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* x86: various changes and cleanups to in_p/out_p delay detailsIngo Molnar2008-01-301-0/+9
| | | | | | | | | | | | | | | various changes to the in_p/out_p delay details: - add the io_delay=none method - make each method selectable from the kernel config - simplify the delay code a bit by getting rid of an indirect function call - add the /proc/sys/kernel/io_delay_type sysctl - change 'io_delay=standard|alternate' to io_delay=0x80 and io_delay=0xed - make the io delay config not depend on CONFIG_DEBUG_KERNEL Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: "David P. Reed" <dpreed@reed.com>
* [NET]: Remove the empty net_tablePavel Emelyanov2008-01-281-8/+0
| | | | | | | | I have removed all the entries from this table (core_table, ipv4_table and tr_table), so now we can safely drop it. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* sysctl: Infrastructure for per namespace sysctlsEric W. Biederman2008-01-281-11/+82
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements the basic infrastructure for per namespace sysctls. A list of lists of sysctl headers is added, allowing each namespace to have it's own list of sysctl headers. Each list of sysctl headers has a lookup function to find the first sysctl header in the list, allowing the lists to have a per namespace instance. register_sysct_root is added to tell sysctl.c about additional lists of sysctl_headers. As all of the users are expected to be in kernel no unregister function is provided. sysctl_head_next is updated to walk through the list of lists. __register_sysctl_paths is added to add a new sysctl table on a non-default sysctl list. The only intrusive part of this patch is propagating the information to decided which list of sysctls to use for sysctl_check_table. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Daniel Lezcano <dlezcano@fr.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* sysctl: Remember the ctl_table we passed to register_sysctl_pathsEric W. Biederman2008-01-281-0/+1
| | | | | | | | | | | | | | | | | By doing this we allow users of register_sysctl_paths that build and dynamically allocate their ctl_table to be simpler. This allows them to just remember the ctl_table_header returned from register_sysctl_paths from which they can now find the ctl_table array they need to free. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Daniel Lezcano <dlezcano@fr.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* sysctl: Add register_sysctl_paths functionEric W. Biederman2008-01-281-15/+74
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are a number of modules that register a sysctl table somewhere deeply nested in the sysctl hierarchy, such as fs/nfs, fs/xfs, dev/cdrom, etc. They all specify several dummy ctl_tables for the path name. This patch implements register_sysctl_path that takes an additional path name, and makes up dummy sysctl nodes for each component. This patch was originally written by Olaf Kirch and brought to my attention and reworked some by Olaf Hering. I have changed a few additional things so the bugs are mine. After converting all of the easy callers Olaf Hering observed allyesconfig ARCH=i386, the patch reduces the final binary size by 9369 bytes. .text +897 .data -7008 text data bss dec hex filename 26959310 4045899 4718592 35723801 2211a19 ../vmlinux-vanilla 26960207 4038891 4718592 35717690 221023a ../O-allyesconfig/vmlinux So this change is both a space savings and a code simplification. CC: Olaf Kirch <okir@suse.de> CC: Olaf Hering <olaf@aepfle.de> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Daniel Lezcano <dlezcano@fr.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* softlockup: fix signednessIngo Molnar2008-01-251-8/+8
| | | | | | | | fix softlockup tunables signedness. mark tunables read-mostly. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: latencytop supportArjan van de Ven2008-01-251-0/+10
| | | | | | | | LatencyTOP kernel infrastructure; it measures latencies in the scheduler and tracks it system wide and per process. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: rt time limitPeter Zijlstra2008-01-251-1/+17
| | | | | | | | | | Very simple time limit on the realtime scheduling classes. Allow the rq's realtime class to consume sched_rt_ratio of every sched_rt_period slice. If the class exceeds this quota the fair class will preempt the realtime class. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* softlockup: automatically detect hung TASK_UNINTERRUPTIBLE tasksIngo Molnar2008-01-251-0/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | this patch extends the soft-lockup detector to automatically detect hung TASK_UNINTERRUPTIBLE tasks. Such hung tasks are printed the following way: ------------------> INFO: task prctl:3042 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message prctl D fd5e3793 0 3042 2997 f6050f38 00000046 00000001 fd5e3793 00000009 c06d8264 c06dae80 00000286 f6050f40 f6050f00 f7d34d90 f7d34fc8 c1e1be80 00000001 f6050000 00000000 f7e92d00 00000286 f6050f18 c0489d1a f6050f40 00006605 00000000 c0133a5b Call Trace: [<c04883a5>] schedule_timeout+0x6d/0x8b [<c04883d8>] schedule_timeout_uninterruptible+0x15/0x17 [<c0133a76>] msleep+0x10/0x16 [<c0138974>] sys_prctl+0x30/0x1e2 [<c0104c52>] sysenter_past_esp+0x5f/0xa5 ======================= 2 locks held by prctl/3042: #0: (&sb->s_type->i_mutex_key#5){--..