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2008-07-25per-task-delay-accounting: add memory reclaim delayKeika Kobayashi
Sometimes, application responses become bad under heavy memory load. Applications take a bit time to reclaim memory. The statistics, how long memory reclaim takes, will be useful to measure memory usage. This patch adds accounting memory reclaim to per-task-delay-accounting for accounting the time of do_try_to_free_pages(). <i.e> - When System is under low memory load, memory reclaim may not occur. $ free total used free shared buffers cached Mem: 8197800 1577300 6620500 0 4808 1516724 -/+ buffers/cache: 55768 8142032 Swap: 16386292 0 16386292 $ vmstat 1 procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 0 5069748 10612 3014060 0 0 0 0 3 26 0 0 100 0 0 0 0 5069748 10612 3014060 0 0 0 0 4 22 0 0 100 0 0 0 0 5069748 10612 3014060 0 0 0 0 3 18 0 0 100 0 Measure the time of tar command. $ ls -s test.dat 1501472 test.dat $ time tar cvf test.tar test.dat real 0m13.388s user 0m0.116s sys 0m5.304s $ ./delayget -d -p <pid> CPU count real total virtual total delay total 428 5528345500 5477116080 62749891 IO count delay total 338 8078977189 SWAP count delay total 0 0 RECLAIM count delay total 0 0 - When system is under heavy memory load memory reclaim may occur. $ vmstat 1 procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 7159032 49724 1812 3012 0 0 0 0 3 24 0 0 100 0 0 0 7159032 49724 1812 3012 0 0 0 0 4 24 0 0 100 0 0 0 7159032 49848 1812 3012 0 0 0 0 3 22 0 0 100 0 In this case, one process uses more 8G memory by execution of malloc() and memset(). $ time tar cvf test.tar test.dat real 1m38.563s <- increased by 85 sec user 0m0.140s sys 0m7.060s $ ./delayget -d -p <pid> CPU count real total virtual total delay total 9021 7140446250 7315277975 923201824 IO count delay total 8965 90466349669 SWAP count delay total 3 21036367 RECLAIM count delay total 740 61011951153 In the later case, the value of RECLAIM is increasing. So, taskstats can show how much memory reclaim influences TAT. Signed-off-by: Keika Kobayashi <kobayashi.kk@ncos.nec.co.jp> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujistu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25tsacct: fix bacct_add_tsk()'s use of do_div()David Howells
Fix bacct_add_tsk()'s use of do_div() on an s64 by making ac_etime a u64 instead and dividing that. Possibly this should be guarded lest the interval calculation turn up negative, but the possible negativity of the result of the division is cast away, and it shouldn't end up negative anyway. This was introduced by patch f3cef7a99469afc159fec3a61b42dc7ca5b6824f. Signed-off-by: David Howells <dhowells@redhat.com> Cc: Jay Lan <jlan@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25task IO accounting: provide distinct tgid/tid I/O statisticsAndrea Righi
Report per-thread I/O statistics in /proc/pid/task/tid/io and aggregate parent I/O statistics in /proc/pid/io. This approach follows the same model used to account per-process and per-thread CPU times. As a practial application, this allows for example to quickly find the top I/O consumer when a process spawns many child threads that perform the actual I/O work, because the aggregated I/O statistics can always be found in /proc/pid/io. [ Oleg Nesterov points out that we should check that the task is still alive before we iterate over the threads, but also says that we can do that fixup on top of this later. - Linus ] Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrea Righi <righi.andrea@gmail.com> Cc: Matt Heaton <matt@hostmonster.com> Cc: Shailabh Nagar <nagar@watson.ibm.com> Acked-by-with-comments: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25bsdacct: fix and add comments around acct_process()Pavel Emelyanov
Fix the one describing what this function is and add one more - about locking absence around pid namespaces loop. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25bsdacct: account dying tasks in all relevant namespacesPavel Emelyanov
This just makes the acct_proces walk the pid namespaces from current up to the top and account a task in each with the accounting turned on. ns->parent access if safe lockless, since current it still alive and holds its namespace, which in turn holds its parent. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.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>
2008-07-25bsdacct: turn acct off for all pidns-s on umount timePavel Emelyanov
All the bsd_acct_strcts with opened accounting are linked into a global list. So, the acct_auto_close(_mnt) walks one and drops the accounting for each. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.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>
2008-07-25bsdacct: switch from global bsd_acct_struct instance to per-pidns onePavel Emelyanov
Allocate the structure on the first call to sys_acct(). After this each namespace, that ordered the accounting, will live with this structure till its own death. Two notes - routines, that close the accounting on fs umount time use the init_pid_ns's acct by now; - accounting routine accounts to dying task's namespace (also by now). Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.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>
