user/sven/linux.git/include/linux/init_task.h, branch v2.6.37.2

signals: move cred_guard_mutex from task_struct to signal_struct

2010-10-28T01:03:12Z

Oleg Nesterov pointed out we have to prevent multiple-threads-inside-exec itself and we can reuse ->cred_guard_mutex for it. Yes, concurrent execve() has no worth. Let's move ->cred_guard_mutex from task_struct to signal_struct. It naturally prevent multiple-threads-inside-exec. Signed-off-by: KOSAKI Motohiro Reviewed-by: Oleg Nesterov Acked-by: Roland McGrath Acked-by: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

rcu: Add a TINY_PREEMPT_RCU

2010-08-20T15:55:00Z

Implement a small-memory-footprint uniprocessor-only implementation of preemptible RCU. This implementation uses but a single blocked-tasks list rather than the combinatorial number used per leaf rcu_node by TREE_PREEMPT_RCU, which reduces memory consumption and greatly simplifies processing. This version also takes advantage of uniprocessor execution to accelerate grace periods in the case where there are no readers. The general design is otherwise broadly similar to that of TREE_PREEMPT_RCU. This implementation is a step towards having RCU implementation driven off of the SMP and PREEMPT kernel configuration variables, which can happen once this implementation has accumulated sufficient experience. Removed ACCESS_ONCE() from __rcu_read_unlock() and added barrier() as suggested by Steve Rostedt in order to avoid the compiler-reordering issue noted by Mathieu Desnoyers (http://lkml.org/lkml/2010/8/16/183). As can be seen below, CONFIG_TINY_PREEMPT_RCU represents almost 5Kbyte savings compared to CONFIG_TREE_PREEMPT_RCU. Of course, for non-real-time workloads, CONFIG_TINY_RCU is even better. CONFIG_TREE_PREEMPT_RCU text data bss dec filename 13 0 0 13 kernel/rcupdate.o 6170 825 28 7023 kernel/rcutree.o ---- 7026 Total CONFIG_TINY_PREEMPT_RCU text data bss dec filename 13 0 0 13 kernel/rcupdate.o 2081 81 8 2170 kernel/rcutiny.o ---- 2183 Total CONFIG_TINY_RCU (non-preemptible) text data bss dec filename 13 0 0 13 kernel/rcupdate.o 719 25 0 744 kernel/rcutiny.o --- 757 Total Requested-by: Loïc Minier Signed-off-by: Paul E. McKenney

kernel: __rcu annotations

2010-08-20T00:18:03Z

This adds annotations for RCU operations in core kernel components Signed-off-by: Arnd Bergmann Signed-off-by: Paul E. McKenney Cc: Al Viro Cc: Jens Axboe Cc: Andrew Morton Reviewed-by: Josh Triplett

Merge branch 'for-35' of git://repo.or.cz/linux-kbuild

2010-06-01T15:55:52Z

* 'for-35' of git://repo.or.cz/linux-kbuild: (81 commits) kbuild: Revert part of e8d400a to resolve a conflict kbuild: Fix checking of scm-identifier variable gconfig: add support to show hidden options that have prompts menuconfig: add support to show hidden options which have prompts gconfig: remove show_debug option gconfig: remove dbg_print_ptype() and dbg_print_stype() kconfig: fix zconfdump() kconfig: some small fixes add random binaries to .gitignore kbuild: Include gen_initramfs_list.sh and the file list in the .d file kconfig: recalc symbol value before showing search results .gitignore: ignore *.lzo files headerdep: perlcritic warning scripts/Makefile.lib: Align the output of LZO kbuild: Generate modules.builtin in make modules_install Revert "kbuild: specify absolute paths for cscope" kbuild: Do not unnecessarily regenerate modules.builtin headers_install: use local file handles headers_check: fix perl warnings export_report: fix perl warnings ...