}, at: [<c0197d11>] do_fsync+0x38/0x7a #1: (jbd_handle){--..}, at: [<c01ca3d2>] journal_start+0xc7/0xe9 <------------------ the current default timeout is 120 seconds. Such messages are printed up to 10 times per bootup. If the system has crashed already then the messages are not printed. if lockdep is enabled then all held locks are printed as well. this feature is a natural extension to the softlockup-detector (kernel locked up without scheduling) and to the NMI watchdog (kernel locked up with IRQs disabled). [ Gautham R Shenoy <ego@in.ibm.com>: CPU hotplug fixes. ] [ Andrew Morton <akpm@linux-foundation.org>: build warning fix. ] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
* sched: group scheduler, fix fairness of cpu bandwidth allocation for task groupsSrivatsa Vaddagiri2008-01-251-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current load balancing scheme isn't good enough for precise group fairness. For example: on a 8-cpu system, I created 3 groups as under: a = 8 tasks (cpu.shares = 1024) b = 4 tasks (cpu.shares = 1024) c = 3 tasks (cpu.shares = 1024) a, b and c are task groups that have equal weight. We would expect each of the groups to receive 33.33% of cpu bandwidth under a fair scheduler. This is what I get with the latest scheduler git tree: Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------------------- Col1 | Col2 | Col3 | Col4 ------|---------|-------|------------------------------------------------------- a | 277.676 | 57.8% | 54.1% 54.1% 54.1% 54.2% 56.7% 62.2% 62.8% 64.5% b | 116.108 | 24.2% | 47.4% 48.1% 48.7% 49.3% c | 86.326 | 18.0% | 47.5% 47.9% 48.5% -------------------------------------------------------------------------------- Explanation of o/p: Col1 -> Group name Col2 -> Cumulative execution time (in seconds) received by all tasks of that group in a 60sec window across 8 cpus Col3 -> CPU bandwidth received by the group in the 60sec window, expressed in percentage. Col3 data is derived as: Col3 = 100 * Col2 / (NR_CPUS * 60) Col4 -> CPU bandwidth received by each individual task of the group. Col4 = 100 * cpu_time_recd_by_task / 60 [I can share the test case that produces a similar o/p if reqd] The deviation from desired group fairness is as below: a = +24.47% b = -9.13% c = -15.33% which is quite high. After the patch below is applied, here are the results: -------------------------------------------------------------------------------- Col1 | Col2 | Col3 | Col4 ------|---------|-------|------------------------------------------------------- a | 163.112 | 34.0% | 33.2% 33.4% 33.5% 33.5% 33.7% 34.4% 34.8% 35.3% b | 156.220 | 32.5% | 63.3% 64.5% 66.1% 66.5% c | 160.653 | 33.5% | 85.8% 90.6% 91.4% -------------------------------------------------------------------------------- Deviation from desired group fairness is as below: a = +0.67% b = -0.83% c = +0.17% which is far better IMO. Most of other runs have yielded a deviation within +-2% at the most, which is good. Why do we see bad (group) fairness with current scheuler? ========================================================= Currently cpu's weight is just the summation of individual task weights. This can yield incorrect results. For ex: consider three groups as below on a 2-cpu system: CPU0 CPU1 --------------------------- A (10) B(5) C(5) --------------------------- Group A has 10 tasks, all on CPU0, Group B and C have 5 tasks each all of which are on CPU1. Each task has the same weight (NICE_0_LOAD = 1024). The current scheme would yield a cpu weight of 10240 (10*1024) for each cpu and the load balancer will think both CPUs are perfectly balanced and won't move around any tasks. This, however, would yield this bandwidth: A = 50% B = 25% C = 25% which is not the desired result. What's changing in the patch? ============================= - How cpu weights are calculated when CONFIF_FAIR_GROUP_SCHED is defined (see below) - API Change - Two tunables introduced in sysfs (under SCHED_DEBUG) to control the frequency at which the load balance monitor thread runs. The basic change made in this patch is how cpu weight (rq->load.weight) is calculated. Its now calculated as the summation of group weights on a cpu, rather than summation of task weights. Weight exerted by a group on a cpu is dependent on the shares allocated to it and also the number of tasks the group has on that cpu compared to the total number of (runnable) tasks the group has in the system. Let, W(K,i) = Weight of group K on cpu i T(K,i) = Task load present in group K's cfs_rq on cpu i T(K) = Total task load of group K across various cpus S(K) = Shares allocated to group K NRCPUS = Number of online cpus in the scheduler domain to which group K is assigned. Then, W(K,i) = S(K) * NRCPUS * T(K,i) / T(K) A load balance monitor thread is created at bootup, which periodically runs and adjusts group's weight on each cpu. To avoid its overhead, two min/max tunables are introduced (under SCHED_DEBUG) to control the rate at which it runs. Fixes from: Peter Zijlstra <a.p.zijlstra@chello.nl> - don't start the load_balance_monitor when there is only a single cpu. - rename the kthread because its currently longer than TASK_COMM_LEN Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: sysctl, proc_dointvec_minmax() expects int values forEric Dumazet2007-12-181-4/+4
| | | | | | | | | | | | | | min_sched_granularity_ns, max_sched_granularity_ns, min_wakeup_granularity_ns and max_wakeup_granularity_ns are declared "unsigned long". This is incorrect since proc_dointvec_minmax() expects plain "int" guard values. This bug only triggers on big endian 64 bit arches. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Revert "hugetlb: Add hugetlb_dynamic_pool sysctl"Nishanth Aravamudan2007-12-171-8/+0
| | | | | | | | | | | | | | | | | | | | This reverts commit 54f9f80d6543fb7b157d3b11e2e7911dc1379790 ("hugetlb: Add hugetlb_dynamic_pool sysctl") Given the new sysctl nr_overcommit_hugepages, the boolean dynamic pool sysctl is not needed, as its semantics can be expressed by 0 in the overcommit sysctl (no dynamic pool) and non-0 in the overcommit sysctl (pool enabled). (Needed in 2.6.24 since it reverts a post-2.6.23 userspace-visible change) Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Acked-by: Adam Litke <agl@us.ibm.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb: introduce nr_overcommit_hugepages sysctlNishanth Aravamudan2007-12-171-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hugetlb: introduce nr_overcommit_hugepages sysctl While examining the code to support /proc/sys/vm/hugetlb_dynamic_pool, I became convinced that having a boolean sysctl was insufficient: 1) To support per-node control of hugepages, I have previously submitted patches to add a sysfs attribute related to nr_hugepages. However, with a boolean global value and per-mount quota enforcement constraining the dynamic pool, adding corresponding control of the dynamic pool on a per-node basis seems inconsistent to me. 2) Administration of the hugetlb dynamic pool with multiple hugetlbfs mount points is, arguably, more arduous than it needs to be. Each quota would need to be set separately, and the sum would need to be monitored. To ease the administration, and to help make the way for per-node control of the static & dynamic hugepage pool, I added a separate sysctl, nr_overcommit_hugepages. This value serves as a high watermark for the overall hugepage pool, while nr_hugepages serves as a low watermark. The boolean sysctl can then be removed, as the condition nr_overcommit_hugepages > 0 indicates the same administrative setting as hugetlb_dynamic_pool == 1 Quotas still serve as local enforcement of the size of the pool on a per-mount basis. A few caveats: 1) There is a race whereby the global surplus huge page counter is incremented before a hugepage has allocated. Another process could then try grow the pool, and fail to convert a surplus huge page to a normal huge page and instead allocate a fresh huge page. I believe this is benign, as no memory is leaked (the actual pages are still tracked correctly) and the counters won't go out of sync. 2) Shrinking the static pool while a surplus is in effect will allow the number of surplus huge pages to exceed the overcommit value. As long as this condition holds, however, no more surplus huge pages will be allowed on the system until one of the two sysctls are increased sufficiently, or the surplus huge pages go out of use and are freed. Successfully tested on x86_64 with the current libhugetlbfs snapshot, modified to use the new sysctl. Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Acked-by: Adam Litke <agl@us.ibm.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Avoid potential NULL dereference in unregister_sysctl_tablePavel Emelyanov2007-12-051-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | register_sysctl_table() can return NULL sometimes, e.g. when kmalloc() returns NULL or when sysctl check fails. I've also noticed, that many (most?) code in the kernel doesn't check for the return value from register_sysctl_table() and later simply calls the unregister_sysctl_table() with potentially NULL argument. This is unlikely on a common kernel configuration, but in case we're dealing with modules and/or fault-injection support, there's a slight possibility of an OOPS. Changing all the users to check for return code from the registering does not look like a good solution - there are too many code doing this and failure in sysctl tables registration is not a good reason to abort module loading (in most of the cases). So I think, that we can just have this check in unregister_sysctl_table just to avoid accidental OOPS-es (actually, the unregister_sysctl_table() did exactly this, before the start_unregistering() appeared). Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sysctl: check length at deprecated_sysctl_warningTetsuo Handa2007-11-141-0/+4
