28 Jan, 2008
1 commit
-
This is where it belongs and then it doesn't take up space for a
process that doesn't do IO.Signed-off-by: Jens Axboe
26 Jan, 2008
3 commits
-
Extend group scheduling to also cover the realtime classes. It uses the time
limiting introduced by the previous patch to allow multiple realtime groups.The hard time limit is required to keep behaviour deterministic.
The algorithms used make the realtime scheduler O(tg), linear scaling wrt the
number of task groups. This is the worst case behaviour I can't seem to get out
of, the avg. case of the algorithms can be improved, I focused on correctness
and worst case.[ akpm@linux-foundation.org: move side-effects out of BUG_ON(). ]
Signed-off-by: Peter Zijlstra
Signed-off-by: Ingo Molnar -
Move the task_struct members specific to rt scheduling together.
A future optimization could be to put sched_entity and sched_rt_entity
into a union.Signed-off-by: Peter Zijlstra
CC: Srivatsa Vaddagiri
Signed-off-by: Ingo Molnar -
Some RT tasks (particularly kthreads) are bound to one specific CPU.
It is fairly common for two or more bound tasks to get queued up at the
same time. Consider, for instance, softirq_timer and softirq_sched. A
timer goes off in an ISR which schedules softirq_thread to run at RT50.
Then the timer handler determines that it's time to smp-rebalance the
system so it schedules softirq_sched to run. So we are in a situation
where we have two RT50 tasks queued, and the system will go into
rt-overload condition to request other CPUs for help.This causes two problems in the current code:
1) If a high-priority bound task and a low-priority unbounded task queue
up behind the running task, we will fail to ever relocate the unbounded
task because we terminate the search on the first unmovable task.2) We spend precious futile cycles in the fast-path trying to pull
overloaded tasks over. It is therefore optimial to strive to avoid the
overhead all together if we can cheaply detect the condition before
overload even occurs.This patch tries to achieve this optimization by utilizing the hamming
weight of the task->cpus_allowed mask. A weight of 1 indicates that
the task cannot be migrated. We will then utilize this information to
skip non-migratable tasks and to eliminate uncessary rebalance attempts.We introduce a per-rq variable to count the number of migratable tasks
that are currently running. We only go into overload if we have more
than one rt task, AND at least one of them is migratable.In addition, we introduce a per-task variable to cache the cpus_allowed
weight, since the hamming calculation is probably relatively expensive.
We only update the cached value when the mask is updated which should be
relatively infrequent, especially compared to scheduling frequency
in the fast path.Signed-off-by: Gregory Haskins
Signed-off-by: Steven Rostedt
Signed-off-by: Ingo Molnar
20 Oct, 2007
3 commits
-
The pgrp field is not used widely around the kernel so it is now marked as
deprecated with appropriate comment.The initialization of INIT_SIGNALS is trimmed because
a) they are set to 0 automatically;
b) gcc cannot properly initialize two anonymous (the second one
is the one with the session) unions. In this particular case
to make it compile we'd have to add some field initialized
right before the .pgrp.This is the same patch as the 1ec320afdc9552c92191d5f89fcd1ebe588334ca one
(from Cedric), but for the pgrp field.Some progress report:
We have to deprecate the pid, tgid, session and pgrp fields on struct
task_struct and struct signal_struct. The session and pgrp are already
deprecated. The tgid value is close to being such - the worst known usage
in in fs/locks.c and audit code. The pid field deprecation is mainly
blocked by numerous printk-s around the kernel that print the tsk->pid to
log.Signed-off-by: Pavel Emelyanov
Cc: Oleg Nesterov
Cc: Sukadev Bhattiprolu
Cc: Cedric Le Goater
Cc: Serge Hallyn
Cc: "Eric W. Biederman"
Cc: Herbert Poetzl
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Since we've switched from using pid->nr to pid->upids->nr some
fields on struct pid are no longer neededSigned-off-by: Pavel Emelyanov
Cc: Oleg Nesterov
Cc: Sukadev Bhattiprolu
Cc: Paul Menage
Cc: "Eric W. Biederman"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Since task will be visible from different pid namespaces each of them have to
be addressed by multiple pids. struct upid is to store the information about
which id refers to which namespace.The constuciton looks like this. Each struct pid carried the reference
counter and the list of tasks attached to this pid. At its end it has a
variable length array of struct upid-s. Each struct upid has a numerical id
(pid itself), pointer to the namespace, this ID is valid in and is hashed into
a pid_hash for searching the pids.The nr and pid_chain fields are kept in struct pid for a while to make kernel
still work (no patch initialize the upids yet), but it will be removed at the
end of this series when we switch to upids completely.Signed-off-by: Sukadev Bhattiprolu
Signed-off-by: Pavel Emelyanov
Cc: Oleg Nesterov
Cc: Paul Menage
Cc: "Eric W. Biederman"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Oct, 2007
2 commits
-
The nslock spinlock is not used in the kernel at all. Remove it.