2008-07-25bsdacct: make internal code work with passed bsd_acct_struct, not globalPavel Emelyanov
This adds the appropriate pointer to all the internal (i.e. static) functions that work with global acct instance. API calls pass a global instance to them (while we still have such). Mostly this is a s/acct_globals./acct->/ over the file. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.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>
2008-07-25bsdacct: turn the acct_lock from on-the-struct to globalPavel Emelyanov
Don't use per-bsd-acct-struct lock, but work with a global one. This lock is taken for short periods, so it doesn't seem it'll become a bottleneck, but it will allow us to easily avoid many locking difficulties in the future. So this is a mostly s/acct_globals.lock/acct_lock/ over the file. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.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>
2008-07-25bsdacct: make check timer accept a bsd_acct_struct argumentPavel Emelyanov
We're going to have many bsd_acct_struct instances, not just one, so the timer (currently working with a global one) has to know which one to work with. Use a handy setup_timer macro for it (thanks to Oleg for one). Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.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>
2008-07-25bsdacct: "truthify" a comment near acct_processPavel Emelyanov
The acct_process does not accept any arguments actually. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.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>
2008-07-25pidns: use kzalloc when allocating new pid_namespace structPavel Emelyanov
It makes many fields initialization implicit helping in auto-setting #ifdef-ed fields (bsd-acct related pointer will be such). Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.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>
2008-07-25bsdacct: rename acct_gbls to bsd_acct_structPavel Emelyanov
After I fixed access to task->tgid in kernel/acct.c, Oleg pointed out some bad side effects with this accounting vs pid namespaces interaction. I.e. when some task in pid namespace sets this accounting up, this blocks all the others from doing the same. Restricting this to init namespace only could help, but didn't look a graceful solution. So here is the approach to make this accounting work with pid namespaces properly. The idea is simple - when a task dies it accounts itself in each namespace it is visible from and which set the accounting up. For example here are the commands run and the output of lastcomm from init and sub namespaces: init_ns# accton pacct sub_ns# accton pacct (this is a different file - sub ns is run in a chroot-ed environment) init_ns# cat /dev/null sub_ns# ls /dev/null init_ns# accton sub_ns# accton sub_ns# lastcomm -f pacct ls 0 [136,0] 0.00 secs Thu May 15 10:30 accton 0 [136,0] 0.00 secs Thu May 15 10:30 init_ns# lastcomm -f pacct accton root pts/0 0.00 secs Thu May 15 14:30 << got from sub cat root pts/1 0.00 secs Thu May 15 14:30 ls root pts/0 0.00 secs Thu May 15 14:30 << got from sub accton root pts/1 0.00 secs Thu May 15 14:30 That was the summary, the details are in patches. This patch: It will be visible in pid_namespace.h file, so fix its name to look better outside the acct.c file. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.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>
2008-07-25accounting: account for user time when updating memory integralsJonathan Lim
Adapt acct_update_integrals() to include user time when calculating the time difference. The units of acct_rss_mem1 and acct_vm_mem1 are also changed from pages-jiffies to pages-usecs to avoid calling jiffies_to_usecs() in xacct_add_tsk() which might overflow. Signed-off-by: Jonathan Lim <jlim@sgi.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25unexport uts_semAdrian Bunk
With the removal of the Solaris binary emulation the export of uts_sem became unused. Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25markers: fix sparse integer as NULL pointer warningHarvey Harrison
kernel/trace/trace_sysprof.c:164:20: warning: Using plain integer as NULL pointer Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25markers: use rcu_barrier_sched() and call_rcu_sched()Mathieu Desnoyers
rcu_barrier_sched() and call_rcu_sched() were introduced in 2.6.26 for the Markers. Change the marker code to use them. It can be seen as a fix since the marker code was using an ugly, temporary, #ifdef hack to work around CONFIG_PREEMPT_RCU. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Paul McKenney <paulmck@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25pidns: remove now unused find_pid function.Pavel Emelyanov
This one had the only users so far - the kill_proc, which is removed, so drop this (invalid in namespaced world) call too. And of course - erase all references on it from comments. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> 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>
