- 31 Mar, 2006 40 commits
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Eric W. Biederman authored
Simplifies the code, reduces the need for 4 pid hash tables, and makes the code more capable. In the discussions I had with Oleg it was felt that to a large extent the cleanup itself justified the work. With struct pid being dynamically allocated meant we could create the hash table entry when the pid was allocated and free the hash table entry when the pid was freed. Instead of playing with the hash lists when ever a process would attach or detach to a process. For myself the fact that it gave what my previous task_ref patch gave for free with simpler code was a big win. The problem is that if you hold a reference to struct task_struct you lock in 10K of low memory. If you do that in a user controllable way like /proc does, with an unprivileged but hostile user space application with typical resource limits of 1000 fds and 100 processes I can trigger the OOM killer by consuming all of low memory with task structs, on a machine wight 1GB of low memory. If I instead hold a reference to struct pid which holds a pointer to my task_struct, I don't suffer from that problem because struct pid is 2 orders of magnitude smaller. In fact struct pid is small enough that most other kernel data structures dwarf it, so simply limiting the number of referring data structures is enough to prevent exhaustion of low memory. This splits the current struct pid into two structures, struct pid and struct pid_link, and reduces our number of hash tables from PIDTYPE_MAX to just one. struct pid_link is the per process linkage into the hash tables and lives in struct task_struct. struct pid is given an indepedent lifetime, and holds pointers to each of the pid types. The independent life of struct pid simplifies attach_pid, and detach_pid, because we are always manipulating the list of pids and not the hash table. In addition in giving struct pid an indpendent life it makes the concept much more powerful. Kernel data structures can now embed a struct pid * instead of a pid_t and not suffer from pid wrap around problems or from keeping unnecessarily large amounts of memory allocated. Signed-off-by:
Eric W. Biederman <ebiederm@xmission.com> Signed-off-by:
Andrew Morton <akpm@osdl.org> Signed-off-by:
Linus Torvalds <torvalds@osdl.org>
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Eric W. Biederman authored
A big problem with rcu protected data structures that are also reference counted is that you must jump through several hoops to increase the reference count. I think someone finally implemented atomic_inc_not_zero(&count) to automate the common case. Unfortunately this means you must special case the rcu access case. When data structures are only visible via rcu in a manner that is not determined by the reference count on the object (i.e. tasks are visible until their zombies are reaped) there is a much simpler technique we can employ. Simply delaying the decrement of the reference count until the rcu interval is over. What that means is that the proc code that looks up a task and later wants to sleep can now do: rcu_read_lock(); task = find_task_by_pid(some_pid); if (task) { get_task_struct(task); } rcu_read_unlock(); The effect on the rest of the kernel is that put_task_struct becomes cheaper and immediate, and in the case where the task has been reaped it frees the task immediate instead of unnecessarily waiting an until the rcu interval is over. Cleanup of task_struct does not happen when its reference count drops to zero, instead cleanup happens when release_task is called. Tasks can only be looked up via rcu before release_task is called. All rcu protected members of task_struct are freed by release_task. Therefore we can move call_rcu from put_task_struct into release_task. And we can modify release_task to not immediately release the reference count but instead have it call put_task_struct from the function it gives to call_rcu. The end result: - get_task_struct is safe in an rcu context where we have just looked up the task. - put_task_struct() simplifies into its old pre rcu self. This reorganization also makes put_task_struct uncallable from modules as it is not exported but it does not appear to be called from any modules so this should not be an issue, and is trivially fixed. Signed-off-by: -
Herbert Poetzl authored
proc_check_chroot() does the check in a very unintuitive way (keeping a copy of the argument, then modifying the argument), and has uncommented sideeffects. Signed-off-by:
Herbert Poetzl <herbert@13thfloor.at> Signed-off-by:
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Andrew Morton authored
This just got nuked in mainline. Bring it back because Eric's patches use it. Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by:
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Eric W. Biederman authored
The core problem: setsid fails if it is called by init. The effect in 2.6.16 and the earlier kernels that have this problem is that if you do a "ps -j 1 or ps -ej 1" you will see that init and several of it's children have process group and session == 0. Instead of process group == session == 1. Despite init calling setsid. The reason it fails is that daemonize calls set_special_pids(1,1) on kernel threads that are launched before /sbin/init is called. The only remaining effect in that current->signal->leader == 0 for init instead of 1. And the setsid call fails. No one has noticed because /sbin/init does not check the return value of setsid. In 2.4 where we don't have the pidhash table, and daemonize doesn't exist setsid actually works for init. I care a lot about pid == 1 not being a special case that we leave broken, because of the container/jail work that I am doing. - Carefully allow init (pid == 1) to call setsid despite the kernel using its session. - Use find_task_by_pid instead of find_pid because find_pid taking a pidtype is going away. Signed-off-by:
