter Zijlstra 提交于
Its a source of fail, also, now that cpu_power is dynamical, its a waste of time. before: <idle>-0 [000] 132.877936: find_busiest_group: avg_load: 0 group_load: 8241 power: 1 after: bash-1689 [001] 137.862151: find_busiest_group: avg_load: 10636288 group_load: 10387 power: 1 [ v2: build fix from From: Andreas Herrmann ] Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: NAndreas Herrmann <andreas.herrmann3@amd.com> Acked-by: NAndreas Herrmann <andreas.herrmann3@amd.com> Acked-by: NGautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083826.425896304@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Keep an average on the amount of time spend on RT tasks and use that fraction to scale down the cpu_power for regular tasks. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: NAndreas Herrmann <andreas.herrmann3@amd.com> Acked-by: NAndreas Herrmann <andreas.herrmann3@amd.com> Acked-by: NGautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083826.287778431@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
The idea is that multi-threading a core yields more work capacity than a single thread, provide a way to express a static gain for threads. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: NAndreas Herrmann <andreas.herrmann3@amd.com> Acked-by: NAndreas Herrmann <andreas.herrmann3@amd.com> Acked-by: NGautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083826.073345955@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Do the placement thing using SD flags. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: NAndreas Herrmann <andreas.herrmann3@amd.com> Acked-by: NAndreas Herrmann <andreas.herrmann3@amd.com> Acked-by: NGautham R Shenoy <ego@in.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> LKML-Reference: <20090901083825.897028974@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 02 9月, 2009 2 次提交
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由 David Howells 提交于
Add a keyctl to install a process's session keyring onto its parent. This replaces the parent's session keyring. Because the COW credential code does not permit one process to change another process's credentials directly, the change is deferred until userspace next starts executing again. Normally this will be after a wait*() syscall. To support this, three new security hooks have been provided: cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in the blank security creds and key_session_to_parent() - which asks the LSM if the process may replace its parent's session keyring. The replacement may only happen if the process has the same ownership details as its parent, and the process has LINK permission on the session keyring, and the session keyring is owned by the process, and the LSM permits it. Note that this requires alteration to each architecture's notify_resume path. This has been done for all arches barring blackfin, m68k* and xtensa, all of which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the replacement to be performed at the point the parent process resumes userspace execution. This allows the userspace AFS pioctl emulation to fully emulate newpag() and the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to alter the parent process's PAG membership. However, since kAFS doesn't use PAGs per se, but rather dumps the keys into the session keyring, the session keyring of the parent must be replaced if, for example, VIOCSETTOK is passed the newpag flag. This can be tested with the following program: #include <stdio.h> #include <stdlib.h> #include <keyutils.h> #define KEYCTL_SESSION_TO_PARENT 18 #define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0) int main(int argc, char **argv) { key_serial_t keyring, key; long ret; keyring = keyctl_join_session_keyring(argv[1]); OSERROR(keyring, "keyctl_join_session_keyring"); key = add_key("user", "a", "b", 1, keyring); OSERROR(key, "add_key"); ret = keyctl(KEYCTL_SESSION_TO_PARENT); OSERROR(ret, "KEYCTL_SESSION_TO_PARENT"); return 0; } Compiled and linked with -lkeyutils, you should see something like: [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: _ses 355907932 --alswrv 4043 -1 \_ keyring: _uid.4043 [dhowells@andromeda ~]$ /tmp/newpag [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: _ses 1055658746 --alswrv 4043 4043 \_ user: a [dhowells@andromeda ~]$ /tmp/newpag hello [dhowells@andromeda ~]$ keyctl show Session Keyring -3 --alswrv 4043 4043 keyring: hello 340417692 --alswrv 4043 4043 \_ user: a Where the test program creates a new session keyring, sticks a user key named 'a' into it and then installs it on its parent. Signed-off-by: NDavid Howells <dhowells@redhat.com> Signed-off-by: NJames Morris <jmorris@namei.org>
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由 Arjan van de Ven 提交于
For counting how long an application has been waiting for (disk) IO, there currently is only the HZ sample driven information available, while for all other counters in this class, a high resolution version is available via CONFIG_SCHEDSTATS. In order to make an improved bootchart tool possible, we also need a higher resolution version of the iowait time. This patch below adds this scheduler statistic to the kernel. Signed-off-by: NArjan van de Ven <arjan@linux.intel.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4A64B813.1080506@linux.intel.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 29 8月, 2009 2 次提交
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由 Paul E. McKenney 提交于
Changes suggested by review comments from Josh Triplett and Mathieu Desnoyers. Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: NJosh Triplett <josh@joshtriplett.org> Acked-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <20090827220012.GA30525@linux.vnet.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Paul E. McKenney 提交于
When offlining CPUs from a multi-level tree, there is the possibility of offlining the last CPU from a given node when there are preempted RCU read-side critical sections that started life on one of the CPUs on that node. In this case, the corresponding tasks will be enqueued via the task_struct's rcu_node_entry list_head onto one of the rcu_node's blocked_tasks[] lists. These tasks need to be moved somewhere else so that they will prevent the current grace period from ending. That somewhere is the root rcu_node. Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <20090827215816.GA30472@linux.vnet.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 23 8月, 2009 2 次提交
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由 Paul E. McKenney 提交于
Now that CONFIG_TREE_PREEMPT_RCU is in place, there is no further need for CONFIG_PREEMPT_RCU. Remove it, along with whatever subtle bugs it may (or may not) contain. Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <125097461396-git-send-email-> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Paul E. McKenney 提交于
Create a kernel/rcutree_plugin.h file that contains definitions for preemptable RCU (or, under the #else branch of the #ifdef, empty definitions for the classic non-preemptable semantics). These definitions fit into plugins defined in kernel/rcutree.c for this purpose. This variant of preemptable RCU uses a new algorithm whose read-side expense is roughly that of classic hierarchical RCU under CONFIG_PREEMPT. This new algorithm's update-side expense is similar to that of classic hierarchical RCU, and, in absence of read-side preemption or blocking, is exactly that of classic hierarchical RCU. Perhaps more important, this new algorithm has a much simpler implementation, saving well over 1,000 lines of code compared to mainline's implementation of preemptable RCU, which will hopefully be retired in favor of this new algorithm. The simplifications are obtained by maintaining per-task nesting state for running tasks, and using a simple lock-protected algorithm to handle accounting when tasks block within RCU read-side critical sections, making use of lessons learned while creating numerous user-level RCU implementations over the past 18 months. Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <12509746134003-git-send-email-> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 19 8月, 2009 1 次提交
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由 KOSAKI Motohiro 提交于
The commit 2ff05b2b (oom: move oom_adj value) moveed the oom_adj value to the mm_struct. It was a very good first step for sanitize OOM. However Paul Menage reported the commit makes regression to his job scheduler. Current OOM logic can kill OOM_DISABLED process. Why? His program has the code of similar to the following. ... set_oom_adj(OOM_DISABLE); /* The job scheduler never killed by oom */ ... if (vfork() == 0) { set_oom_adj(0); /* Invoked child can be killed */ execve("foo-bar-cmd"); } .... vfork() parent and child are shared the same mm_struct. then above set_oom_adj(0) doesn't only change oom_adj for vfork() child, it's also change oom_adj for vfork() parent. Then, vfork() parent (job scheduler) lost OOM immune and it was killed. Actually, fork-setting-exec idiom is very frequently used in userland program. We must not break this assumption. Then, this patch revert commit 2ff05b2b and related commit. Reverted commit list --------------------- - commit 2ff05b2b (oom: move oom_adj value from task_struct to mm_struct) - commit 4d8b9135 (oom: avoid unnecessary mm locking and scanning for OOM_DISABLE) - commit 81236810 (oom: only oom kill exiting tasks with attached memory) - commit 933b787b (mm: copy over oom_adj value at fork time) Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 18 8月, 2009 1 次提交
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由 Hiroshi Shimamoto 提交于
The field stack_canary is only used with CC_STACKPROTECTOR. This patch reduces task_struct size without CC_STACKPROTECTOR. Signed-off-by: NHiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> LKML-Reference: <4A8A44CA.2020701@ct.jp.nec.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 02 8月, 2009 2 次提交
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由 Gregory Haskins 提交于
We currently have an explicit "needs_post" vtable method which returns a stack variable for whether we should later run post-schedule. This leads to an awkward exchange of the variable as it bubbles back up out of the context switch. Peter Zijlstra observed that this information could be stored in the run-queue itself instead of handled on the stack. Therefore, we revert to the method of having context_switch return void, and update an internal rq->post_schedule variable when we require further processing. In addition, we fix a race condition where we try to access current->sched_class without holding the rq->lock. This is technically racy, as the sched-class could change out from under us. Instead, we reference the per-rq post_schedule variable with the runqueue unlocked, but with preemption disabled to see if we need to reacquire the rq->lock. Finally, we clean the code up slightly by removing the #ifdef CONFIG_SMP conditionals from the schedule() call, and implement some inline helper functions instead. This patch passes checkpatch, and rt-migrate. Signed-off-by: NGregory Haskins <ghaskins@novell.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090729150422.17691.55590.stgit@dev.haskins.net> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Frederic Weisbecker 提交于
The might_sleep() test inside cond_resched_lock() assumes the spinlock is held and then preemption is disabled. This is true with CONFIG_PREEMPT but the preempt_count() doesn't change otherwise. Check by starting from the appropriate preempt offset depending on the config. Reported-by: NLi Zefan <lizf@cn.fujitsu.com> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1248458723-12146-1-git-send-email-fweisbec@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 18 7月, 2009 4 次提交
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由 Frederic Weisbecker 提交于
fs/locks.c:flock_lock_file() is the only user of cond_resched_bkl() This helper doesn't do anything more than cond_resched(). The latter naming is enough to explain that we are rescheduling if needed. The bkl suffix suggests another semantics but it's actually a synonym of cond_resched(). Reported-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1247725694-6082-7-git-send-email-fweisbec@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Frederic Weisbecker 提交于
might_sleep() is called late-ish in cond_resched(), after the need_resched()/preempt enabled/system running tests are checked. It's better to check the sleeps while atomic earlier and not depend on some environment datas that reduce the chances to detect a problem. Also define cond_resched_*() helpers as macros, so that the FILE/LINE reported in the sleeping while atomic warning displays the real origin and not sched.h Changes in v2: - Call __might_sleep() directly instead of might_sleep() which may call cond_resched() - Turn cond_resched() into a macro so that the file:line couple reported refers to the caller of cond_resched() and not __cond_resched() itself. Changes in v3: - Also propagate this __might_sleep() pull up to cond_resched_lock() and cond_resched_softirq() Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1247725694-6082-6-git-send-email-fweisbec@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Frederic Weisbecker 提交于
CONFIG_PREEMPT_BKL doesn't exist anymore. So remove this config-on case definition of cond_resched(). Reported-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Reported-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1247725694-6082-5-git-send-email-fweisbec@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Thomas Gleixner 提交于
commit e3c8ca83 (sched: do not count frozen tasks toward load) broke the nr_uninterruptible accounting on freeze/thaw. On freeze the task is excluded from accounting with a check for (task->flags & PF_FROZEN), but that flag is cleared before the task is thawed. So while we prevent that the task with state TASK_UNINTERRUPTIBLE is accounted to nr_uninterruptible on freeze we decrement nr_uninterruptible on thaw. Use a separate flag which is handled by the freezing task itself. Set it before calling the scheduler with TASK_UNINTERRUPTIBLE state and clear it after we return from frozen state. Cc: <stable@kernel.org> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 17 7月, 2009 1 次提交
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由 Oleg Nesterov 提交于