2008-07-25pidns: remove now unused kill_proc functionPavel Emelyanov
This function operated on a pid_t to kill a task, which is no longer valid in a containerized system. It has finally lost all its users and we can safely remove it from the tree. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> 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>
2008-07-25sysctl: check for bogus modesAlexey Dobriyan
Catch, e. g., 644/0644 typo. Signed-off-by: Alexey Dobriyan <adobriyan@parallels.com> Acked-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>
2008-07-25proc: misplaced export of find_get_pidDavid Sterba
Move EXPORT_SYMBOL right after the func Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25workqueues: do CPU_UP_CANCELED if CPU_UP_PREPARE failsOleg Nesterov
The bug was pointed out by Akinobu Mita <akinobu.mita@gmail.com>, and this patch is based on his original patch. workqueue_cpu_callback(CPU_UP_PREPARE) expects that if it returns NOTIFY_BAD, _cpu_up() will send CPU_UP_CANCELED then. However, this is not true since "cpu hotplug: cpu: deliver CPU_UP_CANCELED only to NOTIFY_OKed callbacks with CPU_UP_PREPARE" commit: a0d8cdb652d35af9319a9e0fb7134de2a276c636 The callback which has returned NOTIFY_BAD will not receive CPU_UP_CANCELED. Change the code to fulfil the CPU_UP_CANCELED logic if CPU_UP_PREPARE fails. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Reported-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25workqueues: schedule_on_each_cpu() can use schedule_work_on()Oleg Nesterov
schedule_on_each_cpu() can use schedule_work_on() to avoid the code duplication. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25workqueues: queue_work() can use queue_work_on()Oleg Nesterov
queue_work() can use queue_work_on() to avoid the code duplication. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25workqueues: lockdep annotations for flush_work()Oleg Nesterov
Add lockdep annotations to flush_work() and update the comment. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Jarek Poplawski <jarkao2@o2.pl> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25workqueues: make get_online_cpus() useable for work->func()Oleg Nesterov
workqueue_cpu_callback(CPU_DEAD) flushes cwq->thread under cpu_maps_update_begin(). This means that the multithreaded workqueues can't use get_online_cpus() due to the possible deadlock, very bad and very old problem. Introduce the new state, CPU_POST_DEAD, which is called after cpu_hotplug_done() but before cpu_maps_update_done(). Change workqueue_cpu_callback() to use CPU_POST_DEAD instead of CPU_DEAD. This means that create/destroy functions can't rely on get_online_cpus() any longer and should take cpu_add_remove_lock instead. [akpm@linux-foundation.org: fix CONFIG_SMP=n] Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Gautham R Shenoy <ego@in.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25workqueues: schedule_on_each_cpu: use flush_work()Oleg Nesterov
Change schedule_on_each_cpu() to use flush_work() instead of flush_workqueue(), this way we don't wait for other work_struct's which can be queued meanwhile. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Jarek Poplawski <jarkao2@gmail.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25workqueues: implement flush_work()Oleg Nesterov
Most of users of flush_workqueue() can be changed to use cancel_work_sync(), but sometimes we really need to wait for the completion and cancelling is not an option. schedule_on_each_cpu() is good example. Add the new helper, flush_work(work), which waits for the completion of the specific work_struct. More precisely, it "flushes" the result of of the last queue_work() which is visible to the caller. For example, this code queue_work(wq, work); /* WINDOW */ queue_work(wq, work); flush_work(work); doesn't necessary work "as expected". What can happen in the WINDOW above is - wq starts the execution of work->func() - the caller migrates to another CPU now, after the 2nd queue_work() this work is active on the previous CPU, and at the same time it is queued on another. In this case flush_work(work) may return before the first work->func() completes. It is trivial to add another helper int flush_work_sync(struct work_struct *work) { return flush_work(work) || wait_on_work(work); } which works "more correctly", but it has to iterate over all CPUs and thus it much slower than flush_work(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Max Krasnyansky <maxk@qualcomm.com> Acked-by: Jarek Poplawski <jarkao2@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25workqueues: insert_work: use "list_head *" instead of "int tail"Oleg Nesterov
insert_work() inserts the new work_struct before or after cwq->worklist, depending on the "int tail" parameter. Change it to accept "list_head *" instead, this shrinks .text a bit and allows us to insert the barrier after specific work_struct. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Jarek Poplawski <jarkao2@gmail.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25coredump: kill mm->core_doneOleg Nesterov