Signed-off-by: Pavel Emelyanov
Acked-by: Serge Hallyn
Cc: Cedric Le Goater
Cc: "Eric W. Biederman"
Cc: Herbert Poetzl
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Based on ideas of Andrew:
http://marc.info/?l=linux-kernel&m=102912915020543&w=2Scale the bdi dirty limit inversly with the tasks dirty rate.
This makes heavy writers have a lower dirty limit than the occasional writer.Andrea proposed something similar:
http://lwn.net/Articles/152277/The main disadvantage to his patch is that he uses an unrelated quantity to
measure time, which leaves him with a workload dependant tunable. Other than
that the two approaches appear quite similar.[akpm@linux-foundation.org: fix warning]
Signed-off-by: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 Oct, 2007
2 commits
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When CONFIG_NET=no, init_net is unresolved because net_namespace.c
is not compiled and the include pull init_net definition.This problem was very similar with the ipc namespace where the kernel
can be compiled with SYSV ipc out.This patch fix that defining a macro which simply remove init_net
initialization from nsproxy namespace aggregator.Compiled and booted on qemu-i386 with CONFIG_NET=no and CONFIG_NET=yes.
Signed-off-by: Daniel Lezcano
Acked-by: "Eric W. Biederman"
Signed-off-by: David S. Miller -
This is the network namespace from which all which all sockets
and anything else under user control ultimately get their network
namespace parameters.Signed-off-by: Eric W. Biederman
Signed-off-by: David S. Miller
21 Sep, 2007
1 commit
-
This simplifies signalfd code, by avoiding it to remain attached to the
sighand during its lifetime.In this way, the signalfd remain attached to the sighand only during
poll(2) (and select and epoll) and read(2). This also allows to remove
all the custom "tsk == current" checks in kernel/signal.c, since
dequeue_signal() will only be called by "current".I think this is also what Ben was suggesting time ago.
The external effect of this, is that a thread can extract only its own
private signals and the group ones. I think this is an acceptable
behaviour, in that those are the signals the thread would be able to
fetch w/out signalfd.Signed-off-by: Davide Libenzi
Signed-off-by: Linus Torvalds
17 Jul, 2007
1 commit
-
Basically, it will allow a process to unshare its user_struct table,
resetting at the same time its own user_struct and all the associated
accounting.A new root user (uid == 0) is added to the user namespace upon creation.
Such root users have full privileges and it seems that theses privileges
should be controlled through some means (process capabilities ?)The unshare is not included in this patch.
Changes since [try #4]:
- Updated get_user_ns and put_user_ns to accept NULL, and
get_user_ns to return the namespace.Changes since [try #3]:
- moved struct user_namespace to files user_namespace.{c,h}Changes since [try #2]:
- removed struct user_namespace* argument from find_user()Changes since [try #1]:
- removed struct user_namespace* argument from find_user()
- added a root_user per user namespaceSigned-off-by: Cedric Le Goater
Signed-off-by: Serge E. Hallyn
Acked-by: Pavel Emelianov
Cc: Herbert Poetzl
Cc: Kirill Korotaev
Cc: Eric W. Biederman
Cc: Chris Wright
Cc: Stephen Smalley
Cc: James Morris
Cc: Andrew Morgan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 May, 2007
3 commits
-
This patch series implements the new signalfd() system call.