| | | | | | | | | Original patch assumed args->nlen < CTL_MAXNAME, but it can be false. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched: avoid large irq-latencies in smp-balancingPeter Zijlstra2007-11-091-0/+8
| | | | | | | | | | | | | SMP balancing is done with IRQs disabled and can iterate the full rq. When rqs are large this can cause large irq-latencies. Limit the nr of iterations on each run. This fixes a scheduling latency regression reported by the -rt folks. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Steven Rostedt <rostedt@goodmis.org> Tested-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: cleanup, use NSEC_PER_MSEC and NSEC_PER_SECEric Dumazet2007-11-091-2/+2
| | | | | | | | | | | | | | | | | 1) hardcoded 1000000000 value is used five times in places where NSEC_PER_SEC might be more readable. 2) A conversion from nsec to msec uses the hardcoded 1000000 value, which is a candidate for NSEC_PER_MSEC. no code changed: text data bss dec hex filename 44359 3326 36 47721 ba69 sched.o.before 44359 3326 36 47721 ba69 sched.o.after Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: reintroduce the sched_min_granularity tunablePeter Zijlstra2007-11-091-4/+7
| | | | | | | | | | | | | | | we lost the sched_min_granularity tunable to a clever optimization that uses the sched_latency/min_granularity ratio - but the ratio is quite unintuitive to users and can also crash the kernel if the ratio is set to 0. So reintroduce the min_granularity tunable, while keeping the ratio maintained internally. no functionality changed. [ mingo@elte.hu: some fixlets. ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* pid namespaces: changes to show virtual ids to userPavel Emelyanov2007-10-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is the largest patch in the set. Make all (I hope) the places where the pid is shown to or get from user operate on the virtual pids. The idea is: - all in-kernel data structures must store either struct pid itself or the pid's global nr, obtained with pid_nr() call; - when seeking the task from kernel code with the stored id one should use find_task_by_pid() call that works with global pids; - when showing pid's numerical value to the user the virtual one should be used, but however when one shows task's pid outside this task's namespace the global one is to be used; - when getting the pid from userspace one need to consider this as the virtual one and use appropriate task/pid-searching functions. [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: nuther build fix] [akpm@linux-foundation.org: yet nuther build fix] [akpm@linux-foundation.org: remove unneeded casts] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Paul Menage <menage@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pid namespaces: define is_global_init() and is_container_init()Serge E. Hallyn2007-10-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | is_init() is an ambiguous name for the pid==1 check. Split it into is_global_init() and is_container_init(). A cgroup init has it's tsk->pid == 1. A global init also has it's tsk->pid == 1 and it's active pid namespace is the init_pid_ns. But rather than check the active pid namespace, compare the task structure with 'init_pid_ns.child_reaper', which is initialized during boot to the /sbin/init process and never changes. Changelog: 2.6.22-rc4-mm2-pidns1: - Use 'init_pid_ns.child_reaper' to determine if a given task is the global init (/sbin/init) process. This would improve performance and remove dependence on the task_pid(). 2.6.21-mm2-pidns2: - [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc, ppc,avr32}/traps.c for the _exception() call to is_global_init(). This way, we kill only the cgroup if the cgroup's init has a bug rather than force a kernel panic. [akpm@linux-foundation.org: fix comment] [sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c] [bunk@stusta.de: kernel/pid.c: remove unused exports] [sukadev@us.ibm.com: Fix capability.c to work with threaded init] Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com> Acked-by: Pavel Emelianov <xemul@openvz.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Herbert Poetzel <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* V3 file capabilities: alter behavior of cap_setpcapAndrew Morgan2007-10-181-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The non-filesystem capability meaning of CAP_SETPCAP is that a process, p1, can change the capabilities of another process, p2. This is not the meaning that was intended for this capability at all, and this implementation came about purely because, without filesystem capabilities, there was no way to use capabilities without one process bestowing them on another. Since we now have a filesystem support for capabilities we can fix the implementation of CAP_SETPCAP. The most significant thing about this change is that, with it in effect, no process can set the capabilities of another process. The capabilities of a program are set via the capability convolution rules: pI(post-exec) = pI(pre-exec) pP(post-exec) = (X(aka cap_bset) & fP) | (pI(post-exec) & fI) pE(post-exec) = fE ? pP(post-exec) : 0 at exec() time. As such, the only influence the pre-exec() program can have on the post-exec() program's capabilities are through the pI capability set. The correct implementation for CAP_SETPCAP (and that enabled by this patch) is that it can be used to add extra pI capabilities to the current process - to be picked up by subsequent exec()s when the above convolution rules are applied. Here is how it works: Let's say we have a process, p. It has capability sets, pE, pP and pI. Generally, p, can change the value of its own pI to pI' where (pI' & ~pI) & ~pP = 0. That is, the only new things in pI' that were not present in pI need to be present in pP. The role of CAP_SETPCAP is basically to permit changes to pI beyond the above: if (pE & CAP_SETPCAP) { pI' = anything; /* ie., even (pI' & ~pI) & ~pP != 0 */ } This capability is useful for things like login, which (say, via pam_cap) might want to raise certain inheritable capabilities for use by the children of the logged-in user's shell, but those capabilities are not useful to or needed by the login program itself. One such use might be to limit who can run ping. You set the capabilities of the 'ping' program to be "= cap_net_raw+i", and then only shells that have (pI & CAP_NET_RAW) will be able to run it. Without CAP_SETPCAP implemented as described above, login(pam_cap) would have to also have (pP & CAP_NET_RAW) in order to raise this capability and pass it on through the inheritable set. Signed-off-by: Andrew Morgan <morgan@kernel.org> Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sysctl: deprecate sys_sysctl in a user space visible fashion.Eric W. Biederman2007-10-181-23/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After adding checking to register_sysctl_table and finding a whole new set of bugs. Missed by countless code reviews and testers I have finally lost patience with the binary sysctl interface. The binary sysctl interface has been sort of deprecated for years and finding a user space program that uses the syscall is more difficult then finding a needle in a haystack. Problems continue to crop up, with the in kernel implementation. So since supporting something that no one uses is silly, deprecate sys_sysctl with a sufficient grace period and notice that the handful of user space applications that care can be fixed or replaced. The /proc/sys sysctl interface that people use will continue to be supported indefinitely. This patch moves the tested warning about sysctls from the path where sys_sysctl to a separate path called from both implementations of sys_sysctl, and it adds a proper entry into Documentation/feature-removal-schedule. Allowing us to revisit this in a couple years time and actually kill sys_sysctl. [lethal@linux-sh.org: sysctl: Fix syscall disabled build] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sysctl: Error on bad sysctl tablesEric W. Biederman2007-10-181-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | After going through the kernels sysctl tables several times it has become clear that code review and testing is just not effective in prevent problematic sysctl tables from being used in the stable kernel. I certainly can't seem to fix the problems as fast as they are introduced. Therefore this patch adds sysctl_check_table which is called when a sysctl table is registered and checks to see if we have a problematic sysctl table. The biggest part of the code is the table of valid binary sysctl entries, but since we have frozen our set of binary sysctls this table should not need to change, and it makes it much easier to detect when someone unintentionally adds a new binary sysctl value. As best as I can determine all of the several hundred errors spewed on boot up now are legitimate. [bunk@kernel.org: kernel/sysctl_check.c must #include <linux/string.h>] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sysctl: remove the cad_pid binary sysctl pathEric W. Biederman2007-10-181-1/+0
| | | | | | | | | | It looks like we inadvertently killed the cad_pid binary sysctl support when cap_pid was changed to be a struct pid. Since no one has complained just remove the binary path. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sysctl: simplify the pty sysctl logicEric W. Biederman2007-10-181-11/+0
| | | | | | | | | | | | | Instead of having a bunch of ifdefs in sysctl.c move all of the pty sysctl logic into drivers/char/pty.c As well as cleaning up the logic this prevents sysctl_check_table from complaining that the root table has a NULL data pointer on something with generic methods. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sysctl: remove the binary interface for aio-nr, aio-max-nr, acpi_video_flagsEric W. Biederman2007-10-181-3/+0
| | | | | | | | | | | | | | | | | | aio-nr, aio-max-nr, acpi_video_flags are unsigned long values which sysctl does not handle properly with a 64bit kernel and a 32bit user space. Since no one is likely to be using the binary sysctl values and the ascii interface still works, this patch just removes support for the binary sysctl interface from the kernel. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@sw.ru> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Zach Brown <zach.brown@oracle.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Len Brown <lenb@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sysctl: remove binary sysctl support where it clearly doesn't workEric W. Biederman2007-10-181-7/+0
| | | | | | | | | | | These functions are all wrapper functions for the proc interface that are needed for them to work correctly. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@sw.ru> Acked-by: Andrew Morgan <morgan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sysctl: Factor out sysctl_data.Eric W. Biederman2007-10-181-20/+46
| | | | | | | | | | | | | | | | | | | | There as been no easy way to wrap the default sysctl strategy routine except for returning 0. Which is not always what we want. The few instances I have seen that want different behaviour have written their own version of sysctl_data. While not too hard it is unnecessary code and has the potential for extra bugs. So to make these situations easier and make that part of sysctl more symetric I have factord sysctl_data out of do_sysctl_strategy and exported as a function everyone can use. Further having sysctl_data be an explicit function makes checking for badly formed sysctl tables much easier. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sysctl core: Stop using the unnecessary ctl_table typedefEric W. Biederman2007-10-181-57/+57
| | | | | | | | | | | | | | | In sysctl.h the typedef struct ctl_table ctl_table violates coding style isn't needed and is a bit of a nuisance because it makes it harder to recognize ctl_table is a type name. So this patch removes it from the generic sysctl code. Hopefully I will have enough energy to send the rest of my patches will follow and to remove it from the rest of the kernel. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* softlockup: add a /proc tuning parameterRavikiran G Thirumalai2007-10-171-7/+26
| | | | | | | | | | | | | | | | | | Control the trigger limit for softlockup warnings. This is useful for debugging softlockups, by lowering the softlockup_thresh to identify possible softlockups earlier. This patch: 1. Adds a sysctl softlockup_thresh with valid values of 1-60s (Higher value to disable false positives) 2. Changes the softlockup printk to print the cpu softlockup time [akpm@linux-foundation.org: Fix various warnings and add definition of "two"] Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Shai Fultheim <shai@scalex86.org> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* oom: add oom_kill_allocating_task sysctlDavid Rientjes2007-10-171-0/+9
| | | | | | | | | | | | | | Adds a new sysctl, 'oom_kill_allocating_task', which will automatically kill the OOM-triggering task instead of scanning through the tasklist to find a memory-hogging target. This is helpful for systems with an insanely large number of tasks where scanning the tasklist significantly degrades performance. Cc: Andrea Arcangeli <andrea@suse.de> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: per device dirty thresholdPeter Zijlstra2007-10-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Scale writeback cache per backing device, proportional to its writeout speed. By decoupling the BDI dirty thresholds a number of problems we currently have will go away, namely: - mutual interference starvation (for any number of BDIs); - deadlocks with stacked BDIs (loop, FUSE and local NFS mounts). It might be that all dirty pages are for a single BDI while other BDIs are idling. By giving each BDI a 'fair' share of the dirty limit, each one can have dirty pages outstanding and make progress. A global threshold also creates a deadlock for stacked BDIs; when A writes to B, and A generates enough dirty pages to get throttled, B will never start writeback until the dirty pages go away. Again, by giving each BDI its own 'independent' dirty limit, this problem is avoided. So the problem is to determine how to distribute the total dirty limit across the BDIs fairly and efficiently. A DBI that has a large dirty limit but does not have any dirty pages outstanding is a waste. What is done is to keep a floating proportion between the DBIs based on writeback completions. This way faster/more active devices get a larger share than slower/idle devices. [akpm@linux-foundation.org: fix warnings] [hugh@veritas.com: Fix occasional hang when a task couldn't get out of balance_dirty_pages] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hugetlb: Add hugetlb_dynamic_pool sysctlAdam Litke2007-10-161-0/+8