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Thomas Gleixner authored
The futex timeval is not checked for correctness. The change does not break existing applications as the timeval is supplied by glibc (and glibc always passes a correct value), but the glibc-internal tests for this functionality fail. Signed-off-by:
Thomas Gleixner <tglx@tglx.de> Signed-off-by:
Ingo Molnar <mingo@elte.hu> Signed-off-by:
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Con Kolivas authored
To increase the strength of SCHED_BATCH as a scheduling hint we can activate batch tasks on the expired array since by definition they are latency insensitive tasks. Signed-off-by:
Con Kolivas <kernel@kolivas.org> Acked-by:
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Con Kolivas authored
On runqueue time is used to elevate priority in schedule(). In the code it currently requeues tasks even if their priority is not elevated, which would end up placing them at the end of their runqueue array effectively delaying them instead of improving their priority. Bug spotted by Mike Galbraith <efault@gmx.de> This patch removes this requeueing. Signed-off-by:
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Con Kolivas authored
Tasks waiting in SLEEP_NONINTERACTIVE state can now get to best priority so they need to be included in the idle detection code. Signed-off-by:
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Con Kolivas authored
We watch for tasks that sleep extended periods and don't allow one single prolonged sleep period from elevating priority to maximum bonus to prevent cpu bound tasks from getting high priority with single long sleeps. There is a bug in the current code that also penalises tasks that already have high priority. Correct that bug. Signed-off-by:
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Con Kolivas authored
Alterations to the pipe code in the kernel made it possible for relative starvation to occur with tasks that slept waiting on a pipe getting unfair priority bonuses even if they were otherwise fully cpu bound so the TASK_NONINTERACTIVE flag was introduced which prevented any change to sleep_avg while sleeping waiting on a pipe. This change also leads to the converse though, preventing any priority boost from occurring in truly interactive tasks that wait on pipes. Convert the TASK_NONINTERACTIVE flag to set sleep_type to SLEEP_NONINTERACTIVE which will allow a linear bonus to priority based on sleep time thus allowing interactive tasks to get high priority if they sleep enough. Signed-off-by:
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Con Kolivas authored
The activated flag in task_struct is used to track different sleep types and its usage is somewhat obfuscated. Convert the variable to an enum with more descriptive names without altering the function. Signed-off-by:
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Jack Steiner authored
Currently, count_active_tasks() calls both nr_running() & nr_interruptible(). Each of these functions does a "for_each_cpu" & reads values from the runqueue of each cpu. Although this is not a lot of instructions, each runqueue may be located on different node. Depending on the architecture, a unique TLB entry may be required to access each runqueue. Since there may be more runqueues than cpu TLB entries, a scan of all runqueues can trash the TLB. Each memory reference incurs a TLB miss & refill. In addition, the runqueue cacheline that contains nr_running & nr_uninterruptible may be evicted from the cache between the two passes. This causes unnecessary cache misses. Combining nr_running() & nr_interruptible() into a single function substantially reduces the TLB & cache misses on large systems. This should have no measureable effect on smaller systems. On a 128p IA64 system running a memory stress workload, the new function reduced the overhead of calc_load() from 605 usec/call to 324 usec/call. Signed-off-by:
Jack Steiner <steiner@sgi.com> Acked-by:
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Dimitri Sivanich authored
It seems that run_hrtimer_queue() is calling get_softirq_time() more often than it needs to. With this patch, it only calls get_softirq_time() if there's a pending timer. Signed-off-by:
Dimitri Sivanich <sivanich@sgi.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Thomas Gleixner authored
Replace the nanosleep private sleeper functionality by the generic hrtimer sleeper. Signed-off-by:
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Thomas Gleixner authored
The removal of the data field in the hrtimer structure enforces the embedding of the timer into another data structure. nanosleep now uses a private implementation of the most common used timer callback function (simple task wakeup). In order to avoid the reimplentation of such functionality all over the place a generic hrtimer_sleeper functionality is created. Signed-off-by:
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Richard Purdie authored
Add an LED trigger for IDE disk activity to the ide-disk driver. Signed-off-by:
Richard Purdie <rpurdie@rpsys.net> Acked-by:
Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by:
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Richard Purdie authored
Ensure ide-taskfile.c calls any driver specific end_request function if present. Signed-off-by:
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Richard Purdie authored
Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by:
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Dirk Opfer authored
Adds LED drivers for LEDs found on the Sharp Zaurus c6000 model (tosa). Signed-off-by:
Dirk Opfer <dirk@opfer-online.de> Signed-off-by:
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John Bowler authored
NEW_LEDS support for ixp4xx boards where LEDs are connected to the GPIO lines. This includes a new generic ixp4xx driver (leds-ixp4xx-gpio.c name "IXP4XX-GPIO-LED") Signed-off-by:
John Bowler <jbowler@acm.org> Signed-off-by:
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Richard Purdie authored
Adds an LED driver for LEDs exported by the Sharp LOCOMO chip as found on some models of Sharp Zaurus. Signed-off-by:
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Richard Purdie authored
Adds LED drivers for LEDs found on the Sharp Zaurus c7x0 (corgi, shepherd, husky) and cxx00 (akita, spitz, borzoi) models. Signed-off-by:
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Richard Purdie authored
Add an LED trigger for the charger status as found on the Sharp Zaurus series of devices. Signed-off-by:
Pavel Machek <pavel@suse.cz> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by:
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Richard Purdie authored
Add an example of a complex LED trigger in the form of a generic timer which triggers the LED its attached to at a user specified frequency and duty cycle. Signed-off-by:
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Richard Purdie authored
Add support for LED triggers to the LED subsystem. "Triggers" are events which change the state of an LED. Two kinds of trigger are available, simple ones which can be added to exising code with minimum disruption and complex ones for implementing new or more complex functionality. Signed-off-by:
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Richard Purdie authored
Add the foundations of a new LEDs subsystem. This patch adds a class which presents LED devices within sysfs and allows their brightness to be controlled. Signed-off-by:
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Richard Purdie authored
The LED class/subsystem takes John Lenz's work and extends and alters it to give what I think should be a fairly universal LED implementation. The series consists of several logical units: * LED Core + Class implementation * LED Trigger Core implementation * LED timer trigger (example of a complex trigger) * LED device drivers for corgi, spitz and tosa Zaurus models * LED device driver for locomo LEDs * LED device driver for ARM ixp4xx LEDs * Zaurus charging LED trigger * IDE disk activity LED trigger * NAND MTD activity LED trigger Why? ==== LEDs are really simple devices usually amounting to a GPIO that can be turned on and off so why do we need all this code? On handheld or embedded devices they're an important part of an often limited user interface. Both users and developers want to be able to control and configure what the LED does and the number of different things they'd potentially want the LED to show is large. A subsystem is needed to try and provide all this different functionality in an architecture independent, simple but complete, generic and scalable manner. The alternative is for everyone to implement just what they need hidden away in different corners of the kernel source tree and to provide an inconsistent interface to userspace. Other Implementations ===================== I'm aware of the existing arm led implementation. Currently the new subsystem and the arm code can coexist quite happily. Its up to the arm community to decide whether this new interface is acceptable to them. As far as I can see, the new interface can do everything the existing arm implementation can with the advantage that the new code is architecture independent and much more generic, configurable and scalable. I'm prepared to make the conversion to the LED subsystem (or assist with it) if appropriate. Implementation Details ====================== I've stripped a lot of code out of John's original LED class. Colours were removed as LED colour is now part of the device name. Multiple colours are to be handled as multiple led devices. This means you get full control over each colour. I also removed the LED hardware timer code as the generic timer isn't going to add much overhead and is just as useful. I also decided to have the LED core track the current LED status (to ease suspend/resume handling) removing the need for brightness_get implementations in the LED drivers. An underlying design philosophy is simplicity. The aim is to keep a small amount of code giving as much functionality as possible. The major new idea is the led "trigger". A trigger is a source of led events. Triggers can either be simple or complex. A simple trigger isn't configurable and is designed to slot into existing subsystems with minimal additional code. Examples are the ide-disk, nand-disk and zaurus-charging triggers. With leds disabled, the code optimises away. Examples are nand-disk and ide-disk. Complex triggers whilst available to all LEDs have LED specific parameters and work on a per LED basis. The timer trigger is an example. You can change triggers in a similar manner to the way an IO scheduler is chosen (via /sys/class/leds/somedevice/trigger). So far there are only a handful of examples but it should easy to add further LED triggers without too much interference into other subsystems. Known Issues ============ The LED Trigger core cannot be a module as the simple trigger functions would cause nightmare dependency issues. I see this as a minor issue compared to the benefits the simple trigger functionality brings. The rest of the LED subsystem can be modular. Some leds can be programmed to flash in hardware. As this isn't a generic LED device property, I think this should be exported as a device specific sysfs attribute rather than part of the class if this functionality is required (eg. to keep the led flashing whilst the device is suspended). Future Development ================== At the moment, a trigger can't be created specifically for a single LED. There are a number of cases where a trigger might only be mappable to a particular LED. The addition of triggers provided by the LED driver should cover this option and be possible to add without breaking the current interface. A CPU activity trigger similar to that found in the arm led implementation should be trivial to add. This patch: Add some brief documentation of the design decisions behind the LED class and how it appears to users. Signed-off-by:
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Andrew Morton authored
One of the LEDs driver files wants to use this. Probably drivers/mtd/maps/ipaq-flash.c wants to convert as well - right now it'll be tainting the kernel. Cc: David Woodhouse <dwmw2@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Bowler <jbowler@acm.org> Cc: "'Richard Purdie'" <rpurdie@rpsys.net> Signed-off-by:
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Rafael J. Wysocki authored
Add TIOCL_GETKMSGREDIRECT needed by the userland suspend tool to get the current value of kmsg_redirect from the kernel so that it can save it and restore it after resume. Signed-off-by:
Rafael J. Wysocki <rjw@sisk.pl> Acked-by:
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Jesper Juhl authored
Fix a few memory leaks in drivers/isdn/sc/ioctl.c::sc_ioctl() Signed-off-by:
Jesper Juhl <jesper.juhl@gmail.com> Acked-by:
Karsten Keil <kkeil@suse.de> Signed-off-by:
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Tobias Klauser authored
Delete two useless kmalloc wrappers and use kmalloc/kzalloc. Some weird NULL checks are also simplified. Signed-off-by:
Tobias Klauser <tklauser@nuerscht.ch> Signed-off-by:
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Trond Myklebust authored
sys_flock() currently has a race which can result in a double free in the multi-thread case. Thread 1 Thread 2 sys_flock(file, LOCK_EX) sys_flock(file, LOCK_UN) If Thread 2 removes the lock from inode->i_lock before Thread 1 tests for list_empty(&lock->fl_link) at the end of sys_flock, then both threads will end up calling locks_free_lock for the same lock. Fix is to make flock_lock_file() do the same as posix_lock_file(), namely to make a copy of the request, so that the caller can always free the lock. This also has the side-effect of fixing up a reference problem in the lockd handling of flock. Signed-off-by:
Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by:
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Amy Griffis authored
IN_DELETE events are no longer generated for the removal of a file from a watched directory. This seems to be a result of clearing DCACHE_INOTIFY_PARENT_WATCHED in d_delete() directly before calling fsnotify_nameremove(). Assuming the flag doesn't need to be cleared before dentry_iput(), this should do the trick. Signed-off-by:
Amy Griffis <amy.griffis@hp.com> Cc: John McCutchan <ttb@tentacle.dhs.org> Acked-by:
Robert Love <rml@novell.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: <stable@kernel.org> Signed-off-by:
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OGAWA Hirofumi authored
Since these names on old MSDOS is used as device, so, current fat driver doesn't allow a user to create those names. But many OSes and even Windows can create those names actually, now. This patch removes the reserved name check. Signed-off-by:
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by:
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Paul Jackson authored
Fix memory migration so that it works regardless of what cpuset the invoking task is in. If a task invoked a memory migration, by doing one of: 1) writing a different nodemask to a cpuset 'mems' file, or 2) writing a tasks pid to a different cpuset's 'tasks' file, where the cpuset had its 'memory_migrate' option turned on, then the allocation of the new pages for the migrated task(s) was constrained by the invoking tasks cpuset. If this task wasn't in a cpuset that allowed the requested memory nodes, the memory migration would happen to some other nodes that were in that invoking tasks cpuset. This was usually surprising and puzzling behaviour: Why didn't the pages move? Why did the pages move -there-? To fix this, temporarilly change the invoking tasks 'mems_allowed' task_struct field to the nodes the migrating tasks is moving to, so that new pages can be allocated there. Signed-off-by:Paul Jackson <pj@sgi.com> Acked-by:
Christoph Lameter <clameter@sgi.com> Signed-off-by:
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Paul Jackson authored
Fix unsafe reference to a tasks mm struct, by moving the reference inside of a convenient nearby properly guarded code block. Signed-off-by:
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Paul Jackson authored
Fix cpuset comment involving case of a tasks cpuset pointer being NULL. Thanks to "the_top_cpuset_hack", this code no longer sees NULL task->cpuset pointers. Signed-off-by:
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Andrew Morton authored
local_t's were defined to be unsigned. This increases confusion because atomic_t's are signed. The patch goes through and changes all implementations to use signed longs throughout. Also, x86-64 was using 32-bit quantities for the value passed into local_add() and local_sub(). Fixed. All (actually, both) existing users have been audited. (Also s/__inline__/inline/ in x86_64/local.h) Cc: Andi Kleen <ak@muc.de> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Kyle McMartin <kyle@parisc-linux.org> Signed-off-by:
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Steffen Klassert authored
The "3c59x: use mii_check_media" patch introduced a netif_carrier_off in vortex_up. 10base2 stoped working because of this. This is removed. Tx/Rx reset is back in vortex_up because the 3c900B-Combo stops working after changing from half duplex to full duplex when Tx/Rx reset is done with vortex_timer. Also brought back some mii stuff to be sure that it does not break something else. Thanks to Pete Clements <clem@clem.clem-digital.net> for reporting and testing. Signed-off-by:
Steffen Klassert <klassert@mathematik.tu-chemnitz.de> Signed-off-by:
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