- is_single_threaded(task) is not safe unless task == current, we can't use task->signal or task->mm. - it doesn't make sense unless task == current, the task can fork right after the check. Rename it to current_is_single_threaded() and kill the argument. Signed-off-by: NOleg Nesterov <oleg@redhat.com> Acked-by: NDavid Howells <dhowells@redhat.com> Signed-off-by: NJames Morris <jmorris@namei.org>
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- 11 7月, 2009 2 次提交
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由 Peter Zijlstra 提交于
Optimize cond_resched() by removing one conditional. Currently cond_resched() checks system_state == SYSTEM_RUNNING in order to avoid scheduling before the scheduler is running. We can however, as per suggestion of Matt, use PREEMPT_ACTIVE to accomplish that very same. Suggested-by: NMatt Mackall <mpm@selenic.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: NMatt Mackall <mpm@selenic.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Peter Zijlstra 提交于
Pull the initial preempt_count value into a single definition site. Maintainers for: alpha, ia64 and m68k, please have a look, your arch code is funny. The header magic is a bit odd, but similar to the KERNEL_DS one, CPP waits with expanding these macros until the INIT_THREAD_INFO macro itself is expanded, which is in arch/*/kernel/init_task.c where we've already included sched.h so we're good. Cc: tony.luck@intel.com Cc: rth@twiddle.net Cc: geert@linux-m68k.org Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: NMatt Mackall <mpm@selenic.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 01 7月, 2009 1 次提交
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由 KAMEZAWA Hiroyuki 提交于
With ELF, at generating coredump, some more headers other than used vmas are added. When max_map_count == 65536, a core generated by following kinds of code can be unreadable because the number of ELF's program header is written in 16bit in Ehdr (please see elf.h) and the number overflows. == ... = mmap(); (munmap, mprotect, etc...) if (failed) abort(); == This can happen in mmap/munmap/mprotect/etc...which calls split_vma(). I think 65536 is not safe as _default_ and reduce it to 65530 is good for avoiding unexpected corrupted core. Anyway, max_map_count can be enlarged by sysctl if a user is brave.. Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Jakub Jelinek <jakub@redhat.com> Acked-by: NRoland McGrath <roland@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 19 6月, 2009 2 次提交
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由 Christoph Hellwig 提交于
find_task_by_pid_type_ns is only used to implement find_task_by_vpid and find_task_by_pid_ns, but both of them pass PIDTYPE_PID as first argument. So just fold find_task_by_pid_type_ns into find_task_by_pid_ns and use find_task_by_pid_ns to implement find_task_by_vpid. While we're at it also remove the exports for find_task_by_pid_ns and find_task_by_vpid - we don't have any modular callers left as the only modular caller of he old pre pid namespace find_task_by_pid (gfs2) was switched to pid_task which operates on a struct pid pointer instead of a pid_t. Given the confusion about pid_t values vs namespace that's generally the better option anyway and I think we're better of restricting modules to do it that way. Signed-off-by: NChristoph Hellwig <hch@lst.de> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Li Zefan 提交于
This forward declaration seems pointless. Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 17 6月, 2009 2 次提交
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由 David Rientjes 提交于
The per-task oom_adj value is a characteristic of its mm more than the task itself since it's not possible to oom kill any thread that shares the mm. If a task were to be killed while attached to an mm that could not be freed because another thread were set to OOM_DISABLE, it would have needlessly been terminated since there is no potential for future memory freeing. This patch moves oomkilladj (now more appropriately named oom_adj) from struct task_struct to struct mm_struct. This requires task_lock() on a task to check its oom_adj value to protect against exec, but it's already necessary to take the lock when dereferencing the mm to find the total VM size for the badness heuristic. This fixes a livelock if the oom killer chooses a task and another thread sharing the same memory has an oom_adj value of OOM_DISABLE. This occurs because oom_kill_task() repeatedly returns 1 and refuses to kill the chosen task while select_bad_process() will repeatedly choose the same task during the next retry. Taking task_lock() in select_bad_process() to check for OOM_DISABLE and in oom_kill_task() to check for threads sharing the same memory will be removed in the next patch in this series where it will no longer be necessary. Writing to /proc/pid/oom_adj for a kthread will now return -EINVAL since these threads are immune from oom killing already. They simply report an oom_adj value of OOM_DISABLE. Cc: Nick Piggin <npiggin@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> 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>
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由 Miao Xie 提交于
Fix allocating page cache/slab object on the unallowed node when memory spread is set by updating tasks' mems_allowed after its cpuset's mems is changed. In order to update tasks' mems_allowed in time, we must modify the code of memory policy. Because the memory policy is applied in the process's context originally. After applying this patch, one task directly manipulates anothers mems_allowed, and we use alloc_lock in the task_struct to protect mems_allowed and memory policy of the task. But in the fast path, we didn't use lock to protect them, because adding a lock may lead to performance regression. But if we don't add a lock,the task might see no nodes when changing cpuset's mems_allowed to some non-overlapping set. In order to avoid it, we set all new allowed nodes, then clear newly disallowed ones. [lee.schermerhorn@hp.com: The rework of mpol_new() to extract the adjusting of the node mask to apply cpuset and mpol flags "context" breaks set_mempolicy() and mbind() with MPOL_PREFERRED and a NULL nodemask--i.e., explicit local allocation. Fix this by adding the check for MPOL_PREFERRED and empty node mask to mpol_new_mpolicy(). Remove the now unneeded 'nodes = NULL' from mpol_new(). Note that mpol_new_mempolicy() is always called with a non-NULL 'nodes' parameter now that it has been removed from mpol_new(). Therefore, we don't need to test nodes for NULL before testing it for 'empty'. However, just to be extra paranoid, add a VM_BUG_ON() to verify this assumption.] [lee.schermerhorn@hp.com: I don't think the function name 'mpol_new_mempolicy' is descriptive enough to differentiate it from mpol_new(). This function applies cpuset set context, usually constraining nodes to those allowed by the cpuset. However, when the 'RELATIVE_NODES flag is set, it also translates the nodes. So I settled on 'mpol_set_nodemask()', because the comment block for mpol_new() mentions that we need to call this function to "set nodes". Some additional minor line length, whitespace and typo cleanup.] Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Paul Menage <menage@google.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: David Rientjes <rientjes@google.com> Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 16 6月, 2009 1 次提交
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由 Kay Sievers 提交于
During bootup performance tracing we see repeated occurrences of /sys/kernel/uid/* events for the same uid, leading to a, in this case, rather pointless userspace processing for the same uid over and over. This is usually caused by tools which change their uid to "nobody", to run without privileges to read data supplied by untrusted users. This change delays the execution of the (already existing) scheduled work, to cleanup the uid after one second, so the allocated and announced uid can possibly be re-used by another process. This is the current behavior, where almost every invocation of a binary, which changes the uid, creates two events: $ read START < /sys/kernel/uevent_seqnum; \ for i in `seq 100`; do su --shell=/bin/true bin; done; \ read END < /sys/kernel/uevent_seqnum; \ echo $(($END - $START)) 178 With the delayed cleanup, we get only two events, and userspace finishes a bit faster too: $ read START < /sys/kernel/uevent_seqnum; \ for i in `seq 100`; do su --shell=/bin/true bin; done; \ read END < /sys/kernel/uevent_seqnum; \ echo $(($END - $START)) 1 Acked-by: NDhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: NKay Sievers <kay.sievers@vrfy.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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- 15 6月, 2009 1 次提交
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由 Lennart Poettering 提交于
This patch introduces a new flag SCHED_RESET_ON_FORK which can be passed to the kernel via sched_setscheduler(), ORed in the policy parameter. If set this will make sure that when the process forks a) the scheduling priority is reset to DEFAULT_PRIO if it was higher and b) the scheduling policy is reset to SCHED_NORMAL if it was either SCHED_FIFO or SCHED_RR. Why have this? Currently, if a process is real-time scheduled this will 'leak' to all its child processes. For security reasons it is often (always?) a good idea to make sure that if a process acquires RT scheduling this is confined to this process and only this process. More specifically this makes the per-process resource limit RLIMIT_RTTIME useful for security purposes, because it makes it impossible to use a fork bomb to circumvent the per-process RLIMIT_RTTIME accounting. This feature is also useful for tools like 'renice' which can then change the nice level of a process without having this spill to all its child processes. Why expose this via sched_setscheduler() and not other syscalls such as prctl() or sched_setparam()? prctl() does not take a pid parameter. Due to that it would be impossible to modify this flag for other processes than the current one. The struct passed to sched_setparam() can unfortunately not be extended without breaking compatibility, since sched_setparam() lacks a size parameter. How to use this from userspace? In your RT program simply replace this: sched_setscheduler(pid, SCHED_FIFO, ¶m); by this: sched_setscheduler(pid, SCHED_FIFO|SCHED_RESET_ON_FORK, ¶m); Signed-off-by: NLennart Poettering <lennart@poettering.net> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090615152714.GA29092@tango.0pointer.de> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 24 5月, 2009 1 次提交
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由 Peter Zijlstra 提交于
Instead of en/dis-abling all counters acting on a particular task, en/dis- able all counters we created. [ v2: fix crash on first counter enable ] Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: John Kacur <jkacur@redhat.com> LKML-Reference: <20090523163012.916937244@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 22 5月, 2009 1 次提交
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由 Paul Mackerras 提交于
This replaces the struct perf_counter_context in the task_struct with a pointer to a dynamically allocated perf_counter_context struct. The main reason for doing is this is to allow us to transfer a perf_counter_context from one task to another when we do lazy PMU switching in a later patch. This has a few side-benefits: the task_struct becomes a little smaller, we save some memory because only tasks that have perf_counters attached get a perf_counter_context allocated for them, and we can remove the inclusion of <linux/perf_counter.h> in sched.h, meaning that we don't end up recompiling nearly everything whenever perf_counter.h changes. The perf_counter_context structures are reference-counted and freed when the last reference is dropped. A context can have references from its task and the counters on its task. Counters can outlive the task so it is possible that a context will be freed well after its task has exited. Contexts are allocated on fork if the parent had a context, or otherwise the first time that a per-task counter is created on a task. In the latter case, we set the context pointer in the task struct locklessly using an atomic compare-and-exchange operation in case we raced with some other task in creating a context for the subject task. This also removes the task pointer from the perf_counter struct. The task pointer was not used anywhere and would make it harder to move a context from one task to another. Anything that needed to know which task a counter was attached to was already using counter->ctx->task. The __perf_counter_init_context function moves up in perf_counter.c so that it can be called from find_get_context, and now initializes the refcount, but is otherwise unchanged. We were potentially calling list_del_counter twice: once from __perf_counter_exit_task when the task exits and once from __perf_counter_remove_from_context when the counter's fd gets closed. This adds a check in list_del_counter so it doesn't do anything if the counter has already been removed from the lists. Since perf_counter_task_sched_in doesn't do anything if the task doesn't have a context, and leaves cpuctx->task_ctx = NULL, this adds code to __perf_install_in_context to set cpuctx->task_ctx if necessary, i.e. in the case where the current task adds the first counter to itself and thus creates a context for itself. This also adds similar code to __perf_counter_enable to handle a similar situation which can arise when the counters have been disabled using prctl; that also leaves cpuctx->task_ctx = NULL. [ Impact: refactor counter context management to prepare for new feature ] Signed-off-by: NPaul Mackerras <paulus@samba.org> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <18966.10075.781053.231153@cargo.ozlabs.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 19 5月, 2009 2 次提交
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由 Ingo Molnar 提交于
Properly document the variable-size structure tricks we are doing wrt. struct sched_group and sched_domain, and use the field[0] GCC extension instead of defining a vla array. Dont use unions for this, as pointed out by Linus. [ Impact: cleanup, un-confuse Sparse and LLVM ] Reported-by: NJeff Garzik <jeff@garzik.org> Acked-by: NLinus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <alpine.LFD.2.01.0905180850110.3301@localhost.localdomain> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Eric W. Biederman 提交于