| | | | | | | | | | | | | | | | | | | | | | The maximum size of the huge page pool can be controlled using the overall size of the hugetlb filesystem (via its 'size' mount option). However in the common case the this will not be set as the pool is traditionally fixed in size at boot time. In order to maintain the expected semantics, we need to prevent the pool expanding by default. This patch introduces a new sysctl controlling dynamic pool resizing. When this is enabled the pool will expand beyond its base size up to the size of the hugetlb filesystem. It is disabled by default. Signed-off-by: Adam Litke <agl@us.ibm.com> Acked-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Dave McCracken <dave.mccracken@oracle.com> Cc: William Irwin <bill.irwin@oracle.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Ken Chen <kenchen@google.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched: reintroduce cache-hot affinityIngo Molnar2007-10-151-0/+8
| | | | | | | | reintroduce a simplified version of cache-hot/cold scheduling affinity. This improves performance with certain SMP workloads, such as sysbench. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: speed up and simplify vslice calculationsPeter Zijlstra2007-10-151-6/+3
| | | | | | | | | speed up and simplify vslice calculations. [ From: Mike Galbraith <efault@gmx.de>: build fix ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: remove wait_runtime limitIngo Molnar2007-10-151-11/+0
| | | | | | | | | | remove the wait_runtime-limit fields and the code depending on it, now that the math has been changed over to rely on the vruntime metric. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Mike Galbraith <efault@gmx.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
* sched: remove stat_granIngo Molnar2007-10-151-11/+0
| | | | | | | | | | remove the stat_gran code - it was disabled by default and it causes unnecessary overhead. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Mike Galbraith <efault@gmx.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
* minimal build fixes for uml (fallout from x86 merge)Al Viro2007-10-131-1/+1
| | | | | | | | | | | | | | | | | | | a) include/asm-um/arch can't just point to include/asm-$(SUBARCH) now b) arch/{i386,x86_64}/crypto are merged now c) subarch-obj needed changes d) cpufeature_64.h should pull "cpufeature_32.h", not <asm/cpufeature_32.h> since it can be included from asm-um/cpufeature.h e) in case of uml-i386 we need CONFIG_X86_32 for make and gcc, but not for Kconfig f) sysctl.c shouldn't do vdso_enabled for uml-i386 (actually, that one should be registered from corresponding arch/*/kernel/*, with ifdef going away; that's a separate patch, though). With that and with Stephen's patch ("[PATCH net-2.6] uml: hard_header fix") we have uml allmodconfig building both on i386 and amd64. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [POWERPC] Implement logging of unhandled signalsOlof Johansson2007-10-121-1/+1
| | | | | | | | | | Implement show_unhandled_signals sysctl + support to print when a process is killed due to unhandled signals just as i386 and x86_64 does. Default to having it off, unlike x86 that defaults on. Signed-off-by: Olof Johansson <olof@lixom.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
* sched: add /proc/sys/kernel/sched_compat_yieldIngo Molnar2007-09-191-0/+8
| | | | | | | | | | | | | | | | | | | | | add /proc/sys/kernel/sched_compat_yield to make sys_sched_yield() more agressive, by moving the yielding task to the last position in the rbtree. with sched_compat_yield=0: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2539 mingo 20 0 1576 252 204 R 50 0.0 0:02.03 loop_yield 2541 mingo 20 0 1576 244 196 R 50 0.0 0:02.05 loop with sched_compat_yield=1: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2584 mingo 20 0 1576 248 196 R 99 0.0 0:52.45 loop 2582 mingo 20 0 1576 256 204 R 0 0.0 0:00.00 loop_yield Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
* sched: cleanup, sched_granularity -> sched_min_granularityIngo Molnar2007-08-251-2/+2
| | | | | | | | | due to adaptive granularity scheduling the role of sched_granularity has changed to "minimum granularity", so rename the variable (and the tunable) accordingly. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
* sched: adaptive scheduler granularityPeter Zijlstra2007-08-251-0/+11
| | | | | | | | | | | | | | | | | | Instead of specifying the preemption granularity, specify the wanted latency. By fixing the granlarity to a constany the wakeup latency it a function of the number of running tasks on the rq. Invert this relation. sysctl_sched_granularity becomes a minimum for the dynamic granularity computed from the new sysctl_sched_latency. Then use this latency to do more intelligent granularity decisions: if there are fewer tasks running then we can schedule coarser. This helps performance while still always keeping the latency target. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: fix CONFIG_SCHED_DEBUG dependency of lockdep sysctlsPeter Zijlstra2007-08-251-9/+9