Now that we have core_state->dumper list we can use it to wake up the sub-threads waiting for the coredump completion. This uglifies the code and .text grows by 47 bytes, but otoh mm_struct lessens by sizeof(struct completion). Also, with this change we can decouple exit_mm() from the coredumping code. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25coredump: construct the list of coredumping threads at startup timeOleg Nesterov
binfmt->core_dump() has to iterate over the all threads in system in order to find the coredumping threads and construct the list using the GFP_ATOMIC allocations. With this patch each thread allocates the list node on exit_mm()'s stack and adds itself to the list. This allows us to do further changes: - simplify ->core_dump() - change exit_mm() to clear ->mm first, then wait for ->core_done. this makes the coredumping process visible to oom_kill - kill mm->core_done Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25coredump: turn core_state->nr_threads into atomic_tOleg Nesterov
Turn core_state->nr_threads into atomic_t and kill now unneeded down_write(&mm->mmap_sem) in exit_mm(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25coredump: move mm->core_waiters into struct core_stateOleg Nesterov
Move mm->core_waiters into "struct core_state" allocated on stack. This shrinks mm_struct a little bit and allows further changes. This patch mostly does s/core_waiters/core_state. The only essential change is that coredump_wait() must clear mm->core_state before return. The coredump_wait()'s path is uglified and .text grows by 30 bytes, this is fixed by the next patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25coredump: turn mm->core_startup_done into the pointer to struct core_stateOleg Nesterov
mm->core_startup_done points to "struct completion startup_done" allocated on the coredump_wait()'s stack. Introduce the new structure, core_state, which holds this "struct completion". This way we can add more info visible to the threads participating in coredump without enlarging mm_struct. No changes in affected .o files. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25kill PF_BORROWED_MM in favour of PF_KTHREADOleg Nesterov
Kill PF_BORROWED_MM. Change use_mm/unuse_mm to not play with ->flags, and do s/PF_BORROWED_MM/PF_KTHREAD/ for a couple of other users. No functional changes yet. But this allows us to do further fixes/cleanups. oom_kill/ptrace/etc often check "p->mm != NULL" to filter out the kthreads, this is wrong because of use_mm(). The problem with PF_BORROWED_MM is that we need task_lock() to avoid races. With this patch we can check PF_KTHREAD directly, or use a simple lockless helper: /* The result must not be dereferenced !!! */ struct mm_struct *__get_task_mm(struct task_struct *tsk) { if (tsk->flags & PF_KTHREAD) return NULL; return tsk->mm; } Note also ecard_task(). It runs with ->mm != NULL, but it's the kernel thread without PF_BORROWED_MM. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25introduce PF_KTHREAD flagOleg Nesterov
Introduce the new PF_KTHREAD flag to mark the kernel threads. It is set by INIT_TASK() and copied to the forked childs (we could set it in kthreadd() along with PF_NOFREEZE instead). daemonize() was changed as well. In that case testing of PF_KTHREAD is racy, but daemonize() is hopeless anyway. This flag is cleared in do_execve(), before search_binary_handler(). Probably not the best place, we can do this in exec_mmap() or in start_thread(), or clear it along with PF_FORKNOEXEC. But I think this doesn't matter in practice, and if do_execve() fails kthread should die soon. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25ptrace: simplify ptrace_stop()->sigkill_pending() pathOleg Nesterov
1. SIGKILL can't be blocked, remove this check from sigkill_pending(). 2. When ptrace_stop() sees sigkill_pending() == T, it can just return. Kill "int killed" and simplify the code. This also is more correct, the tracer shouldn't see us in TASK_TRACED if we are not going to stop. I strongly believe this code needs further changes. We should do the "was this task killed" check unconditionally, currently it depends on arch_ptrace_stop_needed(). On the other hand, sigkill_pending() isn't very clever. If the task was killed tkill(SIGKILL), the signal can be already dequeued if the caller is do_exit(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25kernel/signal.c: change vars pid and tgid types to pid_tGustavo Fernando Padovan
Change the type of pid and tgid variables from int to the POSIX type pid_t. Signed-off-by: Gustavo F. Padovan <gustavo@las.ic.unicamp.br> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25signals: make siginfo_t si_utime + si_sstime report times in USER_HZ, not HZMichael Kerrisk
In the switch to configurable HZ in 2.6, the treatment of the si_utime and si_stime fields that are exposed to userland via the siginfo structure looks to have been botched. As things stand, these fields report times in units of HZ, so that userland gets information that varies depending on the HZ that the kernel was configured with. This patch changes the reported values to use USER_HZ units. Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25signals: do_signal_stop: kill the SIGNAL_UNKILLABLE checkOleg Nesterov