I took part of the original Linus code (and you know how badly it can be
broken :), and I added even more breakage ;) Signals are fetched from the same
signal queue used by the process, so signalfd will compete with standard
kernel delivery in dequeue_signal(). If you want to reliably fetch signals on
the signalfd file, you need to block them with sigprocmask(SIG_BLOCK). This
seems to be working fine on my Dual Opteron machine. I made a quick test
program for it:http://www.xmailserver.org/signafd-test.c
The signalfd() system call implements signal delivery into a file descriptor
receiver. The signalfd file descriptor if created with the following API:int signalfd(int ufd, const sigset_t *mask, size_t masksize);
The "ufd" parameter allows to change an existing signalfd sigmask, w/out going
to close/create cycle (Linus idea). Use "ufd" == -1 if you want a brand new
signalfd file.The "mask" allows to specify the signal mask of signals that we are interested
in. The "masksize" parameter is the size of "mask".The signalfd fd supports the poll(2) and read(2) system calls. The poll(2)
will return POLLIN when signals are available to be dequeued. As a direct
consequence of supporting the Linux poll subsystem, the signalfd fd can use
used together with epoll(2) too.The read(2) system call will return a "struct signalfd_siginfo" structure in
the userspace supplied buffer. The return value is the number of bytes copied
in the supplied buffer, or -1 in case of error. The read(2) call can also
return 0, in case the sighand structure to which the signalfd was attached,
has been orphaned. The O_NONBLOCK flag is also supported, and read(2) will
return -EAGAIN in case no signal is available.If the size of the buffer passed to read(2) is lower than sizeof(struct
signalfd_siginfo), -EINVAL is returned. A read from the signalfd can also
return -ERESTARTSYS in case a signal hits the process. The format of the
struct signalfd_siginfo is, and the valid fields depends of the (->code &
__SI_MASK) value, in the same way a struct siginfo would:struct signalfd_siginfo {
__u32 signo; /* si_signo */
__s32 err; /* si_errno */
__s32 code; /* si_code */
__u32 pid; /* si_pid */
__u32 uid; /* si_uid */
__s32 fd; /* si_fd */
__u32 tid; /* si_fd */
__u32 band; /* si_band */
__u32 overrun; /* si_overrun */
__u32 trapno; /* si_trapno */
__s32 status; /* si_status */
__s32 svint; /* si_int */
__u64 svptr; /* si_ptr */
__u64 utime; /* si_utime */
__u64 stime; /* si_stime */
__u64 addr; /* si_addr */
};[akpm@linux-foundation.org: fix signalfd_copyinfo() on i386]
Signed-off-by: Davide Libenzi
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Remove initialization of pgrp and __session in INIT_SIGNALS, as these are
later set by the call to __set_special_pids() in init/main.c by the patch:explicitly-set-pgid-and-sid-of-init-process.patch
Signed-off-by: Sukadev Bhattiprolu
Cc: Cedric Le Goater
Cc: Dave Hansen
Cc: Serge Hallyn
Cc: Eric Biederman
Cc: Oleg Nesterov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Statically initialize a struct pid for the swapper process (pid_t == 0) and
attach it to init_task. This is needed so task_pid(), task_pgrp() and
task_session() interfaces work on the swapper process also.Signed-off-by: Sukadev Bhattiprolu
Cc: Cedric Le Goater
Cc: Dave Hansen
Cc: Serge Hallyn
Cc: Eric Biederman
Cc: Herbert Poetzl
Cc:
Acked-by: Eric W. Biederman
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 May, 2007
1 commit
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This finally renames the thread_info field in task structure to stack, so that
the assumptions about this field are gone and archs have more freedom about
placing the thread_info structure.Nonbroken archs which have a proper thread pointer can do the access to both
current thread and task structure via a single pointer.It'll allow for a few more cleanups of the fork code, from which e.g. ia64
could benefit.Signed-off-by: Roman Zippel
[akpm@linux-foundation.org: build fix]
Cc: Richard Henderson
Cc: Ivan Kokshaysky
Cc: Russell King
Cc: Ian Molton
Cc: Haavard Skinnemoen
Cc: Mikael Starvik
Cc: David Howells
Cc: Yoshinori Sato
Cc: "Luck, Tony"
Cc: Hirokazu Takata
Cc: Geert Uytterhoeven
Cc: Roman Zippel
Cc: Greg Ungerer
Cc: Ralf Baechle
Cc: Ralf Baechle
Cc: Paul Mackerras