Currently when we have a signal pending we have the functionality to restart that the current system call. There are other cases such as nasty lock ordering issues where it makes sense to have a simple fix that uses try lock and restarts the system call. Buying time to figure out how to rework the locking strategy. Signed-off-by: NEric W. Biederman <ebiederm@aristanetworks.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 15 5月, 2009 3 次提交
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由 Thomas Gleixner 提交于
avenrun is an rough estimate so we don't have to worry about consistency of the three avenrun values. Remove the xtime lock dependency and provide a function to scale the values. Cleanup the users. [ Impact: cleanup ] Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Acked-by: NPeter Zijlstra <peterz@infradead.org>
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由 Thomas Gleixner 提交于
Dimitri Sivanich noticed that xtime_lock is held write locked across calc_load() which iterates over all online CPUs. That can cause long latencies for xtime_lock readers on large SMP systems. The load average calculation is an rough estimate anyway so there is no real need to protect the readers vs. the update. It's not a problem when the avenrun array is updated while a reader copies the values. Instead of iterating over all online CPUs let the scheduler_tick code update the number of active tasks shortly before the avenrun update happens. The avenrun update itself is handled by the CPU which calls do_timer(). [ Impact: reduce xtime_lock write locked section ] Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Acked-by: NPeter Zijlstra <peterz@infradead.org>
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由 Peter Zijlstra 提交于
Instead of a per-process mlock gift for perf-counters, use a per-user gift so that there is less of a DoS potential. [ Impact: allow less worst-case unprivileged memory consumption ] Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <20090515132018.496182835@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 13 5月, 2009 2 次提交
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由 Arun R Bharadwaj 提交于
* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-04-16 12:11:36]: This patch migrates all non pinned timers and hrtimers to the current idle load balancer, from all the idle CPUs. Timers firing on busy CPUs are not migrated. While migrating hrtimers, care should be taken to check if migrating a hrtimer would result in a latency or not. So we compare the expiry of the hrtimer with the next timer interrupt on the target cpu and migrate the hrtimer only if it expires *after* the next interrupt on the target cpu. So, added a clockevents_get_next_event() helper function to return the next_event on the target cpu's clock_event_device. [ tglx: cleanups and simplifications ] Signed-off-by: NArun R Bharadwaj <arun@linux.vnet.ibm.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Arun R Bharadwaj 提交于
* Arun R Bharadwaj <arun@linux.vnet.ibm.com> [2009-04-16 12:11:36]: This patch creates the /proc/sys sysctl interface at /proc/sys/kernel/timer_migration Timer migration is enabled by default. To disable timer migration, when CONFIG_SCHED_DEBUG = y, echo 0 > /proc/sys/kernel/timer_migration Signed-off-by: NArun R Bharadwaj <arun@linux.vnet.ibm.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 11 5月, 2009 1 次提交
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由 David Howells 提交于
Rename cred_exec_mutex to reflect that it's a guard against foreign intervention on a process's credential state, such as is made by ptrace(). The attachment of a debugger to a process affects execve()'s calculation of the new credential state - _and_ also setprocattr()'s calculation of that state. Signed-off-by: NDavid Howells <dhowells@redhat.com> Signed-off-by: NJames Morris <jmorris@namei.org>
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- 30 4月, 2009 1 次提交
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由 David Howells 提交于
Don't flush inherited SIGKILL during execve() in SELinux's post cred commit hook. This isn't really a security problem: if the SIGKILL came before the credentials were changed, then we were right to receive it at the time, and should honour it; if it came after the creds were changed, then we definitely should honour it; and in any case, all that will happen is that the process will be scrapped before it ever returns to userspace. Signed-off-by: NDavid Howells <dhowells@redhat.com> Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NJames Morris <jmorris@namei.org>
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