fae5fa44f1fd079ffbed8e0add929dd7bbd1347f changed do_signal_stop() to check SIGNAL_UNKILLABLE, this wasn't needed. If signal_group_exit() == F, the signal sent to SIGNAL_UNKILLABLE task must be already filtered out by the caller, get_signal_to_deliver(). And if signal_group_exit() == T we are not going to stop. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25signals: dequeue_signal: don't check SIGNAL_GROUP_EXIT when setting ↵Oleg Nesterov
SIGNAL_STOP_DEQUEUED dequeue_signal() checks SIGNAL_GROUP_EXIT before setting SIGNAL_STOP_DEQUEUED. This was added by 788e05a67c343fa22f2ae1d3ca264e7f15c25eaf a long ago to avoid the coredump/SIGSTOP race. Since then the related code was changed, and now this subtle check is both incomplete and unneeded at the same time. It is incomplete because nowadays exec() doesn't set SIGNAL_GROUP_EXIT, so in fact we should check signal_group_exit() to avoid a similar race. Fortunately, we doesn't need the check at all. The only function which relies on SIGNAL_STOP_DEQUEUED is do_signal_stop(), and it ignores this flag if signal_group_exit() == T, this covers the SIGNAL_GROUP_EXIT case. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25__exit_signal: don't take rcu lockOleg Nesterov
There is no reason for rcu_read_lock() in __exit_signal(). tsk->sighand can only be changed if tsk does exec, obviously this is not possible. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25signals: change collect_signal() to return voidOleg Nesterov
With the recent changes collect_signal() always returns true. Change it to return void and update the single caller. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25signals: collect_signal: simplify the "still_pending" logicOleg Nesterov
Factor out sigdelset() calls and remove the "still_pending" variable. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25signals: collect_signal: remove the unneeded sigismember() checkOleg Nesterov
collect_signal() checks sigismember(&list->signal, sig), this is not needed. This "sig" was just found by next_signal(), so it must be valid. We have a (completely broken) call to ->notifier in between, but it must not play with sigpending->signal bits or unlock ->siglock. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25posix timers: release_posix_timer: kill the bogus put_task_struct(->it_process);Oleg Nesterov
release_posix_timer() can't be called with ->it_process != NULL. Once sys_timer_create() sets ->it_process it must not call release_posix_timer(), otherwise we can race with another thread doing sys_timer_delete(), this timer is visible to idr_find() and unlocked. The same is true for two other callers (actually, for any possible caller), sys_timer_delete() and itimer_delete(). They must clear ->it_process before unlock_timer() + release_posix_timer(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Cc: john stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25posix timers: timer_delete: remove the bogus "->it_process != NULL" checkOleg Nesterov
sys_timer_delete() and itimer_delete() check "timer->it_process != NULL", this looks completely bogus. ->it_process == NULL means that this timer is already under destruction or it is not fully initialized, this must not happen. sys_timer_delete: the timer is locked, and lock_timer() can't succeed if ->it_process == NULL. itimer_delete: it is called by exit_itimers() when there are no other threads which can play with signal_struct->posix_timers. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Roland McGrath <roland@redhat.com> Cc: john stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25cpuset: two minor code-cleanupsLai Jiangshan
In cpuset_update_task_memory_state() local variable struct task_struct *tsk = current; And local variable tsk is used 14 times and statement task_cs(tsk) is used twice in this function. So using task_cs(tsk) instead of task_cs(current) is better for readability. And "(struct cgroup_scanner *)&scan" is not good for readability also. (and "container_of" is used in cpuset_do_move_task(), not "(cpuset_hotplug_scanner *)scan") Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25cpuset: code-cleanup for started_afterLai Jiangshan
cgroup(cgroup_scan_tasks) will initialize heap->gt for us. This patch removes started_after() and its helper-function. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25cpuset: don't pass empty cpumasks to partition_sched_domains()Lai Jiangshan
I create lots of empty cpusets(empty cpumasks) and turn off the "sched_load_balance" in top cpuset. I found that all these empty cpumasks are passed to partition_sched_domains() in rebuild_sched_domains(), it's very time-consuming for partition_sched_domains() and it's not need. It also reduce memory consumed and some works in rebuild_sched_domains() too. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>