| | | | | | | Make the lockdep sysctls not depend on CONFIG_SCHED_DEBUG. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Remove double inclusion of linux/capability.hChristian Heim2007-08-191-1/+0
| | | | | | | | | Remove the second inclusion of linux/capability.h, which has been introduced with "[PATCH] move capable() to capability.h" (commit c59ede7b78db329949d9cdcd7064e22d357560ef) Signed-off-by: Christian Heim <phreak@gentoo.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix missing numa_zonelist_order sysctlLee Schermerhorn2007-08-111-1/+1
| | | | | | | | | Misplaced #endif is hiding the numa_zonelist_order sysctl when !SECURITY. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ACPI: restore CONFIG_ACPI_SLEEPLen Brown2007-07-291-1/+1
| | | | | | | | | Restore the 2.6.22 CONFIG_ACPI_SLEEP build option, but now shadowing the new CONFIG_PM_SLEEP option. Signed-off-by: Len Brown <len.brown@intel.com> [ Modified to work with the PM config setup changes. ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ACPI: Kconfig: remove CONFIG_ACPI_SLEEP from sourceLen Brown2007-07-251-1/+1
| | | | | | | | | | As it was a synonym for (CONFIG_ACPI && CONFIG_X86), the ifdefs for it were more clutter than they were worth. For ia64, just add a few stubs in anticipation of future S3 or S4 support. Signed-off-by: Len Brown <len.brown@intel.com>
* x86: i386-show-unhandled-signals-v3Masoud Asgharifard Sharbiani2007-07-221-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch makes the i386 behave the same way that x86_64 does when a segfault happens. A line gets printed to the kernel log so that tools that need to check for failures can behave more uniformly between debug.show_unhandled_signals sysctl variable to 0 (or by doing echo 0 > /proc/sys/debug/exception-trace) Also, all of the lines being printed are now using printk_ratelimit() to deny the ability of DoS from a local user with a program like the following: main() { while (1) if (!fork()) *(int *)0 = 0; } This new revision also includes the fix that Andrew did which got rid of new sysctl that was added to the system in earlier versions of this. Also, 'show-unhandled-signals' sysctl has been renamed back to the old 'exception-trace' to avoid breakage of people's scripts. AK: Enabling by default for i386 will be likely controversal, but let's see what happens AK: Really folks, before complaining just fix your segfaults AK: I bet this will find a lot of silent issues Signed-off-by: Masoud Sharbiani <masouds@google.com> Signed-off-by: Andi Kleen <ak@suse.de> [ Personally, I've found the complaints useful on x86-64, so I'm all for this. That said, I wonder if we could do it more prettily.. -Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel/sysctl.c: finish off the warning commentsAndrew Morton2007-07-191-1/+4
| | | | | | | | I've been chasing these comments around this file all week. Hopefully we're straight now. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* lockstat: core infrastructurePeter Zijlstra2007-07-191-0/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce the core lock statistics code. Lock statistics provides lock wait-time and hold-time (as well as the count of corresponding contention and acquisitions events). Also, the first few call-sites that encounter contention are tracked. Lock wait-time is the time spent waiting on the lock. This provides insight into the locking scheme, that is, a heavily contended lock is indicative of a too coarse locking scheme. Lock hold-time is the duration the lock was held, this provides a reference for the wait-time numbers, so they can be put into perspective. 1) lock 2) ... do stuff .. unlock 3) The time between 1 and 2 is the wait-time. The time between 2 and 3 is the hold-time. The lockdep held-lock tracking code is reused, because it already collects locks into meaningful groups (classes), and because it is an existing infrastructure for lock instrumentation. Currently lockdep tracks lock acquisition with two hooks: lock() lock_acquire() _lock() ... code protected by lock ... unlock() lock_release() _unlock() We need to extend this with two more hooks, in order to measure contention. lock_contended() - used to measure contention events lock_acquired() - completion of the contention These are then placed the following way: lock() lock_acquire() if (!_try_lock()) lock_contended() _lock() lock_acquired() ... do locked stuff ... unlock() lock_release() _unlock() (Note: the try_lock() 'trick' is used to avoid instrumenting all platform dependent lock primitive implementations.) It is also possible to toggle the two lockdep features at runtime using: /proc/sys/kernel/prove_locking /proc/sys/kernel/lock_stat (esp. turning off the O(n^2) prove_locking functionaliy can help) [akpm@linux-foundation.org: build fixes] [akpm@linux-foundation.org: nuke unneeded ifdefs] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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