Cc: Benjamin Herrenschmidt
Cc: Heiko Carstens
Cc: Martin Schwidefsky
Cc: Paul Mundt
Cc: Kazumoto Kojima
Cc: Richard Curnow
Cc: William Lee Irwin III
Cc: "David S. Miller"
Cc: Jeff Dike
Cc: Paolo 'Blaisorblade' Giarrusso
Cc: Miles Bader
Cc: Andi Kleen
Cc: Chris Zankel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
09 May, 2007
1 commit
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SPIN_LOCK_UNLOCKED cleanup,use __SPIN_LOCK_UNLOCKED instead
Signed-off-by: Milind Arun Choudhary
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
13 Feb, 2007
1 commit
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Of kernel subsystems that work with pids the tty layer is probably the largest
consumer. But it has the nice virtue that the assiation with a session only
lasts until the session leader exits. Which means that no reference counting
is required. So using struct pid winds up being a simple optimization to
avoid hash table lookups.In the long term the use of pid_nr also ensures that when we have multiple pid
spaces mixed everything will work correctly.Signed-off-by: Eric W. Biederman
Cc: Alan Cox
Cc: Oleg Nesterov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Dec, 2006
1 commit
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This reverts commit 373beb35cd6b625e0ba4ad98baace12310a26aa8.
No one is using this identifier yet. The purpose of this identifier is to
export nsproxy to user space which is wrong. nsproxy is an internal
implementation optimization, which should keep our fork times from getting
slower as we increase the number of global namespaces you don't have to
share.Adding a global identifier like this is inappropriate because it makes
namespaces inherently non-recursive, greatly limiting what we can do with
them in the future.Signed-off-by: Eric W. Biederman
Cc: Cedric Le Goater
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 Dec, 2006
2 commits
-
An fdtable can either be embedded inside a files_struct or standalone (after
being expanded). When an fdtable is being discarded after all RCU references
to it have expired, we must either free it directly, in the standalone case,
or free the files_struct it is contained within, in the embedded case.Currently the free_files field controls this behavior, but we can get rid of
it entirely, as all the necessary information is already recorded. We can
distinguish embedded and standalone fdtables using max_fds, and if it is
embedded we can divine the relevant files_struct using container_of().Signed-off-by: Vadim Lobanov
Cc: Christoph Hellwig
Cc: Al Viro
Cc: Dipankar Sarma
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently, each fdtable supports three dynamically-sized arrays of data: the
fdarray and two fdsets. The code allows the number of fds supported by the
fdarray (fdtable->max_fds) to differ from the number of fds supported by each
of the fdsets (fdtable->max_fdset).In practice, it is wasteful for these two sizes to differ: whenever we hit a
limit on the smaller-capacity structure, we will reallocate the entire fdtable
and all the dynamic arrays within it, so any delta in the memory used by the
larger-capacity structure will never be touched at all.Rather than hogging this excess, we shouldn't even allocate it in the first
place, and keep the capacities of the fdarray and the fdsets equal. This
patch removes fdtable->max_fdset. As an added bonus, most of the supporting
code becomes simpler.Signed-off-by: Vadim Lobanov
Cc: Christoph Hellwig
Cc: Al Viro
Cc: Dipankar Sarma
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
09 Dec, 2006
4 commits
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Add the pid namespace framework to the nsproxy object. The copy of the pid
namespace only increases the refcount on the global pid namespace,
init_pid_ns, and unshare is not implemented.There is no configuration option to activate or deactivate this feature
because this not relevant for the moment.Signed-off-by: Cedric Le Goater
Cc: Kirill Korotaev
Cc: Eric W. Biederman
Cc: Herbert Poetzl
Cc: Sukadev Bhattiprolu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add an identifier to nsproxy. The default init_ns_proxy has identifier 0 and
allocated nsproxies are given -1.This identifier will be used by a new syscall sys_bind_ns.
Signed-off-by: Cedric Le Goater
Cc: Kirill Korotaev
Cc: Eric W. Biederman
Cc: Herbert Poetzl
Cc: Sukadev Bhattiprolu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Rename 'struct namespace' to 'struct mnt_namespace' to avoid confusion with
other namespaces being developped for the containers : pid, uts, ipc, etc.
'namespace' variables and attributes are also renamed to 'mnt_ns'Signed-off-by: Kirill Korotaev
Signed-off-by: Cedric Le Goater
Cc: Eric W. Biederman
Cc: Herbert Poetzl
Cc: Sukadev Bhattiprolu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add an anonymous union and ((deprecated)) to catch direct usage of the
session field.[akpm@osdl.org: fix various missed conversions]
[jdike@addtoit.com: fix UML bug]
Signed-off-by: Jeff Dike
Cc: Cedric Le Goater
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
08 Dec, 2006
1 commit
-
Name some of the remaning 'old_style_spin_init' locks
Signed-off-by: Peter Zijlstra
Acked-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
02 Oct, 2006
5 commits
-
This patch adds basic IPC namespace functionality to
IPC utils:
- init_ipc_ns
- copy/clone/unshare/free IPC ns
- /proc preparationsSigned-off-by: Pavel Emelianov
Signed-off-by: Kirill Korotaev
Cc: "Eric W. Biederman"
Cc: Cedric Le Goater
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patch set allows to unshare IPCs and have a private set of IPC objects
(sem, shm, msg) inside namespace. Basically, it is another building block of
containers functionality.This patch implements core IPC namespace changes:
- ipc_namespace structure
- new config option CONFIG_IPC_NS
- adds CLONE_NEWIPC flag
- unshare support[clg@fr.ibm.com: small fix for unshare of ipc namespace]
[akpm@osdl.org: build fix]
Signed-off-by: Pavel Emelianov
Signed-off-by: Kirill Korotaev
Signed-off-by: Cedric Le Goater
Cc: "Eric W. Biederman"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patch defines the uts namespace and some manipulators.
Adds the uts namespace to task_struct, and initializes a
system-wide init namespace.It leaves a #define for system_utsname so sysctl will compile.
This define will be removed in a separate patch.[akpm@osdl.org: build fix, cleanup]
Signed-off-by: Serge Hallyn
Cc: Kirill Korotaev
Cc: "Eric W. Biederman"
Cc: Herbert Poetzl
Cc: Andrey Savochkin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This moves the mount namespace into the nsproxy. The mount namespace count
now refers to the number of nsproxies point to it, rather than the number of
tasks. As a result, the unshare_namespace() function in kernel/fork.c no
longer checks whether it is being shared.Signed-off-by: Serge Hallyn
Cc: Kirill Korotaev
Cc: "Eric W. Biederman"
Cc: Herbert Poetzl
Cc: Andrey Savochkin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patch adds a nsproxy structure to the task struct. Later patches will
move the fs namespace pointer into this structure, and introduce a new utsname
namespace into the nsproxy.The vserver and openvz functionality, then, would be implemented in large part
by virtualizing/isolating more and more resources into namespaces, each
contained in the nsproxy.[akpm@osdl.org: build fix]
Signed-off-by: Serge Hallyn
Cc: Kirill Korotaev
Cc: "Eric W. Biederman"
Cc: Herbert Poetzl
Cc: Andrey Savochkin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
04 Jul, 2006
4 commits
-
Do 'make oldconfig' and accept all the defaults for new config options -
reboot into the kernel and if everything goes well it should boot up fine and
you should have /proc/lockdep and /proc/lockdep_stats files.Typically if the lock validator finds some problem it will print out
voluminous debug output that begins with "BUG: ..." and which syslog output
can be used by kernel developers to figure out the precise locking scenario.What does the lock validator do? It "observes" and maps all locking rules as
they occur dynamically (as triggered by the kernel's natural use of spinlocks,
rwlocks, mutexes and rwsems). Whenever the lock validator subsystem detects a
new locking scenario, it validates this new rule against the existing set of
rules. If this new rule is consistent with the existing set of rules then the
new rule is added transparently and the kernel continues as normal. If the
new rule could create a deadlock scenario then this condition is printed out.When determining validity of locking, all possible "deadlock scenarios" are
considered: assuming arbitrary number of CPUs, arbitrary irq context and task
context constellations, running arbitrary combinations of all the existing
locking scenarios. In a typical system this means millions of separate
scenarios. This is why we call it a "locking correctness" validator - for all
rules that are observed the lock validator proves it with mathematical
certainty that a deadlock could not occur (assuming that the lock validator
implementation itself is correct and its internal data structures are not
corrupted by some other kernel subsystem). [see more details and conditionals
of this statement in include/linux/lockdep.h and
Documentation/lockdep-design.txt]Furthermore, this "all possible scenarios" property of the validator also
enables the finding of complex, highly unlikely multi-CPU multi-context races
via single single-context rules, increasing the likelyhood of finding bugs
drastically. In practical terms: the lock validator already found a bug in
the upstream kernel that could only occur on systems with 3 or more CPUs, and
which needed 3 very unlikely code sequences to occur at once on the 3 CPUs.
That bug was found and reported on a single-CPU system (!). So in essence a
race will be found "piecemail-wise", triggering all the necessary components
for the race, without having to reproduce the race scenario itself! In its
short existence the lock validator found and reported many bugs before they
actually caused a real deadlock.To further increase the efficiency of the validator, the mapping is not per
"lock instance", but per "lock-class". For example, all struct inode objects
in the kernel have inode->inotify_mutex. If there are 10,000 inodes cached,
then there are 10,000 lock objects. But ->inotify_mutex is a single "lock
type", and all locking activities that occur against ->inotify_mutex are
"unified" into this single lock-class. The advantage of the lock-class
approach is that all historical ->inotify_mutex uses are mapped into a single
(and as narrow as possible) set of locking rules - regardless of how many
different tasks or inode structures it took to build this set of rules. The
set of rules persist during the lifetime of the kernel.To see the rough magnitude of checking that the lock validator does, here's a
portion of /proc/lockdep_stats, fresh after bootup:lock-classes: 694 [max: 2048]
direct dependencies: 1598 [max: 8192]
indirect dependencies: 17896
all direct dependencies: 16206
dependency chains: 1910 [max: 8192]
in-hardirq chains: 17
in-softirq chains: 105
in-process chains: 1065
stack-trace entries: 38761 [max: 131072]
combined max dependencies: 2033928
hardirq-safe locks: 24
hardirq-unsafe locks: 176
softirq-safe locks: 53
softirq-unsafe locks: 137
irq-safe locks: 59
irq-unsafe locks: 176The lock validator has observed 1598 actual single-thread locking patterns,
and has validated all possible 2033928 distinct locking scenarios.More details about the design of the lock validator can be found in
Documentation/lockdep-design.txt, which can also found at:http://redhat.com/~mingo/lockdep-patches/lockdep-design.txt
[bunk@stusta.de: cleanups]
Signed-off-by: Ingo Molnar
Signed-off-by: Arjan van de Ven
Signed-off-by: Adrian Bunk
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Accurate hard-IRQ-flags and softirq-flags state tracing.
This allows us to attach extra functionality to IRQ flags on/off
events (such as trace-on/off).Signed-off-by: Ingo Molnar
Signed-off-by: Arjan van de Ven
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Locking init improvement:
- introduce and use __SPIN_LOCK_UNLOCKED for array initializations,
to pass in the name string of locks, used by debuggingSigned-off-by: Ingo Molnar
Signed-off-by: Arjan van de Ven
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Generic lock debugging:
- generalized lock debugging framework. For example, a bug in one lock
subsystem turns off debugging in all lock subsystems.- got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from
the mutex/rtmutex debugging code: it caused way too much prototype
hackery, and lockdep will give the same information anyway.- ability to do silent tests
- check lock freeing in vfree too.
- more finegrained debugging options, to allow distributions to
turn off more expensive debugging features.There's no separate 'held mutexes' list anymore - but there's a 'held locks'
stack within lockdep, which unifies deadlock detection across all lock
classes. (this is independent of the lockdep validation stuff - lockdep first
checks whether we are holding a lock already)Here are the current debugging options:
CONFIG_DEBUG_MUTEXES=y
CONFIG_DEBUG_LOCK_ALLOC=ywhich do:
config DEBUG_MUTEXES
bool "Mutex debugging, basic checks"config DEBUG_LOCK_ALLOC
bool "Detect incorrect freeing of live mutexes"Signed-off-by: Ingo Molnar
Signed-off-by: Arjan van de Ven
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
28 Jun, 2006
2 commits
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Core functions for the rt-mutex subsystem.
Signed-off-by: Ingo Molnar
Signed-off-by: Thomas Gleixner
Signed-off-by: Arjan van de Ven
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add framework to boost/unboost the priority of RT tasks.
This consists of:
- caching the 'normal' priority in ->normal_prio
- providing a functions to set/get the priority of the task
- make sched_setscheduler() aware of boostingThe effective_prio() cleanups also fix a priority-calculation bug pointed out
by Andrey Gelman, in set_user_nice().has_rt_policy() fix: Peter Williams
Signed-off-by: Ingo Molnar
Signed-off-by: Thomas Gleixner
Signed-off-by: Arjan van de Ven
Cc: Andrey Gelman
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
27 Jun, 2006
1 commit
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To keep the dcache from filling up with dead /proc entries we flush them on
process exit. However over the years that code has gotten hairy with a
dentry_pointer and a lock in task_struct and misdocumented as a correctness
feature.I have rewritten this code to look and see if we have a corresponding entry in
the dcache and if so flush it on process exit. This removes the extra fields
in the task_struct and allows me to trivially handle the case of a
/proc//task/ entry as well as the current /proc/ entries.Signed-off-by: Eric W. Biederman
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Mar, 2006
1 commit
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daemonize() calls set_special_pids(1,1), while init and kernel threads spawned
from init/main.c:init() run with 0,0 special pids. This patch changes
INIT_SIGNALS() so that that they run with ->pgrp == ->session == 1 also. This
patch relies on fact that swapper's pid == 1.Now we have no hashed zero pids in pid_hash[].
User-space visibible change is that now /sbin/init runs with (1,1) special
pids and becomes a session leader.Quoting Eric W. Biederman:
>
> daemonize consuming pids (1,1) then consumes pgrp 1. So that when
> /sbin/init calls setsid() it thinks /sbin/init is a process group
> leader and setsid() fails. So /sbin/init wants pgrp 1 session 1
> but doesn't get it. I am pretty certain daemonize did not exist so
> /sbin/init got pgrp 1 session 1 in 2.4.
>
> That is the bug that is being fixed.
>
> This patch takes things one step farther and essentially calls
> setsid() for pid == 1 before init is execed. That is new behavior
> but it cleans up the kernel as we now do not need to support the
> case of a process without a process group or a session.
>
> The only process that could have possibly cared was /sbin/init
> and it already calls setsid() because it doesn't want that.
>
> If this was going to break anything noticeable the change in behavior
> from 2.4 to 2.6 would have already done that.Signed-off-by: Oleg Nesterov
Cc: "Eric W. Biederman"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