INIT_SIGHAND: use SIG_DFL instead of NULL

2010-05-27T16:12:52Z

Cosmetic, no changes in the compiled code. Just s/NULL/SIG_DFL/ to make it more readable and grep-friendly. Note: probably SIG_IGN makes more sense, we could kill ignore_signals(). But then kernel_init() should do flush_signal_handlers() before exec(). Signed-off-by: Oleg Nesterov Cc: Cedric Le Goater Cc: Dave Hansen Cc: Eric Biederman Cc: Herbert Poetzl Cc: Mathias Krause Acked-by: Roland McGrath Acked-by: Serge Hallyn Cc: Sukadev Bhattiprolu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pids: init_struct_pid.tasks should never see the swapper process

2010-05-27T16:12:52Z

"statically initialize struct pid for swapper" commit 820e45db says: 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. OK, but: - it doesn't make sense to add init_task.pids[].node into init_struct_pid.tasks[], and in fact this just wrong. idle threads are special, they shouldn't be visible on any global list. In particular do_each_pid_task(init_struct_pid) shouldn't see swapper. This is the actual reason why kill(0, SIGKILL) from /sbin/init (which starts with 0,0 special pids) crashes the kernel. The signal sent to pgid/sid == 0 must never see idle threads, even if the previous patch fixed the crash itself. - we have other idle threads running on the non-boot CPUs, see the next patch. Change INIT_STRUCT_PID/INIT_PID_LINK to create the empty/unhashed hlist_head/hlist_node. Like any other idle thread swapper can never exit, so detach_pid()->__hlist_del() is not possible, but we could change INIT_PID_LINK() to set pprev = &next if needed. All we need is the valid swapper->pids[].pid == &init_struct_pid. Reported-by: Mathias Krause Signed-off-by: Oleg Nesterov Cc: Cedric Le Goater Cc: Dave Hansen Cc: Eric Biederman Cc: Herbert Poetzl Cc: Mathias Krause Acked-by: Roland McGrath Acked-by: Serge Hallyn Cc: Sukadev Bhattiprolu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

INIT_TASK() should initialize ->thread_group list

2010-05-27T16:12:51Z

The trivial /sbin/init doing int main(void) { kill(0, SIGKILL) } crashes the kernel. This happens because __kill_pgrp_info(init_struct_pid) also sends SIGKILL to the swapper process which runs with the uninitialized ->thread_group. Change INIT_TASK() to initialize ->thread_group properly. Note: the real problem is that the swapper process must not be visible to signals, see the next patch. But this change is right anyway and fixes the crash. Reported-and-tested-by: Mathias Krause Signed-off-by: Oleg Nesterov Cc: Cedric Le Goater Cc: Dave Hansen Cc: Eric Biederman Cc: Herbert Poetzl Cc: Mathias Krause Acked-by: Roland McGrath Acked-by: Serge Hallyn Acked-by: Sukadev Bhattiprolu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

proc: turn signal_struct->count into "int nr_threads"

2010-05-27T16:12:47Z

No functional changes, just s/atomic_t count/int nr_threads/. With the recent changes this counter has a single user, get_nr_threads() And, none of its callers need the really accurate number of threads, not to mention each caller obviously races with fork/exit. It is only used to report this value to the user-space, except first_tid() uses it to avoid the unnecessary while_each_thread() loop in the unlikely case. It is a bit sad we need a word in struct signal_struct for this, perhaps we can change get_nr_threads() to approximate the number of threads using signal->live and kill ->nr_threads later. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Oleg Nesterov Cc: Alexey Dobriyan Cc: "Eric W. Biederman" Acked-by: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

rcu: remove all rcu head initializations, except on_stack initializations

2010-05-11T23:10:47Z

Remove all rcu head inits. We don't care about the RCU head state before passing it to call_rcu() anyway. Only leave the "on_stack" variants so debugobjects can keep track of objects on stack. Signed-off-by: Mathieu Desnoyers Signed-off-by: Paul E. McKenney

nsproxy: remove INIT_NSPROXY()

2010-03-12T23:52:40Z

Remove INIT_NSPROXY(), use C99 initializer. Remove INIT_IPC_NS(), INIT_NET_NS() while I'm at it. Note: headers trim will be done later, now it's quite pointless because results will be invalidated by merge window. Signed-off-by: Alexey Dobriyan Acked-by: Serge Hallyn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds